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ACTION OF PIIOSPHORUS PENTACHLORIDE ON BENZAMlDE. 1143

Benxamide. By ARTHURWALSH TITHERLEY and ELIZABETHWORRALL. DURINGan investigation, which is still in progress, of the behaviour of secondary with pentachloride, the action of the latter on simple primary amides came incidentally under considera- tion. Practically the whole of our available knowledge of the behaviour of primary amides with arises from Wallach’s extensive investigation (AnnuZen,1877, 184, l),which apparently left little further to be done in this direction. The net result of his work, based chiefly on the case of ethyl oxamate (oxa- methane) led him to the conclusion (i) that the carbonylic in the amido-group was first replaced by two atoms ; (ii) that the resulting “ dichloramide ” (I) which was very unstable, readily lost (1 molecule), yielding the unstable ‘‘ imide chloride ” (TI), and (iii) that the latter finally lost another molecule of hydrogen chloride, yielding the , thus :- *CO*NH,cc$ *CCl,*KH, -”: *CCl:NH -I?!!*CN, (1.) (11.) In the case of oxamethnne, unstable derivatives of types (I) and (11) were isolated in an impure condition, but apparently, in the case of all the other amides investigated, phosphorus derivatives containing oxygen and chlorine were produced. A derivative containing phos- phorus was also obtained by Wallach in the case of oxamethane,

Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. having the formula C,H,O,Ci,NP. In the case of benzamide, with phosphorus pentachloride in the cold, Wallach obtained a liquid which he considered to be a mixture of benzonitrile and phosphoryl chloride, but by gentle warming he obtained a liquid which, on coolingstrongly, set to a crystalline mass containing phosphorus. This compound decomposed at once in air, and was not further investigated. A critical survey of Wallach’s results would suggest that the general action of phosphorus pentachloride on simple primary amides leads to the production of phosphorus compounds and not the simple derivatives of types I and 11, and that such phosphorus compounds readily decompose on heating yielding phosphoryl chloride and the corresponding nitrile. The inconclusiveness of Wallach’s results with respect to benzamide led the authors to examine its behaviour wilh phosphorus pentachloride more closely. The conclusions which have been arrived at are mentioned below, but after these had been reached and the work had been nearly completed, a, recent paper by Steinkopf View Article Online 1144 TITHERLEY AND WORRALLi THE ACTION OF (Ber., 1908, 41, 3571) came under the authors' notice, in which the action of phosphorus pentachloride on halogenated acetamides is described, and, to a large extent, similar conclusions have been drawn. Originally it was intended by the authors to describe their work on benzamide and dibenzamide in one paper, but as the portion referring to the latter is incomplete, it was considered advisable, since Steinkopf is at work in a similar field, to publish at once the results so far as they relate to benzamide. When benzamide and phosphorus pentachloride react at 15O, slightly more than one molecular equivalent of hydrogen chloride is evolved, and since in no circumstances does interaction occur without formation of hydrogen chloride it is clear that the ' dichloride,' C,H,*CCl,*NH, (aa-dichloro benzy lamine), cannot be formed except :as an intermediate stage. The production of this derivative, however, as a first stage in the reaction can hardly be doubted in view of the general facts established by Wallach. In the subsequent change in- volving elimination of one molecule of hydrogen chloride, two things may be expected, namely, (i) the aa-dichlorobenzylamine may lose hydrogen chloride, yielding a-chlorobenzimide, or (ii) it may react with the phosphoryl chloride present, yielding a phosphorus derivative : I. C,H,*CCl,.NH, --+ C,H5*CC1:NH -I- HCl. (a-Chlorobenzimide, 1 11. C,H~°CUI~*N_EI,+ POCl, --+- C,H5*CCI,oN13*POC1,4- HCl. (aa-l>iclilo~obenzylphos~~li~iiliC:cliloride.) In any case the liquid obtained in ths action between benzamide and phosphorus pentachloride at 15' cannot be a mixture of benzo- nitrile and phosphoryl chloride as Wallach supposed, since such a mixture would require the loss of two molecular equivalents of Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. hydrogen chloride. This liquid, on treatment with water, yields bensonitrile, whilst on keeping in the cold for several hours in absence of moisture it slowly loses a molecule of hydrogen chloride, leaving a mixturs which consists essentially of benzonitrile and phosphoryl chloride, and the same result is attained very rapidly by heating the liquid produced at 15' to 50'. A totally different result, however, is obtained if the action between benzamide and phosphorus pentachloride is carried out at 50', or even at 15O, when such solvents as or are present. The resulting liquid obtained under these conditions on careful treatment with water yields a mass of colourless crystals containing chlorine and phosphorus, which on investigation proved to be a benzoyl derivative of phosphamic chloride, namely, C,H,*CO*N€€*POCl,. This remarkable difference in results, produced by such slight difference in conditions, led the authors to examine closely the pro- View Article Online PHOSPHORUS PENTACHLORIDE ON BENZAMIDE. 1145

ducts obtained under a large variety of conditions, and the conclusions arrived at may be stated thus : I. In the cold without solvent the ‘di~hloramide,~first formed, immediately loses hydrogen chloride, yielding chiefly a mixture of a-chlorobenzimide, C,H,*CCl: NH, and phosphoryl chloride, together with other products in small quantities (see p. 1148). The former is very unstable, and decomposes slowly at 15*, and immediately at SO”, or, on treatment with water, into benzonitrile and hydrogen chloride. On account of its instability it is impossible to isolate this a-chloro- benzimide, which, moreover, could not be separated by strong cooling or treatment with light petroleum, 11. In the cold, in presence :of benzene or chloroform, the ‘di- chloramide ’ first formed immediately reacts with the phosphoryl chloride simultaneously produced, yielding aa-dichlorobenzylphos- phamic chloride, C,H,*CCl,*NH*POCl,, which, on heating to 50°, loses hydrogen chloride, yielding a-chlorobenzylidenephosphamic chloride : C6H5*CC12*NH*POCI,-+ C6H5*CCI:X*POCl, + HCI. This product, moreover, results directly when benzamide and phos- phorus pentachloride, without a solvent, are heated to SO’, two molecules of hydrogen chloride being evolved, but a considerable amount of benzonitrile and phosphoryl chloride is also formed. The influence of a solvent in inducing the formation of phosphorus deriv- atives is very striking, and by adding benzene at different stages of the action and examining the resulting product, after exposure to moist air, for benzoylphosphamic chloride, it was possible to shaw that the influence of the solvent in the reaction between benzarnide and phosphorus pentachloride is not operative after the first molecule of hydrogen chloride has been evolved, but exerts itself in the reaction Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. involving elimination of hydrogen chloride. The effect of a solvent, which is similar to that of heat, must be to induce the hypothetical aa-dichlorobenzylamine to react with the phosphoryl chloride with liberation of hydrogen chloride, whilst in absence of solvent at lower temperatures the act-dichlorobenzylamine spontaneously decomposes without acting on the phosphoryl chloride, yielding a-chlorobenzimide, C,H,*CCl:NH. There is, however, no direct proof available of the actual production of the latter compound ; treatment of the supposed mixture of this substance and phosphoryl chloride with a benzene solution of aniline at low temperatures failed to yield phenylbenz- amidine, but having regard to the great instability which might be expected to characterise a-chlorobenzimide, it is likely that the aniline simply effected removal * of hydrogen chloride yielding benzonitrile * A siuilar removal of hydrogen chloride: by aniline Iias been shown to take place with certain phosphorus derivatives (see p. 1146). View Article Online 1146 TITHERLEY AND WORRALL: THE ACTION OF

which was found, Moreover, attempts to prepare a-chlorobenzimide by the action of hydrogen chloride on benzonitrile at low temperatures were unsuccessful. In regard to the two possible reactions, I. C,H,*CCl,*NH, -+ C,H,*CCl:NH + HCl. 11. C,H5*CC1,*NH, +POCl, -+ C,~,~CCl,*NH*POCJ~+HCI, it would appear that whilst the velocity of (I) is not influenced by benzene and chloroform the velocity of (11) is greatly accelerated by these solvents and by rise of temperature. As already noted, Wallach (Zoc. cit.) isolated a cornpound similar to that formed in (11), by the action of phosphorus pentachloride on oxamethane. The product of the action in the cold was a clear liquid, evidently consisting of a mixture of phosphory ;chloride and the unstable compound, CO,Et.CCI,*N H2, which was precipitaied in needles by light petroleum. The mother liquor, however, on keeping, deposited crystals the composition of which corresponded with the formula C0,Et*CCl,*NH9POC12. The most interesting feature, however, in councvion with this substance is the fact that it was only formed under the c'ztalytic influence of R trace of moisture. As in tho authors' expeiiments moisture was carefully excluded by means of phosphoric oxide, it is probable that benzene and chloroform behaved catalytically in a similar manner, that is, accelera- ting reaction (11) above, and indeed it was shown in one ex1)eriment that a relatively small quantity of chloroform gave LL nearly quanti- tative yield of the phosphorus derivative. The behaviour of a-clilorobenzylideLIephosph~~iicchloride with moisture is very remarkable, seeing that the two chlorine atoms

Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. attached to phosphorus escape action, whilst that attached to carbon is replaced by hydroxyl, yielding the benzoylphosphamic chloride, C,H,*C(OH):NPOCl, C,H5*C1O-NH*YOCl,, already referred to, from which benzoylphosphamic acid, CYsH,*CO*Nll*YO(OH),. may be readily obtained. This curiorxs action is probably attributable to the steric hindrance of the phenyl group, and suggests that tho C6H5--g c1 trichloro-derivative has an Lcszti-configurutiori, POCl,*N Both chlorobenzylidenephosphamic chloride and benxoylphospharnic chloride readily react with aniline. In each case one of the chlorine atoms attached to phosphorus is [inirnediately replaced by the anilino- group, whilst the other tends to lie eliminated more slowly as hydrogen chloride under the influence of the aniline, instead of being replaced. The final product of the action of aniline on a-chlorobenzylidene- View Article Online PHOSPHORUS PENTACHLORJDE ON RENZAMIDE. 1147

phosphamic chloride after several days is phenyliminophosphoryl- phenylbenzamidine, C,H,*C(NHPh):N*PO:NPh, and not the expected trianilino-derivative. The changes which have been observed are shown in the following scheme :

I $PhNITa Ph'NH2, COPh*EH*POCl*NHPh I Eciizoylarn iiioanilii iophosphoryl 4 chloride, 111. p. 176". I CCIPh:N*POCl'NHPh -"? CCIPh:N*PO:NPh ?$ I OII*CPh:N*PO:NPh 72 COPh*NH*PO:NPh + Phenyli~ni~~oplios~,horylbenza~rii~lc,tn. p. 2.26". NHPh*CPh:N*PO:NPh Phenyliminophosphoryl- phenylbenzamidiiie, in. p. 227".

Steinkopf, to whose work reference has been made (loc. cit.), obtained, by the action of phosphorus pentachloride on halogen- substituted acetnmides, phosphorus derivatives containing the grouping *CCl:N-POCI,, but tacitly assumes that the production of such derivntives * is due to the influence of the halogen atoms in the substituted amides, and incidentally notes that benzamide and phosphorus pentachloride yield benzonitrile, apparently on Wallach's authority, which, however, is not justified. Having regard to the observations of Wallach, Steinkopf, and the authors, it would appear that the production of phosphorus derivatives may be expected with all primary amides ; the simple derivatives containing the groups, *CCl,*NH, and *CCl:NK may only be expected when catalytic influences arc excluded, but, the separation of such unstable derivatives Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. from the accompanying phosphoryl chloride is usually impossible.

E x P E R I M E N TA L, Action of Phosphorus Pentccchloyide on Benxu mide, without Solvent. 1. At 8O.-An intimate mixture of very finely powdered benzamide (1.5 gram) and phosphorus pentachloride (2.6 grams) contained in a small tube, provided with a phosphoric oxide trap and delivery tube, * S teinkopf regards tliesc coinpounds as p~losphorr~nsrlerivntivcs, liis system of nomenclature, which is quite different from that adopted by the authors, having been devised to distinguish the constitution of such compounds from true phosphoric derivatives containing the gronping *o*Po<. TI~I~,lie caHs CCI,*CC~:N*YOCI,, '' trichloracetiniid chlorid phosphorigsiiilu e dichlorid, " and CC1,*CO*NH*POCl2, '' trichloracetsmid phospliorigciiiiure dichlorid." As, howcvtar, all these compoiinds anti those of the authors, on hytlrolgbis, yicld pliosphoric acid and not phosphorous acid, the authors prefer to regd theni as phosphamic clerivativcs. VOL. xcv. 4F View Article Online 1148 TITHERLEY AND WORRALL: THE ACTION OF

was kept at 8" and the hydrogen chloride evolved was collected in water. In three hours action had ceased and a pale yellow liquid resulted. The hydrogen chloride absorbed by the water was titrated with alkali, and, after correcting for the vohme of the apparatus, was found to be 0.38 gram (1 mol. =0*45 gram HCl). The pale yellow liquid was apparently stable at Oo, and did not solidify at -2%". On exposure to atmospheric moisture it yielded a syrup consisting chiefly of benzonitrile and , which were also formed on treatment with water ; benzoylphosphamic chloride was not produced in appreciable quantity. Above 15" the liquid obtained at 8" steadily decomposed, evolving hydrogen chloride, and at 50' the decomposition was complete in five minutes. The hydrogen chloride evolved weighed 0.4125 gram (1 mol. = 0.45 gram HC1). The liquid remaining after heating at 50" was found to con- sist essentially of benzonitrile and phosphoryl chloride. In another ex- periment, using larger quantities, the liquid obtained at 8' was cooled to 0' and treated with light petroleum, which precipitated an almost colourless oil ; this oil was washed at 0' by shaking repeatedly with small quantities of light petroleum in which, however, it was appreciably soluble. The washings contained phosphoryl chloride in quantity, which was shown by analysis after decomposition by water. The oil precipitated by the petroleum was not a pure substance and Contained phosphorus, although in relatively small quan tity, and the yield of the oil was small. A portion, after being kept in a vacuum for a short time, was aualysecl volumetrically by decomposing with water and titrating with sodium carbonate (using methyl-orange) and silver nitrate.

1.813 required 19.5 C.C. 2l'-Na,CO3 and 168.5 C.C. N/10 AgNO,.

Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. P = 4.6 ; C1= 32.9. Assuming the phosphorus derivative (phosphoryl chloride, which is miscible with light petroleum, being excluded) to be (a) C,H,*CCI ,*NH*POCI2, or (b) C,H5*CC1:N*POCI,, from the above values it is possible to calculate the net amount of chlorine in the remaining substance. This gives (a) C1=21.02 or (6) C1=27*2 per cent, C,€15*CC1:NH requires C1- 25.44 per cent, Owing to the extremely easy decomposability of the substance, and the readiness with which benzonitrile is produced, on attempted purification no more katisfactory data than the above could be obtained. Besides benzonitrile and benzoylphosphamic acid, the oil gave on treatment with water a small quantity of a phosphorous acid derivative yielding dibenzamide on h~drolysis,which separated in View Article Online PHOSPIIORUS PEKTACHLORIDE ON BENZAMlDE. 1149

needles (m. p. 148') on heating the aqueous solution at 100' for about two hours. 2. At 15".-The action between benzamide and phosphorus penta- chloride was found to be very much more rapid at 15" than So, and only required from thirty to forty minutes for completion. 1.5 benzamide gave 0.510 HC1 (1 mol. = 0.45 HCl). The resulting pale yellow liquid neither solidified on cooling nor yielded crystals of benzoylphosphamic chloride on exposure to atmospheric moist tire, even af ter previous admixture with benzene, or heating to 50". In all its properties it was similar to the liquid obtained at 8", although it probably contained relatively less a-chloro- benziniide, since at 15' hydrogen chloride mas slowly but continnously disengaged. 3. At 5Oo.-In the action between benzarnide and phosphorus pentachloride at 50" which was very vigorous, the hydrogen chloride amounted to 2 mols. and the action was complete in twelve minutes. The resulting pale yellow liquid was found to vary in composition and on cooling to - 20' sometimes set to an almost solid crystalline mass ; in most cases it became vlscous without solidifying. In all cases ob- served there appeared to be a considerable qnantity of benzonitrile and phosphoryl chloride formed, but the main product mas a-chloro- benzylidenephosphsmic chloride. Attempts were made to isolate the latter in a pure condition by treatment with light petroleum at a low temperature but it was found impossible to remove the accompanying substances in this way. On exposure to sir it rapidly absorbs moisture forming benzoylphosphamic chloride (m. p. llOo, see p. 1151) whilst on treatment with water it is instantly decomposed, yielding this compound as an insoluble white crystalline solid and henzoylphosphamic acid

Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. which is fonnd in the aqueous solution. The variation in the com- position of the liquid obtained in the reaction 50' was readily followed by noting the relative amounts of benzoylphosphamic chloride and benzonitrile obtained after exposure to air, the yield of phosphamic chloride being smaller the greater the lapse of time between mixing the benzamide and phosphorus pentachloride, and raising the temperature to 50". In no case was the quantitative yield of the phosphamic chloride obtained.

Action of Phosphorus Pentachloride on Benxanzide in Presence of a Xolvent . a-Cl~ZorobesPxyEideizephosp~amic Chloride, CY,H,* CC1: N*POCl 2. 1. Using Cldoroform.-A vigorous act.ion took place in the cold with evolution of hydrogen chloride, and the resulting chloroform solution on exposure deposited a large amount of benzoylphosphamic 4F2 View Article Online 1150 TITIIERTAEY AND WORRAT-L: THE ACTION OF

chloride iu colourless plates, together with a relatively small quantity of a syrup consihting of benzonitrile and phosphoric acid. The hydrogen chloride evolved in the action in the cold was not measured, owing to its moderate in chloroform. At 60' it amounted to 75 per cent. of the theoretical quantity for two molecules, and 2.7 grams of benzoylphosphamic chloride mere obtained from 3 grams of benzamide. Several attempts 'were made to obtain pure a-chloro- benzylidenephosphamic chloride, using the chloroform method by modifying the conditions, but in all cases some benzonitrile and phosphoryl chloride were formed. By rising a small qrmnt,ity of chloroform in the reaction at 50°, and subsequently heating in a vacuum at 60°, an oil was obtained consisting chiefly of a-chIorobenzylidene~}iosphtzmic chloride, but contaiuing some henzonitrile : 2.382 required 29-69 C.C. N-Na,CO, and 225.5 C.C. N/lO-AgNO,. Ratio, P : C1= 1 : 3.2 ; P = 9.1 ; C1= 34.6. These figi~res correspond with a mixture of 84 per cent. of a-chlorobeizzylidenephosphnmic chloride and 16 per cent. of benzo- nitrile. In another experiment a purer product was obtained by using only a trace of chloroform at SOo, and proceeding as before. The benzonitrile it contained was determined and corrected for : 2.3538 gave 0,159 C,I%,.CN and 0.8830 Blg2P207. 2.3538 required 235.0 C.C. &/lo AgNO,. Y= 11.24 ; C1= 38.01. (After correcting for C,;W,.CN.) C7H,0NCI,P requires P = 12.09 ; C1= 41.53 per cent. The low chlorine value is attributed to the loss of hydrogen chloride, due to moisture, which it is almost impossible to exclude

Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. during the treatment in a vacuum. 2. OTsing Bs.nzene.--The same results were obtained as with chloro- form, and the met,hod employed was similar : 3.0 benzamide gave (I) 1.022 HCl at lSo, and (2) 1.60 HCl at SOo. (1) 1 mol. HC1=0.92, and (2) 2 mols. HC1= 1.84. By carrying out the reaction at 50' in presence of a small quantity of benzene, an oil was obtained after heating at 60' in a vacuum, which on analysis was found to contain 90 per cent, of a-chloro- benzylidenephosphamic chloride. In the reaction at 1.5." from 3-4 grams of benznmidc, 4 grams of benzoylphosphamic chloride were obtained by exposure to rrioist air immediately the reaction was over; by previously keeping for twenty-four hours at 15', however, the yield of benzoylphosphamic chloride was very much diminished, and a correspondingly large amount of benzoiiitrile mas obtained. It mould seem, therefore, that the first product of the reaction, aa-dichloro- View Article Online PHOSPHORUS PENTACHLORIDE OX BENZAMIDE. 1151

benzylphosphamic chloride, slowly decomposes in benzene solution at the ordinary temperature into benzonitrile and phosphoryl chloride.

BenxoylpJbospJbamic Chloride, C,H,*CO*NUL*POCl,. An intimate mixture of 24.2 grams of finely-powdered benzamide and 414 grams of phosphorus pentachloritle was rapidly treated with 100 grams of pure benzene, and the mixture immediately heated in a bath at 50". After twenty minutes the action, which was very vigorous, was complete, and the liquid was exposed to air in a shallow dish for twelve hours. Masses of large, colourless crystals continually separated as moisture was absorbed, arid finally a practically dry solid was left. The crystals were quickly washed with cold water and dried at room-temperature on porous porcelain. They melted at llOo, and weighed 43.5 grams (theory requires 47.6 grams). The substance was quite pure. Prepared by a similar method to the above, using chloro- form instead of benzene, a smaller yield was obtained : 0-313s required 38.3 C.C. N/lO-Na,CO, and 26.0 C.C. N/lO-hgNO,. Ratio, P : C1= 1 : 2.1 ; C1= 29.42. 0,4654 required 58.0 C.C.N/10-Na,C03 and 38.5 C.C. NIIO-AgNO,. Ratio, P : GI = 1 : 1.97 ; C1= 29-36. 0.6324 gave 0.2894 Mg2P,07; P = 12.77. l0109S,byKjeldahl's method, required4'7.6 C.C. N/lO.HCl ; N = 6.00. C7H,0,NC1,P requires P = 13.02 ; C1= 29.5 ; N = 5.88 per cent. Benxoylphospharnic chloride crystallises in colourless plates melting at 115" when pure arid rapidly heated, but usually at 110' owing to decomposition, which begins even below 100'. When heated at 120', hydrogen chloride is rapidly evolved, the decomposition is complete in fifteen minutes, and the liquid separates into two layers, the upper Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. consisting of benzonitrile and phosphoryl chloride, the lower of phos- phoric acid. 0 wing to its easy decomposition, benzoylphosphamic chloride could riot be satisfactorily recrystallised from hot solvents. It is practically insoluble in cold benzene or light petroleum, sparingly soluble in hot benzene, cold , ether, or chloroform, and mode- xately so in acetone ; the solutions readily decompose in presence of moisture with formation of benzoplphosphamic acid. A similar decomposition occurs slowly with the pure dry substance, which on this account cannot be kept long in ordinary moist air. On the other hand, treatment with cold water has no appreciable action on the substance, which is insoluble, but when boiled in water it is rapidly and completely decomposed into hydrochloric and phosphoric acids and benzamide, which crystallises out on cooling. Benxoylphosphamic chloride is immediately decomposed in the cold by alka,lis, even by aqueous sodium hydrogen (:arbonate (with efferves- View Article Online 1152 TITHERLEY AND WORRALL: THE ACTION OF

cence) and sodium acetate, yielding R salt, of benzoylphosphamic acid ; when treated with sodium hydroxide, three molecular equivalents of the latter are required for neutralisation, using methyl-orange, and four using phenolphthalein as indicators. By treatment with aniline it yields different derivatives, according to conditions.

Yl'lerLylirnii~o~hos~~ol.?/kbenxanzide, C,H, C O*NHa PO: NPh E' C,H,*C(OH): N*PO:NPh.

Five grnms of benzoylphospharnic chloride, suspended in 30 C.C. of water, were treated with 8 grams of aniline, and the mixture was well triturated. The thin, oily emulsion first formed rapidly hardened, and in a few minutes voluminous white masses of a granular solid separated. After thirty minutes the whole was stirred with dilute hydrochloric acid, and the insoluble portion was collected and crystallised from alcohol. The pure substance separated in colourless, silky needles, melting at 336*, and weighed 5.4 grams (yield theoretical) : 0.4944, by Kjeldahl's method, required 37-1 C.C. hT/lO-HC1. N = 10.55.

0,4368 ,, J9 ?, ,, 33.7 C.C. N/lO-HCl. N= 10.S2, 0,3458gave 0.1580 Mg,P,O,. P = 12.55. C13Hl102N,P requires N = 10*S5; P = 12.01 per cent. Phen2/lii?ainop1~osphoryZbenxamide is sparingly soluble in alcohol, ether, benzene or carbon tetrachloride and moderately so in acetone, chloroform or methyl alcohol. It is insoluble in aqueous sodium carbonate, but completely soluble in dilute sodium hydroxide and is reprecipitated by acids from the alkaline solution, in a gelatinous

Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. form melting at about 226'. This behaviour with alkali is similar to tbat of dibenzamide and indicates a similarity between the groups *CO*NHPO-and *CO*NH*CO. Like dibenzamide also, the compound is soluble in an excess of concentrated ammonia, although it is not changed on heating with this solvent. The tautomeric form, corresponding with the salts to which the compound gives rise must be regarded as C,H,*C(OH):N*PO:NPh and not bthe alternative form C,H,*CO-N:P(OH):NPh, which should represent an acid soliible in sodium carbonate,

Bsn~o~Zanzinocc~~iZir~o~~os~~oryZCIdoride, C,H,*CO*NH*POCl*NHPh.

4.8 Grams of benzoylphosphamic chloride suspended in 50 C.C. of absolute ether were treated with 7 grams of pure auiline and the mixture was shaken and kept for twelve hours. A large quantity of white solid matter was deposited; this was washed with ether, and View Article Online PHOSPHORUS PENTACHLORlDE ON BENZAMIDE. 1153

treated as described below. The ethereal filtrate on evaporation left a white solid consisting of a mixture of phenyliminophosphoryl- benzamide and an unstable substance, which were separated by digestion with 1 per cent. sodium hydroxide, in which the former is immediately, and the latter only slowly, soluble. By quickly washing and drying on porous porcelain it was obtained in an approximately pure state, but by crystallisation from alcohol or other solvents it mas converted into phenyliminophosphorylbenzamide (m. p. 226'). As an analysis of the unpurified Substance gave N = 12.27 it probably con- sisted of the dianilino-derivative, C,H,*CO.NH.PO( NHPh), (N = 11-96 per cent.), but this could not be verified. The insoluble solid obtained above in the action of aniline on benzoylphospharnic chloride was washed with water to remove aniline hydrochloride, and the residue, weighing 4.1 grams, consisting of nearly pure benzoylaminoanilinophosphoryl chloride was crystal- lised from alcohol, from which it separated in fine, silky needles melting at 176". 0.1298 gave 11.4 C.C. N, (moist) at 24' and 747 mni. ; N= 9.66. 0.2682 ,, 0.1282 AgCl ; C1= 11.83. C1,H,,O,N,CIP requires N = 9.51 ; C1= 12.05 per cent. The chloi o-derivative is moderately soluble in methyl or ethyl alcohol or acetone, and sparingly so in elher, benzene or chloroform. With aniline it reacts at once giving phenyliminophosphorylbenzamide, and it dissolves readily and decomposes in sodium hydroxide. The alkaline solution on acidifying deposits, after a few minutes, fine, colourless needles, appreciably soluble in cold water. The substance, which melts at 16Z0, does not contain chlorine, and as it is soluble with effervescence in sodium hydrogen carbonate it probably consists of the

Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. acid, C6H,*CO-NH*PO(NHPh)OH,but it was not obtained in suflicient quantity for analysis.

Benxoy/phosphamic Acid, C,H,* CO*NH.PO(OH),. This acid was prepared by dissolving benzoylphosphamic chloride in pure acetone, adding the calculated amount of water and allowing the solution to evaporate. Transparent crusts of crystals slowly separated consisting of the nearly pure acid, the yield being almost theoretical. After crystallisation from methyl alcohol containing benzene it melted at 157-155". 0.4572 gave 0.2582 Mg,P,07 ; P = 15.69. 0.3933 by Kjeldahl's method required 20.3 C.C. ; N/lO-HCl ; N = 7.23. C,H,O,NP requires P = 15.43 ; N = 6.96 per cent. Benxoyl~hosp~~ccnzicacid is readily soluble in water, methyl or ethyl alcohol, sparingly so in acetone, and insoluble in benzene, ether, View Article Online 1154 ACTION OF PHOSPHORUS PENTACHLOBIDE ON BENZAMIDE.

chloroform, or ethyl acetate. On boiling with water for a few minutes it is completely decomposed in to beuzamide and phosphoric acid. A neutral solution of the ammonium salt gives a nearly white precipitate with ferric chloride and voluminou8, white precipitates with silver nitrate, barium chloride and calcium chloride but no precipitate with magnesia mixture. The free acid, like phosphoric acid, requires one molecular equivalent of sodium hydroxide for neutralisation, using methyl-orange as indicator, and t.wo using phenol- phthalein.

Phenyliminop?~osp~~or~l~~~~n~~benxa912id~n~,C6H5*C(N HPh) :N*PO:NPh. When aniline was allowed to act on a-chlorobenzylidenephosphamic chloride in benzene solution for twenty-four hours and the clear filtrate from the aniline hydrochloride mas left exposed to air a mixture was gradually deposited consisting of phenyliminophos- phorylbenzamide (m. p. 226") and phenyliminophosphoryIpheny1- benzarnidine (m. p. 227') which were readily separated by treatment with dilute sodium hydroxide, the compound melting at 227" being insoluble. A better yield of the latter was obtained by allowing the aniline to act for a longer time. A mixture of 9 grams of benzamide, 15.5 grams of phosphorus pentachloride, and 20 grams of pure benzene was rapidly placed in a bath at 50°, and kept at this temperature for forty minutes until action had ceased. The resulting solution of a-chlorobenzylidene- phosphamic chloride was cooled to 0" and treated gradually with 50 grams of pure aniline and kept for forty-eight hours. The insoluble aniline hydrochloride was collected and the filtrate left in an open dish for twelve hours. A white solid (30 grams) was deposited which

Published on 01 January 1909. Downloaded by Dalhousie University 19/05/2015 08:44:17. was collected and washed with benzene. This solid was a mixture and contained chlorine ; on keeping its alcoholic solution phenylimino- ~?~os~?~or?/l~~J~enyZbenxccnz,idine(1 3 grams) was deposited as a white, microcrystalline powder. On recrystallisation from boiling alcohol, in which it is not very soluble, it was obtained in fine needles melting at 227-228" : 0.2531 gave 0,0872 Mg,P,O,, and required 22.4 C.C. N,lO-HCl; P = 9.62 ; N = 12.39. C,,H,,ON,P requires P -- 9.31 ; N = 12.61 per cent. The compound is sparingly soluble in methyl or ethyl alcohol or chloroform and practically insoluble in ether, benzene, or carbon tetrachloride. It is moderately soluble in acetone, and separates as a mealy powder on adding n small quintity of water to the hot solution. ORGANICLAEOKAI oit~, UNIVEKSIry OF LIVEI:IWL,