Research ArticleSynthesis and Biological Evaluation of New(minus)-Gossypol-Derived Schiff Bases and Hydrazones

Vu Van Vu1 Trinh Thi Nhung1 Nguyen Thi Thanh1 Luu Van Chinh2 Vu Dinh Tien1

Vu Thu Thuy1 Do Thi Thao3 Nguyen Hai Nam4 Angela Koeckritz5 and Tran Khac Vu1

1School of Chemical Engineering Hanoi University of Science and Technology No 1 Dai Co Viet Hai Ba Trung Hanoi Vietnam2Institute ofNatural Products Chemistry VietnamAcademy of Science andTechnology 18HoangQuocViet CauGiayHanoi Vietnam3Institute of Biotechnology Vietnam Academy of Science and Technology 18 Hoang Quoc Viet Cau Giay Hanoi Vietnam4Hanoi University of Pharmacy (HUP) 13-15 Le Thanh Tong Hanoi Vietnam5Leibniz Institute for Catalysis at the University of Rostock Albert-Einstein-Str 29A 18059 Rostock Germany

Correspondence should be addressed to Tran Khac Vu vutrankhachusteduvn

Received 8 June 2017 Revised 19 August 2017 Accepted 13 September 2017 Published 17 October 2017

Academic Editor Mire Zloh

Copyright copy 2017 Vu Van Vu et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A series of 14 new (minus)-gossypol Schiff bases and hydrazones have been synthesized via an in situ procedure in high yields Structuraldata showed that all target compounds exist as the enamine tautomer Bioassays showed that several compounds exhibited cytotoxiceffects against three human cancer cell lines Compound 8a showed the greatest cytotoxic effect against hepatocellular carcinoma(HepG2) lung carcinoma (LU-1) and breast cancer (MCF-7) cell lines with IC50 values of 2093 1358 and 940 120583M respectivelyHowever in an antibacterial test compounds 8a and 8b inhibited Staphylococcus aureus and Bacillus cereus and compound 8einhibited only Staphylococcus aureus at the same MIC values of 1024 120583gml

1 Introduction

Cancer is characterized by uncontrolled cell growth metas-tasis and invasion and is responsible for approximately 13of all human deaths throughout the world [1] The threemost common and fatal types are lung liver and breastcancer Currently although there has been a lot of success inboth cancer chemotherapy and anticancer drug developmentresearch cancer remains a significant challenge in the futurebecause of the drug resistance and adverse side effects ofchemotherapy [2] Novel antitumor agents based on naturalproducts are becoming increasingly more popular in orderto overcome these limitations and develop more effectiveanticancer agents [3]

Gossypol (1) (Figure 1) a polyphenolic dialdehyde foundin high concentrations in the pigment glands of the cottonplant Gossypium has recently received increased attentiondue to its wide range of biological activities especiallyanticancer [4ndash7] contraceptive [8] antiviral [9ndash11] andantimicrobial [12] activities However the application of

gossypol as a therapeutic agent has been limited because ofa number of serious side effects [13] that have been shownto be associated with the aldehyde groups More recentlysignificant attention has been focused on the potentialtherapeutic value of gossypol as a promising starting pointfor the development of antitumor or antiviral derivativesfor medicinal applications with enhanced bioactivity andreduced side effects [14ndash18] in which the aldehyde groupsare altered to give gossypol derivatives (eg Schiff basesesters and ethers) Many of these derivatives exhibit a varietyof unusual disease-inhibiting activities especially anticanceractivity [19] Research regarding the biological effects ofgossypol both in vitro and in vivo showed that the (minus)-enantiomer is more potent than the (+)-enantiomer or theracemic mixture (1) [20] It has also been hypothesized thatwhile low doses of (minus) gossypol are selective higher doses ofeither enantiomer result in nonselective action [21 22] Alsorelated to the mechanism of action (minus)-gossypol has beenreported to target Bcl-2 Bcl-xL andMcl-1 proteins with highaffinities and is now in clinical trials as an orally administered

HindawiJournal of ChemistryVolume 2017 Article ID 3687182 8 pageshttpsdoiorg10115520173687182

2 Journal of Chemistry

HO

HO

OOH HO

O OH

OH

HO

HOOH HO

OH

OH

O OH HHO

HOOH

HO

O

OH

OH

O

H

H

1

2

34

5

67

1

2

3

4

5

6

7

(plusmn)-Gossypol (1)

R-(minus)-Gossypol (2) S-(+)-Gossypol (3)

Figure 1 Racemic gossypol and its enantiomers

HO

HOOH

HO

O

OHO

H

H

O

HOOH

HO

HN

O

OH

NH

R

R

(i)OH + RNH

R = 4-Cl

Schiff bases 4(andashd)

R = 4-F

R = 4-OCH3

R = 4-CH3

R-(minus)-Gossypol (2)

(4a)(4b)(4c)(4d)

Scheme 1 Synthesis of (minus)-gossypol Schiff bases 4andashd (i) EtOH 8 h rt 607ndash818

agent for the treatment of several types of human cancer[21 22] Intrigued by this observation we synthesized andevaluated new (minus)-gossypol hydrazones for their cytotoxiceffects against three human cancer cell lines This paperreports the results of this study

2 Results and Discussion

21 Chemistry New Schiff bases and hydrazones of (minus)-gossypol were synthesized as outlined (Schemes 1ndash3) Thestartingmaterial (minus)-gossypol was first prepared according toa known procedure with modification [23] using L-trypto-phan methyl ester as an effective agent for the resolu-tion of racemic gossypol The yield of (minus)-gossypol (2)obtained was comparable to that reported in the litera-ture [23] (see Supplementary Material available online athttpsdoiorg10115520173687182)

Schiff bases 4andashd were synthesized (Scheme 1) Thereactions of (minus)-gossypol (2) with primary amines includ-ing 4-chlorobenzylamine 4-fluorobenzylamine 4-methyl-benzylamine and 4-methoxybenzylamine were conducted

in ethanol at room temperature for 8 h The resulting Schiffbases 4andashd were obtained by simple filtering and washingwith methanol and dichloromethaneThe NMR data showedthe enamine-enamine tautomer of these Schiff bases viacharacteristic chemical shifts of NH protons resulting fromhydrogen bonding formation ranging from 1334 to 1349 ppmin the 1H NMR spectrum [24] In the 13C NMR spectrumthe chemical shifts of ketone C-7 were observed at the lowestfield from 1719 to 1723 ppm followed by the chemical shiftsof C-6 around 162 ppmThe chemical shifts of C-1 were easilyobserved at around 149 ppm

Novel hydrazones 8andashe were synthesized in a three-stepprocedure as outlined (Scheme 2) First benzoic acid deriva-tives 5andashewere converted to the corresponding esters 6andashe inquantitative yields by Fisher esterification These esters werethen refluxed with hydrazine hydrate (80) in ethanol to givethe corresponding hydrazides (7andashe) in high yields whichwere then used for the next step without further purificationUnlike the case of Schiff bases 4andashd hydrazides (7andashe) wereless active than the primary amines Initially hydrazides(7andashe) were reacted with (minus)-gossypol (2) in ethanol at room

Journal of Chemistry 3

O

OHR R

O

R

O

HO

HOOH

HO

O

OH

OH

O

H

H2

O

HOOH

HO

HN

O

OH

NH

NH

HN

R

R

O

O

5andashe 6andashe 7andashe

(i) (ii)

(iii)

8andashe

NHNH

+

OCH

R = 2-FR = 3-FR = 4-FR = 3-CH3

R = 4-CH3

(a)(b)

(d)(e)

(c)

Scheme 2 Synthesis of (minus)-gossypol hydrazone 8andashe (i) MeOH H2SO4 MeOH reflux 12 h (ii) EtOH NH2NH2 (80) rt 10 h (iii) EtOHZnCl2 rt 16 h 504ndash630

R

HO

HOOH

HO

O

OH

OH

O

H

H2

+

O

HOOH

HO

HN

O

OH

NH

NH

HN

O

O

OR

OR

O

OH

R

R

(i) (ii)

(iii)

9andashe 10andashe 11andashe

12andashe

OCH3NHNH2

= 2-F= 3-F= 4-F= 2-Cl= 3-Cl

RRRRR

(a)(b)

(d)(e)

(c)

Scheme 3 Synthesis of hydrazones 12andashe (i) MeOH H2SO4 MeOH reflux 12 h (ii) EtOH NH2NH2 (80) rt 10 h (iii) EtOH ZnCl2 rt12 h 487ndash530

temperature for 16 h with very poor yields The reaction wasnext carried out at reflux but failed to give the desired prod-ucts owing to the decomposition of gossypol Hydrazones areeasily prepared in the presence of acetic acid as a catalystHowever the reaction of 7andashewith (minus)-gossypol did not pro-ceed as expected in the presence of acetic acid In this studyZnCl2 was examined and found to be an excellent catalyst forthe hydrazone formation The reaction of hydrazides (7andashe)with (minus)-gossypol (2) in the presence of a small amount of

ZnCl2 led to the formation of a series of hydrazones (8andashe)in high yields To the best of our knowledge this is the firsttime that ZnCl2 has been used as an effective catalyst for thesynthesis of new gossypol hydrazones (8andashe) An analysis of1H and 13C NMR spectra data showed that hydrazones 8andasheexist as the enamine-enamine tautomer [24]

Compound 8c was used as an example for the struc-tural elucidation of hydrazones The 1H NMR spectrum ofcompound 8c showed the characteristic resonance signal of

4 Journal of Chemistry

NH at the lowest field 120575 1476 ppm due to hydrogen bondingwith the adjacent ketone group The chemical shift at 1205751239 ppm is attributed to the other NH group Additionallythe resonance signal at 120575 1019 ppm as a sharp singlet is alsoattributed to 6-OH The vinylic proton in the enamine iseasily observed as a single peak at 881 ppm signals at higherfield belonging to the protons H-4 and 1-OH at 120575 816 and763 ppm respectively are coupled Besides the presence ofthe aromatic ring protons can be observed as doublets (J =80Hz) at 120575 802 and 737 ppm The 13C NMR showed allthe signals of the gossypol skeleton and aromatic rings inwhich the signals at 1652 and 1633 ppm are attributed to C-7 and C-6 respectively The carbon connected to Fluorinein the aromatic ring resonates at 120575 1617 ppm based on thecharacteristic splitting of Fluorine and the hydrazide carbonylat 120575 1532 ppm

Novel hydrazones 12andashewere synthesized in the samewayas mentioned above starting from different phenylacetic acidderivatives (9andashe) (Scheme 3) The structure of synthesizedhydrazones was confirmed similarly based on NMR andmass spectroscopy data

3 Biological Activity

The in vitro cytotoxic evaluation of the synthesized com-pounds was carried out according to the described protocol[25] Briefly a stock solution of the target compound wasprepared in dimethylsulfoxide (DMSO) at a concentrationof 1mgmL followed by dilution to obtain a solution ata concentration of 100 120583gmL which was serially dilutedfurther for bioassays in 96-well plates The determination ofIC50 was carried out using three cancer cell lines HepG2 LU-1 and MCF-7 with ellipticine and (minus)-gossypol as positivecontrols The IC50 values were determined from a dose-dependent curve plotted from five different concentrationregimens (0ndash100 120583M) At each regimen mean of triplicateexperiment was used for a point in the curve The bioassayresults are described in Table 1

The bioassay results (Table 1) showed that only half of thetarget compounds exhibited cytotoxic effects against cancercell lines tested ranging from940 to 9955120583MUnexpectedlySchiff bases 4andashc bearing both electron withdrawing groups(Cl and F) and an electron donating group (CH3) at thepara position of the aromatic ring showed no cytotoxicityagainst all three cell lines except compound 4d whichcontains an electron donating group (OCH3) 4d revealeda weak inhibitory effect against only the LU-1 cell lineFor hydrazones 12andashe compounds 12c-e containing electronwithdrawing groups at ortho meta and para positions wereinactive against all cell lines However compounds 12a and12b containing electronwithdrawing groups at ortho and parapositions exhibited weak-to-moderate cytotoxic effects Theobservation also shows that cytotoxic effects of hydrazones8andashe derived from benzoic acid derivatives were better thanthose of phenyl acetic acid derivatives excluding compound8e and that series 8andashd were more cytotoxic towards MCF-7 and LU-1 than towards HepG2 cell line It seems that theelectron withdrawing group (F) at ortho position contributestowards greater toxicity compared to the meta position In

terms of IC50 values all synthesized hydrazones exhibited lesspotency than that of the control ellipticine or the parent(minus)-gossypol and some other gossypol derivatives reported[16 17] Regarding mechanism of action most of gossypolderivatives were reported to target Bcl-2 family proteins [20]In this study it is early and hard to come upwith amechanismof action at this stage without predicted binding models ofdesigned hydrazones to such target protein as Bcl-2 or Mcl-1[20ndash22]However it can be predicted that such possible targetproteins as Bcl-2 or Mcl-1 participate in the mechanism ofaction

Among synthesized hydrazones compound 8a showedthe best cytotoxic effect against HepG2 LU-1 and MCF-7with IC50 values of 2093 1358 and 940 120583M respectivelyAccordingly this compound could be considered as a lead forfuture design of gossypol hydrazones in which bioisostericreplacements in ortho position of the phenyl ring could beperformed to improve the cytotoxic activity

In order to expand the biological spectrum of gossypolderivatives synthesized hydrazones were also evaluated forantibacterial activity against human pathogenic bacteriaincluding Staphylococcus aureus (ATCC 6538) Bacillus cereus(ATCC 21768) Bacillus subtilis (ATCC 6633) Escherichia coli(ATCC 25931) and Pseudomonas aeruginosa (ATCC 9027)according to described protocol [26] Briefly five bacterialspecies including two Gram-negative strains (Escherichia coliATCC 25931 and Pseudomonas aeruginosa ATCC 9027) andthree Gram-positive strains (Bacillus subtilis ATCC 6633Bacillus subtilisATCC6633 and Staphylococcus aureusATCC6538) were obtained from the ATCC (Manassas VA USA)The bacterial strains were cultured aerobically on nutrientagar (NA) plates at 37∘C for 24 h For the antibacterial activitytest the bacteria were aerobically cultured in nutrient broth(NB) at 37∘C for 24 h and then suspended in sterile saline ata density equivalent to that of the 05 McFarland standardsBacterial suspensions with a concentration of 105 cfuml wereused for in vitro antibacterial activity test

The results (Table 2) showed that most of the synthe-sized hydrazones were inactive against the bacteria testedCompounds 8a and 8b inhibited Staphylococcus aureus andBacillus cereus and 8e inhibited only Staphylococcus aureusat the same MIC values of 1024 120583gml and showed lessbacterial activity than that of the parent compound (minus)-gossypol and some aza-derivatives of gossypol [24] From thestructure activity relationship inactivity or weak activity ofnew hydrazones can be a result of the presence in its structureof the moieties attached to gossypol which probably do notenable better interaction of these derivatives with the lipidbilayer of bacteria

4 Conclusions

We have presented the synthesis of new Schiff bases andhydrazones of (minus)-gossypol and screened for in vitro cyto-toxic activity against several human cancer cell lines andantibacterial activity against human pathogenic bacteria Inthis research for the first time ZnCl2 has been effectivelyused for the synthesis of gossypol hydrazones Although nocompounds were as effective as positive controls or gossypol

Journal of Chemistry 5

Table 1 Cytotoxic activity of target compounds

Number Compounds IC50 (120583M)HepG2 LU-1 MCF-7

(1) 4a gt100 gt100 gt100(2) 4b gt100 gt100 gt100(3) 4c gt100 gt100 gt100(4) 4d gt100 6683 gt100(5) 8a 2093 1358 940(6) 8b 5582 5682 4848(7) 8c 8972 7983 8640(8) 8d 8646 6456 6572(9) 8e gt100 gt100 gt100(10) 12a 5568 5470 6333(11) 12b 9530 9955 gt100(12) 12c gt100 gt100 gt100(13) 12d gt100 gt100 gt100(14) 12e gt100 gt100 gt100(15) Ellipticine 171 187 191(16) (minus)-Gossypol 45 43 40Note The reference substance ellipticine exhibited cytotoxic activity against HepG2 (ATCC-HB 8065) LU-1 (ATCC-HTB-57) and MCF-7 (ATCC- HTB22)with IC50 values of 171 187 and 191120583M respectively The values shown for these compounds are the average of three determinations

Table 2 Antibacterial activity of compounds against human pathogenic bacteria

Number Compounds MIC (120583gml)

Staphylococcusaureus (ATCC 6538)

Bacillus cereus(ATCC 21768)

Bacillus subtilis(ATCC 6633)

Escherichia coli(ATCC 25931)

Pseudomonasaeruginosa (ATCC

9027)(1) 4a mdash mdash mdash mdash mdash(2) 4b mdash mdash mdash mdash mdash(3) 4c mdash mdash mdash mdash mdash(4) 4d mdash mdash mdash mdash mdash(5) 8a 1024 1024 mdash mdash(6) 8b 1024 mdash 1024 mdash mdash(7) 8c mdash mdash mdash mdash mdash(8) 8d mdash mdash mdash mdash mdash(9) 8e 1024 mdash mdash mdash mdash(10) 12a mdash mdash mdash mdash mdash(11) 12b mdash mdash mdash mdash mdash(12) 12c mdash mdash mdash mdash mdash(13) 12d mdash mdash mdash mdash mdash(14) 12e mdash mdash mdash mdash mdash(15) Streptomycin sulfate 20 20 5 20 20(16) (minus)-Gossypol 15 15 16 Ndlowast NdlowastlowastNot determined

in terms of biological effects the research could make con-tribution to the discovery of new gossypol derivatives basedon research published herein

5 Experimental

All chemicals and reaction solvents were purchased fromMerck and Sigma-Aldrich Melting points were determined

in open capillaries on a Shimadzu Electrothermal IA 9200apparatus and uncorrected IR spectra were recorded ona Impact 410 FTIR using KBr discs 1D-NMR and 2D-NMR Spectra were recorded on a Bruker AVANCE 500MHzspectrometer in CDCl3 and DMSO-d6 Chemical shifts (120575)are in ppm relative to TMS multiplicities are shown asfollows s (singlet) d (doublet) t (triplet) and m (multiplet)and coupling constants (119869) are expressed in hertz (Hz)HRMS

6 Journal of Chemistry

was recorded by using a FT-ICRMSandESI-TOF-MSAgilent6230 spectrophotometer (Varian) Progress of the reactionwas monitored by thin-layer chromatography (TLC) usingprecoated TLC sheets with ultraviolet (UV) fluorescent silicagel (Merck 60F254) and spots were visualized by UV lamp at254 nmColumn chromatographywas carried out using silicagel (40ndash230mesh)

51 Separation of (minus)-Gossypol from (plusmn)-Gossypol A solu-tion of L-tryptophan methyl ester hydrochloride (9824 g0038mol) and NaOH (152 g 0038mol) in ethanol (60mL)was stirred at 45∘C and the racemic gossypol (985 g0019mol) was added The mixture was stirred for 2 h Thereaction was monitored by TLC and then allowed to warm toroom temperatureThe resulting precipitate from the reactionwas then filtered washed with cold ethanol and dried underreduced pressure to obtain Schiff base intermediate (828 g95) Schiff base intermediate (8808 g 959mmol) wasdissolved in a mixture of acetic acid and ether (4 1) (50mL)The reaction mixture was kept at minus5ndash0∘C under nitrogenatmosphere and concentrated hydrochloric acid (15mL)was slowly added for 10 minutes The reaction was thenstirred at room temperature for 72 and monitored by TLCAfter the completion of reaction the resulting D-tryptophanmethyl ester was filtered and washed by an amount ofdichloromethane The filtrate was concentrated to drynessand was dissolved in 30mL of mixture of dichloromethaneand n-hexane (2 1) and was kept at 4∘C for crystallization(minus)-Gossypol was obtained by filtering andwashingwith coldacetone in 852 yield (423 g) 944 ee by HPLC

52 General Procedure for the Synthesis of Schiff Bases (4andashd)A mixture of (minus)-gossypol (100mg 1 eq and 0193mmol)and corresponding amines (22 eq 042mmol) in EtOH(10mL) was stirred at room temperature for 8 hThe resultingprecipitate was then filtered and washed with cold methanoland dichloromethane to afford desired Schiff bases 4andashd

(R8Z81015840Z)-881015840-Bis(((4-chlorobenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4a) Yield 778 mp 227ndash229∘C 1H NMR (500MHz DMSO-d6) 1345 (t 119869 = 55Hz2H NH) 985 (d 119869 = 125Hz 2H) 837 (s 2H) 783 (s2H) 744 (m 3H) 739 (d 119869 = 85Hz 4H) 475 (m 4HArCH2) 369 (m 2H CH(CH3)2) 194 (s 6H 2CH3)143 (t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHzDMSO-d6) 1722 1624 1496 1462 1367 1324 1314 12941287 1269 1267 1203 1166 1158 1035 523 265 2032014 HR-ESIMS [M + H]+ found 76524945 calculatedC44H43Cl2N2O6 76524982

(R8Z81015840Z)-881015840-Bis(((4-fluorobenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4b) Yield 818 mp 223ndash225∘C 1H NMR (500MHz DMSO-d6) 1347 (t 119869 = 50Hz2H NH) 987 (d 119869 = 125Hz 2H) 837 (s 2H) 784 (s 2H)745ndash737 (m 6H) 721 (m 4H) 474 (brs 4H ArCH2) 370(m 2H CH(CH3)2) 194 (s 6H 2CH3) 143 (t 119869 = 65Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 1721 1626

1623 1607 1496 1462 1338 1313 1296 1269 1267 12031166 1156 1034 523 265 203 201 HR-ESIMS [M + H]+found 73330890 calculated C44H43F2N2O6 73330892

(R8Z81015840Z)-881015840-Bis(((4-methylbenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4c) Yield 607 mp 211ndash213∘C 1H NMR (500MHz DMSO-d6) 1349 (t 119869 = 60Hz2H NH) 988 (d 119869 = 125Hz 2H) 836 (s 2H) 786 (s 2H)745 (s 2H) 726 (d 119869 = 80Hz 4H Ar) 719 (d 119869 = 80Hz4H Ar) 470 (m 4H ArCH2) 369 (m 2H CH(CH3)2)228 (s CH3) 193 (s 6H 2CH3) 143 (t 119869 = 70Hz 12H4CH3)

13C NMR (125MHz DMSO-d6) 1719 1624 14971462 1369 1345 1313 1293 1287 1275 1266 1266 12021158 1034 529 265 206 202 201 HR-ESIMS [M + H]+found 72535891 calculated C46H49N2O6 72535906

(R8Z81015840Z)-881015840-Bis(((4-methoxybenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-bin-aphthalene]-771015840(8H81015840H)-dione (4d) Yield 650 mp 230ndash232∘C 1H NMR (500MHz DMSO-d6) 1334 (s 2H NH)989 (d 119869 = 70Hz 2H) 742 (s 2H) 736ndash729 (m 6H)695ndash692 (m 6H) 468 (br 4H 2CH2-Ph) 375 (m 2HCH(CH3)2) 372 (s 6H OCH3) 198 (s 6H 2CH3) 145 (t119869 = 70Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)1723 1625 1592 1589 1497 1312 1302 1293 12911266 1163 1142 1139 1034 552 527 529 265 206202 HR-ESIMS [M + H]+ found 75734880 calculatedC46H49N2O8 75734889

53 Representative Procedure for the Synthesis of Hydrazones(8andashe and 12andashe) A mixture of 2-fluorobenzoic acid (5a)(1 g 713mmol) in MeOH (20mL) was stirred for a fewminutes Concentrated H2SO4 (1mL) was added and themixture was refluxed for 12 h The reaction was monitoredby TLC using 119899-hexane with ethyl acetate as a developingsystemCH2Cl2 (30mL)was then added and themixturewasextracted with distilled H2O (3 times 20mL) The organic phasewas separated dried on anhydrous Na2SO4 and evaporatedunder vacuum to afford corresponding ester 6a in almostquantitative yield in oil form (109 g) The oil was thendissolved in EtOH and NH2NH2sdotH2O (3 eq) was addedThe mixture was refluxed for 10 h CH2Cl2 (30mL) was thenadded and extracted with distilled H2O (3 times 20mL) Theorganic phase was separated dried on anhydrous Na2SO4and evaporated under vacuum to afford correspondinghydrazide 7a in very good yield (white solid 102 g 93)and used for next step (minus)-Gossypol (200mg 038mmol)and ZnCl2 (5mg) were added to the solution of hydrazide 7a(122 g 080mmol and 21 eq) in ethanol (10mL)The reactionwas stirred at room temperature for 16 h The resultingprecipitate was then filtered and washed with cold methanoland dichloromethane to give hydrazone 8a

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-fluorobenzohydrazide)(8a) Yield 504 mp 236ndash238∘C 1H NMR (500MHzDMSO-d6) 1453 (s 2H NH) 1232 (s 2H NH) 1009 (s

Journal of Chemistry 7

2H) 882 (s 2H) 817 (s 2H) 769 (m 2H) 761ndash756 (m4H) 736ndash732 (m 4H) 391 (m 2H CH(CH3)2) 199 (s 6H2CH3) 148 (t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHzDMSO-d6) 1602 1600 1583 1535 1508 1499 1331 13301328 1303 1287 1279 1247 1225 1224 1188 1163 11611159 1073 560 209 205 HR-ESIMS [M + H]+ found79128920 calculated C44H41F2N4O8 79128925

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(3-fluorobenzohydrazide)(8b) Yield 630 mp 230ndash233∘C 1H NMR (500MHzDMSO-d6) 1469 (s 2H NH) 1243 (s 2H NH) 1020(s 2H) 883 (s 2H) 819 (s 2H) 779 (dd 119869 = 75Hz4H) 763 (s 2H) 758 (m 2H) 746ndash742 (m 2H) 769 (m2H) 761ndash756 (m 4H) 736ndash732 (m 4H) 391 (m 2HCH(CH3)2) 199 (s 6H 2CH3) 148 (t 119869 = 70Hz 12H4CH3)

13C NMR (125MHz DMSO-d6) 1629 1614 16091536 1507 1501 1439 1349 1327 1307 1287 1279 12391189 1187 1162 1146 1144 1073 560 260 204

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(4-fluorobenzohydrazide)(8c) Yield 579 mp 235ndash237∘C 1H NMR (500MHzDMSO-d6) 1476 (s 2H NH) 1239 (s 2H NH) 1019 (s2H) 881 (s 2H) 816 (s 2H) 802 (d 119869 = 80Hz 4H) 763(s 2H) 737 (d 119869 = 80Hz 4H) 392 (m 2H CH(CH3)2)203 (s 6H 2CH3) 150 (t 119869 = 60Hz 12H 4CH3)

13CNMR(125MHz DMSO-d6) 1652 1633 1617 1532 1508 15011439 1327 1304 1291 12864 12773 11887 11615 1159011559 11542 10737 560 260 204

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(3-methylbenzohydrazide)(8d) Yield 578 mp 204ndash206∘C 1H NMR (500MHzDMSO-d6) 1477 (s 2H NH) 1229 (s 2H NH) 1016 (s2H) 881 (s 2H) 880 (s 2H) 812 (s 2H) 775ndash772 (m4H) 762 (s 2H) 740 (m 4H) 391 (m 2H CH(CH3)2)237 (s 6H 2 CH3) 202 (s 6H 2CH3) 147 (t 119869 = 55Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16579 1530715072 15008 13783 13259 13251 12863 12839 1281412765 12480 11884 11618 10739 2660 2091 2056

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(4-methylbenzohydrazide)(8e) Yield 604 mp 213ndash215∘C 1H NMR (500MHzDMSO-d6) 1481 (s 2H NH) 1228 (s 2H NH) 1018 (s2H) 881 (s 2H) 880 (s 2H) 813 (s 2H) 786 (d 119869 = 75Hz2H) 745 (d 119869 = 75Hz 2H) 763 (s 2H) 733 (d 119869 = 80Hz2H) 728 (d 119869 = 70Hz 2H) 392 (m 2H CH(CH3)2) 237(d 119869 = 105Hz 6H 2 CH3) 202 (s 6H 2CH3) 147 (t119869 = 55 Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)16256 15291 15072 15009 14206 14168 13261 1297312941 12902 12897 12766 12716 11881 11616 107412101 2096 2058 HR-ESIMS [M + H]+ found 78333931calculated C46H47N4O8 78333939

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(2-fluorophenyl)acetohy-drazide) (12a) Yield 517 mp 202ndash204∘C 1H NMR(500MHz DMSO-d6) 1526 (s 2H NH) 1289 (s 2H NH)1083 (s 2H) 961 (s 2H) 903 (s 2H) 844 (s 2H) 823 (m2H) 816 (m 2H) 801 (m 4H) 473 (brs 2H CH(CH3)2)448 (s 4H CH2-Ph) 283 (s 6H 2CH3) 231 (t 119869 = 50Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16521 1615515961 15213 15081 14972 14383 13285 13195 1289812765 12429 12253 11863 11602 11515 11498 107253384 2056 2051 HR-ESIMS [M + H]+ found 81932005calculated C46H45F2N4O8 81932055

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(3-fluorophenyl)acetohy-drazide) (12b) Yield 487 mp 188ndash190∘C 1H NMR(500MHz DMSO-d6) 1441 (s 2H NH) 1204 (s 2H NH)996 (s 2H) 876 (s 2H) 817 (s 2H) 759 (s 2H) 737 (m2H) 717 (d 119869 = 75Hz 4H) 708 (m 2H) 390 (brs 2HCH(CH3)2) 362 (s 4H CH2-Ph) 199 (s 6H 2CH3) 148(t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)16560 16301 16107 15221 15077 14973 14384 1382113265 13021 12866 12768 12526 11862 11599 1158111355 10721 4020 2655 2055

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(4-fluorophenyl)acetohy-drazide) (12c) Yield 548 mp 195ndash197∘C 1H NMR(500MHz DMSO-d6) 1442 (s 2H NH) 1200 (s 2H NH)998 (s 2H) 876 (s 2H) 815 (s 2H) 760 (s 2H) 736ndash730(m 4H) 717ndash710 (m 4H) 389 (brs 2H 2H CH(CH3)2)356 (s 4H CH2-Ph) 198 (s 6H 2CH3) 147 (t 119869 = 50Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16883 1660316212 16019 15211 15078 14973 14383 13263 1288512763 11862 11600 11511 11497 10722 4020 2650 2051

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(2-chlorophenyl)acetohy-drazide) (12d) Yield 527 mp 206ndash208∘C 1H NMR(500MHz DMSO-d6) 1443 (s 2H NH) 1207 (s 2H NH)999 (s 2H) 878 (s 2H) 819 (s 2H) 761 (s 2H) 744 (m4H) 731 (m 4H) 391 (brs 2H 2H CH(CH3)2) 376 (s 4HCH2-Ph) 200 (s 6H 2CH3) 148 (t 119869 = 55Hz 12H 4CH3)13C NMR (125MHz DMSO-d6) 16507 15203 1507914971 14385 13355 13341 13264 13243 13215 1290412891 12868 12763 12710 11862 11602 10725 3831 2055205

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(3-chlorophenyl)acetohy-drazide) (12e) Yield 530 mp 194ndash196∘C 1H NMR(500MHz DMSO-d6) 1439 (s 2H NH) 1204 (s 2H NH)997 (s 2H) 877 (s 2H) 819 (s 2H) 760 (s 2H) 739ndash728(m 8H) 389 (brs 2H 2H CH(CH3)2) 360 (s 4H CH2-Ph)

8 Journal of Chemistry

199 (s 6H 2CH3) 147 (t 119869 = 55Hz 12H 4CH3)13C NMR

(125MHz DMSO-d6) 16558 15224 15077 14972 1438213789 13286 13015 12898 12865 12787 12769 1266511863 11600 10721 401 2055 2050 HR-ESIMS [M + H]+found 85126141 calculated C46H45Cl2N4O8 85126144

Conflicts of Interest

The authors confirm that there are no conflicts of interestrelated to the contents of this article

Acknowledgments

The authors acknowledge the financial support via Project082015HETH-NETHT

References

[1] N Howlader A M Noone M Krapcho et al SEER CancerStatistics Review 1975ndash2012 National Cancer InstituteBethesda MD USA Based on November 2014 SEER data sub-mission posted to the SEER web site April 2015 httpseercancergovcsr1975 2012

[2] I K Mellinghoff and C L Sawyers ldquoThe emergence of resis-tance to targeted cancer therapeuticsrdquo Pharmacogenomics vol3 no 5 pp 603ndash623 2002

[3] M EWall andM CWani ldquoCamptothecin and taxol discoveryto clinicmdashthirteenth Bruce F Cain Memorial Award LecturerdquoCancer Research vol 55 no 4 pp 753ndash760 1995

[4] C L Oliver J A Bauer K G Wolter et al ldquoIn vitro effects ofthe BH3mimetic (-)-gossypol on head and neck squamous cellcarcinoma cellsrdquo Clinical Cancer Research vol 10 no 22 pp7757ndash7763 2004

[5] M Zhang H Liu Z Tian B N Griffith M Ji and Q QLi ldquoGossypol induces apoptosis in human PC-3 prostate can-cer cells by modulating caspase-dependent and caspase-inde-pendent cell death pathwaysrdquo Life Sciences vol 80 no 8 pp767ndash774 2007

[6] R M Mohammad S Wang S Banerjee X Wu J Chen andF H Sarkar ldquoNonpeptidic small-molecule inhibitor of Bcl-2andBcl-X119871 (minus)-gossypol enhances biological effect of genisteinagainst BxPC-3 human pancreatic cancer cell linerdquo Pancreasvol 31 no 4 pp 317ndash324 2005

[7] M Zhang H Liu R Guo et al ldquoMolecular mechanism ofgossypol-induced cell growth inhibition and cell death ofHT-29human colon carcinoma cellsrdquo Biochemical Pharmacology vol66 no 1 pp 93ndash103 2003

[8] D W Hahn C Rusticus A Probst R Homm and A NJohnson ldquoAntifertility and endocrine activities of gossypol inrodentsrdquo Contraception vol 24 no 1 pp 97ndash105 1981

[9] J Yang G Chen L L Li et al ldquoSynthesis and anti-H5N1activity of chiral gossypol derivatives and its analogs implicatedby a viral entry blocking mechanismrdquo Bioorganic amp MedicinalChemistry Letters vol 23 no 9 pp 2619ndash2623 2013

[10] J Yang F Zhang J Li et al ldquoSynthesis and antiviral activities ofnovel gossypol derivativesrdquo Bioorganic amp Medicinal ChemistryLetters vol 22 no 3 pp 1415ndash1420 2012

[11] R J Radloff L M Deck R E Royer and D L Vander JagtldquoAntiviral activities of gossypol and its derivatives against her-pes simplex virus type IIrdquo Pharmacological Research Communi-cations vol 18 no 11 pp 1063ndash1073 1986

[12] G Tegos F R Stermitz O Lomovskaya and K Lewis ldquoMul-tidrug pump inhibitors uncover remarkable activity of plantantimicrobialsrdquo Antimicrobial Agents and Chemotherapy vol46 no 10 pp 3133ndash3141 2002

[13] X S Liang A J Rogers C L Webber et al ldquoDeveloping gossy-pol derivatives with enhanced antitumor activityrdquo Investiga-tional New Drugs vol 13 no 3 pp 181ndash186 1995

[14] R E Royer R G Mills L M Deck G J Mertz and D LVander Jagt ldquoInhibition of human immunodeficiency virustype I replication by derivatives of gossypolrdquo PharmacologicalResearch vol 24 no 4 pp 407ndash412 1991

[15] L Tai-Shun R F Schinazi J Zhu et al ldquoAnti-HIV-1 activityand cellular pharmacology of various analogs of gossypolrdquo Bio-chemical Pharmacology vol 46 no 2 pp 251ndash255 1993

[16] Y Lu S Wu Y Yue et al ldquoGossypol with hydrophobic linearesters exhibits enhanced antitumor activity as an inhibitor ofantiapoptotic proteinsrdquoACSMedicinal Chemistry Letters vol 7no 12 pp 1185ndash1190 2016

[17] L Li Z Li K Wang et al ldquoDesign synthesis and biologicalactivities of aromatic gossypol schiff base derivativesrdquo Journalof Agricultural and Food Chemistry vol 62 no 46 pp 11080ndash11088 2014

[18] Z Yonghua C Xu L Yingchao C Xueli and H XiaofengldquoSynthesis and biological evaluation of a novel apogossypolonederivativerdquo Letters in Drug Design amp Discovery vol 14 pp 96ndash101 2017

[19] Y Lu J Li C Dong J Huang H Zhou and W Wang ldquoRecentadvances in gossypol derivatives and analogs a chemistry andbiology viewrdquo Future Medicinal Chemistry vol 9 no 11 pp1243ndash1275 2017

[20] J Qiu L R Levin J Buck and M M Reidenberg ldquoDifferentpathways of cell killing by gossypol enantiomersrdquo ExperimentalBiology and Medicine vol 227 no 6 pp 398ndash401 2002

[21] G Tang C-Y Yang Z Nikolovska-Coleska et al ldquoPyrogallol-based molecules as potent inhibitors of the antiapoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol 50 no 8 pp1723ndash1726 2007

[22] G Wang Z Nikolovska-Coleska C Yang et al ldquoStructure-based design of potent small-molecule inhibitors of anti-apoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol49 no 21 pp 6139ndash6142 2006

[23] H-X Jiang X-X Cao H Huang and B Jiang ldquoAn expedientroute for the practical preparation of optically active (-)-gossypolrdquo Tetrahedron Asymmetry vol 18 no 20 pp 2437ndash2441 2007

[24] P Przybylski K Pyta J Stefanska et al ldquoSynthesis crystalstructures and antibacterial activity studies of aza-derivatives ofphytoalexin from cotton plant - gossypolrdquo European Journal ofMedicinal Chemistry vol 44 no 11 pp 4393ndash4403 2009

[25] K Likhitwitayawuid C K Angerhofer G A Cordell J MPezzuto and N Ruangrungsi ldquoCytotoxic and antimalarial bis-benzylisoquinoline alkaloids from Stephania erectardquo Journal ofNatural Products vol 56 no 1 pp 30ndash38 1993

[26] C Kurekci S L Bishop-Hurley P E Vercoe Z Durmic R AM Al Jassim and C S McSweeney ldquoScreening of Australianplants for antimicrobial activity against Campylobacter jejunirdquoPhytotherapy Research vol 26 no 2 pp 186ndash190 2012

4 Journal of Chemistry

NH at the lowest field 120575 1476 ppm due to hydrogen bondingwith the adjacent ketone group The chemical shift at 1205751239 ppm is attributed to the other NH group Additionallythe resonance signal at 120575 1019 ppm as a sharp singlet is alsoattributed to 6-OH The vinylic proton in the enamine iseasily observed as a single peak at 881 ppm signals at higherfield belonging to the protons H-4 and 1-OH at 120575 816 and763 ppm respectively are coupled Besides the presence ofthe aromatic ring protons can be observed as doublets (J =80Hz) at 120575 802 and 737 ppm The 13C NMR showed allthe signals of the gossypol skeleton and aromatic rings inwhich the signals at 1652 and 1633 ppm are attributed to C-7 and C-6 respectively The carbon connected to Fluorinein the aromatic ring resonates at 120575 1617 ppm based on thecharacteristic splitting of Fluorine and the hydrazide carbonylat 120575 1532 ppm

Novel hydrazones 12andashewere synthesized in the samewayas mentioned above starting from different phenylacetic acidderivatives (9andashe) (Scheme 3) The structure of synthesizedhydrazones was confirmed similarly based on NMR andmass spectroscopy data

3 Biological Activity

The in vitro cytotoxic evaluation of the synthesized com-pounds was carried out according to the described protocol[25] Briefly a stock solution of the target compound wasprepared in dimethylsulfoxide (DMSO) at a concentrationof 1mgmL followed by dilution to obtain a solution ata concentration of 100 120583gmL which was serially dilutedfurther for bioassays in 96-well plates The determination ofIC50 was carried out using three cancer cell lines HepG2 LU-1 and MCF-7 with ellipticine and (minus)-gossypol as positivecontrols The IC50 values were determined from a dose-dependent curve plotted from five different concentrationregimens (0ndash100 120583M) At each regimen mean of triplicateexperiment was used for a point in the curve The bioassayresults are described in Table 1

The bioassay results (Table 1) showed that only half of thetarget compounds exhibited cytotoxic effects against cancercell lines tested ranging from940 to 9955120583MUnexpectedlySchiff bases 4andashc bearing both electron withdrawing groups(Cl and F) and an electron donating group (CH3) at thepara position of the aromatic ring showed no cytotoxicityagainst all three cell lines except compound 4d whichcontains an electron donating group (OCH3) 4d revealeda weak inhibitory effect against only the LU-1 cell lineFor hydrazones 12andashe compounds 12c-e containing electronwithdrawing groups at ortho meta and para positions wereinactive against all cell lines However compounds 12a and12b containing electronwithdrawing groups at ortho and parapositions exhibited weak-to-moderate cytotoxic effects Theobservation also shows that cytotoxic effects of hydrazones8andashe derived from benzoic acid derivatives were better thanthose of phenyl acetic acid derivatives excluding compound8e and that series 8andashd were more cytotoxic towards MCF-7 and LU-1 than towards HepG2 cell line It seems that theelectron withdrawing group (F) at ortho position contributestowards greater toxicity compared to the meta position In

terms of IC50 values all synthesized hydrazones exhibited lesspotency than that of the control ellipticine or the parent(minus)-gossypol and some other gossypol derivatives reported[16 17] Regarding mechanism of action most of gossypolderivatives were reported to target Bcl-2 family proteins [20]In this study it is early and hard to come upwith amechanismof action at this stage without predicted binding models ofdesigned hydrazones to such target protein as Bcl-2 or Mcl-1[20ndash22]However it can be predicted that such possible targetproteins as Bcl-2 or Mcl-1 participate in the mechanism ofaction

Among synthesized hydrazones compound 8a showedthe best cytotoxic effect against HepG2 LU-1 and MCF-7with IC50 values of 2093 1358 and 940 120583M respectivelyAccordingly this compound could be considered as a lead forfuture design of gossypol hydrazones in which bioisostericreplacements in ortho position of the phenyl ring could beperformed to improve the cytotoxic activity

In order to expand the biological spectrum of gossypolderivatives synthesized hydrazones were also evaluated forantibacterial activity against human pathogenic bacteriaincluding Staphylococcus aureus (ATCC 6538) Bacillus cereus(ATCC 21768) Bacillus subtilis (ATCC 6633) Escherichia coli(ATCC 25931) and Pseudomonas aeruginosa (ATCC 9027)according to described protocol [26] Briefly five bacterialspecies including two Gram-negative strains (Escherichia coliATCC 25931 and Pseudomonas aeruginosa ATCC 9027) andthree Gram-positive strains (Bacillus subtilis ATCC 6633Bacillus subtilisATCC6633 and Staphylococcus aureusATCC6538) were obtained from the ATCC (Manassas VA USA)The bacterial strains were cultured aerobically on nutrientagar (NA) plates at 37∘C for 24 h For the antibacterial activitytest the bacteria were aerobically cultured in nutrient broth(NB) at 37∘C for 24 h and then suspended in sterile saline ata density equivalent to that of the 05 McFarland standardsBacterial suspensions with a concentration of 105 cfuml wereused for in vitro antibacterial activity test

The results (Table 2) showed that most of the synthe-sized hydrazones were inactive against the bacteria testedCompounds 8a and 8b inhibited Staphylococcus aureus andBacillus cereus and 8e inhibited only Staphylococcus aureusat the same MIC values of 1024 120583gml and showed lessbacterial activity than that of the parent compound (minus)-gossypol and some aza-derivatives of gossypol [24] From thestructure activity relationship inactivity or weak activity ofnew hydrazones can be a result of the presence in its structureof the moieties attached to gossypol which probably do notenable better interaction of these derivatives with the lipidbilayer of bacteria

4 Conclusions

We have presented the synthesis of new Schiff bases andhydrazones of (minus)-gossypol and screened for in vitro cyto-toxic activity against several human cancer cell lines andantibacterial activity against human pathogenic bacteria Inthis research for the first time ZnCl2 has been effectivelyused for the synthesis of gossypol hydrazones Although nocompounds were as effective as positive controls or gossypol

Journal of Chemistry 5

Table 1 Cytotoxic activity of target compounds

Number Compounds IC50 (120583M)HepG2 LU-1 MCF-7

(1) 4a gt100 gt100 gt100(2) 4b gt100 gt100 gt100(3) 4c gt100 gt100 gt100(4) 4d gt100 6683 gt100(5) 8a 2093 1358 940(6) 8b 5582 5682 4848(7) 8c 8972 7983 8640(8) 8d 8646 6456 6572(9) 8e gt100 gt100 gt100(10) 12a 5568 5470 6333(11) 12b 9530 9955 gt100(12) 12c gt100 gt100 gt100(13) 12d gt100 gt100 gt100(14) 12e gt100 gt100 gt100(15) Ellipticine 171 187 191(16) (minus)-Gossypol 45 43 40Note The reference substance ellipticine exhibited cytotoxic activity against HepG2 (ATCC-HB 8065) LU-1 (ATCC-HTB-57) and MCF-7 (ATCC- HTB22)with IC50 values of 171 187 and 191120583M respectively The values shown for these compounds are the average of three determinations

Table 2 Antibacterial activity of compounds against human pathogenic bacteria

Number Compounds MIC (120583gml)

Staphylococcusaureus (ATCC 6538)

Bacillus cereus(ATCC 21768)

Bacillus subtilis(ATCC 6633)

Escherichia coli(ATCC 25931)

Pseudomonasaeruginosa (ATCC

9027)(1) 4a mdash mdash mdash mdash mdash(2) 4b mdash mdash mdash mdash mdash(3) 4c mdash mdash mdash mdash mdash(4) 4d mdash mdash mdash mdash mdash(5) 8a 1024 1024 mdash mdash(6) 8b 1024 mdash 1024 mdash mdash(7) 8c mdash mdash mdash mdash mdash(8) 8d mdash mdash mdash mdash mdash(9) 8e 1024 mdash mdash mdash mdash(10) 12a mdash mdash mdash mdash mdash(11) 12b mdash mdash mdash mdash mdash(12) 12c mdash mdash mdash mdash mdash(13) 12d mdash mdash mdash mdash mdash(14) 12e mdash mdash mdash mdash mdash(15) Streptomycin sulfate 20 20 5 20 20(16) (minus)-Gossypol 15 15 16 Ndlowast NdlowastlowastNot determined

in terms of biological effects the research could make con-tribution to the discovery of new gossypol derivatives basedon research published herein

5 Experimental

All chemicals and reaction solvents were purchased fromMerck and Sigma-Aldrich Melting points were determined

in open capillaries on a Shimadzu Electrothermal IA 9200apparatus and uncorrected IR spectra were recorded ona Impact 410 FTIR using KBr discs 1D-NMR and 2D-NMR Spectra were recorded on a Bruker AVANCE 500MHzspectrometer in CDCl3 and DMSO-d6 Chemical shifts (120575)are in ppm relative to TMS multiplicities are shown asfollows s (singlet) d (doublet) t (triplet) and m (multiplet)and coupling constants (119869) are expressed in hertz (Hz)HRMS

6 Journal of Chemistry

was recorded by using a FT-ICRMSandESI-TOF-MSAgilent6230 spectrophotometer (Varian) Progress of the reactionwas monitored by thin-layer chromatography (TLC) usingprecoated TLC sheets with ultraviolet (UV) fluorescent silicagel (Merck 60F254) and spots were visualized by UV lamp at254 nmColumn chromatographywas carried out using silicagel (40ndash230mesh)

51 Separation of (minus)-Gossypol from (plusmn)-Gossypol A solu-tion of L-tryptophan methyl ester hydrochloride (9824 g0038mol) and NaOH (152 g 0038mol) in ethanol (60mL)was stirred at 45∘C and the racemic gossypol (985 g0019mol) was added The mixture was stirred for 2 h Thereaction was monitored by TLC and then allowed to warm toroom temperatureThe resulting precipitate from the reactionwas then filtered washed with cold ethanol and dried underreduced pressure to obtain Schiff base intermediate (828 g95) Schiff base intermediate (8808 g 959mmol) wasdissolved in a mixture of acetic acid and ether (4 1) (50mL)The reaction mixture was kept at minus5ndash0∘C under nitrogenatmosphere and concentrated hydrochloric acid (15mL)was slowly added for 10 minutes The reaction was thenstirred at room temperature for 72 and monitored by TLCAfter the completion of reaction the resulting D-tryptophanmethyl ester was filtered and washed by an amount ofdichloromethane The filtrate was concentrated to drynessand was dissolved in 30mL of mixture of dichloromethaneand n-hexane (2 1) and was kept at 4∘C for crystallization(minus)-Gossypol was obtained by filtering andwashingwith coldacetone in 852 yield (423 g) 944 ee by HPLC

52 General Procedure for the Synthesis of Schiff Bases (4andashd)A mixture of (minus)-gossypol (100mg 1 eq and 0193mmol)and corresponding amines (22 eq 042mmol) in EtOH(10mL) was stirred at room temperature for 8 hThe resultingprecipitate was then filtered and washed with cold methanoland dichloromethane to afford desired Schiff bases 4andashd

(R8Z81015840Z)-881015840-Bis(((4-chlorobenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4a) Yield 778 mp 227ndash229∘C 1H NMR (500MHz DMSO-d6) 1345 (t 119869 = 55Hz2H NH) 985 (d 119869 = 125Hz 2H) 837 (s 2H) 783 (s2H) 744 (m 3H) 739 (d 119869 = 85Hz 4H) 475 (m 4HArCH2) 369 (m 2H CH(CH3)2) 194 (s 6H 2CH3)143 (t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHzDMSO-d6) 1722 1624 1496 1462 1367 1324 1314 12941287 1269 1267 1203 1166 1158 1035 523 265 2032014 HR-ESIMS [M + H]+ found 76524945 calculatedC44H43Cl2N2O6 76524982

(R8Z81015840Z)-881015840-Bis(((4-fluorobenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4b) Yield 818 mp 223ndash225∘C 1H NMR (500MHz DMSO-d6) 1347 (t 119869 = 50Hz2H NH) 987 (d 119869 = 125Hz 2H) 837 (s 2H) 784 (s 2H)745ndash737 (m 6H) 721 (m 4H) 474 (brs 4H ArCH2) 370(m 2H CH(CH3)2) 194 (s 6H 2CH3) 143 (t 119869 = 65Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 1721 1626

1623 1607 1496 1462 1338 1313 1296 1269 1267 12031166 1156 1034 523 265 203 201 HR-ESIMS [M + H]+found 73330890 calculated C44H43F2N2O6 73330892

(R8Z81015840Z)-881015840-Bis(((4-methylbenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4c) Yield 607 mp 211ndash213∘C 1H NMR (500MHz DMSO-d6) 1349 (t 119869 = 60Hz2H NH) 988 (d 119869 = 125Hz 2H) 836 (s 2H) 786 (s 2H)745 (s 2H) 726 (d 119869 = 80Hz 4H Ar) 719 (d 119869 = 80Hz4H Ar) 470 (m 4H ArCH2) 369 (m 2H CH(CH3)2)228 (s CH3) 193 (s 6H 2CH3) 143 (t 119869 = 70Hz 12H4CH3)

13C NMR (125MHz DMSO-d6) 1719 1624 14971462 1369 1345 1313 1293 1287 1275 1266 1266 12021158 1034 529 265 206 202 201 HR-ESIMS [M + H]+found 72535891 calculated C46H49N2O6 72535906

(R8Z81015840Z)-881015840-Bis(((4-methoxybenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-bin-aphthalene]-771015840(8H81015840H)-dione (4d) Yield 650 mp 230ndash232∘C 1H NMR (500MHz DMSO-d6) 1334 (s 2H NH)989 (d 119869 = 70Hz 2H) 742 (s 2H) 736ndash729 (m 6H)695ndash692 (m 6H) 468 (br 4H 2CH2-Ph) 375 (m 2HCH(CH3)2) 372 (s 6H OCH3) 198 (s 6H 2CH3) 145 (t119869 = 70Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)1723 1625 1592 1589 1497 1312 1302 1293 12911266 1163 1142 1139 1034 552 527 529 265 206202 HR-ESIMS [M + H]+ found 75734880 calculatedC46H49N2O8 75734889

53 Representative Procedure for the Synthesis of Hydrazones(8andashe and 12andashe) A mixture of 2-fluorobenzoic acid (5a)(1 g 713mmol) in MeOH (20mL) was stirred for a fewminutes Concentrated H2SO4 (1mL) was added and themixture was refluxed for 12 h The reaction was monitoredby TLC using 119899-hexane with ethyl acetate as a developingsystemCH2Cl2 (30mL)was then added and themixturewasextracted with distilled H2O (3 times 20mL) The organic phasewas separated dried on anhydrous Na2SO4 and evaporatedunder vacuum to afford corresponding ester 6a in almostquantitative yield in oil form (109 g) The oil was thendissolved in EtOH and NH2NH2sdotH2O (3 eq) was addedThe mixture was refluxed for 10 h CH2Cl2 (30mL) was thenadded and extracted with distilled H2O (3 times 20mL) Theorganic phase was separated dried on anhydrous Na2SO4and evaporated under vacuum to afford correspondinghydrazide 7a in very good yield (white solid 102 g 93)and used for next step (minus)-Gossypol (200mg 038mmol)and ZnCl2 (5mg) were added to the solution of hydrazide 7a(122 g 080mmol and 21 eq) in ethanol (10mL)The reactionwas stirred at room temperature for 16 h The resultingprecipitate was then filtered and washed with cold methanoland dichloromethane to give hydrazone 8a

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-fluorobenzohydrazide)(8a) Yield 504 mp 236ndash238∘C 1H NMR (500MHzDMSO-d6) 1453 (s 2H NH) 1232 (s 2H NH) 1009 (s

Journal of Chemistry 7

2H) 882 (s 2H) 817 (s 2H) 769 (m 2H) 761ndash756 (m4H) 736ndash732 (m 4H) 391 (m 2H CH(CH3)2) 199 (s 6H2CH3) 148 (t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHzDMSO-d6) 1602 1600 1583 1535 1508 1499 1331 13301328 1303 1287 1279 1247 1225 1224 1188 1163 11611159 1073 560 209 205 HR-ESIMS [M + H]+ found79128920 calculated C44H41F2N4O8 79128925

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(3-fluorobenzohydrazide)(8b) Yield 630 mp 230ndash233∘C 1H NMR (500MHzDMSO-d6) 1469 (s 2H NH) 1243 (s 2H NH) 1020(s 2H) 883 (s 2H) 819 (s 2H) 779 (dd 119869 = 75Hz4H) 763 (s 2H) 758 (m 2H) 746ndash742 (m 2H) 769 (m2H) 761ndash756 (m 4H) 736ndash732 (m 4H) 391 (m 2HCH(CH3)2) 199 (s 6H 2CH3) 148 (t 119869 = 70Hz 12H4CH3)

13C NMR (125MHz DMSO-d6) 1629 1614 16091536 1507 1501 1439 1349 1327 1307 1287 1279 12391189 1187 1162 1146 1144 1073 560 260 204

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(4-fluorobenzohydrazide)(8c) Yield 579 mp 235ndash237∘C 1H NMR (500MHzDMSO-d6) 1476 (s 2H NH) 1239 (s 2H NH) 1019 (s2H) 881 (s 2H) 816 (s 2H) 802 (d 119869 = 80Hz 4H) 763(s 2H) 737 (d 119869 = 80Hz 4H) 392 (m 2H CH(CH3)2)203 (s 6H 2CH3) 150 (t 119869 = 60Hz 12H 4CH3)

13CNMR(125MHz DMSO-d6) 1652 1633 1617 1532 1508 15011439 1327 1304 1291 12864 12773 11887 11615 1159011559 11542 10737 560 260 204

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(3-methylbenzohydrazide)(8d) Yield 578 mp 204ndash206∘C 1H NMR (500MHzDMSO-d6) 1477 (s 2H NH) 1229 (s 2H NH) 1016 (s2H) 881 (s 2H) 880 (s 2H) 812 (s 2H) 775ndash772 (m4H) 762 (s 2H) 740 (m 4H) 391 (m 2H CH(CH3)2)237 (s 6H 2 CH3) 202 (s 6H 2CH3) 147 (t 119869 = 55Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16579 1530715072 15008 13783 13259 13251 12863 12839 1281412765 12480 11884 11618 10739 2660 2091 2056

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(4-methylbenzohydrazide)(8e) Yield 604 mp 213ndash215∘C 1H NMR (500MHzDMSO-d6) 1481 (s 2H NH) 1228 (s 2H NH) 1018 (s2H) 881 (s 2H) 880 (s 2H) 813 (s 2H) 786 (d 119869 = 75Hz2H) 745 (d 119869 = 75Hz 2H) 763 (s 2H) 733 (d 119869 = 80Hz2H) 728 (d 119869 = 70Hz 2H) 392 (m 2H CH(CH3)2) 237(d 119869 = 105Hz 6H 2 CH3) 202 (s 6H 2CH3) 147 (t119869 = 55 Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)16256 15291 15072 15009 14206 14168 13261 1297312941 12902 12897 12766 12716 11881 11616 107412101 2096 2058 HR-ESIMS [M + H]+ found 78333931calculated C46H47N4O8 78333939

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(2-fluorophenyl)acetohy-drazide) (12a) Yield 517 mp 202ndash204∘C 1H NMR(500MHz DMSO-d6) 1526 (s 2H NH) 1289 (s 2H NH)1083 (s 2H) 961 (s 2H) 903 (s 2H) 844 (s 2H) 823 (m2H) 816 (m 2H) 801 (m 4H) 473 (brs 2H CH(CH3)2)448 (s 4H CH2-Ph) 283 (s 6H 2CH3) 231 (t 119869 = 50Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16521 1615515961 15213 15081 14972 14383 13285 13195 1289812765 12429 12253 11863 11602 11515 11498 107253384 2056 2051 HR-ESIMS [M + H]+ found 81932005calculated C46H45F2N4O8 81932055

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(3-fluorophenyl)acetohy-drazide) (12b) Yield 487 mp 188ndash190∘C 1H NMR(500MHz DMSO-d6) 1441 (s 2H NH) 1204 (s 2H NH)996 (s 2H) 876 (s 2H) 817 (s 2H) 759 (s 2H) 737 (m2H) 717 (d 119869 = 75Hz 4H) 708 (m 2H) 390 (brs 2HCH(CH3)2) 362 (s 4H CH2-Ph) 199 (s 6H 2CH3) 148(t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)16560 16301 16107 15221 15077 14973 14384 1382113265 13021 12866 12768 12526 11862 11599 1158111355 10721 4020 2655 2055

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(4-fluorophenyl)acetohy-drazide) (12c) Yield 548 mp 195ndash197∘C 1H NMR(500MHz DMSO-d6) 1442 (s 2H NH) 1200 (s 2H NH)998 (s 2H) 876 (s 2H) 815 (s 2H) 760 (s 2H) 736ndash730(m 4H) 717ndash710 (m 4H) 389 (brs 2H 2H CH(CH3)2)356 (s 4H CH2-Ph) 198 (s 6H 2CH3) 147 (t 119869 = 50Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16883 1660316212 16019 15211 15078 14973 14383 13263 1288512763 11862 11600 11511 11497 10722 4020 2650 2051

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(2-chlorophenyl)acetohy-drazide) (12d) Yield 527 mp 206ndash208∘C 1H NMR(500MHz DMSO-d6) 1443 (s 2H NH) 1207 (s 2H NH)999 (s 2H) 878 (s 2H) 819 (s 2H) 761 (s 2H) 744 (m4H) 731 (m 4H) 391 (brs 2H 2H CH(CH3)2) 376 (s 4HCH2-Ph) 200 (s 6H 2CH3) 148 (t 119869 = 55Hz 12H 4CH3)13C NMR (125MHz DMSO-d6) 16507 15203 1507914971 14385 13355 13341 13264 13243 13215 1290412891 12868 12763 12710 11862 11602 10725 3831 2055205

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(3-chlorophenyl)acetohy-drazide) (12e) Yield 530 mp 194ndash196∘C 1H NMR(500MHz DMSO-d6) 1439 (s 2H NH) 1204 (s 2H NH)997 (s 2H) 877 (s 2H) 819 (s 2H) 760 (s 2H) 739ndash728(m 8H) 389 (brs 2H 2H CH(CH3)2) 360 (s 4H CH2-Ph)

8 Journal of Chemistry

199 (s 6H 2CH3) 147 (t 119869 = 55Hz 12H 4CH3)13C NMR

(125MHz DMSO-d6) 16558 15224 15077 14972 1438213789 13286 13015 12898 12865 12787 12769 1266511863 11600 10721 401 2055 2050 HR-ESIMS [M + H]+found 85126141 calculated C46H45Cl2N4O8 85126144

Conflicts of Interest

The authors confirm that there are no conflicts of interestrelated to the contents of this article

Acknowledgments

The authors acknowledge the financial support via Project082015HETH-NETHT

References

[1] N Howlader A M Noone M Krapcho et al SEER CancerStatistics Review 1975ndash2012 National Cancer InstituteBethesda MD USA Based on November 2014 SEER data sub-mission posted to the SEER web site April 2015 httpseercancergovcsr1975 2012

[2] I K Mellinghoff and C L Sawyers ldquoThe emergence of resis-tance to targeted cancer therapeuticsrdquo Pharmacogenomics vol3 no 5 pp 603ndash623 2002

[3] M EWall andM CWani ldquoCamptothecin and taxol discoveryto clinicmdashthirteenth Bruce F Cain Memorial Award LecturerdquoCancer Research vol 55 no 4 pp 753ndash760 1995

[4] C L Oliver J A Bauer K G Wolter et al ldquoIn vitro effects ofthe BH3mimetic (-)-gossypol on head and neck squamous cellcarcinoma cellsrdquo Clinical Cancer Research vol 10 no 22 pp7757ndash7763 2004

[5] M Zhang H Liu Z Tian B N Griffith M Ji and Q QLi ldquoGossypol induces apoptosis in human PC-3 prostate can-cer cells by modulating caspase-dependent and caspase-inde-pendent cell death pathwaysrdquo Life Sciences vol 80 no 8 pp767ndash774 2007

[6] R M Mohammad S Wang S Banerjee X Wu J Chen andF H Sarkar ldquoNonpeptidic small-molecule inhibitor of Bcl-2andBcl-X119871 (minus)-gossypol enhances biological effect of genisteinagainst BxPC-3 human pancreatic cancer cell linerdquo Pancreasvol 31 no 4 pp 317ndash324 2005

[7] M Zhang H Liu R Guo et al ldquoMolecular mechanism ofgossypol-induced cell growth inhibition and cell death ofHT-29human colon carcinoma cellsrdquo Biochemical Pharmacology vol66 no 1 pp 93ndash103 2003

[8] D W Hahn C Rusticus A Probst R Homm and A NJohnson ldquoAntifertility and endocrine activities of gossypol inrodentsrdquo Contraception vol 24 no 1 pp 97ndash105 1981

[9] J Yang G Chen L L Li et al ldquoSynthesis and anti-H5N1activity of chiral gossypol derivatives and its analogs implicatedby a viral entry blocking mechanismrdquo Bioorganic amp MedicinalChemistry Letters vol 23 no 9 pp 2619ndash2623 2013

[10] J Yang F Zhang J Li et al ldquoSynthesis and antiviral activities ofnovel gossypol derivativesrdquo Bioorganic amp Medicinal ChemistryLetters vol 22 no 3 pp 1415ndash1420 2012

[11] R J Radloff L M Deck R E Royer and D L Vander JagtldquoAntiviral activities of gossypol and its derivatives against her-pes simplex virus type IIrdquo Pharmacological Research Communi-cations vol 18 no 11 pp 1063ndash1073 1986

[12] G Tegos F R Stermitz O Lomovskaya and K Lewis ldquoMul-tidrug pump inhibitors uncover remarkable activity of plantantimicrobialsrdquo Antimicrobial Agents and Chemotherapy vol46 no 10 pp 3133ndash3141 2002

[13] X S Liang A J Rogers C L Webber et al ldquoDeveloping gossy-pol derivatives with enhanced antitumor activityrdquo Investiga-tional New Drugs vol 13 no 3 pp 181ndash186 1995

[14] R E Royer R G Mills L M Deck G J Mertz and D LVander Jagt ldquoInhibition of human immunodeficiency virustype I replication by derivatives of gossypolrdquo PharmacologicalResearch vol 24 no 4 pp 407ndash412 1991

[15] L Tai-Shun R F Schinazi J Zhu et al ldquoAnti-HIV-1 activityand cellular pharmacology of various analogs of gossypolrdquo Bio-chemical Pharmacology vol 46 no 2 pp 251ndash255 1993

[16] Y Lu S Wu Y Yue et al ldquoGossypol with hydrophobic linearesters exhibits enhanced antitumor activity as an inhibitor ofantiapoptotic proteinsrdquoACSMedicinal Chemistry Letters vol 7no 12 pp 1185ndash1190 2016

[17] L Li Z Li K Wang et al ldquoDesign synthesis and biologicalactivities of aromatic gossypol schiff base derivativesrdquo Journalof Agricultural and Food Chemistry vol 62 no 46 pp 11080ndash11088 2014

[18] Z Yonghua C Xu L Yingchao C Xueli and H XiaofengldquoSynthesis and biological evaluation of a novel apogossypolonederivativerdquo Letters in Drug Design amp Discovery vol 14 pp 96ndash101 2017

[19] Y Lu J Li C Dong J Huang H Zhou and W Wang ldquoRecentadvances in gossypol derivatives and analogs a chemistry andbiology viewrdquo Future Medicinal Chemistry vol 9 no 11 pp1243ndash1275 2017

[20] J Qiu L R Levin J Buck and M M Reidenberg ldquoDifferentpathways of cell killing by gossypol enantiomersrdquo ExperimentalBiology and Medicine vol 227 no 6 pp 398ndash401 2002

[21] G Tang C-Y Yang Z Nikolovska-Coleska et al ldquoPyrogallol-based molecules as potent inhibitors of the antiapoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol 50 no 8 pp1723ndash1726 2007

[22] G Wang Z Nikolovska-Coleska C Yang et al ldquoStructure-based design of potent small-molecule inhibitors of anti-apoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol49 no 21 pp 6139ndash6142 2006

[23] H-X Jiang X-X Cao H Huang and B Jiang ldquoAn expedientroute for the practical preparation of optically active (-)-gossypolrdquo Tetrahedron Asymmetry vol 18 no 20 pp 2437ndash2441 2007

[24] P Przybylski K Pyta J Stefanska et al ldquoSynthesis crystalstructures and antibacterial activity studies of aza-derivatives ofphytoalexin from cotton plant - gossypolrdquo European Journal ofMedicinal Chemistry vol 44 no 11 pp 4393ndash4403 2009

[25] K Likhitwitayawuid C K Angerhofer G A Cordell J MPezzuto and N Ruangrungsi ldquoCytotoxic and antimalarial bis-benzylisoquinoline alkaloids from Stephania erectardquo Journal ofNatural Products vol 56 no 1 pp 30ndash38 1993

[26] C Kurekci S L Bishop-Hurley P E Vercoe Z Durmic R AM Al Jassim and C S McSweeney ldquoScreening of Australianplants for antimicrobial activity against Campylobacter jejunirdquoPhytotherapy Research vol 26 no 2 pp 186ndash190 2012

Journal of Chemistry 5

Table 1 Cytotoxic activity of target compounds

Number Compounds IC50 (120583M)HepG2 LU-1 MCF-7

(1) 4a gt100 gt100 gt100(2) 4b gt100 gt100 gt100(3) 4c gt100 gt100 gt100(4) 4d gt100 6683 gt100(5) 8a 2093 1358 940(6) 8b 5582 5682 4848(7) 8c 8972 7983 8640(8) 8d 8646 6456 6572(9) 8e gt100 gt100 gt100(10) 12a 5568 5470 6333(11) 12b 9530 9955 gt100(12) 12c gt100 gt100 gt100(13) 12d gt100 gt100 gt100(14) 12e gt100 gt100 gt100(15) Ellipticine 171 187 191(16) (minus)-Gossypol 45 43 40Note The reference substance ellipticine exhibited cytotoxic activity against HepG2 (ATCC-HB 8065) LU-1 (ATCC-HTB-57) and MCF-7 (ATCC- HTB22)with IC50 values of 171 187 and 191120583M respectively The values shown for these compounds are the average of three determinations

Table 2 Antibacterial activity of compounds against human pathogenic bacteria

Number Compounds MIC (120583gml)

Staphylococcusaureus (ATCC 6538)

Bacillus cereus(ATCC 21768)

Bacillus subtilis(ATCC 6633)

Escherichia coli(ATCC 25931)

Pseudomonasaeruginosa (ATCC

9027)(1) 4a mdash mdash mdash mdash mdash(2) 4b mdash mdash mdash mdash mdash(3) 4c mdash mdash mdash mdash mdash(4) 4d mdash mdash mdash mdash mdash(5) 8a 1024 1024 mdash mdash(6) 8b 1024 mdash 1024 mdash mdash(7) 8c mdash mdash mdash mdash mdash(8) 8d mdash mdash mdash mdash mdash(9) 8e 1024 mdash mdash mdash mdash(10) 12a mdash mdash mdash mdash mdash(11) 12b mdash mdash mdash mdash mdash(12) 12c mdash mdash mdash mdash mdash(13) 12d mdash mdash mdash mdash mdash(14) 12e mdash mdash mdash mdash mdash(15) Streptomycin sulfate 20 20 5 20 20(16) (minus)-Gossypol 15 15 16 Ndlowast NdlowastlowastNot determined

in terms of biological effects the research could make con-tribution to the discovery of new gossypol derivatives basedon research published herein

5 Experimental

All chemicals and reaction solvents were purchased fromMerck and Sigma-Aldrich Melting points were determined

in open capillaries on a Shimadzu Electrothermal IA 9200apparatus and uncorrected IR spectra were recorded ona Impact 410 FTIR using KBr discs 1D-NMR and 2D-NMR Spectra were recorded on a Bruker AVANCE 500MHzspectrometer in CDCl3 and DMSO-d6 Chemical shifts (120575)are in ppm relative to TMS multiplicities are shown asfollows s (singlet) d (doublet) t (triplet) and m (multiplet)and coupling constants (119869) are expressed in hertz (Hz)HRMS

6 Journal of Chemistry

was recorded by using a FT-ICRMSandESI-TOF-MSAgilent6230 spectrophotometer (Varian) Progress of the reactionwas monitored by thin-layer chromatography (TLC) usingprecoated TLC sheets with ultraviolet (UV) fluorescent silicagel (Merck 60F254) and spots were visualized by UV lamp at254 nmColumn chromatographywas carried out using silicagel (40ndash230mesh)

51 Separation of (minus)-Gossypol from (plusmn)-Gossypol A solu-tion of L-tryptophan methyl ester hydrochloride (9824 g0038mol) and NaOH (152 g 0038mol) in ethanol (60mL)was stirred at 45∘C and the racemic gossypol (985 g0019mol) was added The mixture was stirred for 2 h Thereaction was monitored by TLC and then allowed to warm toroom temperatureThe resulting precipitate from the reactionwas then filtered washed with cold ethanol and dried underreduced pressure to obtain Schiff base intermediate (828 g95) Schiff base intermediate (8808 g 959mmol) wasdissolved in a mixture of acetic acid and ether (4 1) (50mL)The reaction mixture was kept at minus5ndash0∘C under nitrogenatmosphere and concentrated hydrochloric acid (15mL)was slowly added for 10 minutes The reaction was thenstirred at room temperature for 72 and monitored by TLCAfter the completion of reaction the resulting D-tryptophanmethyl ester was filtered and washed by an amount ofdichloromethane The filtrate was concentrated to drynessand was dissolved in 30mL of mixture of dichloromethaneand n-hexane (2 1) and was kept at 4∘C for crystallization(minus)-Gossypol was obtained by filtering andwashingwith coldacetone in 852 yield (423 g) 944 ee by HPLC

52 General Procedure for the Synthesis of Schiff Bases (4andashd)A mixture of (minus)-gossypol (100mg 1 eq and 0193mmol)and corresponding amines (22 eq 042mmol) in EtOH(10mL) was stirred at room temperature for 8 hThe resultingprecipitate was then filtered and washed with cold methanoland dichloromethane to afford desired Schiff bases 4andashd

(R8Z81015840Z)-881015840-Bis(((4-chlorobenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4a) Yield 778 mp 227ndash229∘C 1H NMR (500MHz DMSO-d6) 1345 (t 119869 = 55Hz2H NH) 985 (d 119869 = 125Hz 2H) 837 (s 2H) 783 (s2H) 744 (m 3H) 739 (d 119869 = 85Hz 4H) 475 (m 4HArCH2) 369 (m 2H CH(CH3)2) 194 (s 6H 2CH3)143 (t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHzDMSO-d6) 1722 1624 1496 1462 1367 1324 1314 12941287 1269 1267 1203 1166 1158 1035 523 265 2032014 HR-ESIMS [M + H]+ found 76524945 calculatedC44H43Cl2N2O6 76524982

(R8Z81015840Z)-881015840-Bis(((4-fluorobenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4b) Yield 818 mp 223ndash225∘C 1H NMR (500MHz DMSO-d6) 1347 (t 119869 = 50Hz2H NH) 987 (d 119869 = 125Hz 2H) 837 (s 2H) 784 (s 2H)745ndash737 (m 6H) 721 (m 4H) 474 (brs 4H ArCH2) 370(m 2H CH(CH3)2) 194 (s 6H 2CH3) 143 (t 119869 = 65Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 1721 1626

1623 1607 1496 1462 1338 1313 1296 1269 1267 12031166 1156 1034 523 265 203 201 HR-ESIMS [M + H]+found 73330890 calculated C44H43F2N2O6 73330892

(R8Z81015840Z)-881015840-Bis(((4-methylbenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4c) Yield 607 mp 211ndash213∘C 1H NMR (500MHz DMSO-d6) 1349 (t 119869 = 60Hz2H NH) 988 (d 119869 = 125Hz 2H) 836 (s 2H) 786 (s 2H)745 (s 2H) 726 (d 119869 = 80Hz 4H Ar) 719 (d 119869 = 80Hz4H Ar) 470 (m 4H ArCH2) 369 (m 2H CH(CH3)2)228 (s CH3) 193 (s 6H 2CH3) 143 (t 119869 = 70Hz 12H4CH3)

13C NMR (125MHz DMSO-d6) 1719 1624 14971462 1369 1345 1313 1293 1287 1275 1266 1266 12021158 1034 529 265 206 202 201 HR-ESIMS [M + H]+found 72535891 calculated C46H49N2O6 72535906

(R8Z81015840Z)-881015840-Bis(((4-methoxybenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-bin-aphthalene]-771015840(8H81015840H)-dione (4d) Yield 650 mp 230ndash232∘C 1H NMR (500MHz DMSO-d6) 1334 (s 2H NH)989 (d 119869 = 70Hz 2H) 742 (s 2H) 736ndash729 (m 6H)695ndash692 (m 6H) 468 (br 4H 2CH2-Ph) 375 (m 2HCH(CH3)2) 372 (s 6H OCH3) 198 (s 6H 2CH3) 145 (t119869 = 70Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)1723 1625 1592 1589 1497 1312 1302 1293 12911266 1163 1142 1139 1034 552 527 529 265 206202 HR-ESIMS [M + H]+ found 75734880 calculatedC46H49N2O8 75734889

53 Representative Procedure for the Synthesis of Hydrazones(8andashe and 12andashe) A mixture of 2-fluorobenzoic acid (5a)(1 g 713mmol) in MeOH (20mL) was stirred for a fewminutes Concentrated H2SO4 (1mL) was added and themixture was refluxed for 12 h The reaction was monitoredby TLC using 119899-hexane with ethyl acetate as a developingsystemCH2Cl2 (30mL)was then added and themixturewasextracted with distilled H2O (3 times 20mL) The organic phasewas separated dried on anhydrous Na2SO4 and evaporatedunder vacuum to afford corresponding ester 6a in almostquantitative yield in oil form (109 g) The oil was thendissolved in EtOH and NH2NH2sdotH2O (3 eq) was addedThe mixture was refluxed for 10 h CH2Cl2 (30mL) was thenadded and extracted with distilled H2O (3 times 20mL) Theorganic phase was separated dried on anhydrous Na2SO4and evaporated under vacuum to afford correspondinghydrazide 7a in very good yield (white solid 102 g 93)and used for next step (minus)-Gossypol (200mg 038mmol)and ZnCl2 (5mg) were added to the solution of hydrazide 7a(122 g 080mmol and 21 eq) in ethanol (10mL)The reactionwas stirred at room temperature for 16 h The resultingprecipitate was then filtered and washed with cold methanoland dichloromethane to give hydrazone 8a

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-fluorobenzohydrazide)(8a) Yield 504 mp 236ndash238∘C 1H NMR (500MHzDMSO-d6) 1453 (s 2H NH) 1232 (s 2H NH) 1009 (s

Journal of Chemistry 7

2H) 882 (s 2H) 817 (s 2H) 769 (m 2H) 761ndash756 (m4H) 736ndash732 (m 4H) 391 (m 2H CH(CH3)2) 199 (s 6H2CH3) 148 (t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHzDMSO-d6) 1602 1600 1583 1535 1508 1499 1331 13301328 1303 1287 1279 1247 1225 1224 1188 1163 11611159 1073 560 209 205 HR-ESIMS [M + H]+ found79128920 calculated C44H41F2N4O8 79128925

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(3-fluorobenzohydrazide)(8b) Yield 630 mp 230ndash233∘C 1H NMR (500MHzDMSO-d6) 1469 (s 2H NH) 1243 (s 2H NH) 1020(s 2H) 883 (s 2H) 819 (s 2H) 779 (dd 119869 = 75Hz4H) 763 (s 2H) 758 (m 2H) 746ndash742 (m 2H) 769 (m2H) 761ndash756 (m 4H) 736ndash732 (m 4H) 391 (m 2HCH(CH3)2) 199 (s 6H 2CH3) 148 (t 119869 = 70Hz 12H4CH3)

13C NMR (125MHz DMSO-d6) 1629 1614 16091536 1507 1501 1439 1349 1327 1307 1287 1279 12391189 1187 1162 1146 1144 1073 560 260 204

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(4-fluorobenzohydrazide)(8c) Yield 579 mp 235ndash237∘C 1H NMR (500MHzDMSO-d6) 1476 (s 2H NH) 1239 (s 2H NH) 1019 (s2H) 881 (s 2H) 816 (s 2H) 802 (d 119869 = 80Hz 4H) 763(s 2H) 737 (d 119869 = 80Hz 4H) 392 (m 2H CH(CH3)2)203 (s 6H 2CH3) 150 (t 119869 = 60Hz 12H 4CH3)

13CNMR(125MHz DMSO-d6) 1652 1633 1617 1532 1508 15011439 1327 1304 1291 12864 12773 11887 11615 1159011559 11542 10737 560 260 204

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(3-methylbenzohydrazide)(8d) Yield 578 mp 204ndash206∘C 1H NMR (500MHzDMSO-d6) 1477 (s 2H NH) 1229 (s 2H NH) 1016 (s2H) 881 (s 2H) 880 (s 2H) 812 (s 2H) 775ndash772 (m4H) 762 (s 2H) 740 (m 4H) 391 (m 2H CH(CH3)2)237 (s 6H 2 CH3) 202 (s 6H 2CH3) 147 (t 119869 = 55Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16579 1530715072 15008 13783 13259 13251 12863 12839 1281412765 12480 11884 11618 10739 2660 2091 2056

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(4-methylbenzohydrazide)(8e) Yield 604 mp 213ndash215∘C 1H NMR (500MHzDMSO-d6) 1481 (s 2H NH) 1228 (s 2H NH) 1018 (s2H) 881 (s 2H) 880 (s 2H) 813 (s 2H) 786 (d 119869 = 75Hz2H) 745 (d 119869 = 75Hz 2H) 763 (s 2H) 733 (d 119869 = 80Hz2H) 728 (d 119869 = 70Hz 2H) 392 (m 2H CH(CH3)2) 237(d 119869 = 105Hz 6H 2 CH3) 202 (s 6H 2CH3) 147 (t119869 = 55 Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)16256 15291 15072 15009 14206 14168 13261 1297312941 12902 12897 12766 12716 11881 11616 107412101 2096 2058 HR-ESIMS [M + H]+ found 78333931calculated C46H47N4O8 78333939

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(2-fluorophenyl)acetohy-drazide) (12a) Yield 517 mp 202ndash204∘C 1H NMR(500MHz DMSO-d6) 1526 (s 2H NH) 1289 (s 2H NH)1083 (s 2H) 961 (s 2H) 903 (s 2H) 844 (s 2H) 823 (m2H) 816 (m 2H) 801 (m 4H) 473 (brs 2H CH(CH3)2)448 (s 4H CH2-Ph) 283 (s 6H 2CH3) 231 (t 119869 = 50Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16521 1615515961 15213 15081 14972 14383 13285 13195 1289812765 12429 12253 11863 11602 11515 11498 107253384 2056 2051 HR-ESIMS [M + H]+ found 81932005calculated C46H45F2N4O8 81932055

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(3-fluorophenyl)acetohy-drazide) (12b) Yield 487 mp 188ndash190∘C 1H NMR(500MHz DMSO-d6) 1441 (s 2H NH) 1204 (s 2H NH)996 (s 2H) 876 (s 2H) 817 (s 2H) 759 (s 2H) 737 (m2H) 717 (d 119869 = 75Hz 4H) 708 (m 2H) 390 (brs 2HCH(CH3)2) 362 (s 4H CH2-Ph) 199 (s 6H 2CH3) 148(t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)16560 16301 16107 15221 15077 14973 14384 1382113265 13021 12866 12768 12526 11862 11599 1158111355 10721 4020 2655 2055

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(4-fluorophenyl)acetohy-drazide) (12c) Yield 548 mp 195ndash197∘C 1H NMR(500MHz DMSO-d6) 1442 (s 2H NH) 1200 (s 2H NH)998 (s 2H) 876 (s 2H) 815 (s 2H) 760 (s 2H) 736ndash730(m 4H) 717ndash710 (m 4H) 389 (brs 2H 2H CH(CH3)2)356 (s 4H CH2-Ph) 198 (s 6H 2CH3) 147 (t 119869 = 50Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16883 1660316212 16019 15211 15078 14973 14383 13263 1288512763 11862 11600 11511 11497 10722 4020 2650 2051

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(2-chlorophenyl)acetohy-drazide) (12d) Yield 527 mp 206ndash208∘C 1H NMR(500MHz DMSO-d6) 1443 (s 2H NH) 1207 (s 2H NH)999 (s 2H) 878 (s 2H) 819 (s 2H) 761 (s 2H) 744 (m4H) 731 (m 4H) 391 (brs 2H 2H CH(CH3)2) 376 (s 4HCH2-Ph) 200 (s 6H 2CH3) 148 (t 119869 = 55Hz 12H 4CH3)13C NMR (125MHz DMSO-d6) 16507 15203 1507914971 14385 13355 13341 13264 13243 13215 1290412891 12868 12763 12710 11862 11602 10725 3831 2055205

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(3-chlorophenyl)acetohy-drazide) (12e) Yield 530 mp 194ndash196∘C 1H NMR(500MHz DMSO-d6) 1439 (s 2H NH) 1204 (s 2H NH)997 (s 2H) 877 (s 2H) 819 (s 2H) 760 (s 2H) 739ndash728(m 8H) 389 (brs 2H 2H CH(CH3)2) 360 (s 4H CH2-Ph)

8 Journal of Chemistry

199 (s 6H 2CH3) 147 (t 119869 = 55Hz 12H 4CH3)13C NMR

(125MHz DMSO-d6) 16558 15224 15077 14972 1438213789 13286 13015 12898 12865 12787 12769 1266511863 11600 10721 401 2055 2050 HR-ESIMS [M + H]+found 85126141 calculated C46H45Cl2N4O8 85126144

Conflicts of Interest

The authors confirm that there are no conflicts of interestrelated to the contents of this article

Acknowledgments

The authors acknowledge the financial support via Project082015HETH-NETHT

References

[1] N Howlader A M Noone M Krapcho et al SEER CancerStatistics Review 1975ndash2012 National Cancer InstituteBethesda MD USA Based on November 2014 SEER data sub-mission posted to the SEER web site April 2015 httpseercancergovcsr1975 2012

[2] I K Mellinghoff and C L Sawyers ldquoThe emergence of resis-tance to targeted cancer therapeuticsrdquo Pharmacogenomics vol3 no 5 pp 603ndash623 2002

[3] M EWall andM CWani ldquoCamptothecin and taxol discoveryto clinicmdashthirteenth Bruce F Cain Memorial Award LecturerdquoCancer Research vol 55 no 4 pp 753ndash760 1995

[4] C L Oliver J A Bauer K G Wolter et al ldquoIn vitro effects ofthe BH3mimetic (-)-gossypol on head and neck squamous cellcarcinoma cellsrdquo Clinical Cancer Research vol 10 no 22 pp7757ndash7763 2004

[5] M Zhang H Liu Z Tian B N Griffith M Ji and Q QLi ldquoGossypol induces apoptosis in human PC-3 prostate can-cer cells by modulating caspase-dependent and caspase-inde-pendent cell death pathwaysrdquo Life Sciences vol 80 no 8 pp767ndash774 2007

[6] R M Mohammad S Wang S Banerjee X Wu J Chen andF H Sarkar ldquoNonpeptidic small-molecule inhibitor of Bcl-2andBcl-X119871 (minus)-gossypol enhances biological effect of genisteinagainst BxPC-3 human pancreatic cancer cell linerdquo Pancreasvol 31 no 4 pp 317ndash324 2005

[7] M Zhang H Liu R Guo et al ldquoMolecular mechanism ofgossypol-induced cell growth inhibition and cell death ofHT-29human colon carcinoma cellsrdquo Biochemical Pharmacology vol66 no 1 pp 93ndash103 2003

[8] D W Hahn C Rusticus A Probst R Homm and A NJohnson ldquoAntifertility and endocrine activities of gossypol inrodentsrdquo Contraception vol 24 no 1 pp 97ndash105 1981

[9] J Yang G Chen L L Li et al ldquoSynthesis and anti-H5N1activity of chiral gossypol derivatives and its analogs implicatedby a viral entry blocking mechanismrdquo Bioorganic amp MedicinalChemistry Letters vol 23 no 9 pp 2619ndash2623 2013

[10] J Yang F Zhang J Li et al ldquoSynthesis and antiviral activities ofnovel gossypol derivativesrdquo Bioorganic amp Medicinal ChemistryLetters vol 22 no 3 pp 1415ndash1420 2012

[11] R J Radloff L M Deck R E Royer and D L Vander JagtldquoAntiviral activities of gossypol and its derivatives against her-pes simplex virus type IIrdquo Pharmacological Research Communi-cations vol 18 no 11 pp 1063ndash1073 1986

[12] G Tegos F R Stermitz O Lomovskaya and K Lewis ldquoMul-tidrug pump inhibitors uncover remarkable activity of plantantimicrobialsrdquo Antimicrobial Agents and Chemotherapy vol46 no 10 pp 3133ndash3141 2002

[13] X S Liang A J Rogers C L Webber et al ldquoDeveloping gossy-pol derivatives with enhanced antitumor activityrdquo Investiga-tional New Drugs vol 13 no 3 pp 181ndash186 1995

[14] R E Royer R G Mills L M Deck G J Mertz and D LVander Jagt ldquoInhibition of human immunodeficiency virustype I replication by derivatives of gossypolrdquo PharmacologicalResearch vol 24 no 4 pp 407ndash412 1991

[15] L Tai-Shun R F Schinazi J Zhu et al ldquoAnti-HIV-1 activityand cellular pharmacology of various analogs of gossypolrdquo Bio-chemical Pharmacology vol 46 no 2 pp 251ndash255 1993

[16] Y Lu S Wu Y Yue et al ldquoGossypol with hydrophobic linearesters exhibits enhanced antitumor activity as an inhibitor ofantiapoptotic proteinsrdquoACSMedicinal Chemistry Letters vol 7no 12 pp 1185ndash1190 2016

[17] L Li Z Li K Wang et al ldquoDesign synthesis and biologicalactivities of aromatic gossypol schiff base derivativesrdquo Journalof Agricultural and Food Chemistry vol 62 no 46 pp 11080ndash11088 2014

[18] Z Yonghua C Xu L Yingchao C Xueli and H XiaofengldquoSynthesis and biological evaluation of a novel apogossypolonederivativerdquo Letters in Drug Design amp Discovery vol 14 pp 96ndash101 2017

[19] Y Lu J Li C Dong J Huang H Zhou and W Wang ldquoRecentadvances in gossypol derivatives and analogs a chemistry andbiology viewrdquo Future Medicinal Chemistry vol 9 no 11 pp1243ndash1275 2017

[20] J Qiu L R Levin J Buck and M M Reidenberg ldquoDifferentpathways of cell killing by gossypol enantiomersrdquo ExperimentalBiology and Medicine vol 227 no 6 pp 398ndash401 2002

[21] G Tang C-Y Yang Z Nikolovska-Coleska et al ldquoPyrogallol-based molecules as potent inhibitors of the antiapoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol 50 no 8 pp1723ndash1726 2007

[22] G Wang Z Nikolovska-Coleska C Yang et al ldquoStructure-based design of potent small-molecule inhibitors of anti-apoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol49 no 21 pp 6139ndash6142 2006

[23] H-X Jiang X-X Cao H Huang and B Jiang ldquoAn expedientroute for the practical preparation of optically active (-)-gossypolrdquo Tetrahedron Asymmetry vol 18 no 20 pp 2437ndash2441 2007

[24] P Przybylski K Pyta J Stefanska et al ldquoSynthesis crystalstructures and antibacterial activity studies of aza-derivatives ofphytoalexin from cotton plant - gossypolrdquo European Journal ofMedicinal Chemistry vol 44 no 11 pp 4393ndash4403 2009

[25] K Likhitwitayawuid C K Angerhofer G A Cordell J MPezzuto and N Ruangrungsi ldquoCytotoxic and antimalarial bis-benzylisoquinoline alkaloids from Stephania erectardquo Journal ofNatural Products vol 56 no 1 pp 30ndash38 1993

[26] C Kurekci S L Bishop-Hurley P E Vercoe Z Durmic R AM Al Jassim and C S McSweeney ldquoScreening of Australianplants for antimicrobial activity against Campylobacter jejunirdquoPhytotherapy Research vol 26 no 2 pp 186ndash190 2012

6 Journal of Chemistry

was recorded by using a FT-ICRMSandESI-TOF-MSAgilent6230 spectrophotometer (Varian) Progress of the reactionwas monitored by thin-layer chromatography (TLC) usingprecoated TLC sheets with ultraviolet (UV) fluorescent silicagel (Merck 60F254) and spots were visualized by UV lamp at254 nmColumn chromatographywas carried out using silicagel (40ndash230mesh)

51 Separation of (minus)-Gossypol from (plusmn)-Gossypol A solu-tion of L-tryptophan methyl ester hydrochloride (9824 g0038mol) and NaOH (152 g 0038mol) in ethanol (60mL)was stirred at 45∘C and the racemic gossypol (985 g0019mol) was added The mixture was stirred for 2 h Thereaction was monitored by TLC and then allowed to warm toroom temperatureThe resulting precipitate from the reactionwas then filtered washed with cold ethanol and dried underreduced pressure to obtain Schiff base intermediate (828 g95) Schiff base intermediate (8808 g 959mmol) wasdissolved in a mixture of acetic acid and ether (4 1) (50mL)The reaction mixture was kept at minus5ndash0∘C under nitrogenatmosphere and concentrated hydrochloric acid (15mL)was slowly added for 10 minutes The reaction was thenstirred at room temperature for 72 and monitored by TLCAfter the completion of reaction the resulting D-tryptophanmethyl ester was filtered and washed by an amount ofdichloromethane The filtrate was concentrated to drynessand was dissolved in 30mL of mixture of dichloromethaneand n-hexane (2 1) and was kept at 4∘C for crystallization(minus)-Gossypol was obtained by filtering andwashingwith coldacetone in 852 yield (423 g) 944 ee by HPLC

52 General Procedure for the Synthesis of Schiff Bases (4andashd)A mixture of (minus)-gossypol (100mg 1 eq and 0193mmol)and corresponding amines (22 eq 042mmol) in EtOH(10mL) was stirred at room temperature for 8 hThe resultingprecipitate was then filtered and washed with cold methanoland dichloromethane to afford desired Schiff bases 4andashd

(R8Z81015840Z)-881015840-Bis(((4-chlorobenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4a) Yield 778 mp 227ndash229∘C 1H NMR (500MHz DMSO-d6) 1345 (t 119869 = 55Hz2H NH) 985 (d 119869 = 125Hz 2H) 837 (s 2H) 783 (s2H) 744 (m 3H) 739 (d 119869 = 85Hz 4H) 475 (m 4HArCH2) 369 (m 2H CH(CH3)2) 194 (s 6H 2CH3)143 (t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHzDMSO-d6) 1722 1624 1496 1462 1367 1324 1314 12941287 1269 1267 1203 1166 1158 1035 523 265 2032014 HR-ESIMS [M + H]+ found 76524945 calculatedC44H43Cl2N2O6 76524982

(R8Z81015840Z)-881015840-Bis(((4-fluorobenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4b) Yield 818 mp 223ndash225∘C 1H NMR (500MHz DMSO-d6) 1347 (t 119869 = 50Hz2H NH) 987 (d 119869 = 125Hz 2H) 837 (s 2H) 784 (s 2H)745ndash737 (m 6H) 721 (m 4H) 474 (brs 4H ArCH2) 370(m 2H CH(CH3)2) 194 (s 6H 2CH3) 143 (t 119869 = 65Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 1721 1626

1623 1607 1496 1462 1338 1313 1296 1269 1267 12031166 1156 1034 523 265 203 201 HR-ESIMS [M + H]+found 73330890 calculated C44H43F2N2O6 73330892

(R8Z81015840Z)-881015840-Bis(((4-methylbenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-binaph-thalene]-771015840(8H81015840H)-dione (4c) Yield 607 mp 211ndash213∘C 1H NMR (500MHz DMSO-d6) 1349 (t 119869 = 60Hz2H NH) 988 (d 119869 = 125Hz 2H) 836 (s 2H) 786 (s 2H)745 (s 2H) 726 (d 119869 = 80Hz 4H Ar) 719 (d 119869 = 80Hz4H Ar) 470 (m 4H ArCH2) 369 (m 2H CH(CH3)2)228 (s CH3) 193 (s 6H 2CH3) 143 (t 119869 = 70Hz 12H4CH3)

13C NMR (125MHz DMSO-d6) 1719 1624 14971462 1369 1345 1313 1293 1287 1275 1266 1266 12021158 1034 529 265 206 202 201 HR-ESIMS [M + H]+found 72535891 calculated C46H49N2O6 72535906

(R8Z81015840Z)-881015840-Bis(((4-methoxybenzyl)amino)methylene)-111015840661015840-tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-[221015840-bin-aphthalene]-771015840(8H81015840H)-dione (4d) Yield 650 mp 230ndash232∘C 1H NMR (500MHz DMSO-d6) 1334 (s 2H NH)989 (d 119869 = 70Hz 2H) 742 (s 2H) 736ndash729 (m 6H)695ndash692 (m 6H) 468 (br 4H 2CH2-Ph) 375 (m 2HCH(CH3)2) 372 (s 6H OCH3) 198 (s 6H 2CH3) 145 (t119869 = 70Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)1723 1625 1592 1589 1497 1312 1302 1293 12911266 1163 1142 1139 1034 552 527 529 265 206202 HR-ESIMS [M + H]+ found 75734880 calculatedC46H49N2O8 75734889

53 Representative Procedure for the Synthesis of Hydrazones(8andashe and 12andashe) A mixture of 2-fluorobenzoic acid (5a)(1 g 713mmol) in MeOH (20mL) was stirred for a fewminutes Concentrated H2SO4 (1mL) was added and themixture was refluxed for 12 h The reaction was monitoredby TLC using 119899-hexane with ethyl acetate as a developingsystemCH2Cl2 (30mL)was then added and themixturewasextracted with distilled H2O (3 times 20mL) The organic phasewas separated dried on anhydrous Na2SO4 and evaporatedunder vacuum to afford corresponding ester 6a in almostquantitative yield in oil form (109 g) The oil was thendissolved in EtOH and NH2NH2sdotH2O (3 eq) was addedThe mixture was refluxed for 10 h CH2Cl2 (30mL) was thenadded and extracted with distilled H2O (3 times 20mL) Theorganic phase was separated dried on anhydrous Na2SO4and evaporated under vacuum to afford correspondinghydrazide 7a in very good yield (white solid 102 g 93)and used for next step (minus)-Gossypol (200mg 038mmol)and ZnCl2 (5mg) were added to the solution of hydrazide 7a(122 g 080mmol and 21 eq) in ethanol (10mL)The reactionwas stirred at room temperature for 16 h The resultingprecipitate was then filtered and washed with cold methanoland dichloromethane to give hydrazone 8a

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-fluorobenzohydrazide)(8a) Yield 504 mp 236ndash238∘C 1H NMR (500MHzDMSO-d6) 1453 (s 2H NH) 1232 (s 2H NH) 1009 (s

Journal of Chemistry 7

2H) 882 (s 2H) 817 (s 2H) 769 (m 2H) 761ndash756 (m4H) 736ndash732 (m 4H) 391 (m 2H CH(CH3)2) 199 (s 6H2CH3) 148 (t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHzDMSO-d6) 1602 1600 1583 1535 1508 1499 1331 13301328 1303 1287 1279 1247 1225 1224 1188 1163 11611159 1073 560 209 205 HR-ESIMS [M + H]+ found79128920 calculated C44H41F2N4O8 79128925

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(3-fluorobenzohydrazide)(8b) Yield 630 mp 230ndash233∘C 1H NMR (500MHzDMSO-d6) 1469 (s 2H NH) 1243 (s 2H NH) 1020(s 2H) 883 (s 2H) 819 (s 2H) 779 (dd 119869 = 75Hz4H) 763 (s 2H) 758 (m 2H) 746ndash742 (m 2H) 769 (m2H) 761ndash756 (m 4H) 736ndash732 (m 4H) 391 (m 2HCH(CH3)2) 199 (s 6H 2CH3) 148 (t 119869 = 70Hz 12H4CH3)

13C NMR (125MHz DMSO-d6) 1629 1614 16091536 1507 1501 1439 1349 1327 1307 1287 1279 12391189 1187 1162 1146 1144 1073 560 260 204

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(4-fluorobenzohydrazide)(8c) Yield 579 mp 235ndash237∘C 1H NMR (500MHzDMSO-d6) 1476 (s 2H NH) 1239 (s 2H NH) 1019 (s2H) 881 (s 2H) 816 (s 2H) 802 (d 119869 = 80Hz 4H) 763(s 2H) 737 (d 119869 = 80Hz 4H) 392 (m 2H CH(CH3)2)203 (s 6H 2CH3) 150 (t 119869 = 60Hz 12H 4CH3)

13CNMR(125MHz DMSO-d6) 1652 1633 1617 1532 1508 15011439 1327 1304 1291 12864 12773 11887 11615 1159011559 11542 10737 560 260 204

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(3-methylbenzohydrazide)(8d) Yield 578 mp 204ndash206∘C 1H NMR (500MHzDMSO-d6) 1477 (s 2H NH) 1229 (s 2H NH) 1016 (s2H) 881 (s 2H) 880 (s 2H) 812 (s 2H) 775ndash772 (m4H) 762 (s 2H) 740 (m 4H) 391 (m 2H CH(CH3)2)237 (s 6H 2 CH3) 202 (s 6H 2CH3) 147 (t 119869 = 55Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16579 1530715072 15008 13783 13259 13251 12863 12839 1281412765 12480 11884 11618 10739 2660 2091 2056

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(4-methylbenzohydrazide)(8e) Yield 604 mp 213ndash215∘C 1H NMR (500MHzDMSO-d6) 1481 (s 2H NH) 1228 (s 2H NH) 1018 (s2H) 881 (s 2H) 880 (s 2H) 813 (s 2H) 786 (d 119869 = 75Hz2H) 745 (d 119869 = 75Hz 2H) 763 (s 2H) 733 (d 119869 = 80Hz2H) 728 (d 119869 = 70Hz 2H) 392 (m 2H CH(CH3)2) 237(d 119869 = 105Hz 6H 2 CH3) 202 (s 6H 2CH3) 147 (t119869 = 55 Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)16256 15291 15072 15009 14206 14168 13261 1297312941 12902 12897 12766 12716 11881 11616 107412101 2096 2058 HR-ESIMS [M + H]+ found 78333931calculated C46H47N4O8 78333939

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(2-fluorophenyl)acetohy-drazide) (12a) Yield 517 mp 202ndash204∘C 1H NMR(500MHz DMSO-d6) 1526 (s 2H NH) 1289 (s 2H NH)1083 (s 2H) 961 (s 2H) 903 (s 2H) 844 (s 2H) 823 (m2H) 816 (m 2H) 801 (m 4H) 473 (brs 2H CH(CH3)2)448 (s 4H CH2-Ph) 283 (s 6H 2CH3) 231 (t 119869 = 50Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16521 1615515961 15213 15081 14972 14383 13285 13195 1289812765 12429 12253 11863 11602 11515 11498 107253384 2056 2051 HR-ESIMS [M + H]+ found 81932005calculated C46H45F2N4O8 81932055

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(3-fluorophenyl)acetohy-drazide) (12b) Yield 487 mp 188ndash190∘C 1H NMR(500MHz DMSO-d6) 1441 (s 2H NH) 1204 (s 2H NH)996 (s 2H) 876 (s 2H) 817 (s 2H) 759 (s 2H) 737 (m2H) 717 (d 119869 = 75Hz 4H) 708 (m 2H) 390 (brs 2HCH(CH3)2) 362 (s 4H CH2-Ph) 199 (s 6H 2CH3) 148(t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)16560 16301 16107 15221 15077 14973 14384 1382113265 13021 12866 12768 12526 11862 11599 1158111355 10721 4020 2655 2055

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(4-fluorophenyl)acetohy-drazide) (12c) Yield 548 mp 195ndash197∘C 1H NMR(500MHz DMSO-d6) 1442 (s 2H NH) 1200 (s 2H NH)998 (s 2H) 876 (s 2H) 815 (s 2H) 760 (s 2H) 736ndash730(m 4H) 717ndash710 (m 4H) 389 (brs 2H 2H CH(CH3)2)356 (s 4H CH2-Ph) 198 (s 6H 2CH3) 147 (t 119869 = 50Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16883 1660316212 16019 15211 15078 14973 14383 13263 1288512763 11862 11600 11511 11497 10722 4020 2650 2051

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(2-chlorophenyl)acetohy-drazide) (12d) Yield 527 mp 206ndash208∘C 1H NMR(500MHz DMSO-d6) 1443 (s 2H NH) 1207 (s 2H NH)999 (s 2H) 878 (s 2H) 819 (s 2H) 761 (s 2H) 744 (m4H) 731 (m 4H) 391 (brs 2H 2H CH(CH3)2) 376 (s 4HCH2-Ph) 200 (s 6H 2CH3) 148 (t 119869 = 55Hz 12H 4CH3)13C NMR (125MHz DMSO-d6) 16507 15203 1507914971 14385 13355 13341 13264 13243 13215 1290412891 12868 12763 12710 11862 11602 10725 3831 2055205

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(3-chlorophenyl)acetohy-drazide) (12e) Yield 530 mp 194ndash196∘C 1H NMR(500MHz DMSO-d6) 1439 (s 2H NH) 1204 (s 2H NH)997 (s 2H) 877 (s 2H) 819 (s 2H) 760 (s 2H) 739ndash728(m 8H) 389 (brs 2H 2H CH(CH3)2) 360 (s 4H CH2-Ph)

8 Journal of Chemistry

199 (s 6H 2CH3) 147 (t 119869 = 55Hz 12H 4CH3)13C NMR

(125MHz DMSO-d6) 16558 15224 15077 14972 1438213789 13286 13015 12898 12865 12787 12769 1266511863 11600 10721 401 2055 2050 HR-ESIMS [M + H]+found 85126141 calculated C46H45Cl2N4O8 85126144

Conflicts of Interest

The authors confirm that there are no conflicts of interestrelated to the contents of this article

Acknowledgments

The authors acknowledge the financial support via Project082015HETH-NETHT

References

[1] N Howlader A M Noone M Krapcho et al SEER CancerStatistics Review 1975ndash2012 National Cancer InstituteBethesda MD USA Based on November 2014 SEER data sub-mission posted to the SEER web site April 2015 httpseercancergovcsr1975 2012

[2] I K Mellinghoff and C L Sawyers ldquoThe emergence of resis-tance to targeted cancer therapeuticsrdquo Pharmacogenomics vol3 no 5 pp 603ndash623 2002

[3] M EWall andM CWani ldquoCamptothecin and taxol discoveryto clinicmdashthirteenth Bruce F Cain Memorial Award LecturerdquoCancer Research vol 55 no 4 pp 753ndash760 1995

[4] C L Oliver J A Bauer K G Wolter et al ldquoIn vitro effects ofthe BH3mimetic (-)-gossypol on head and neck squamous cellcarcinoma cellsrdquo Clinical Cancer Research vol 10 no 22 pp7757ndash7763 2004

[5] M Zhang H Liu Z Tian B N Griffith M Ji and Q QLi ldquoGossypol induces apoptosis in human PC-3 prostate can-cer cells by modulating caspase-dependent and caspase-inde-pendent cell death pathwaysrdquo Life Sciences vol 80 no 8 pp767ndash774 2007

[6] R M Mohammad S Wang S Banerjee X Wu J Chen andF H Sarkar ldquoNonpeptidic small-molecule inhibitor of Bcl-2andBcl-X119871 (minus)-gossypol enhances biological effect of genisteinagainst BxPC-3 human pancreatic cancer cell linerdquo Pancreasvol 31 no 4 pp 317ndash324 2005

[7] M Zhang H Liu R Guo et al ldquoMolecular mechanism ofgossypol-induced cell growth inhibition and cell death ofHT-29human colon carcinoma cellsrdquo Biochemical Pharmacology vol66 no 1 pp 93ndash103 2003

[8] D W Hahn C Rusticus A Probst R Homm and A NJohnson ldquoAntifertility and endocrine activities of gossypol inrodentsrdquo Contraception vol 24 no 1 pp 97ndash105 1981

[9] J Yang G Chen L L Li et al ldquoSynthesis and anti-H5N1activity of chiral gossypol derivatives and its analogs implicatedby a viral entry blocking mechanismrdquo Bioorganic amp MedicinalChemistry Letters vol 23 no 9 pp 2619ndash2623 2013

[10] J Yang F Zhang J Li et al ldquoSynthesis and antiviral activities ofnovel gossypol derivativesrdquo Bioorganic amp Medicinal ChemistryLetters vol 22 no 3 pp 1415ndash1420 2012

[11] R J Radloff L M Deck R E Royer and D L Vander JagtldquoAntiviral activities of gossypol and its derivatives against her-pes simplex virus type IIrdquo Pharmacological Research Communi-cations vol 18 no 11 pp 1063ndash1073 1986

[12] G Tegos F R Stermitz O Lomovskaya and K Lewis ldquoMul-tidrug pump inhibitors uncover remarkable activity of plantantimicrobialsrdquo Antimicrobial Agents and Chemotherapy vol46 no 10 pp 3133ndash3141 2002

[13] X S Liang A J Rogers C L Webber et al ldquoDeveloping gossy-pol derivatives with enhanced antitumor activityrdquo Investiga-tional New Drugs vol 13 no 3 pp 181ndash186 1995

[14] R E Royer R G Mills L M Deck G J Mertz and D LVander Jagt ldquoInhibition of human immunodeficiency virustype I replication by derivatives of gossypolrdquo PharmacologicalResearch vol 24 no 4 pp 407ndash412 1991

[15] L Tai-Shun R F Schinazi J Zhu et al ldquoAnti-HIV-1 activityand cellular pharmacology of various analogs of gossypolrdquo Bio-chemical Pharmacology vol 46 no 2 pp 251ndash255 1993

[16] Y Lu S Wu Y Yue et al ldquoGossypol with hydrophobic linearesters exhibits enhanced antitumor activity as an inhibitor ofantiapoptotic proteinsrdquoACSMedicinal Chemistry Letters vol 7no 12 pp 1185ndash1190 2016

[17] L Li Z Li K Wang et al ldquoDesign synthesis and biologicalactivities of aromatic gossypol schiff base derivativesrdquo Journalof Agricultural and Food Chemistry vol 62 no 46 pp 11080ndash11088 2014

[18] Z Yonghua C Xu L Yingchao C Xueli and H XiaofengldquoSynthesis and biological evaluation of a novel apogossypolonederivativerdquo Letters in Drug Design amp Discovery vol 14 pp 96ndash101 2017

[19] Y Lu J Li C Dong J Huang H Zhou and W Wang ldquoRecentadvances in gossypol derivatives and analogs a chemistry andbiology viewrdquo Future Medicinal Chemistry vol 9 no 11 pp1243ndash1275 2017

[20] J Qiu L R Levin J Buck and M M Reidenberg ldquoDifferentpathways of cell killing by gossypol enantiomersrdquo ExperimentalBiology and Medicine vol 227 no 6 pp 398ndash401 2002

[21] G Tang C-Y Yang Z Nikolovska-Coleska et al ldquoPyrogallol-based molecules as potent inhibitors of the antiapoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol 50 no 8 pp1723ndash1726 2007

[22] G Wang Z Nikolovska-Coleska C Yang et al ldquoStructure-based design of potent small-molecule inhibitors of anti-apoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol49 no 21 pp 6139ndash6142 2006

[23] H-X Jiang X-X Cao H Huang and B Jiang ldquoAn expedientroute for the practical preparation of optically active (-)-gossypolrdquo Tetrahedron Asymmetry vol 18 no 20 pp 2437ndash2441 2007

[24] P Przybylski K Pyta J Stefanska et al ldquoSynthesis crystalstructures and antibacterial activity studies of aza-derivatives ofphytoalexin from cotton plant - gossypolrdquo European Journal ofMedicinal Chemistry vol 44 no 11 pp 4393ndash4403 2009

[25] K Likhitwitayawuid C K Angerhofer G A Cordell J MPezzuto and N Ruangrungsi ldquoCytotoxic and antimalarial bis-benzylisoquinoline alkaloids from Stephania erectardquo Journal ofNatural Products vol 56 no 1 pp 30ndash38 1993

[26] C Kurekci S L Bishop-Hurley P E Vercoe Z Durmic R AM Al Jassim and C S McSweeney ldquoScreening of Australianplants for antimicrobial activity against Campylobacter jejunirdquoPhytotherapy Research vol 26 no 2 pp 186ndash190 2012

Journal of Chemistry 7

2H) 882 (s 2H) 817 (s 2H) 769 (m 2H) 761ndash756 (m4H) 736ndash732 (m 4H) 391 (m 2H CH(CH3)2) 199 (s 6H2CH3) 148 (t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHzDMSO-d6) 1602 1600 1583 1535 1508 1499 1331 13301328 1303 1287 1279 1247 1225 1224 1188 1163 11611159 1073 560 209 205 HR-ESIMS [M + H]+ found79128920 calculated C44H41F2N4O8 79128925

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(3-fluorobenzohydrazide)(8b) Yield 630 mp 230ndash233∘C 1H NMR (500MHzDMSO-d6) 1469 (s 2H NH) 1243 (s 2H NH) 1020(s 2H) 883 (s 2H) 819 (s 2H) 779 (dd 119869 = 75Hz4H) 763 (s 2H) 758 (m 2H) 746ndash742 (m 2H) 769 (m2H) 761ndash756 (m 4H) 736ndash732 (m 4H) 391 (m 2HCH(CH3)2) 199 (s 6H 2CH3) 148 (t 119869 = 70Hz 12H4CH3)

13C NMR (125MHz DMSO-d6) 1629 1614 16091536 1507 1501 1439 1349 1327 1307 1287 1279 12391189 1187 1162 1146 1144 1073 560 260 204

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(4-fluorobenzohydrazide)(8c) Yield 579 mp 235ndash237∘C 1H NMR (500MHzDMSO-d6) 1476 (s 2H NH) 1239 (s 2H NH) 1019 (s2H) 881 (s 2H) 816 (s 2H) 802 (d 119869 = 80Hz 4H) 763(s 2H) 737 (d 119869 = 80Hz 4H) 392 (m 2H CH(CH3)2)203 (s 6H 2CH3) 150 (t 119869 = 60Hz 12H 4CH3)

13CNMR(125MHz DMSO-d6) 1652 1633 1617 1532 1508 15011439 1327 1304 1291 12864 12773 11887 11615 1159011559 11542 10737 560 260 204

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(3-methylbenzohydrazide)(8d) Yield 578 mp 204ndash206∘C 1H NMR (500MHzDMSO-d6) 1477 (s 2H NH) 1229 (s 2H NH) 1016 (s2H) 881 (s 2H) 880 (s 2H) 812 (s 2H) 775ndash772 (m4H) 762 (s 2H) 740 (m 4H) 391 (m 2H CH(CH3)2)237 (s 6H 2 CH3) 202 (s 6H 2CH3) 147 (t 119869 = 55Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16579 1530715072 15008 13783 13259 13251 12863 12839 1281412765 12480 11884 11618 10739 2660 2091 2056

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(4-methylbenzohydrazide)(8e) Yield 604 mp 213ndash215∘C 1H NMR (500MHzDMSO-d6) 1481 (s 2H NH) 1228 (s 2H NH) 1018 (s2H) 881 (s 2H) 880 (s 2H) 813 (s 2H) 786 (d 119869 = 75Hz2H) 745 (d 119869 = 75Hz 2H) 763 (s 2H) 733 (d 119869 = 80Hz2H) 728 (d 119869 = 70Hz 2H) 392 (m 2H CH(CH3)2) 237(d 119869 = 105Hz 6H 2 CH3) 202 (s 6H 2CH3) 147 (t119869 = 55 Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)16256 15291 15072 15009 14206 14168 13261 1297312941 12902 12897 12766 12716 11881 11616 107412101 2096 2058 HR-ESIMS [M + H]+ found 78333931calculated C46H47N4O8 78333939

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(2-fluorophenyl)acetohy-drazide) (12a) Yield 517 mp 202ndash204∘C 1H NMR(500MHz DMSO-d6) 1526 (s 2H NH) 1289 (s 2H NH)1083 (s 2H) 961 (s 2H) 903 (s 2H) 844 (s 2H) 823 (m2H) 816 (m 2H) 801 (m 4H) 473 (brs 2H CH(CH3)2)448 (s 4H CH2-Ph) 283 (s 6H 2CH3) 231 (t 119869 = 50Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16521 1615515961 15213 15081 14972 14383 13285 13195 1289812765 12429 12253 11863 11602 11515 11498 107253384 2056 2051 HR-ESIMS [M + H]+ found 81932005calculated C46H45F2N4O8 81932055

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(3-fluorophenyl)acetohy-drazide) (12b) Yield 487 mp 188ndash190∘C 1H NMR(500MHz DMSO-d6) 1441 (s 2H NH) 1204 (s 2H NH)996 (s 2H) 876 (s 2H) 817 (s 2H) 759 (s 2H) 737 (m2H) 717 (d 119869 = 75Hz 4H) 708 (m 2H) 390 (brs 2HCH(CH3)2) 362 (s 4H CH2-Ph) 199 (s 6H 2CH3) 148(t 119869 = 70Hz 12H 4CH3)

13C NMR (125MHz DMSO-d6)16560 16301 16107 15221 15077 14973 14384 1382113265 13021 12866 12768 12526 11862 11599 1158111355 10721 4020 2655 2055

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(4-fluorophenyl)acetohy-drazide) (12c) Yield 548 mp 195ndash197∘C 1H NMR(500MHz DMSO-d6) 1442 (s 2H NH) 1200 (s 2H NH)998 (s 2H) 876 (s 2H) 815 (s 2H) 760 (s 2H) 736ndash730(m 4H) 717ndash710 (m 4H) 389 (brs 2H 2H CH(CH3)2)356 (s 4H CH2-Ph) 198 (s 6H 2CH3) 147 (t 119869 = 50Hz12H 4CH3)

13C NMR (125MHz DMSO-d6) 16883 1660316212 16019 15211 15078 14973 14383 13263 1288512763 11862 11600 11511 11497 10722 4020 2650 2051

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(2-chlorophenyl)acetohy-drazide) (12d) Yield 527 mp 206ndash208∘C 1H NMR(500MHz DMSO-d6) 1443 (s 2H NH) 1207 (s 2H NH)999 (s 2H) 878 (s 2H) 819 (s 2H) 761 (s 2H) 744 (m4H) 731 (m 4H) 391 (brs 2H 2H CH(CH3)2) 376 (s 4HCH2-Ph) 200 (s 6H 2CH3) 148 (t 119869 = 55Hz 12H 4CH3)13C NMR (125MHz DMSO-d6) 16507 15203 1507914971 14385 13355 13341 13264 13243 13215 1290412891 12868 12763 12710 11862 11602 10725 3831 2055205

N1015840N101584010158401015840-((1Z11015840Z)-((R)-111015840661015840-Tetrahydroxy-551015840-diisopropyl-331015840-dimethyl-771015840-dioxo-[221015840-binaphthalene]-881015840(7H71015840H)-diylidene)bis(methanylylidene))bis(2-(3-chlorophenyl)acetohy-drazide) (12e) Yield 530 mp 194ndash196∘C 1H NMR(500MHz DMSO-d6) 1439 (s 2H NH) 1204 (s 2H NH)997 (s 2H) 877 (s 2H) 819 (s 2H) 760 (s 2H) 739ndash728(m 8H) 389 (brs 2H 2H CH(CH3)2) 360 (s 4H CH2-Ph)

8 Journal of Chemistry

199 (s 6H 2CH3) 147 (t 119869 = 55Hz 12H 4CH3)13C NMR

(125MHz DMSO-d6) 16558 15224 15077 14972 1438213789 13286 13015 12898 12865 12787 12769 1266511863 11600 10721 401 2055 2050 HR-ESIMS [M + H]+found 85126141 calculated C46H45Cl2N4O8 85126144

Conflicts of Interest

The authors confirm that there are no conflicts of interestrelated to the contents of this article

Acknowledgments

The authors acknowledge the financial support via Project082015HETH-NETHT

References

[1] N Howlader A M Noone M Krapcho et al SEER CancerStatistics Review 1975ndash2012 National Cancer InstituteBethesda MD USA Based on November 2014 SEER data sub-mission posted to the SEER web site April 2015 httpseercancergovcsr1975 2012

[2] I K Mellinghoff and C L Sawyers ldquoThe emergence of resis-tance to targeted cancer therapeuticsrdquo Pharmacogenomics vol3 no 5 pp 603ndash623 2002

[3] M EWall andM CWani ldquoCamptothecin and taxol discoveryto clinicmdashthirteenth Bruce F Cain Memorial Award LecturerdquoCancer Research vol 55 no 4 pp 753ndash760 1995

[4] C L Oliver J A Bauer K G Wolter et al ldquoIn vitro effects ofthe BH3mimetic (-)-gossypol on head and neck squamous cellcarcinoma cellsrdquo Clinical Cancer Research vol 10 no 22 pp7757ndash7763 2004

[5] M Zhang H Liu Z Tian B N Griffith M Ji and Q QLi ldquoGossypol induces apoptosis in human PC-3 prostate can-cer cells by modulating caspase-dependent and caspase-inde-pendent cell death pathwaysrdquo Life Sciences vol 80 no 8 pp767ndash774 2007

[6] R M Mohammad S Wang S Banerjee X Wu J Chen andF H Sarkar ldquoNonpeptidic small-molecule inhibitor of Bcl-2andBcl-X119871 (minus)-gossypol enhances biological effect of genisteinagainst BxPC-3 human pancreatic cancer cell linerdquo Pancreasvol 31 no 4 pp 317ndash324 2005

[7] M Zhang H Liu R Guo et al ldquoMolecular mechanism ofgossypol-induced cell growth inhibition and cell death ofHT-29human colon carcinoma cellsrdquo Biochemical Pharmacology vol66 no 1 pp 93ndash103 2003

[8] D W Hahn C Rusticus A Probst R Homm and A NJohnson ldquoAntifertility and endocrine activities of gossypol inrodentsrdquo Contraception vol 24 no 1 pp 97ndash105 1981

[9] J Yang G Chen L L Li et al ldquoSynthesis and anti-H5N1activity of chiral gossypol derivatives and its analogs implicatedby a viral entry blocking mechanismrdquo Bioorganic amp MedicinalChemistry Letters vol 23 no 9 pp 2619ndash2623 2013

[10] J Yang F Zhang J Li et al ldquoSynthesis and antiviral activities ofnovel gossypol derivativesrdquo Bioorganic amp Medicinal ChemistryLetters vol 22 no 3 pp 1415ndash1420 2012

[11] R J Radloff L M Deck R E Royer and D L Vander JagtldquoAntiviral activities of gossypol and its derivatives against her-pes simplex virus type IIrdquo Pharmacological Research Communi-cations vol 18 no 11 pp 1063ndash1073 1986

[12] G Tegos F R Stermitz O Lomovskaya and K Lewis ldquoMul-tidrug pump inhibitors uncover remarkable activity of plantantimicrobialsrdquo Antimicrobial Agents and Chemotherapy vol46 no 10 pp 3133ndash3141 2002

[13] X S Liang A J Rogers C L Webber et al ldquoDeveloping gossy-pol derivatives with enhanced antitumor activityrdquo Investiga-tional New Drugs vol 13 no 3 pp 181ndash186 1995

[14] R E Royer R G Mills L M Deck G J Mertz and D LVander Jagt ldquoInhibition of human immunodeficiency virustype I replication by derivatives of gossypolrdquo PharmacologicalResearch vol 24 no 4 pp 407ndash412 1991

[15] L Tai-Shun R F Schinazi J Zhu et al ldquoAnti-HIV-1 activityand cellular pharmacology of various analogs of gossypolrdquo Bio-chemical Pharmacology vol 46 no 2 pp 251ndash255 1993

[16] Y Lu S Wu Y Yue et al ldquoGossypol with hydrophobic linearesters exhibits enhanced antitumor activity as an inhibitor ofantiapoptotic proteinsrdquoACSMedicinal Chemistry Letters vol 7no 12 pp 1185ndash1190 2016

[17] L Li Z Li K Wang et al ldquoDesign synthesis and biologicalactivities of aromatic gossypol schiff base derivativesrdquo Journalof Agricultural and Food Chemistry vol 62 no 46 pp 11080ndash11088 2014

[18] Z Yonghua C Xu L Yingchao C Xueli and H XiaofengldquoSynthesis and biological evaluation of a novel apogossypolonederivativerdquo Letters in Drug Design amp Discovery vol 14 pp 96ndash101 2017

[19] Y Lu J Li C Dong J Huang H Zhou and W Wang ldquoRecentadvances in gossypol derivatives and analogs a chemistry andbiology viewrdquo Future Medicinal Chemistry vol 9 no 11 pp1243ndash1275 2017

[20] J Qiu L R Levin J Buck and M M Reidenberg ldquoDifferentpathways of cell killing by gossypol enantiomersrdquo ExperimentalBiology and Medicine vol 227 no 6 pp 398ndash401 2002

[21] G Tang C-Y Yang Z Nikolovska-Coleska et al ldquoPyrogallol-based molecules as potent inhibitors of the antiapoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol 50 no 8 pp1723ndash1726 2007

[22] G Wang Z Nikolovska-Coleska C Yang et al ldquoStructure-based design of potent small-molecule inhibitors of anti-apoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol49 no 21 pp 6139ndash6142 2006

[23] H-X Jiang X-X Cao H Huang and B Jiang ldquoAn expedientroute for the practical preparation of optically active (-)-gossypolrdquo Tetrahedron Asymmetry vol 18 no 20 pp 2437ndash2441 2007

[24] P Przybylski K Pyta J Stefanska et al ldquoSynthesis crystalstructures and antibacterial activity studies of aza-derivatives ofphytoalexin from cotton plant - gossypolrdquo European Journal ofMedicinal Chemistry vol 44 no 11 pp 4393ndash4403 2009

[25] K Likhitwitayawuid C K Angerhofer G A Cordell J MPezzuto and N Ruangrungsi ldquoCytotoxic and antimalarial bis-benzylisoquinoline alkaloids from Stephania erectardquo Journal ofNatural Products vol 56 no 1 pp 30ndash38 1993

[26] C Kurekci S L Bishop-Hurley P E Vercoe Z Durmic R AM Al Jassim and C S McSweeney ldquoScreening of Australianplants for antimicrobial activity against Campylobacter jejunirdquoPhytotherapy Research vol 26 no 2 pp 186ndash190 2012

8 Journal of Chemistry

199 (s 6H 2CH3) 147 (t 119869 = 55Hz 12H 4CH3)13C NMR

(125MHz DMSO-d6) 16558 15224 15077 14972 1438213789 13286 13015 12898 12865 12787 12769 1266511863 11600 10721 401 2055 2050 HR-ESIMS [M + H]+found 85126141 calculated C46H45Cl2N4O8 85126144

Conflicts of Interest

The authors confirm that there are no conflicts of interestrelated to the contents of this article

Acknowledgments

The authors acknowledge the financial support via Project082015HETH-NETHT

References

[1] N Howlader A M Noone M Krapcho et al SEER CancerStatistics Review 1975ndash2012 National Cancer InstituteBethesda MD USA Based on November 2014 SEER data sub-mission posted to the SEER web site April 2015 httpseercancergovcsr1975 2012

[2] I K Mellinghoff and C L Sawyers ldquoThe emergence of resis-tance to targeted cancer therapeuticsrdquo Pharmacogenomics vol3 no 5 pp 603ndash623 2002

[3] M EWall andM CWani ldquoCamptothecin and taxol discoveryto clinicmdashthirteenth Bruce F Cain Memorial Award LecturerdquoCancer Research vol 55 no 4 pp 753ndash760 1995

[4] C L Oliver J A Bauer K G Wolter et al ldquoIn vitro effects ofthe BH3mimetic (-)-gossypol on head and neck squamous cellcarcinoma cellsrdquo Clinical Cancer Research vol 10 no 22 pp7757ndash7763 2004

[5] M Zhang H Liu Z Tian B N Griffith M Ji and Q QLi ldquoGossypol induces apoptosis in human PC-3 prostate can-cer cells by modulating caspase-dependent and caspase-inde-pendent cell death pathwaysrdquo Life Sciences vol 80 no 8 pp767ndash774 2007

[6] R M Mohammad S Wang S Banerjee X Wu J Chen andF H Sarkar ldquoNonpeptidic small-molecule inhibitor of Bcl-2andBcl-X119871 (minus)-gossypol enhances biological effect of genisteinagainst BxPC-3 human pancreatic cancer cell linerdquo Pancreasvol 31 no 4 pp 317ndash324 2005

[7] M Zhang H Liu R Guo et al ldquoMolecular mechanism ofgossypol-induced cell growth inhibition and cell death ofHT-29human colon carcinoma cellsrdquo Biochemical Pharmacology vol66 no 1 pp 93ndash103 2003

[8] D W Hahn C Rusticus A Probst R Homm and A NJohnson ldquoAntifertility and endocrine activities of gossypol inrodentsrdquo Contraception vol 24 no 1 pp 97ndash105 1981

[9] J Yang G Chen L L Li et al ldquoSynthesis and anti-H5N1activity of chiral gossypol derivatives and its analogs implicatedby a viral entry blocking mechanismrdquo Bioorganic amp MedicinalChemistry Letters vol 23 no 9 pp 2619ndash2623 2013

[10] J Yang F Zhang J Li et al ldquoSynthesis and antiviral activities ofnovel gossypol derivativesrdquo Bioorganic amp Medicinal ChemistryLetters vol 22 no 3 pp 1415ndash1420 2012

[11] R J Radloff L M Deck R E Royer and D L Vander JagtldquoAntiviral activities of gossypol and its derivatives against her-pes simplex virus type IIrdquo Pharmacological Research Communi-cations vol 18 no 11 pp 1063ndash1073 1986

[12] G Tegos F R Stermitz O Lomovskaya and K Lewis ldquoMul-tidrug pump inhibitors uncover remarkable activity of plantantimicrobialsrdquo Antimicrobial Agents and Chemotherapy vol46 no 10 pp 3133ndash3141 2002

[13] X S Liang A J Rogers C L Webber et al ldquoDeveloping gossy-pol derivatives with enhanced antitumor activityrdquo Investiga-tional New Drugs vol 13 no 3 pp 181ndash186 1995

[14] R E Royer R G Mills L M Deck G J Mertz and D LVander Jagt ldquoInhibition of human immunodeficiency virustype I replication by derivatives of gossypolrdquo PharmacologicalResearch vol 24 no 4 pp 407ndash412 1991

[15] L Tai-Shun R F Schinazi J Zhu et al ldquoAnti-HIV-1 activityand cellular pharmacology of various analogs of gossypolrdquo Bio-chemical Pharmacology vol 46 no 2 pp 251ndash255 1993

[16] Y Lu S Wu Y Yue et al ldquoGossypol with hydrophobic linearesters exhibits enhanced antitumor activity as an inhibitor ofantiapoptotic proteinsrdquoACSMedicinal Chemistry Letters vol 7no 12 pp 1185ndash1190 2016

[17] L Li Z Li K Wang et al ldquoDesign synthesis and biologicalactivities of aromatic gossypol schiff base derivativesrdquo Journalof Agricultural and Food Chemistry vol 62 no 46 pp 11080ndash11088 2014

[18] Z Yonghua C Xu L Yingchao C Xueli and H XiaofengldquoSynthesis and biological evaluation of a novel apogossypolonederivativerdquo Letters in Drug Design amp Discovery vol 14 pp 96ndash101 2017

[19] Y Lu J Li C Dong J Huang H Zhou and W Wang ldquoRecentadvances in gossypol derivatives and analogs a chemistry andbiology viewrdquo Future Medicinal Chemistry vol 9 no 11 pp1243ndash1275 2017

[20] J Qiu L R Levin J Buck and M M Reidenberg ldquoDifferentpathways of cell killing by gossypol enantiomersrdquo ExperimentalBiology and Medicine vol 227 no 6 pp 398ndash401 2002

[21] G Tang C-Y Yang Z Nikolovska-Coleska et al ldquoPyrogallol-based molecules as potent inhibitors of the antiapoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol 50 no 8 pp1723ndash1726 2007

[22] G Wang Z Nikolovska-Coleska C Yang et al ldquoStructure-based design of potent small-molecule inhibitors of anti-apoptotic Bcl-2 proteinsrdquo Journal of Medicinal Chemistry vol49 no 21 pp 6139ndash6142 2006

[23] H-X Jiang X-X Cao H Huang and B Jiang ldquoAn expedientroute for the practical preparation of optically active (-)-gossypolrdquo Tetrahedron Asymmetry vol 18 no 20 pp 2437ndash2441 2007

[24] P Przybylski K Pyta J Stefanska et al ldquoSynthesis crystalstructures and antibacterial activity studies of aza-derivatives ofphytoalexin from cotton plant - gossypolrdquo European Journal ofMedicinal Chemistry vol 44 no 11 pp 4393ndash4403 2009

[25] K Likhitwitayawuid C K Angerhofer G A Cordell J MPezzuto and N Ruangrungsi ldquoCytotoxic and antimalarial bis-benzylisoquinoline alkaloids from Stephania erectardquo Journal ofNatural Products vol 56 no 1 pp 30ndash38 1993

[26] C Kurekci S L Bishop-Hurley P E Vercoe Z Durmic R AM Al Jassim and C S McSweeney ldquoScreening of Australianplants for antimicrobial activity against Campylobacter jejunirdquoPhytotherapy Research vol 26 no 2 pp 186ndash190 2012

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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