Research ArticleDesign, Synthesis, and Biological Evaluation of Triazolyl- andTriazinyl-Quinazolinediones as Potential Antitumor Agents

Abeer N. Al-Romaizan,1 Nesreen S. Ahmed ,1,2 and Sherin M. Elfeky1,3

1Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia2Department of %erapeutic Chemistry, Pharmaceutical, and Drug Industries Research Division, National Research Center,El Buhouth Street, Dokki, Cairo 12622, Egypt3Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 355516, Egypt

Correspondence should be addressed to Nesreen S. Ahmed; nesreen69eg@yahoo.com

Received 22 October 2018; Revised 12 December 2018; Accepted 25 December 2018; Published 3 February 2019

Academic Editor: Zhong-Wen Liu

Copyright © 2019 Abeer N. Al-Romaizan et al.-is is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work isproperly cited.

Novel 6(3-1H-1,2,4-triazol-1-yl)-3-phenylquinazoline-2,4(1H,3H)-diones (7a–e) were synthesized from different enaminones(6a–e) with 6-hydrazinyl-3-phenylquinazoline-2,4(1H,3H)-dione. 2,6(4-2-Substituted-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-diones (8a–k) were synthesized from the reaction of 1-(2,4-dioxo-3-phenyl-1,2,3,4-tetrahydroquinazolin-6-yl)thiourea,urea, or guanidine (3a–c) with enaminones (6a–e), and a series from 3-substituted-2-imino-1,3,5-triazin-1(2H)-yl-sulfonyl-phenyl-1-methylquinazoline-2,4(1H,3H)-dione (12a–j) were obtained from the reaction of N-(diaminomethylene)-4-(1-methyl-2,4-dioxo-1,2-dihydroquinazolin-3(4H)-yl)benzenesulfonamide (11) with the enaminone (6a–j). -e antitumor activity of the synthesizedcompounds was evaluated against two human cell lines: human colon carcinoma HCT116 and human hepatocellular carcinomaHEP-G2. Some of the tested compounds showed significant potency compared to the reference drug staurosporin.

1. Introduction

Quinazolines are such interesting scaffolds that cover a widerange of biological activity depending on the nature andposition of substituents and are reported to act as an an-tidepressant, antipsychotic, sedative, analgesic, antibacterial,anti-inflammatory, and others [1]. -ere are different classesof quinazolinones depending on the position of substituents:2-substituted-4(3H)-quinazolinones, 3-substituted-4(3H)-quinazolinones, 4-substituted quinazolinones, 2,3-disubstituted-4(3H)-quinazolinones, and 2,4-disubstituted-4(3H)-quinazolinones. Depending on the position of theoxo group, these quinazolinones can be further classifiedinto three main groups: 2(1H)-quinazolinones, 4(3H)-quinazolinones, and 2,4(1H,3H)-quinazolinones. -eydiffer in their synthetic approaches and in their startingmaterials [2]. Quinazolinones were reported to act as an-titumor agents through different mechanisms. Methoxylated-2-benzyl thioquinazoline-4(3H) ones were reported to act as

antitumor agents through targeting dihydrofolate reductaseenzyme (DHFR) [3]. A series of 2[(3-substituted-4(3H)-quinazoline-2-yl-thio]N-(3,4,5)trimethoxy phenyl)acetamideswere reported to act as antitumor agents against a numberof cancer cell lines [4]. Also a series of 6-methyl-2-thioxoquinazoline-4(1H)-ones were reported to act as anti-tumor candidates through targeting and inhibiting the epi-dermal growth factor receptor (EGFR) [5]. EGFR is atransmembrane protein that is closely related to the receptortyrosine kinase. Both play a significant role in cell pro-liferation differentiation, survival, and metabolism. Over-expression of EGFR is associated with the development ofvarious tumors where 30% of breast cancer was reported tohave a correlation with overexpression of the growth factorreceptor ErbB2. Blocking EGFR binding site would thusprevent EGFR expressing tumors [6, 7]. Erlotinib is an an-titumor agent that is used for nonsmall cell lung cancer andpancreatic cancer, and it is reported that it acts through theinhibition of EGFR [8]. Gefitinib is a marketed antitumor

HindawiJournal of ChemistryVolume 2019, Article ID 9104653, 12 pageshttps://doi.org/10.1155/2019/9104653

agent that acts through inhibiting EGFR as well [9]. Botherlotinib and gefitinib (Figure 1) belong to a class of EGFRinhibitors that are 4-anilinoquinazolines [10]. Another class ofreported EGFR inhibitors is 2-styryl-4aminoquinazolines (SQ-I) (Figure 1). -is class was reported to show potent in vitroantiproliferative activity against different cell lines compared togefitinib [11]. In the present work, new compounds ofquinazoline-2,4(1H,3H)-diones were designed through in-troducing substituted N-containing ring systems: triazole or 2-oxo-, 2-thia-, 2-imino-triazine moieties at C6, or introductionof 2- imino-triazine through a phenyl sulfonyl linker at N3 ofthe quinazolinone ring (Figure 2).-e antitumor activity of thenew derivatives was evaluated via the MTT assay.

2. Experimental

2.1. Chemistry. Melting points were recorded using Stuartmelting apparatus. IR spectra (KBr) were recorded on anFT-IR spectrometer (]max/cm−1). Nuclear magnetic reso-nance (1H NMR and 13C NMR) spectra were recorded onBruker 400MHz and 300MHz spectrometer using DMSO-d6 or CDCl3 as solvents; the chemical shifts are expressedin δ ppm using TMS as an internal standard. Mass spectrawere recorded on Shimadzu QP-GC/MS mass spectrom-eters at the microanalytical unit of Faculty of Science ofCairo University. Elemental microanalyses were carriedout, and the results were within ±0.3 from the theoreticalvalues. Solvent evaporation was performed under reducedpressure using Buchi R-3000 Rotacool Rotary Evaporator,and thin layer chromatography was performed on pre-coated (0.25mm) silica gel GF254 plates (E. Merck, Ger-many); compounds were detected with 254 nm UV lamp.All chemicals and starting materials were commercialchemicals obtained from Sigma-Aldrich.

2.1.1. Synthesis of 6(3-1H-1,2,4-Triazol-1-yl)-3-phenylquinazoline-2,4(1H,3H)-diones and 6(4-2-Substituted-1,3,5-Triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-diones

(1) Synthesis of 6-Bromo-3-phenylquinazoline-2,4(1H,3H)-dione (1). 5-Bromoisatoic anhydride (1mmol) reactedwith aniline (1mmol) in ethanol (20ml) in presence of fewdrops of acetic acid under ultrasonic irradiation at 80°C for25min to afford only one isolable product examined by TLC.-e solution was concentrated under suction poured oncrushed ice, filtered off, and recrystallized from aqueousethanol to obtain the desired product in yields of 95%(254–255°C [12], m.p. 249–252°C).

(2) Synthesis of 6-Hydrazinyl-3-phenylquinazoline-2,4(1H,3H)-dione (2). 6-Bromo-3-phenylquinazoline-2,4(1H,3H)-dione(1) (1mmol) was allowed to reflux in neat hydrazine hydrate(10ml) for 12 hours, and the reaction was monitored withTLC. -e solution was poured on ice and allowed to stir tillthe hydrazide accumulated and then was filtered off andrecrystallized from aqueous ethanol. Yield: 88%, m.p.:150–152°C, and IR (]max/cm−1) 1659 and 1639 (2C�O),3470, 3389, and 3373 (NH, NH2); 1H NMR (DMSO-d6): δ

8.53 (s, 1H, C5-H), 7.80 (d, 1H, C8-H), 7.72 (d, 1H, C7-H),7.27 (m, 4H, Ar-H), 7.21 (m, 1H, Ar-H), 6.51 (s, 1H, -NH),and 3.48 (m, 3H, -NHNH2).

(3) General Procedure for Synthesis of 3a–c. 6-Bromo-3-phenylquinazoline-2,4(1H,3H)-dione (1) (1mmol) wasallowed to reflux with urea, thiourea, or guanidine (1mmol)in ethanol (20ml) for 12 hours. -e reaction was monitoredby TLC until no starting materials were present. -e pre-cipitate formed on cooling was filtered off and recrystallizedfrom aqueous ethanol in yields of 90–92%. -e followingcompounds were prepared:

1-(2,4-Dioxo-3-phenyl-1,2,3,4-tetrahydroquinazolin-6-yl)urea (3a). Yield 92% and m.p.:130–132°C; 1H NMR(DMSO-d6): δ 9.24 (s, 1H, NH), 8.10 (s, 1H, C5-H), 7.82(m, 4H,Ar-H), 7.74 (d, 1H, C8-H), 7.24 (d, 1H,C7-H), 6.65(m, 1H, Ar-H), 5.52 (s, 1H, N1-H), and 3.67 (s, 2H, NH2)1-(2,4-Dioxo-3-phenyl-1,2,3,4-tetrahydroquinazolin-6-yl)thiourea ( 3b ). Yield 91% and m.p.: 173–175°C; 1HNMR (DMSO-d6): δ 8.75 (s, 1H, NH), 8.53 (s, 1H,C5-H), 7.81 (d, 1H, C8-H), 7.73 (d, 1H, C7-H), 7.22 (m,2H, Ar-H), 7.14 (m, 2H, Ar-H), 7.11 (s, 1H, Ar-H), 6.96(s, 1H, N1-H), and 4.06 (s, 2H, NH2)1-(2,4-Dioxo-3-phenyl-1,2,3,4-tetrahydroquinazolin-6-yl)guanidine ( 3c ). Yield 90%, m.p.: 160–162°C, and IR(]max/cm−1) 1718 and 1679 (C�O), 3423, 3393 and 3383(NH, NH2); 1H NMR (DMSO-d6): δ 8.61 (s, 1H, NH),8.40 (s, 1H, C5-H), 8.04 (d, 1H, C8-H), 7.86 (d, 1H, C7-H), 7.52 (m, 3H, Ar-H), 7.45 (m, 1H, Ar-H), 7.00 (s, 1H,N1-H), 5.35 (s, 2H, NH2), and 4.04 (s, 1H, NH)

(4) General Procedure for Synthesis of 6a–e. Substitutedacetophenones or 2-acetyl thiophene (furan) (1mmol) wererefluxed with DMF-DMA (1.2mmol) for 8–12 hours inethanol (20ml). -e reaction was monitored with TLC till nostarting materials were detectable. -e corresponding enami-nones derivatives were afforded in yields of 92–97%. -e so-lutions were evaporated under suction. -e precipitates werecollected and recrystallized from aqueous ethanol.-e followingcompounds were prepared:

(E)-3-(Dimethylamino)-1-(furan-2-yl)prop-2-en-1-one( 6a ). 92°C [13], yield: 93%, and m.p.: 95–97°C(E)-3-(Dimethylamino)-1-(thiophen-2-yl)prop-2-en-1-one ( 6b ). 147–149°C [14], yield 92%, and m.p.:140–141°C(E)-3-(Dimethylamino)-1-phenylprop-2-en-1-one ( 6c ).92°C [15], yield 95%, and m.p.: 93–95°C(E)-3-(Dimethylamino)-1-(4-nitrophenyl)prop-2-en-1-one ( 6d ). 139–141°C [16], yield: 96%, and m.p.:151–153°C(E)-3-(Dimethylamino)-1-(4-fluorophenyl)prop-2-en-1-one ( 6e ). 94–96°C [16], yield: 97%, andm.p.: 100–101°C

(5) General Procedure for Synthesis of 7a–e. Enaminones(6a–e) (1mmol) and 6-hydrazinyl-3-phenylquinazoline-

2 Journal of Chemistry

2,4(1H,3H)-dione (2) (1mmol) were re uxed together inethanol (20ml) for 24 hours. �e reaction was monitoredusing TLC till termination. �e solutions were dried undersuction, and the obtained precipitates were recrystallizedfrom petroleum ether in yields of 93–96%. �e followingcompounds were prepared:

6-(3-(Furan-2-yl)-1H-1,2,4-triazol-1-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 7a ).Yield: 95%,m.p.: 154–156°C, and IR(]max/cm−1) 1707 and 1638 (2C�O), 3383 (NH); 1HNMR (DMSO-d6): δ 10.07 (s, 1H, C-H trizole), 7.70 (m,3H, C-H quinazoline), 7.30–7.11 (m, 6H, Ar-H), 6.79 (m,2H, Ar-H), and 6.43 (s, 1H, N-H quinazoline). Ms: [M+

371] consistent with themolecular formula C20H13N5O3.

3-Phenyl-6-(3-(thiophen-2-yl)-1H-1,2,4-triazol-1-yl)quinazoline-2,4(1H,3H)-dione ( 7b ). Yield: 94%, m.p.:160–162°C, and IR (]max/cm−1) 1702 and 1637(2C�O), 3375 (NH); 1H NMR (DMSO-d6): δ 10.00(s, 1H, C-H trizole), 7.70 (d, 3H, C-H quinazoline),7.01–7.33 (m, 6H, Ar-H), 6.79 (m, 2H, Ar-H), and6.43 (s, 1H, N-H quinazoline).3-Phenyl-6-(3-phenyl-1H-1,2,4-triazol-1-yl)quinazoline-2,4(1H,3H)-dione ( 7c ). Yield: 93%, m.p.: 80–82°C, andIR (]max/cm−1) 1712 and 1660 (2C�O), 3492 (NH); 1HNMR (CDCl3): δ 9.88 (s, 1H, C-H trizole), 8.40 (s, 1H,C5-H), 7.85 (d, 1H, J� 8.0Hz, C8-H), 7.64 (d, 1H,J� 8.1Hz, C7-H), 7.62–7.26 (m, 10 H, Ar-H), and 6.38

N

N

HN

O

O

O

O

(a)

N

N

HN Cl

F

O

O

N

O

(b)

N

HNN

O

Cl

(c)

Figure 1: Di�erent EGFR inhibitors: (a) erlotinib; (b) ge¡tinib; (c) SQ-I.

N

N

O

O

R1

R2R3

R1 = H, CH3

R2 =S

N N

NHN

O

O,

R3 = H

NN

N

N N

N X

X = O, S, N

Figure 2: Design of new quinazolinones as antitumor agents.

Journal of Chemistry 3

(s, 1H, N-H quinazoline); 13C NMR (CDCl3): δ 128.2,128.3, 128.4, 128.5, 128.6, 128.7, 129.5, 129.7, 129.9,130.1, 133.1, 133.3, 133.5, 134.1, 136.4, 138.2, 146.2,146.4, 150.0, 152.7, 161.0, and 161.2.6-(3-(4-Nitrophenyl)-1H-1,2,4-triazol-1-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 7d ).Yield: 96%,m.p.:177–179°C, and IR(]max/cm−1) 1706 and 1677 (2C�O), 3430 (NH); 1H NMR(CDCl3): δ 9.80 (s, 1H, C-H triazole), 8.33–8.10 (m, 3H, C-Hquinazoline), 8.12 (d, 2H, Ar-H), 7.75 (d, 3H, Ar-H), 7.41 (m,4H, Ar-H), and 6.38 (s, 1H, N-H quinaozline);13C NMR(CDCl3): δ 115.7, 122.6, 123.4, 124.8, 126.5, 126.9, 127.8, 129.28,129.3, 129.4, 129.7, 132.3, 133.6, 135.0, 137.2, 140.2, 146.2,146.4,149.5, 159.7, 161.1, and 162.1.6-(3-(4-Fluorophenyl)-1H-1,2,4-triazol-1-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 7e ).Yield: 96%, m.p.: 110–112°C, and IR(]max/cm−1) 1701 and 1675 (2C�O), 3433 (NH); 1H NMR(CDCl3): δ 9.96 (s,1H, C-H triazole), 8.12 (s, 1H, C5-H),7.74 (d, 1H, J� 8.3Hz, C8-H), 7.56 (d, 1H, J� 8.3Hz, C7-H), 7.52–7.42 (m, 6H, Ar-H), 7.41–7.14 (m, 3H, Ar-H),and 6.40 (s, 1H, N-H quinazoline); 13C NMR (CDCl3):δ 115.2, 117.9, 123.4, 124.4, 126.5, 126.9, 128.5, 129.3,129.7, 131.3, 132.1, 133.9, 133.9, 134.7, 137.1, 138.2,139.0, 140.0, 146.8, 159.7, 161.2, 162.6, and 171.2.

(6) General Procedure for Synthesis of 8a–k. Enaminones(6a–e) (1 mmol) and 1-(2,4-dioxo-3-phenyl-1,2,3,4-tetrahydroquinazolin-6-yl)thiourea, urea, or guanidine (3a–c) (1mmol) were refluxed in ethanol (20ml) for 24 hours.-ereaction was monitored using TLC till termination. -e so-lutions were dried under suction. -e obtained precipitateswere recrystallized from petroleum ether to obtain productsin yields of 92–97%. -e following compounds wereprepared:

6-(4-(Furan-2-yl)-2-oxo-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 8a ). Yield: 92%,m.p.: 83–85°C, and IR (]max/cm−1) 1707, 1688 and1631 (3C�O), 3432 (NH); 1H NMR (CDCl3): δ 9.40(s, 1H, C-H triazine), 8.09 (s, 1H, C5-H), 7.82 (d, 1H,J� 8.3Hz, C8-H), 7.72 (d, 1H, J� 8.3Hz, C7-H), 7.70–7.34 (m, 5H, Ar-H), 6.99 (s, 1H, N-H quinazoline), and6.64–6.59 (m, 3H, Ar-H); 13C NMR (CDCl3): δ 108.7,111.2, 112.6, 117.7, 120.7, 122.0, 124.8, 126.7, 129.5,130.4, 131.9, 132.8, 136.4, 137.7, 144.6, 147.1, 151.2,153.3, 157.9, 162.8, and 164.5.6-(2-Oxo-4-(thiophen-2-yl)-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 8b ). Yield: 93%,m.p.: 96–98°C, and IR (]max/cm−1) 1711, 1682 and1642 (3C�O), 3454 (NH); 1H NMR (CDCl3): δ 9.06 (s,1H, C-H triazine), 8.53 (s, 1H, C5-H), 8.20 (d, 1H,J � 8, C8-H), 7.79 (d, 1H, J � 8.2 Hz., C7-H), 7.77–7.50(m, 8H, Ar-H), and 6.77 (s, 1H, N-H quinazoline);13C NMR (CDCl3): δ 118.3, 126.4, 128.2, 128.4, 129.6,131.5, 132.5, 134.7, 134.8, 135.3, 135.4, 137.5, 138.9,142.6, 143.2, 143.7, 150.3, 154.1, 155.4, 167.0, and169.8.

6-(2-Oxo-4-phenyl-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 8c ). Yield: 92%, m.p.: 80–82°C, and IR(]max/cm−1)1723, 1656 and 1630 (3C�O), 3431 (NH); 1HNMR (CDCl3): δ 9.08 (s, 1H, C-H triazine), 8.53 (s, 1H,C5-H),7.87 (d, 1H, J� 8.4Hz, C8-H), 7.72 (d, 1H, 8.4Hz.,C7-H),7.71 (m, 2H, Ar-H), 7.65–7.61 (m, 3H, Ar-H),7.60–7.20 (m, 5H, Ar-H), and 6.19 (s, 1H, N-H qui-nazoline); 13CNMR (CDCl3): δ 119.9, 124.3,127.3, 127.7,128.6, 128.9, 129.5, 129.9, 131.3, 132.4, 132.9, 134.0,134.3, 135.3, 137.0, 138.1, 142.0, 142.8, 151.2, 157.2,157.4, 160.5, and 162.4.6-(4-(4-Nitrophenyl)-2-oxo-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 8d ). Yield:95%, m.p.: 168–170°C, and IR (]max/cm−1) 1723, 1657and 1637, (3C�O), 3431 (NH); 1H NMR (CDCl3): δ 9.11(s, 1H, C-H triazine), 8.47–8.00 (m, 7H, Ar-H), 7.83–7.76 (m, 4H, Ar-H), 7.17 (m, 1H, Ar-H), and 6.99 (s, 1H,N-H quinazoline); 13C NMR (CDCl3): δ 118.8, 120.3,120.9, 123.5, 123.9, 124.0, 124.2, 128.3, 130.2, 130.6,130.7, 134.0, 135.9, 137.4, 138.6, 139.8, 140.8, 150.5,151.3, 153.9, 156.4, 158.4, and 164.7.6-(4-(4-Fluorophenyl)-2-oxo-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 8e ). Yield: 96%,m.p.: 115–117°C, and IR (]max/cm−1) 1722, 1682 and1642 (3C�O), 3441 (NH); 1H NMR (CDCl3): δ 9.02 (s,1H, C-H triazine), 8.33–7.90 (m, 4H, Ar-H), 7.89 (d,1H, J� 8.5Hz., C8-H), 7.83 (d, 1H, J� 8.5Hz., C7-H),7.80–7.23 (m,6H, Ar-H), and 6.85 (s, 1H, N-H qui-nazoline); 13C NMR (CDCl3): δ 115.7, 115.9, 115.9,116.1, 119.6, 129.2, 129.3, 130.0, 130.3, 130.8, 131.1,132.5, 132.6, 132.8, 133.3, 133.7, 134.3, 138.2, 138.3,151.0, 159.3, 164.4, 165.5, and 171.2.6-(4-(Furan-2-yl)-2-thioxo-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 8f ). Yield: 94%,m.p.: 146–148°C, and IR (]max/cm−1) 1732 and 1629(2C�O), 3436 (NH); 1H NMR (CDCl3): δ 8.81 (s, 1H,C-H triazine), 8.09 (s, 1H, C5-H), 7.92–7.42 (m, 6H,Ar-H), 7.23 (m, 1H, Ar-H), 6.95–6.89 (m, 3H, Ar-H),and 6.66 (s, 1H, N-H quinazoline); 13C NMR(CDCl3): δ 111.7, 113.0, 116.0, 119.0, 121.1, 123.3,124.6, 126.1, 127.1, 128.2, 129.5, 134.2, 138.1, 141.1,142.6, 146.7, 149.5, 150.3, 164.3, 165.6, and 180.8. Ms:[M+ 415]. Consistent with the molecular formulaC21H13N5O3S.3-Phenyl-6-(4-(thiophen-2-yl)-2-thioxo-1,3,5-triazin-1(2H)-yl)quinazoline-2,4(1H,3H)-dione ( 8g ). Yield: 93%, m.p.:111–113°C, and IR (]max/cm−1) 1721 and 1641 (2C�O),3431 (NH); 1HNMR (CDCl3): δ 9.02 (s, 1H, C-H triazine),8.53–7.72 (m, 7H, Ar-H), 7.21–7.09 (m, 4H, Ar-H), and6.76 (s, 1H, N-H quinazoline); 13C NMR (CDCl3): δ 125.3,128.1, 128.2, 128.3, 128.4, 128.5, 128.7, 129.4, 130.9, 131.1,132.5, 132.6, 132.7, 135.4, 135.4, 135.5, 138.8, 142.5, 157.9,159.5, and 186.2. Ms: [M+ 431]. Consistent with the mo-lecular formula C21H13N5O2S2.3-Phenyl-6-(4-phenyl-2-thioxo-1,3,5-triazin-1(2H)-yl)quinazoline-2,4(1H,3H)-dione ( 8h ). Yield: 93%, m.p.:

4 Journal of Chemistry

110–112°C, and IR (]max/cm−1) 1653 and 1717 (2C�O),3431 (NH); 1H NMR (CDCl3): δ 9.07 (s, 1H, C-H tri-azine), 8.71 (s, 1H, C5-H), 8.03 (d, 1H, J� 7.6Hz, C8-H),7.53 (d, 1H, J� 7.6Hz., C7-H) 7.53–7.47 (m, 4H, Ar-H),7.47–7.07 (m,6H, Ar-H), and 6.99 (s, 1H, N-H quina-zoline); 13C NMR (CDCl3): δ 120.1, 122.8, 124.6, 125.4,127.2, 128.70, 128.9, 130.1, 131.4, 133.7, 134.5, 135.7,138.3, 139.7, 141.1, 142.4, 143.1, 143.8, 145.5, 146.5,158.3, 167.4, and 178.5. Ms: [M+ 425]. Consistent withthe molecular formula C23H15N5O2S.6-(4-(4-Nitrophenyl)-2-thioxo-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 8i ). Yield: 95%,m.p.: 198–200°C, and IR (]max/cm−1) 1708 and 1625(2C�O), 3430 (NH); 1H NMR (CDCl3): δ 9.11 (s, 1H,C-H triazine), 8.82 (s, 1H, C5-H), 8.80 (d, 1H, J� 8.2Hz,C8-H), 8.72 (d, 1H, J� 8.2Hz, C7-H), 8.31 (d, 2H,J� 6.8Hz, Ar-H),8.03 (d, 2H, J� 6.8Hz, Ar-H) 7.55–7.20 (m, 5H, Ar-H), and 6.99 (s, 1H, N-H quinazoline);13C NMR (CDCl3): δ 120.3, 122.1, 123.6, 124.1, 124.8,127.4, 128.2, 130.3, 131.2, 133.8, 135.7, 137.4, 138.8,141.4, 143.2, 147.4, 148.8, 149.9, 153.3, 159.1, 162.2,164.8, and 177.8. Ms: [M+ 470]. Consistent with themolecular formula C23H14N6O4S.6-(4-(4-Fluorophenyl)-2-thioxo-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 8j ). Yield:97%, m.p.:118–120°C, and IR (]max/cm−1) 1704 and1657 (C�O), 3393 (NH); 1H NMR (CDCl3): δ 9.00 (s,1H, C-H triazine), 8.60 (d, 2H, J� 5.2Hz., Ar-H), 8.53(s, 1H, C5-H), 8.06 (d, 2H, J� 5.2Hz., Ar-H), 7.89 (d,1H, J� 8.3Hz, C8-H),7.78 (d, 1H, J� 8.3Hz., C7-H)7.42–7.23 (m, 1H, Ar-H), 7.21–7.09 (m, 5H, Ar-H), and6.99 (s, 1H, N-H quinazoline); 13C NMR (CDCl3): δ111.2, 113.0, 116.2, 117.7, 122.0, 127.1, 129.3, 131.6,133.8, 136.2, 138.5, 139.4, 143.9, 145.6, 148.4, 151.4,154.6, 157.0, 158.3, 161.7, 164.1, 165.2, 171.2, and 178.9.6-(2-Imino-4-(thiophen-2-yl)-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-dione ( 8k ). Yield: 94%,m.p.:172–174°C, and IR (]max/cm−1) 1708 and 1638(2C�O), 3240 and 3434 (2NH); 1H NMR (CDCl3): δ9.26 (s, 1H, C-H triazine), 8.53 (s, 1H, C5-H), 7.85 (d,1H, J� 8.4Hz., C8-H), 7.80 (d, 1H, J� 8.4Hz., C7-H),7.73–7.45 (m, 3H, Ar-H), 7.22–7.13 (m, 5H, Ar-H), 6.99(s, 1H, N-H quinazoline), and 6.74 (s, 1H, NH); 13CNMR (CDCl3): δ 111.7, 116.4, 119.2, 124.1, 128.4, 129.7,132.5, 133.4, 135.4, 135.4, 137.2, 138.9, 140.2, 142.6,144.5, 146.2, 149.9, 152.7, 155.9, 164.9, and 166.4. Ms:[M+ 414]. Consistent with the molecular formulaC21H14N6O2S.

2.1.2. Synthesis of 3-Substituted-2-Imino-1,3,5-triazin-1(2H)-yl-sulfonyl-phenyl-1-methylquinazoline-2,4(1H,3H)-dione(12a–j)

(1) Synthesis of N-(Diaminomethylene)-4-(1-methyl-2,4-dioxo-1,2-dihydroquinazolin-3(4H)-yl)benzenesulfonamide( 11 ). N-methyl isatoic anhydride (9) (2mmol) was refluxedwith sulfaguanidine (10) (2mmol) in glacial acetic acid(30ml) under ultrasound irradiation at 80°C for 90min. -e

reaction was monitored with TLC till no starting materials weredetectable. -e solution was poured on crushed ice. -e pre-cipitate was collected by filtration and recrystallized fromaqueous ethanol. Yield (97%), m.p.: 172–174°C, and IR (]max/cm−1) 1705 and 1632 (2C�O), 3431, 3345 and 3240 (NH, NH2);1H NMR (DMSO-d6): δ 10.33 (s, 1H, NH), 7.84 (d, 2H, Ar- H),7.40 (m, 4H, Ar-H), 6.75 (m, 2H, Ar-H), 5.71 (s, 2H, NH2), 2.81(s, 3H, CH3), and 1.92 (s, 1H, NH). Ms: [M+ 373]. Consistentwith the molecular formula C16H15N5O4S.

(2) General Procedure for Synthesis of 6f–j. Differentsubstituted acetophenones (1mmol) were refluxed withDMF-DMA (1.2mmol) for 8–12 hours. In ethanol (20ml),reaction was monitored with TLC till no starting materialswere detectable. -e corresponding enaminones derivativeswere afforded in yields of 92–97%. -e solutions wereevaporated under suction. -e precipitates were collectedand recrystallized from aqueous ethanol. -e followingcompounds were prepared:

(E)-1-(2-Bromophenyl)-3-(dimethylamino)prop-2-en-1-one ( 6f ). Liq. [17]; yield: 92% and liq.(E)-3-(Dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-one ( 6g ). Liq. [18]; yield 92% and liq.(E)-3-(Dimethylamino)-1-(p-tolyl)prop-2-en-1-one ( 6h ).m.p.: 112–114°C [19]; yield 94% and m.p.: 115–117°C(E)-3-(Dimethylamino)-1-(pyridin-2-yl)prop-2-en-1-one( 6i ). m.p.: 135–136°C [20]; yield 97% and m.p.:136–138°C(E)-3-(Dimethylamino)-1-(4-methoxyphenyl)prop-2-en-1-one ( 6j ). m.p.:98–100°C [21]; yield 96% and m.p.:104–106°C

(3) General Procedure for Synthesis of 12a–j. N-(Diamino-methylene)-4-(1-methyl-2,4-dioxo-1,2-dihydroquinazolin-3(4H)-yl)benzenesulfonamide (11) (1mmol) and (E)-3-(dimethylamino)-1-arylprop-2-en-1-ones (6a–j) (1mmol)in DMF/ethanol were refluxed for 8–12 hours. -e reactionwas monitored with TLC till no starting materials were de-tectable. -e solutions were concentrated under suction.Poured on ice, the precipitates formed were collected byfiltration and recrystallized from aqueous ethanol, and theproducts were obtained in yields of 93–98%. -e followingcompounds were prepared:

3-(4-((4-(Furan-2-yl)-2-imino-1,3,5-triazin-1(2H)-yl)sulfonyl)phenyl)-1-methylquinazoline-2,4(1H,3H)-dione( 12a ). Yield 95%, m.p.: 230–232°C, and IR (]max/cm−1) 1707 and 1660 (C�O), and 3345 (NH); 1HNMR (CDCl3): δ 10.30 (s, 1H, NH), 8.09 (d, 2H, Ar-H), 8.02 (d, 2H, Ar-H), 7.87 (m, 3H, Ar-H), 7.76 (s,1H, C-H triazine), 7.74–7.38 (m, 4H, C-H quinazo-line), and 3.64 (s, 3H, CH3); 13C NMR (CDCl3): δ29.7, 108.8, 111.3, 115.9, 117.8, 118.9, 123.8, 125.1,127.7, 128.6, 129.1, 131.2, 133.9, 135.8, 136.7, 140.8,145.7, 147.9, 152.0, 153.9, 160.1, and 162.5. Ms: [M+

476]. Consistent with the molecular formulaC22H16N6O5S.

Journal of Chemistry 5

3-(4-((2-Imino-4-(thiophen-2-yl)-1,3,5-triazin-1(2H)-yl)sulfonyl)phenyl)-1-methylquinazoline-2,4(1H,3H)-dione(12b ). Yield 94%, m.p.: 257–259°C, and IR (]max/cm−1)1701 and 1631 (2C�O), and 3347 (NH); 1H NMR(DMSO-d6): δ 10.30 (s, 1H, NH), 7.84–7.71 (m, 5H, Ar-H), 7.69 (s, 1H, C-H triazine), 7.41–7.36 (m, 6H, Ar-H),and 3.35 (s, 3H, CH3); 13C NMR (DMSO-d6): δ 29.3,110.7, 114.0, 115.1, 119.7, 120.3, 121.4, 122.5, 123.8,126.2, 127.2, 129.0, 129.8, 133.0, 134.8, 136.4, 138.9,141.6, 150.1, 158.0, 166.7, and 168.25. Ms: [M+ 492].Consistent with the molecular formula C22H16N6O4S2.3-(4-((2-Imino-4-phenyl-1,3,5-triazin-1(2H)-yl)sulfonyl)phenyl)-1-methylquinazoline-2,4(1H,3H)-dione ( 12c ).Yield 94%, m.p.: 255–257°C, and IR (]max/cm−1) 1704and 1631 (C�O) and 3347 (NH); 1H NMR (DMSO-d6):δ 10.30 (s, 1H, NH), 7.85–7.70 (m, 4H, Ar-H),7.69 (s,1H, C-H triazine), 7.40 (m, 3H, Ar-H), 6.72–6.64 (m,6H, Ar-H), and 3.37 (s, 3H, CH3); 13C NMR (DMSO-d6): δ 29.3, 110.7, 114.0, 115.1, 117.2, 119.7,120.3, 122.4,123.6, 126.2, 126.2, 127.1, 129.0, 130.1, 133.0, 133.2,134.7, 138.9, 141.6, 150.1, 158.0, 160.3, 166.0, and 168.2.Ms: [M+ 486]. Consistent with the molecular formulaC24H18N6O4S.3-(4-((2-Imino-4-(4-nitrophenyl)-1,3,5-triazin-1(2H)-yl)sulfonyl)phenyl)-1-methylquinazoline-2,4(1H,3H)-dione(12d ). Yield 93%, m.p.: 262–264°C, and IR (]max/cm−1)1705 and 1632 (2C�O) and 3350 (NH); 1H NMR(DMSO-d6): δ 10.30 (s, 1H, NH), 8.36 (m, 4H, Ar-H),7.96–7.74 (m, 4H, Ar-H),7.72 (s, 1H, C-H triazine), 7.39(m, 1H, C8-H), 7.31 (m, 1H, C5-H), 6.69 (m, 2H, C-Hquinazoline), and 3.40 (s, 3H, CH3); 13C NMR (DMSO-d6): δ 29.3, 110.7, 114.0, 115.1, 119.8, 124.0, 124.3, 126.2,126.8, 128.9, 129.1, 130.2, 133.1, 137.9, 138.9, 141.6,144.5, 145.9, 150.1, 152.04, 154.4, 155.8, 158.0, and168.2. Ms: [M+ 531]. Consistent with the molecularformula C24H17N7O6S.3-(4-((4-(4-Fluorophenyl)-2-imino-1,3,5-triazin-1(2H)-yl)sulfonyl)phenyl)-1-methylquinazoline-2,4(1H,3H)-dione( 12e ). Yield 96%, m.p.: 248–250°C, and IR (]max/cm−1)1717 and 1631 (2C�O) and 3350 (NH); 1H NMR(CDCl3): δ 10.03 (s, 1H, NH), 8.09 (d, 2H, J� 8.3Hz., Ar-H), 7.92 (d, 2H, J� 8.3Hz, Ar-H), 7.89–7.38 (m, 8H, Ar-H), 7.07 (s, 1H, C-H triazine), and 3.55 (s, 3H, CH3); 13CNMR (CDCl3): δ 30.9, 115.6, 117.4, 119.3, 123.8, 124.9,126.2, 127.2, 128.0, 128.6, 129.0, 130.0, 131.3, 133.1, 137.2,139.8, 143.6, 147.5, 150.0, 153.9, 157.4, 159.1, 165.7, 167.9,and 171.2. Ms: [M+ 504]. Consistent with the molecularformula C24H17FN6O4S.3-(4-((4-(2-Bromophenyl)-2-imino-1,3,5-triazin-1(2H)-yl)sulfonyl)phenyl)-1-methylquinazoline-2,4(1H,3H)-dione(12f ). Yield 93%, m.p.:220–222°C, and IR (]max/cm−1)1702 and 1632 (2C�O) and 3342 (NH); 1H NMR(CDCl3): δ 10.17 (s, 1H, NH), 8.11 (d, 2H, J� 8.8Hz,Ar-H), 8.01 (d, 2H, J� 8.8Hz, Ar-H), 7.84–7.77 (m, 4H,Ar-H), 7.61 (s, 1H, C-H triazine), 7.60–7.30 (m, 4H, Ar-H), and 3.52 (s, 3H,CH3); 13C NMR (CDCl3): δ 29.7,117.2, 118.8, 121.5, 122.3, 123.2, 125.2, 126.9, 128.1,

128.6, 130.1, 131.9, 132.8, 133.3, 135.5, 137.6, 143.4,148.4, 149.3, 149.4, 150.9, 152.0, 156.3, and 160.9. Ms:[M+ 564]. Consistent with the molecular formulaC24H17BrN6O4S.3-(4-((4-(2-Hydroxyphenyl)-2-imino-1,3,5-triazin-1(2H)-yl)sulfonyl)phenyl)-1-methylquinazoline-2,4(1H,3H)-dione( 12g ). Yield 93%, m.p.: 252–254°C, and IR (]max/cm−1)1705 and 1632 (2C�O) and 3349 (NH); 1H NMR(DMSO-d6): δ 10.30 (s, 1H, NH), 7.85–7.65 (m, 4H, Ar-H),7.65 (s, 1H, C-H triazine), 7.61–7.30 (m, 4H, C-Hquinazoline), 6.72–6.64 (m, 6H, Ar-H), 5.67 (br, 1H,OH), and 3.34 (s, 3H, CH3); 13C NMR (DMSO-d6): δ29.4, 110.7, 114.0, 114.2, 115.2, 118.8, 119.8, 121.9, 122.3,124.1, 126.3, 127,5, 129.0, 130.5, 133.1, 134.5, 138.9, 141.7,150.2, 152.2, 155.6, 158.0, 162.4, and 168.2.Ms: [M+ 502].Consistent with the molecular formula C24H18N6O5S.3-(4-((2-Imino-4-(p-tolyl)-1,3,5-triazin-1(2H)-yl)sulfonyl)phenyl)-1-methylquinazoline-2,4(1H,3H)-dione ( 12h ).Yield 94%, m.p.: 277–279°C, and IR (]max/cm−1) 1702and 1631 (C�O) and 3348 (NH); 1HNMR (DMSO-d6): δ10.30 (s, 1H, NH), 7.84 (d, 2H, Ar-H), 7.68 (m, 2H, Ar-H), 7.67 (s, 1H, C-H triazine),7.66–7.30 (m, 4H, C-Hquinazoline), 6.72–6.64 (m, 4H, Ar-H), 3.36 (s, 3H, CH3),and 2.90 (s, 3H, CH3); 13CNMR (DMSO-d6): δ 20.9, 29.4,110.7, 114.1, 115.1, 119.8, 121.2, 123.3, 124,4, 126.3, 127.2,128.1, 129.0, 130.1, 131.4, 133.1, 134.3, 138.9, 140.5, 141.7,146.2, 150.2, 152.2, 158.0, and 168.2. Ms: [M+ 500].Consistent with the molecular formula C25H20N6O4S.3-(4-((2-Imino-4-(pyridin-2-yl)-1,3,5-triazin-1(2H)-yl)sulfonyl)phenyl)-1-methylquinazoline-2,4(1H,3H)-dione(12i ). Yield 98%, m.p.: 253–255°C, and IR (]max/cm−1)1631 and 1705 (2C�O), 3347 (NH); 1H NMR (DMSO-d6): δ 10.30 (s, 1H, NH), 7.85 (d, 2H, Ar-H), 7.79–7.70(m, 2H, Ar-H),7.68 (s, 1H, C-H triazine) 7.65–7.30 (m,4H, Ar-H), 6.72–6.64 (m, 4H, Ar-H), and 3.36 (s, 3H,CH3); 13C NMR (DMSO-d6): δ 29.4, 110.7, 114.1,115.1, 118.2, 119.8, 121.2, 123.1, 123.2, 124.2, 126.3,129.0, 130.1, 131.3, 133.1, 135.2, 137.5, 138.9, 141.7,146.3, 150.2, 158.1, and 168.2. Ms: [M+ 487]. Con-sistent with the molecular formula C23H17N7O4S.3-(4-((2-Imino-4-(4-methoxyphenyl)-1,3,5-triazin-1(2H)-yl)sulfonyl)phenyl)-1-methylquinazoline-2,4(1H,3H)-dione( 12j ). Yield 97%, m.p.: 271–273°C, and IR (]max/cm−1)1631 and 1705 (2C�O) and 3345 (NH); 1H NMR(DMSO-d6): δ 10.30 (s, 1H, NH), 7.85 (d, 2H, J� 8.2Hz.Ar-H), 7.74 (d, 2H, J� 8.2Hz., Ar-H),7.69 (s, 1H, C-Htriazine), 7.61–7.31 (m, 4H, C-H quinazoline), 6.72–6.64(m, 4H, Ar-H), 3.84 (s, 3H, CH3), and 3.34 (s, 3H, CH3);13C NMR (DMSO-d6): δ 29.3, 54.8, 110.7, 112.8, 113.1,114.0, 115.1, 115.7, 119.7, 122.4, 126.2, 129.0, 132.3, 133.0,134.2, 137.3, 138.4, 138.9, 141.6, 147.4, 150.1, 157.5, 158.0,167.2, and 168.2. Ms: [M+ 516]. Consistent with themolecular formula C25H20N6O5S.

2.2. Antitumor Activity. Standard MTTmethod was used toevaluate the antitumor activity of the synthesized com-pounds against HepG2 andHCT116 human tumor cell lines.

6 Journal of Chemistry

-e quantitative assay depends on the ability of the mito-chondrial dehydrogenase of viable cells to cleave the tet-razolium ring of MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide). -e produced purplecolor is measured spectrophotometrically, and thus the in-crease or decrease in the cell number can indicate the anti-tumor activity of tested compounds. -e antitumor activitywas conveyed as the concentration of the compound thatcaused 50% growth inhibition (IC50, mean± SEM) in com-parison to the growth of untreated cells. Cells for cell line wereobtained from American Type Culture Collection and cul-tured using DMEM (Invitrogen) supplemented with 10% FBS(Hyclone,), 10 μg/ml of insulin (Sigma), and 1% penicillin-streptomycin. 96-well plate was used for the test. Cells weretreated with serial concentrations of test compounds andincubated for 48 hours at 37°c, and then the plate was ex-amined under invertedmicroscope before theMTTassay.-ecultures were removed from the incubator to laminar flowhood, and MTT was added as 10% of the culture mediumvolume and then incubated for 2–4 hours. After removal fromthe incubator, the formed formazan crystals were dissolved;using MTT solubilizing solution, the absorbance was mea-sured at a wavelength of 570 nm [22, 23].

3. Results and Discussion

3.1. Chemistry

3.1.1. Synthesis of 6(3-1H-1,2,4-Triazol-1-yl)-3-phenylquinazoline-2,4(1H,3H)-diones and 6(4-2-Substituted-1,3,5-Triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-diones. Synthesis of quina-zolinones involves different starting materials: one of whichis isatoic anhydride derivatives. In the present work,6-bromo-3-phenylquinazoline-2,4(1H,3H)-dione (1) wasprepared. Adapting the procedure of Niranjan et al. [24]where 5-bromoisatoic anhydride reacted with aniline inethanol in presence of few drops of acetic acid under ul-trasonic irradiation, the intermediate was taken to the nextstep, where it reacted with hydrazine hydrate to afford 6-hydrazinyl-3-phenylquinazoline-2,4(1H,3H)-dione (2). -eintermediate was characterized by IR spectrum that showedtwo carbonyl bands at 1639 cm−1 and 1659 cm−1; two NHbroad bands appeared at 3373 cm−1 and 3389 cm−1 and aspike characteristic for NH2 at 3470 cm−1. -e hydrazinylderivative was also characterized by 1H NMR where 4protons exchangeable with D2O appeared at 6.5 ppm and3.4 ppm corresponding to the proton at NH of the quina-zoline ring and the three hydrazine protons, respectively.6-Bromo-3-phenylquinazoline-2,4(1H,3H)-dione (1) alsoreacted with urea, thiourea, or guanidine in ethanol to afford1-(2,4-dioxo-3-phenyl-1,2,3,4-tetrahydroquinazolin-6-yl)thiourea, urea, or guanidine (3a–c). Urea derivative (3a)was characterized by 1H NMR that showed three peaksexchangeable with D2O: one peak was upfield at 3.6 ppmcorresponding to two protons of the urea’s NH2 group,and the other was downfield at 9.2 ppm corresponding toone proton of the urea’s NH group. -e third peak was at5.5 ppm corresponding to one proton of NH of the quina-zoline ring. Similarly, thiourea derivative (3b) was

characterized by three peaks in 1H NMR at 4.0 ppm corre-sponding to two protons of the thiourea’s NH2 group, at8.7 ppm corresponding to one proton of thiourea’s NHproton, and at 6.9 ppm corresponding to the NH proton ofthe quinazoline ring. Guanidine derivative (3c), on the otherhand, was characterized by IR spectrum that showed twocarbonyl stretching bands at 1679 cm−1 and 1718 cm−1, twoNH stretching bands at 3383 and 3393, and NH2 stretchingband at 3423 cm−1. It was also characterized by 1H NMR thatshowed four peaks that were exchangeable with the D2O onepeak downfield at 8.6 ppm and another at 7.0 ppm. Eachcorresponds to one proton: one of the guanidine NH groupand the other for the NH proton of the quinazoline ring. Apeak appeared downfield at 5.3 ppm corresponding to twoprotons of the terminal amino group of the guanidine, while apeak appeared upfield at 4.0 ppm corresponding to oneproton of the guanidine NH group. Dimethylformamidedimethyl acetal (DMF-DMA) is a very valuable reagent fororganic synthesis. It has an electrophilic site represented bythe carbon atom carrying two methoxy groups and nucleo-philic site represented by dimethyl amino carrying a lone pairof electrons. -us, DMF-DMA is involved in two types ofreactions: methylation and formylation. Methylation involvesthe synthesis of methyl esters from acids. Formylation in-volves the formation of enaminones from active methylenes.It can be further cyclized into heterocyclic ring systems, whereenaminones can react with hydrazides to afford the corre-sponding azoles. It can react with urea, thiourea, and gua-nidine to afford the corresponding triazines [25, 26]. In thecurrent work, differently substituted acetophenones or 2-acetyl thiophene (furan) reacted with DMF-DMA to preparethe corresponding enaminone derivatives. -is was taken tothe next step, where enaminones (6a–e) in a cyclization re-action with 6-hydrazinyl-3-phenylquinazoline-2,4(1H,3H)-dione (2) afforded the corresponding 6(3-1H-1,2,4-triazol-1-yl)-3-phenylquinazoline-2,4-(1H,3H)-diones (7a–e), asshown in Scheme 1.

-e series was characterized by 13C NMR where twocarbonyl peaks appeared downfield at above 160 ppm. In 1HNMR, the characteristic peaks of NH and NH2 of the hy-drazine moiety disappeared indicating the cyclization totriazole. -e compounds were also characterized by massspectrometry, IR spectroscopy showed characteristic carbonylbands at above 1600 cm−1, and the stretching bands of NHand NH2 disappeared. Enaminones (6a–e) also reacted with1-(2,4-dioxo-3-phenyl-1,2,3,4-tetrahydroquinazolin-6-yl)thiourea, urea, or guanidine (3a–c) to afford the corre-sponding 6(4-2-substituted-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4-(1H,3H)-diones (8a–k) through acyclization reaction as shown in Scheme 1. -e series werecharacterized by mass spectrometry, IR spectroscopy, 1HNMR, and 13C NMR. -e 2-oxo-1,3,5-triazinyl derivatives(8a–e) showed three characteristic carbonyl stretchingbands above 1600 cm−1 in the IR spectrum with only onesecondary amine stretching band above 3200 cm−1 corre-sponding to NH of the quinazoline ring, and the stretchingbands of the terminal urea moiety disappeared indictingcyclization. In 13C NMR, the compounds showed threepeaks downfield at above 160 ppm corresponding to carbonyl

Journal of Chemistry 7

carbons. �e 2-thioxo-1,3,5-triazinyl derivatives (8f–8j), onthe other hand, showed only two carbonyl stretching bandsabove 1600 cm−1, where the thioxo group shows no char-acteristic stretching bands. And only one stretching band oftheNH secondary amine is above 3200 cm−1. In 13CNMR, thecompounds showed two down¡eld peaks at above 160 ppmcorresponding to carbonyl carbons and one thioxo carbon at

above 170 ppm. �e 2-imino-1,3,5-triazinyl derivative (8k)showed two characteristic carbonyl bands in the IR spectrumabove 1600 cm−1 and two characteristic secondary aminebands above 3200 cm−1 one for NH of the quinazoline ringand the other for the 2-imino group of the substituting tri-azine ring at C6. �e imino group appeared as a singletdown¡eld at 9.2 ppm in 1H NMR.

NH

N

O

O

Br

1

NH2-NH2(NH2)2CX

NH

N

O

O

NHNH2

2 X = O, S, NH

NH

N

O

O

HN

NH2

X

3(a–c)

Ar= , , Ph, 4-NO2-Ph, 4-F-PhSO

N

NH

O

O

N

NH2

N

O

ArH

NH

N

O

O

N NN

Ar

7(a–e)

NOCH3

OCH3

+ Ar

O

CH3

Ar

O

N

4 5(a–e)

6(a–e)

+ +

N

NH

O

O

N

NH2X

N Ar

OH

NH

N

O

O

N N

N ArX

8(a–k)

8a X= O, Ar =

8b X = O, Ar =

8c X = O, Ar = Ph8d X = O, Ar = 4-NO2-Ph8e X = O, Ar = 4-F-Ph

O

S

8g X = S, Ar =

8h X = S, Ar = Ph8i X = S, Ar = 4-NO2-Ph8j X = S, Ar = 4-F-Ph

8k X = NH, Ar =

S

8f X = S, Ar = O

S

Scheme 1: Synthesis of 6(3-1H-1,2,4-triazol-1-yl)-3-phenylquinazoline-2,4(1H,3H)-diones and 6(4-2-substituted-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-dione.

8 Journal of Chemistry

3.1.2. Synthesis of 3-Substituted-2-Imino-1,3,5-triazin-1(2H)-yl-sulfonyl-phenyl-1-methylquinazoline-2,4(1H,3H)-dione (12a–j). N-methyl isatoic anhydride (9) reacted withsulfaguanidine (10) in glacial acetic acid under ultrasoundirradiation to a�ord synthesis of N-(diaminomethylene)-4-(1-methyl-2,4-dioxo-1,2-dihydroquinazolin-3(4H)-yl)benzenesulfonamide (11). �e intermediate was char-acterized by mass spectrometry, IR, and 1H NMR

spectroscopy. �e IR spectrum showed two carbonylstretching bands at above 1600 cm−1 and two secondaryamines stretching bands at 3240 cm−1 and 3345 cm−1 and oneprimary amine stretching band at 3431 cm−1. In 1H NMRspectrum, the compound showed a singlet up¡eld at 2.8 ppmcorresponding to three protons of the N-methyl. It alsoshowed three peaks exchangeable with D2O: one down¡eld at10.3 ppm corresponding to the imino group proton, at

N

O

O

OH2N

S

OO

N NH2

NH2

+

N

N

O

O

SO

O

NNH2

NH2

N N

N ArHN

N

N

O

O

SO

O

9 10

11

12(a–j)

N

N

O

O

SO

O

HNNH

NOCH3

OCH3

+ Ar

O

CH3

Ar

O

N

4 5(a–j) 6(a–j)

N

NH2HN

N

N

O

O

SO

O N

O

Ar

H

SO NAr = , Ph, 4-NO2-Ph, 4-F-Ph, 2-Br-Ph, 2-OH-Ph, 4-CH3-Ph,, , 4-OCH3-Ph

NH2

Scheme 2: Synthesis of 3-substituted-2-imino-1,3,5-triazin-1(2H)-yl-sulfonyl-phenyl-1-methylquinazoline-2,4(1H,3H)-dione (12a–j).

Journal of Chemistry 9

5.7 ppm corresponding to two NH2 protons, and one upfieldat 1.9 ppm corresponding to the NH proton. -at in-termediate reacted in the cyclization reaction with differentenaminones to afford 3-substituted-2-imino-1,3,5-triazin-1(2H)-yl-sulfonyl-phenyl-1-methylquinazoline-2,4(1H,3H)-dione (12a–j), as shown in Scheme 2. -e compounds werecharacterized by mass spectrometry, IR, 1H NMR, and 13CNMR spectroscopy.-e primary amine stretching bands andone of the secondary amine stretching bands disappeared inthe IR spectrum, indicating the cyclization. And two of theD2O exchangeable peaks disappeared in 1H NMR: the one at1.9 ppm, and the peak of NH2 at 5.7 ppm as additionalevidence that the cyclization reaction took place to yield thedesired products.

3.2. Antitumor Screening against HEP-G2 and HCT116 CellLines. -e antitumor activity of compounds 7a, 7b, 8a, 8b,8c, 8f, 8j, 12d, 12e, and 12j was investigated compared tostaurosporin as a reference drug against human hepato-cellular carcinoma cell line (HEP-G2) and human coloncarcinoma cell line (HCT116) using the standard MTTassay method [22]. Tumor cells were incubated eitheralone (negative control) or with different concentrationsof the test compounds (100, 25, 6.25, 1.56, and 0.39 μg).According to Table 1, the tested compounds exhibitedcytotoxic activity of variant degrees depending upon thesubstituted heterocyclic ring hybridized with the quinazolinescaffold. With respect to HepG-2 cancer cell lines, the de-rivatives 2-oxo-4-phenyl-1,3,5-triazinylquinazoline 8c and 2-thioxo-4-p-fluorophenyl-1,3,5-triazinylquinazoline 8j repre-sented significant potency of about 2.6 folds higher than thatof the reference drug (IC50; 2.68, 2.52 µM, respectively vs IC50staurosporin; 7.18 µM). Slight reduction in the activity wasdetected by the 4-furan-2-oxo-1,3,5-triazine analogue 8a butstill was 1.5 fold more potent than staurosporin (IC50,4.53 µM). An observable decrease in the potency was detectedupon replacement of the furan heterocyclic ring with thio-phene core as compound 8b (IC50; 23.72 µM). Unfortunately,drastic drop in the sensitivity of the cancer cells was observedby the 2-thioxo-4-furan analogue 8f (IC50; 118.1 µM). It couldbe noted that the conjugation of aromatic homocyclic sub-stituents at triazine-C4 produces greater cytotoxic activityagainst liver cancer cell (HepG-2) than that obtained by theheterocyclic moieties. Similarly, the five-membered hetero-cyclic triazole derivative 7c bearing a phenyl ring at triazole-C3 represented about 2.1 folds more potent cytotoxic activityagainst HepG-2 cancer cell lines than that of the standarddrug of IC50; 3.20 µM, while the activity slightly decreasedupon the attachment of a furan moiety at the triazole-C3instead of the aromatic homocyclic ring as compound 7a(IC50; 9.24 µM). It could be noted that the attachment ofaromatic homocyclic moieties to the triazine/triazole ringsenhances the cytotoxic activity of the compounds more thanthat of the heterocyclic moieties, which can be explained dueto the increase in the hydrophobicity of the derivatives whichenables them to cause a rapid membrane disruption mech-anism to kill varying cancer cells [27]. On the other hand, theattachment of the 2-imino-triazine ring via sulfonylphenyl

linker to the quinazoline ring-N3 as compounds 12d, 12e, and12f led to 2-3-fold reduction in the cytotoxic potency of IC50values of 13.53, 24.54, and 14.39 µM, respectively, in com-parison to staurosporin.

With respect to HCT116 cancer cell lines, interestingly,the compound 8c produced the most potent activity againstthe tested cancer cells of the IC50 value: 1.57 µM vs IC50staurosporin; 11.26 µM, followed by 8a and 8b of IC50 2.21,4.75 µM. -e activity is about 11-fold greater than the ref-erence drug. -e sensitivity of colon cancer cells observablydecreased against 8j (IC50; 30.93 µM), while dramatic dropin the sensitivity was detected against compound 8f of IC50(206.6 µM). -e triazole derivative 7c produced equipotentactivity to that of the reference drug, while 7a exhibited agreat decrease in the potency of IC50 (99.43 µM). Despite theactivity of the sulphonyl derivatives 12d and 12e being 2–3folds less than staurosporin in case of HepG-2 cancer cells,their potency increased to about 1.5 folds higher than that ofthe reference drug in case of HCT116 cancer cells (IC50: 6.59and 7.70 µM), while 12f produced dramatic drop in theactivity (IC50: 109.3 µM). It could be concluded the newcompounds are promising cytotoxic agents; the six-membered triazine derivatives 8 produced potent broadcytotoxic activity against the two tested cancer cell linesfollowed by the triazole analogues 7a and 7c and then thesulphonyl derivatives 12d and 12e. Further derivatization isrequired for the previous compounds to optimize the an-ticancer activity.

4. Conclusion

In this study, novel quinazoline-2,4(1H,3H)-diones (7a–e),(8a–k), and (12a–j) were developed for cytotoxic evaluationagainst liver Hep-G2 and colon HCT116 cell lines. -e newcompounds are promising cytotoxic agents. Among thetested compounds, the six-membered triazine derivatives 8produced potent broad cytotoxic activity against Hep-G2and HCT116 cancer cell lines compared to staurosporinfollowed by the triazole analogues 7a and 7c and then thesulphonyl derivatives 12d and 12e.

Data Availability

All data are available as data file in the website of the journal.

Table 1: In vitro antitumor activity of the tested compounds.

Compound numberIC50 µM

HepG2 HCT1167a 9.24± 0.33 99.43± 4.27c 3.20± 0.11 11.74± 0.678a 4.53± 0.12 2.21± 0.098b 23.72± .1.9 4.75± 0.188c 2.63± 0.13 1.57± 0.068f 118.1± 5.6 206.6± 9.58j 2.52± 0.69 30.93± 1.4112d 13.53± 0.71 6.59± 0.2712e 24.54± 1.6 7.70± 0.3812g 14.39± 0.8 109.3± 7.1Staurosporin 7.18± 0.32 11.26 0.81

10 Journal of Chemistry

Conflicts of Interest

-e authors declare that there are no conflicts of interest.

Acknowledgments

-e project was funded by the Deanship of Scientific Re-search (DSR) at King Abdulaziz University, Jeddah, undergrant no. G-130-247-39. -e authors, therefore, acknowl-edge with thanks DSR for technical and financial support.

Supplementary Materials

-e supplementary materials are the PDF files for theoriginal spectroscopic date in the following order (13C NMR,1H NMR, Mass, and IR). (Supplementary Materials)

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