444 MORGAN AND REEVES: RESEARCHES ON

LVI.--Researches on Residual A f in i ty and CO- ordination. Part X V . Interactions of Acetylpro- pionylmethane and the Tetrachlorides of Selenium and Tellurium. By GILBERT T. MORGAN and HARRY GORDON REEVES.

As the result of earlier investigations, an explanation has been advanced for the complicated changes occurring in the interactions of acetylacetone and the tetrachlorides of selenium and tellurium (T., 1920, 117, 1456; 1921, 119, 610; 1922, 121, 922, 2432), but it remains to be seen whether this interpretation of experimental facts is consistent with the behaviour of other homologous aliphatic p-diketones when these are subjected t o the action of the above- mentioned tetrachlorides. It is evident that each of t,hese chlorides induces a characteristic tautomeric change in acetylecetone, this

Publ

ishe

d on

01

Janu

ary

1923

. Dow

nloa

ded

by U

nive

rsity

of

Win

dsor

on

24/1

0/20

14 2

2:01

:31.

View Article Online / Journal Homepage / Table of Contents for this issue

RESIDUAL AFFINITY AND CO-ORDINATION. PART XV. 445

alteration of chemical structure being manifested by the nature and constitution of the products.

Selenium tetrachloride removes from acetylacetone the two hydrogen atoms originally present in the methylene group of acetylacetone, yielding selenium acetylacetone, a non-enolic dirneric substance, Se2(C5H602)2, the structural formula for which has been recently demonstrated (T., 1922, 121, 2432).

The reaction of tellurium tetrachloride and acetylacetone differed from that of selenium tetrachloride and the same P-diketone in its point of attack on the organic molecule and consequently in the chemical structures of the more numerous products, namely, tellurium acetylacetone dichloride, tellurium bisacetylacetone dichloride, and tellurium 0-ethylacetylacetone trichloride, the last of these arising from the intervention of ethyl chloride present in chloroform B.P. (T., 1922, 121, 923). It is highly probable that the addition of tellurium to the diketonic chain is preceded by enolisation of acetylacetone into the modification CH,*CO*CH,*C( OH):CH,, a reactive form of the substance capable of combining with tellurium tetrachloride to form the additive compound CH,*CO-CH,.CCl( OH)*CH,*TeCl, (compare Bielecki and Henri, Compt. rend., 1914, 158, 1022). This intermediate product by loss of hydrogen chloride furnishes a hypothetical substance, CH,*CO*CH,*CO*CH2*TeC13, from which the three foregoing stable tellurium compounds are derivable.

I n view of these intricate chemical changes, it became of interest to study the behaviour of acetylpropionylmethane (propionyl- acetone), the next homologue of acetylacetone, towards the two tetrachlorides.

I. Selenium Acetylpropion ylmethune . Towards selenium tetrachloride, acetylpropionylmethane reacts

in a manner closely resembling acetylacetone. The condensation occurs most smoothly with the copper derivative of the diketone and there is only one seleniferous product, the non-enolic dimeric selenium acetylpropionylmethune (setenium propionylacetone ; formula I or IT), accompanied by acetyl~ropioiz~lchloromethnne, C,H 5*C 0 CHC1.C 0 CH, .

Selenium acetylpropionylmethane, an analogue of selenium acetylacetone, undergoes similar reactions with hydriodic and hydrocyanic acids and with excess of propionylacetone, the only practical difference being that the products are less stable, probably owing in part to their greater fusibility.

Diselenium bisacetylp rop ion y lmet hune , Se, : ( C ,H ,O OH), , obtained by the action of hydriodic acid, is a yellow oil identified by conversion into its yellow copper derivative, Se,:(C6H8O*0),:Cu.

Publ

ishe

d on

01

Janu

ary

1923

. Dow

nloa

ded

by U

nive

rsity

of

Win

dsor

on

24/1

0/20

14 2

2:01

:31.

View Article Online

446 MORGAN AND REEVES: RESEARCHES ON

Cyano-3-selenium acetylpropionylmethane, CN*Se*C,H,O*OH, a very fusible, colourless solid produced by the addition of hydrogen cyanide, is characterised by its crystalline copper derivative,

Selenium OC- bisacetylpropionylmethane, O:C,H,O*Se*C,H,O*OH, arising from the addition of acetylpropionylmethane employed in excess, is an oil yielding a greenish-yellow copper salt.

(CN*Se*C 6H80*0)2CU.

11. Tellurium Acetylpropionylmethne. The condensation of tellurium tetrachloride and acetylpropionyl-

methane proceeds more simply than in the case of acetylacetone. In this instance only one product is isolated, namely, tellurium acetylpropionylmethane dichloride (VII) , which, however, on treat- ment with ethyl chloride in chloroform furnishes tellurium 0- ethyhcetylpropionylmethune trichloride (VIII).

C,H,,o, + TeCl, = (C6H80,)TeC1, + 2HC1. ( C6H802)TeCl, + C2H5C1 = (C,H,*O*C,H,O)-TeCI,.

The addition of tellurium tetrachloride to the methylene enolic form of acetylpropionylmethane takes place through the inter- mediate phases represented by formulie 111, IV, and V, after which elimination of hydrogen chloride leads to tellurium acetylpropionyl- methane dichloride (VII).* On treatment with sulphurous acid or alkali sdphites and bisulphites, the foregoing dichloride undergoes reduction to tellurium acetylpropionylmethane (VI), a well-defined, golden-yellow substance more soluble in water than its lower homologue, tellurium acetylacetone. The new product, which is of monomeric complexity, behaves as an unsaturated compound, combining additively with chlorine to regenerate the dichloride and

* The formulae for the tellurium compounds are based on the assumption that the preliminary change (VII) is an enolisation of the group CH,-CO-, but there is an alternative possibility that this tautomeric rearrangement may have taken place in the group CH,CH,.CO, thus giving rise to CH,.CH:C(OH). These alternatives are presented in formul3e I and I1 for the selenium derivative.

Publ

ishe

d on

01

Janu

ary

1923

. Dow

nloa

ded

by U

nive

rsity

of

Win

dsor

on

24/1

0/20

14 2

2:01

:31.

View Article Online

RESIDUAL AFFINITY AND CO-ORDINATION. PART XV. 447

with bromine and iodine to form, respectively, tellurium acetyl- propionylmethane dibromide and di-iodide.

Reference has already been made (T., 1922, 121, 940) to the intense germicidal action of aqueous solutions of tellurium acetyl- propionylmethane, and the bacteriological and physiological study of this and other tellurium derivatives of the p-diketones is under investigation by Dr. E. A. Cooper. The following results show the disinfecting action of a series of these tellurium compounds.

B. Coli communis. Concentration Phenol

1 in 500,000 1,000 Tellurium 3-methylacetylacetone 1 in 800,000 1,600 Tellurium acetylpropionylrnethane 1 in 2,500,000 5,000

Substance. disinfecting at 37". coefficient. Tellurium acetylacetone . . . . . . . . . . . . . . .

Summary.

1. The lengthening of the P-diketone chain in passing from acetylacetone to its next homologue, acetylpropionylmethane, does not alter materially the nature of the interaction with selenium tetrachloride.

2. The condensation with tellurium tetrachloride is simplified in the case of acetylpropionylrnethane, the only product isolated being tellurium acetylpropionylmethane dichloride.

E x P E R I M E N T A L.

I. Selenium Series.

Owing to the small yield of the starting material, acetylpro- pionylmethane (propionylacetone), obtained by the sodium ethoxide process the following modification was adopted. Forty-two C.C.

of methyl ethyl ketone (d =0*9538, 1 mol.) were added slowly and

Publ

ishe

d on

01

Janu

ary

1923

. Dow

nloa

ded

by U

nive

rsity

of

Win

dsor

on

24/1

0/20

14 2

2:01

:31.

View Article Online

448 MORGAN AND REEVES: RESEAROHES ON

with vigorous shaking to a mixture of 11 grams (1 atom) of clean sodium wire and 190 C.C. of dry redistilled ethyl acetate contained in a reflux apparatus cooled to 0". After twelve hours, the mixture was heated on the water-bath for one and a half hours, cooled, and poured on to crushed ice. The ethereal layer was extracted twice with water, the combined aqueous layers neutralised with dilute acetic acid and treated with the calculated amount of N/8-cupric acetate. The precipitated pale blue copper acetylpropionylmethane after washing with water was dried a t 80" : m. p. 197-198"; yield 32% grams or 47.8 per cent. on the weight of methyl ethyl ketone.

Acetylpropionylmethane (b. p. 158") was obtained in almost quantitative yield by decomposing the copper salt with dilute sulphuric acid in presence of ether, the ethereal extract being fractionated after drying over sodium sulphate.

Selenium Acetylpropionylmethane (Selenium Propionyhcetone) (Formula? I and II).-Copper acetylpropionylmethane (10.2 grams, 1 mol.) was added slowly with shaking to 7-8 grams of freshly prepared selenium tetrachloride, suspended in 56 C.C. of chloroform B.P., care being taken to exclude moisture. Hydrogen chloride was evolved, the solution reddened, and the tetrachloride gradually dissolved while cupric chloride (5 grams) with a trace of selenium was precipitated. After thirty minutes at the ordinary temper- ature, this deposit was removed and the deep red, fuming, lachry- matory filtrate was evaporated rapidly in a current of air, when the residue, a reddish-brown oil, solidified almost completely and on trituration with absolute alcohol yielded yellow, crystalline selenium acetylpropionylmethane (yield 24.5 per cent .). Recrystallised from absolute alcohol, this product separated in pale yellow, glistening plates melting at 137"; its solution in benzene or alcohol had a yellow colour; it was only faintly acid to litmus and dissolved in aqueous sodium hydroxide to a yellow solution, gradually decom - posing with precipitation of selenium [Found : C = 37.62; H == 4-41 ; Se = 41.12. C,,H,,O,Se, requires C = 37.66; H = 4.22 ; Se = 41-40 per cent. An ebullioscopic molecular weight deter- mination in benzene (c = 2.17) gave nf = 372. (C6H,o2:Se), requires M = 382-6.1

Selenium acetylpropionylmethane was practically insoluble in water or ether; i t yielded selenium on warming with alcoholic aniline and became superficially coated with red selenium on exposure to light. 3-Acetylpropionylchloromethune, copper salt . T h e alcohol employed

in assisting the initial crystallisation of crude selenium acetyl- propionylmethane was evaporated in a current of air, leaving a residue of red lachrymatory oil and a supernatant layer of hydro-

Publ

ishe

d on

01

Janu

ary

1923

. Dow

nloa

ded

by U

nive

rsity

of

Win

dsor

on

24/1

0/20

14 2

2:01

:31.

View Article Online

RESIDUAL AFFINITY AND CO-ORDINATION. PART XV. 449

chloric acid. An ethereal solution of the oil, when shaken with aqueous copper acetate, yielded a yellowish-green, granular pre- cipitate of copper 3-acetylpropionylchloromethne, Cu(C,H,02C1),, which crystallised from chloroform in olive-green plates melting a t 137-138' (Found : c1= 19.66; c u = 17.44. C,2H,,0,C1,Cu requires C1 = 19-76; Cu = 17.72 per cent.). This result confirmed the following equation representing the formation of selenium acetylpropionylmethane :

2SeCl4 -f- 2Cl2Hl,0,C~ = (C6H8O2:Se), + ~ C U C & + 2HCl + 2CH,*CH2*CO*CHC1*CO*CH,.

Diseleniurn Bisacetylpro~ionylmethane, Se,:(C,H,O*OH),.-Two molecular proportions (0-63 gram) of 60 per cent. hydriodic acid diluted with 40 C.C. of water were added to 0.9 gram of selenium acetylpropionylmethane (1 mol.) suspended in 150 C.C. of ether cooled by adding 1 gram of crushed ice, the mixture being shaken vigorously. The brown colour of the ethereal layer due to iodine was removed by adding N/10-thiosulphate, the decolorised solution dried over sodium sulphate, and the ether removed in a vacuum. The residual yellow oil (0.4 gram, 42 per cent.) would not solidify but had the characteristic offensive odour of the diselenium bis- P-diketones (Morgan, Drew, and Barker, Eoc. cit.). It contained Se = 41.93. C,,H,,O,Se, requires Se = 41.13 per cent. On shaking with ether and cupric acetate, it readily yielded a mustard yellow copper salt, Se,:(C6H,0*O),:Cu (Found : c = 31.98; H ==

3-98. C,,H,,O,Se,Cu requires C = 32.30; M = 3.62 per cent.). Cyano-3-selenium Acetylpropionylmethane, cN*8e*c6Hso*oH.-

One gram of powdered selenium acetylpropionylmethane dissolved in four or five minutes to a pale yellow solution when shaken with 6 C.C. of redistilled hydrogen cyanide and 12 C.C. of dry ether. After removing the volatile constituents of the solution in a vacuum, a mass of flat, six-sided needles was obtained melting a t 27.5'. These crystals, which had a distinct odour of burnt rubber similar to that of the other cyanoselenium derivatives, liquefied on keeping for a short time to a yellow oil which did not solidify again on cooling. Both the oil and the original crystals gave a red ferric chloride coloration. Owing to this instability the crystalline cyano-deriv- ative was converted into copper salt, (CN*Se*C6H80*O),Cu, by dissolving in ether and shaking with aqueous cupric acetate. The well-defined, crystalline, pale blue copper derivative (yield 70 per cent .), which gradually decomposed on keeping, was readily soluble in chloroform (Found : N = 5.67 ; Se = 31.3 ; Cu = 12.2. C,,H,,O,N,Se,Cu requires N = 5.62; Se = 31.84; cu = 12.76 per cent .).

B*

Publ

ishe

d on

01

Janu

ary

1923

. Dow

nloa

ded

by U

nive

rsity

of

Win

dsor

on

24/1

0/20

14 2

2:01

:31.

View Article Online

450 MORGAN AND REEVES: RESEARCHES ON

Selenium OC-bisacetylpropionylmethane, Se< C ofc,SH,o H O*OH , was

obtained as an oil which could not be induced to crystallise on refluxing 1 gram of powdered selenium acetylpropionylmethane, 2 grams of acetylpropionylmethane, and 14 C.C. of chloroform, a trace of solid sodium hydroxide being added as catalyst. After ten to fifteen minutes, the solution assumed a pink tint owing to a slight elimination of selenium; the chloroform and excess of P-diketone were removed in a vacuum over sodium hydroxide. The residual oily selenium bisacetylpropionylmethane, which had the characteristic odour of burnt rubber, was readily soluble in chloro- form but only sparingly soluble in petroleum. On shaking its warm petroleum solution with aqueous cupric acetate, the greenish- yellow copper salt was obtained, which gave analytical numbers approximating to the formula (C,,H,,O,Se),Cu.

11. Tellurium Series. Tellurium Acetylpropionylmethane Dichloride (Formula VII) .--

Acetylpropionylmethane (3.54 grams, 2 mols.) and 3 grams of sublimed tellurium tetrachloride (1 mol.), suspended in 24 C.C. of chloroform B.P., were heated under reflux for one and a half hours, when the evolution of hydrogen chloride had ceased. The yellow filtrate from a slight deposit of tellurium was concentrated in a vacuum desiccator over lime until three crops of tellurium acetyl- propionylmethane dichloride were obtained (total 2.2 grams). This dichloride was almost insoluble in water, but dissolved sparingly in ether, benzene, or chloroform and very readily in cold acetone, from which solvent it crystallised slowly in large, transparent prisms melting with decomposition a t 170-171 '. When recrystallised from hot alcohol, the substance was obtained in white nodules becoming discoloured at 175" and changing to a black mass a t 185" (Found : C1= 22.89; Te = 40.94. C6H80,C1,Te requires C1 = 22.83; Te = 41.01 per cent.).

Tellurium acetylpropionylmethane dichloride resembled closely its isomeride, tellurium 3-methylacetylacetone dichloride (T., 1922, loc. cit.); on keeping for some time, it became brownish-grey owing to slight decomposition with elimination of tellurium. On repeating the foregoing preparation in pure " salicylide " chloroform, no other product than the dichloride was observed :

C6H,,0, + TeC1, = C,H,O,:TeCl, + 2HC1. Tellurium Acetylpropionylmethne (Formula VI) .-Powdered

potassium metabisulphite (2.8 grams E 4 mols. KHSO,) was added during ten minutes to a well-stirred suspension of 2 grams of tellurium acetylpropionylmethane dichloride in 40 c .c. of ice-cold water -

Publ

ishe

d on

01

Janu

ary

1923

. Dow

nloa

ded

by U

nive

rsity

of

Win

dsor

on

24/1

0/20

14 2

2:01

:31.

View Article Online

RESIDUAL AFFINITY AND CO-ORDINATION. PART xv. 451

Sulphur dioxide was evolved, the dichloride dissolved to a golden- yellow solution, and after removing a slight deposit of tellurium the filtrate was concentrated until well-defined, golden-yellow, acicular prisms separated. This product was recrystallised from hot benzene and obtained in golden-yellow needles melting a t 100" (1.2 grams, yield 79 per cent.) [Found : C = 29.85; H = 3.66; Te = 53.00. C,H,O,Te requires c = 30.06 ; H = 3.36 ; Te = 53.24 per cent. An ebullioscopic determination of molecular weight in benzene (c = 0.85) gave N = 233. C,H,O,Te requires M ='239.6]. The foregoing reduction was also readily accomplished by means of sodium sulphite, but with a somewhat decreased yield. Tellurium acetylpropionylmethane was much more soluble in water than in organic media, but fairly soluble in cold benzene or chloroform. Its aqueous solution, which slowly deposited tellurium, has been employed in bacteriological work, showing the highest germicidal activity of its series of tellurium derivatives (T., 1922, loc. cit.).

Tellurium acetylpropion ylmet hane d i bromide, C ,H ,O,:TeBr, , pre - pared by mixing tellurium acetylpropionylmethane and bromine in chloroform solution, separated in pale yellow nodules, and when crystallised from hot alcohol was obtained in white prisms melting and decomposing a t 156" (Found : Br = 40.39. C,H,O,Br,Te requires Br = 40.00 per cent.).

Tellurium acet ylpropionylmethane di-iodide, C,H,O,:TeI,, was obtained as crimson needles and in quantitative yield from its generators in chloroform solution ; it crystallised from hot alcohol in reddish-purple needles ; the lighter variety sintered at 130" and intumesced at 190", the darker form sintered a t 135" and intumesced at 185" (Found : 1 = 51.33. C,H,O,I,Te requires I = 51.43 per cent.).

Tellurium O-Ethylacetylpropionylmethane Trichloride (Formula VIII).-Powdered tellurium acetylpropionylmethane dichloride (1-5 grams) was added to 25 C.C. of chloroform B.P. saturated with hydrogen chloride, 3 C.C. of ethyl chloride were added, and the yellow solution was heated under reflux for two hours. On cooling, a small amount of tellurium dioxide was precipitated, and the brownish-yellow filtrate concentrated in a vacuum over lime. The yellowish-brown, oily residue solidified completely to a crystalline, yellowish-white solid, which was extracted with cold chloroform. The filtered extract, when concentrated under reduced pressure, yielded a buff -coloured, crystalline solid, which was redissolved in chloroform and precipitated by light petroleum. It then separated in pale yellow, prismatic needles commencing to change at 112" and decomposing a t 120" (Found : C1 = 28.50; Te = 34.12. C,H1402c13Te requires c1 = 28.30; Te = 33-91 per cent.).

R* 2

Publ

ishe

d on

01

Janu

ary

1923

. Dow

nloa

ded

by U

nive

rsity

of

Win

dsor

on

24/1

0/20

14 2

2:01

:31.

View Article Online

452 COLLMS AND WOOD: THE ADSORPTION OF

Tellurium 0-ethyhcetylpropionylmethane trichloride slowly became brownish-grey owing to elimination of traces of tellurium. Dis- solved in chloroform, it developed no red coloration with alcoholic ferric chloride; however, on boiling and leaving over-night, a deep red coloration developed. On treatment with aqueous sodium hydroxide, the trichloride underwent destructive hydrolysis, gave a greenish-yellow solution, and evolved a, characteristic earthy odour of the 0-ethyl ether of acetylpropionylmethane.

The authors desire to express their thanks to the Advisory Council of the Department of Scientific and Industrial Research for grants which have partly defrayed the expenses of this investigation. UNIVERSITY OF BIRMINGHAM,

EDOBASTON. [Received, December 13th, 1922.1

Publ

ishe

d on

01

Janu

ary

1923

. Dow

nloa

ded

by U

nive

rsity

of

Win

dsor

on

24/1

0/20

14 2

2:01

:31.

View Article Online