1394 RUHEMANN : FORMATION OF PYRAZOLONE DERIVATIVES XC. -Formation of Pyrazolone Derivatives from Chlorofumaric: acid. By SIEGFRIED RUHEMANN, Ph.D., M.A. CLAUS and Voeller (Ber., 1881, 14, lsl), and W. H. Perkin, senior (Trans., 1888, 53, 702), by the action of ammonia on ethylic chloro- fumarate, obtained, in addition to ethylic chlorofnmaramate, the diamide of amidofumaric acid. The readiuess with which the chlo- rine atom of the ethereal salt is replaced by the nmido-group, rendered it probable that hydrazine would also effect a similar snb- stitution, and a t the same time bring about a condensation to a pyr- azolone compound. Such a change does, in fact, take place, and gives rise to the formation of ethylic 5-pyrazolone-3-carboxylate, as represented by the equation COOC2H~*CH:CCl*C00 C2H5 + SNH,*NH, = C OOCJ€5.$-7H2 N GO ‘4H + CZHCO + NHZ.NH2,HCl. This substance is identical with the compound which v.Rothen- burg (J. pr. Chem., 1893, 51, 53) obtained froin the ethereal salts of oxalacetic azld acetylenedicarboxylic acids. We have, therefore, to assume that the condensation of ethylic chlorof amarate and hydr- azine hydrate to the pyrazolone derivative is accompanied by a mole- cular transformation similar to that which brings about the formation of ethylic 5 -pyrazolone-4-carboxyla te from e thy1 ic dicarboxyglu ta- conate and the hydrazine (Ber., 1894, 27,1658 ; lS9.5, 28, 987).FRO31 CHLOHOFUXXRIC ACID. 1395 The action of hydrazine hydrate on ethylic chlorofumarate pro- ceeds with great development of heat. The product, 011 cooling, sets to a mass of crystals if the reagents are employed in the proportion of 1 mol.of the ethereal salt to 2 mols. o€ hydrazine hydrate; but, in using an excess of the base, no solid separates until the liquid is neutralised with hjdrochloric acid. The crystals are collected, and dissolved in boiling water, from which, on cooling, colourless needles separate, softening a t 180" and melting a t 184--155O. They are readily soluble in alcohol and ether, and their. aqueous solution is coloured red by ferric chloride. The following analytical data corresporid with thc formula, C,€r,N,O,. 0-2500 gave 0.4220 CO, and 0.1116 H20. 0.2i94 ,, 40 C.C. moist nitrogen at 22" and 762 mm. N = 17.87. C,H,N,O, requires C = 46.15 ; H = 5.12 ; N = 17.94 per cent.For identification, the compound obtnined by v. Rothenburg was prepared from ethylic oxalncetate. This product gives the same reactions, and melts at the same temperature as does the substance produced from ethylic chlorofumarate, whilst v. ltothenburg gives the melting point 1 7 9 O , and states that the ethereal salt is almost illsoluble in water. Besides ethjlic 5-pyr~zolone-3-carboxylate, there is formed a com- pound which is very readily soluble in water, and is contained in tbe mother liquor from the pyrazolone derivative. This reduces Fehling's solution, and crystallises from concentrated aqueous solu- tion in plates decomposing at about 236'. It was not further examined, but there can be no doubt that it is identical with tho substauce formed along with ethylic pyrazolonecarboxylate from the ethereal salt of oxalacetic acid, which v.Rothenburg characterised as py razol 011 e- 3- carbony l h y dr azi n e . E th ylic pyrazolone-3-cnrboxylate dissolves readily in potash and in ammonia ; its solutioii in water, after being neiitralised with ammonia, yields, with silver nitrate, a white precipitate; this is washed wit11 water and dried a t 100'. Analysis of the silver compouud proves it t o have the formula CaHsAg,N20,. C = 46.03; H = 4.96. 0.3810 left on ignition 0.2218 Ag. Ag = 58.21. CaH6Ag,N2O3 requires Ag = 58.38 per cent. The hydrolysis of the ethereal salt is brought about by boiling its solution in potash, and is complete after two hours' heating. On addition of an excess of hydrochloric acid to the alkaline liquid, the pyrazolonecarboxylic acid is thrown down ; this dissolves in boiling water, and, on cooling, separates i n microscopic plates.On account VOL. LXIX. 5 A1 396 RUHEMANN : FORJIATIOS OF PTRAZOLONE DERIVATIVES of the difficulty with which the acid dissolves in water, there is no danger of its becoming contaminated with inorganic matter, as v. Rothenburg (loc. c i t . ) states to be the case if potash is used as the liydrolytic agent. The acid, prepared according t o the above direc- tions, burns away without leaving a trace of ash, and, on analysis, gives nnmbers closely agreeing with the formula C,H4N,0,. 0.2238 gave 0.3062 C02 and 0.0658 H,O. 0.2386 ,, 46 C.C. moist nitrogen at 25' and 765 mm. N = 21.64. C~H4N203 requires C = 37.50; H = 3.36 ; N = 21.87 per cent.The acid does not melt, but begins to decompose a t about 260' ; its C = 37-31 ; H = 3.26. aqueous fiolution becomes violet on addition of ferric chloride. Action of Phen ylhydraziiie 09% Ethylic CJilorofuma~ate. Whilst the interaction of hydrazine hydrate and ethylic chloro- fumarate is accompanied with development of heat, no perceptible change takes place on mixing the etheyeal salt with phenylhydrazine, and, even on allowing the mixture to stand a t the ordinary tew- perature for several days only a small quantity of phenylhydrazine hydrochloride separates. Reaction, however, takes place more readily on heating the mixture on the water bath for a few hours. The product is then allowed to cool, and, after addition of ether, t,he ilydrochloride of phenylhydrazine is filtered off.On removal of the ether, an oil remains which does not solidify, but, when heated in an oil bath at 170', yields, in addition to a resin, a sparingly soluble, crystalline substance. Their separation may be effected by digesting with alcohol, which dissolves the resin, leaving the white solid behind. This is soluble with difficulty in boiling glacial acetic acid, and, on cooling, scparates in colourless needles which melt and decompose at 272". Analysis of this substance gave numbers corresponding with the formula C24H22N40s. 0.2068 gave 0.4i06 C02 and 0.0936 H20. C = 62.06 ; H = 5.02. 03226 ,, 0.5078 ,, 0.1024 ,, C = 62.19; H = 5.11. 0.1266 ,, 14 C.C. moist nitrogen at 24' and 758 mm. N = 12.36. CwH,,N40, requires C = 62.33; H = 4.76; N "'- 12.12 per cent.The compound dissolves in potash and in ammonia, forming yel- low solutions ; the ammoniacal solution, on addition of silver nitrate, jields a precipitate which darkens on warming. The product gives the pyrazole-blue reaction with ferric chloride, bromine water, or potassium nitrite. The reagents are to be added carefully to the substance suspended in acetic acid, as au excess of the reagent destroys the colour. These properties characterise the compound asFROM CHLOROFUblARTC ACID. 1397 a pyrazolone derivative, and it is to be looked upon as the ethereal salt of bis-phenylpyrazolonecmboxylic acid, N CO CO N C 00 C2H5* H-Q H - f C 00 CZH, The formation of this ethereal salt may be interpreted by assuming that at first partial transformation of ethylic chlorofumarate into ethylic pheriylliydrazofnmarate takes place, which then, under the oxidising influence of phenylhydrazine, suEers a condensation to the bis-pyrazolone compound. Ethylic phenylpyrazolone-3-carboxylate, which W. Wislicenus (Annulen, 1888, 246, 320) obtained from ethylic oxalacetate, might have been expected to be formed, but could not be isolated. I must express my thanks to Dr. Wolf, of Mc.Qil1 Universitj, for help afforded me in the course of the above experiments. Gonrille and Cniics College, Cambridge.