988 RlITTER AND SEN ACTION OF PHENYLHYDRAZINE I XXXIV.-Action oj' Pheriylhydrazine on Opianic, Nitro-opiunic and Phthulonic Acids Some Derivatives of Hydrazo- and Azii-phthalide. By PRAFULLA CHANDRA MITTER and JNANENDRA NATH SEN. THE action of phenylhydrazine on opiaiiic and nitro-opianic acids was first studied by Liebermaim (Ber. 1886 19 763) who found that' in the case of opianic acid on0 molecule of the acid reacts with one molecule of phenylhydrazine with the elimination of two molecules of water and the formation of a compound insoluble in alkalis t o which he attributed a ring strubture. I n the case of nitreopianic acid an intermediate product soluble in alkalis which therefore was regarded as the ordinary phenyl-hydrazine derivative of nitro-opianic acid was isolated.This sub-stance could be purified by dissolving in cold acetone and pre-cipitation with water. On recrystallisation from glacial acetic acid however it' was converted into a compound insoluble in alkalis and containing one molecule of water less than the phenyl-hydrazine derivative and t o this coinpound too a ring structure was assigned. A behaviour similar to that of opianic acid on treatment with phenylhydrazine had been observed by Roser in the case of a number of o-keto-carboxylic acids (Ber. 1885 18 802). I n every case from one molecule of keto-acid and one molecule of phenyl-hydrazine with the hydrazine 11 y d r azine For the stances in two molecules of water instead of one were eliminated, formation of ring compounds. Intermediate phenyl-derivatives formed by the primary action of phenyl-on the aldehydo-group could not be obtained.preparation of these compounds Roser heated the sub-alcoholic solution with phenyl hydrazine and acetic acid ON OPIANIC NITRO-OPIRNIC AND PHTHALONIC ACIDS. 989 whilst Liebermann treated the substances in aqueous solution with phenylhydrazine hydrochloride and sodium acetate. In both cases the reaction Look place in the presence of acetic acid. It has been found that in ethereal solution and with the free base the reaction takes place in a novel manner with the loss of only one molecule of wafer. The products can in some cases be crystallised from dilute acetone. They vary in their degree of stability aiid in some cases remain unchanged for days especially during the cold season.On treatment with acetic acid the substances are instantaneously converted by loss of a further moleculk of water into ring com-pounds identical with those obtained by Liebermann and others. For the phenylhydrazine derivative (for example from opianic acid) we have the choice of two alternative formulz, /\CH:N*NHPh 5Hd /\CH(NH*NHPh)>o lie01 Ico -- \/ R I P 0 Meo\/Co2H JIeO (1. ) (11.) We are in favour of formula 11 because on subsequent oxida-tion with mercuric oxide in acetone solution the phenylhydrazine derivatives are converted into deep-coloured substances which give all the usual reactioiis of azo-compounds. The formation of an azo-compound by oxidation is a definite indication in favour of the hycirazo-structure.With the ordinary formula such a change cannot be explained without assuming a considerable amount of molecular rearrangement and redistribution of linkiugs. The azophthalides which have been prepared in this way repre-sent an altogether new class of azo-compounds. The mechanism of the reaction in this case and in the case of amines generally appears to be as follows. The elimination of water takes place in the first instance between the aldehydo-group on the one hand and the amino- or imino-group on the other. The hydrogen atom of the carboxyl group subsequently oscillates to the nitrogen forming a phthalide ring. In the case of a primary amine the change may be represented thus : 'J""s(NHR)>~. )--In the case of secondary amines two molecules of the ainine react with one molecule of the aldehyde aiid when the hydrogen atom of the carboxyl group oscillates to the nitrogen atom a molecul 990 MITTER AND SEN ACTION OF PHENYLHYDRAZINE of the amine is regenerated which is at once detached from the condensation product thus : I n the case of phenylhydrazine the action is exactly similar thus: \/\CH(NH *NHPb) I /co-->o./\/ The formation of stable azo-compounds by oxidation would thus be readily explained and they would have the structure repre-sented below : \/\CH(NH*NHPh)> ),)co--The oscillating hydrogen atom can of course reveri a t any moment to the original position which it apparently does in acid and alkaline media. This explains the solubility of the substance in alkalis as well as the formation of the phthalazone ring under the dehydrating influence of different acids.On oxidation t o the azo-compounds the hydrogen atom is removed with the result that the products become insoluble in alkalis unlike the hydrazo-compounds. Such oscillation of hydrogen of the carboxyl group to doubly or trebly linked atoms or radicles in the 0-position with respect to the carboxyl group is not without many parallels. E X P E R I M E N T A L . fnterctctioii of I'her~yliLynrtcsirte uw? Oyitrrric ,4 cid. Opianic acid is rather sparingly soluble in ether but 011 adding the acid to an ethereal solution of phenylhydrazine i t dissolves readily. The solution on keeping deposits minute crystals of the phenylhydrazine derivative. Five grams of phenylhydrazine hydrochloride were 'created with sodium hydroxide and to the ethereal solution of the liberated base 5 grams of opianic acid were gradually added with constant stirring the vessel being kept cool with ice-water.The acid dis-solved and on scratching the sides of the vessel minute crystals soon appeared. To ensure completion of the reaction the mixture was allowed to remain for about half an hour. The precipitate was washed repeatedly with ether and then dried in the air. The yield was 5.5 grams ON OPIANIC NITRO-OPIANIC AND PHTHALONIC ACIDS. 991 The substance crystallises from dilute acetone in pale piilk needles melting and decomposing a t 146O. It is soluble not only in dilute alkali carbonate but also in dilute sodium hydroxide and ammonia and less readily so in sodium hydrogen carbonate.I n the cold it does not dissolve in hydrochloric acid but on warming solution takes place. Concentra.ted nitric acid dissolves i t immedi-ately with the evolution of nitrous fumes and the production of a deep red colour. With concentrated sulphuric acid i t gives no colour. Acetic acid transforms i t into the ring compound: 0.1454 gave 0.3413 CO and 0.0786 H,O. 0’0996 , 7.9 C.C. N a t 2 1 . 5 O and 760 mm. N=9*19. The substance was dissolved in dilute standard alkali and the It was found 0-1889 required 6.4 C.C. N/lO-acid whilst this weight of a mono-C=64*02; H=6*01. Cl,Hl,O,N requires C = 64.00 ; H = 5.33 ; N =9.33 per cent. excess of alkali titrated with standard oxalic acid. to be monobasic. basic acid of the above formula requires 6.28 C.C.N/lO-acid. P h e ?i y la z om e co tz in. One gram of phenylhydrazorneconin (formula 11) was dissolved in 25 C.C. of pure acetone (free from methyl alcohol) and heated on the water-bath with 4 grams of red mercuric oxide the liquid being kept almost a t boiling point. The colour of the solution gradually changed to crimson-red. After remaining overnight the mixture was filtered and the filtrate allowed to evaporate in the air when a pasty mass was left which became hard on treatment with ether. The substance was dissolved in acetone and ether added to the solution. A pale yellow flocculent precipitate was formed which had a tendency t o become tarry and after removing this by filtration the filtrate was allowed t o evaporate in a vacuum over Bulphuric acid.A residue was left which after crystallisa-tion from dilute acetic acid was obtained as a yellow crystalline powder melting a t 1 6 4 O . I’henylazomeconilz gives all the usual reactions of an azo-com-pound. With concentrated sulphuric acid i t gives a violet colour. The colour of the substance itself is discharged by treatment with a solution of stannous chloride and hydrochloric acid. It dissoIves in glacial acetic acid with a red colour which intensifies on warm-ing. If to this solution zinc dust is added and the whole heated for a moment the colour changes t o pale yellow with the forma-tion of a precipitate. I n alcohol i t dissolves with a pink colour, which deepens on the addition of alkalis. It is readily soluble in acetone chloroform or benzene 992 MITTER AND SEN ACTION OF PHENYLHYDRAZINE 0.1034 gave 0.2438 CO and 0.0449 H,O.0*1003 , 8.4 C.C. N a t 2 5 O and 760 mm. N=9.59. C=64*34; H-4.82. C,,H,,O,N requires c = 64.43 ; H = 4.69 ; N = 9.39 per cent. Phenylop’azone. One gram of phenylhydrazomeconin was dissolved in hot glacial acetic acid the solution boiled for about five minutes and water added when the ring compound was precipitated in almost colour-less flakes. It was purified by redissolving it in dilute acetic acid and boiling with animal charcoal. On filtration and cooling, crystals separated which were perfectly transparent and melted sharply a t 175O. (Found C= 68.62 ; H = 5.26. C,,H,,0,N2 requires C = 68.08 ; H =4*96 per cent.) This substance is identical with the opianylphenylhydrazide described by Liebermann.It is insoluble in alkalis or alkali carbonates and does not develop any colour with concentrated sulphuric o r nitric acids. Interaction of Phenylhydrazirze atid Nitro-opianic A cid. To an ethereal solution of phenylhydrazine (from 1.5 grams of the hydrochloride) 1 gram of nitro-opianic acid was gradually added. I n a few minutes after solution was complete a red oil settled to the bottom which on stirring solidified to a crystalline mass which was collected and washed with ether. It crystallised from dilute acetone in red needles melting a t 184O (Found: N= 12.26. C;,Hl5O6N3 requires N = 12-17 per cent.) evidently identical with Liebermann’s (‘ nitro-opianic acid phenylhydrazine.” The substance is soluble in alkalis or alkali carbonates.With sulphuric acid i t gives but a pale green colour. Phenylhydrazonitromeconin (0 8 gram) was dissolved in 15 C.C. of pure acetone and 1.5 grams of red mercuric oxide were added. The liquid was kept gently boiling on a water-bath under reflux for about two hours after which it was left a t the ordinary temperature for twenty-four hours. The mixture was then filtered, the residue repeatedly extracted with boiling acetone and the acetone solution evaporated when a brick-red crystalline mass was obtained. This was treated with excess of sodium carbonate to remove any trace of the hydrazo-compound thoroughly washed with water and crystallised from dilute acetone from which i ON OPIANIC NITRO-OPIANIC AND PHTHALONIC ACIDS. 993 separated as an orange crystalline powder melting sharply a t 217'.The substance is sparingly soluble in acetone and insoluble in all other common solvents. With concentrated sulphuric acid i t gives a blue colour: 0.0959 gave 0.1976 CO and 0.0286 H,O. 0.1632 , 17 C.C. N a t 20° and 760.01 mm. N=12*14. C=56.19; H=3*32. C,,H,,06N requires C = 55-97 ; H'= 3-79 ; N = 12.26 per cent. With phthalonic acid and phenylhydrazine an intermediate hydrazo-compound was obtained which could be oxidised t o the corresponding azo-compound by means of mercuric oxide in acetone solution. It was also coaverted into the corresponding ring com-pound by dehydration with acetic acid. The hydrazo- and azo-compounds .have not however been obtained in a conclition sufficiently pure for analysis. Phenylpht halazoneca~-box~lic A cid, /\cop- YPh. (\/C(CO,H > N One gram of phenylhydrazophthalidecarboxylic acid was dis-solved in warm glacial acetic acid and hot water added t o the solu-tion. On cooling crystals of the ring compound were obtained in matted needles melting a t 208O. The substance is identical with the aiihydrophenylhydrazi~~e-o-carboxyphenylglyoxylic acid pre-pared by Henriques (Ber. 1888 21 1610). Further investigations are in progress. SIR T. N. PALIT LABORATORY, COLLEGE OF SCIENOE, UNIVERSITY OF CALCUTTA. (Receinetl June 18th 191 7.