Ethyl aconitate has been shown by one of us (Ber., 20, 3367) to be transformed by ammonia into a pyridine-derivative. The above considerations render it probable that in this reaction the ammonium salt of an imido-acid is also formed. We are therefore reinvestigating this reaction. University Laboratory, Cambridge. XXXII.-Action of Chloroform and Alcoholic Potash on Hydrazines. Part II. By S. RUHEMANN, Ph.D., M.A. IN a former communication made to the Society in conjunction with W. J. Elliott (Trans., 1888, 850), it has been shown that the action of chloroform and alcoholic potash on phenylhydrazine is unlike that which takes place with the primary amines of the fatty and aromatic series. The product of the reaction, when freed from the unaltered base by means of dilute sulphuric acid, loses the odour of isonitrile after a short time, and is for the most part transformed into a very stable, odourless compound, which does not reduce Fehling's solution. The quantity of hydrazine transformed into this substance is, however, very small, if the operation is effected in the manner formerly described. After various attempts to improve the yield, I found that the most successful result was obtained when alcoholic potash was added to the solution of the base in chloroform and alcohol, instead of (as described in a former paper) adding chloroform to the solution of the base in alcoholic potash. As already mentioned, a considerable quantity of resinous matter is formed in the preparation of this substance; the further examination of this resin shows that it contains a crystalline compound, which is very easily soluble in alcohol and ether, and can be extracted with boiling water. The aqueous solution, if decolorised by boiling with animal charcoal, yields colourless plates on cooling; these melt at 144°, and reduce Fehling's solution. This substance is formylphenylhydrazine, as in fact was found by a comparison with the product obtained by F. Just's method (Ber., 19, 1201), and by a nitrogen determination, which gave N Theory for CH.NHÁNH CHO. 20.59 Found. 20.69 The formation of this compound in the isonitrile reaction is interesting, as rendering it probable that the isonitriles formed by the action of chloroform and alcoholic potash on primary amines arise in a similar manner, as the former split up under the influence of mineral acids. The reason why formanilide and its homologues have not been observed in this reaction is that they are readily attacked by chloroform and alcoholic potash. Indeed, on adding these reagents to a solution of formanilide, phenyl isocyanide is at once produced; the corresponding formyl compounds of phenylhydrazine and paratolylhydrazine, however, were found to be much more stable. In a former communication it was shown that the compound melting at 180°, which is produced along with formylphenylhydrazine, has the formula CH2N. This was derived from analysis, from the determination of the molecular weight, and from the composition of the nitro-derivative and sulphonic acid produced from it. Its probable C&H, NH⚫N:C constitution has been expressed by the formula C&H, NH⚫N:C 5 A closer study of the behaviour of this substance led, however, to the conclusion that it is a tertiary base. The formation of a basic product from 2 mols. of the hypothetical isonitrile, CH, NH-N:C, may be simply interpreted as follows: The two molecules condense directly to a ring in a way similar to the condensation of 2 mols. of a-ketonamines or a-ketonanilides in the formation of aldines, with the difference that in this latter case the condensation is accompanied by a splitting off of 2 mols. of water. A compound of the constitution given above is to be regarded CHÍNH、 as a derivative of the type NNH CH>N, a ring containing four nitrogen-atoms and two carbon-atoms, which may be called, according to Widmann's proposal (J. pr. Chem., N.F., 38, 185), tetrazine. Compounds which may be regarded as derived from a nucleus consisting of four nitrogen- and two carbon-atoms are already known. These are the bodies produced by v. Pechmann (Ber., 21, 2751) by the oxidation of the osazones of 1.2 diketone compounds, and called by him osotetrazones. These substances are coloured, neutral compounds, easily reconverted by the action of reducing agents into the osazones from which they were formed. Quite different, however, is the behaviour of the representative of the tetrazines produced from phenylhydrazine in the isonitrile reac tion, and this also confirms the view of its constitution expressed above. Diphenyltetrazine, CHINA, is dissolved with difficulty by boiling hydrochloric acid, and the solution, on cooling, deposits long, white needles of the hydrochloride, which may also be prepared by passing hydrogen chloride into an ethereal solution of the base. This salt is, however, not very stable; when boiled with water or dried at 100°, it splits into its components, base and acid; alcohol readily dissolves it, but, on boiling, the same decomposition seems to take place. The analysis of the salt, dried over sulphuric acid and potassium hydroxide, gave numbers which correspond to the formula CH12N,HC1: The hydrochloride forms a double salt with platinic chloride, which may best be prepared by adding a concentrated solution of the metallic chloride to the slightly warmed solution of the base in alcohol and hydrochloric acid. After a few minutes the double salt crystallises out in yellow plates, which are washed with alcohol and dried at 100°. Analysis of it led to the formula (CHN)2,H,PtCl.. This platinum salt is sparingly soluble in alcohol, and crystallises from it in yellow, glittering plates, which decompose about 300°. The formation of a hydrochloride and of a platinochloride shows that diphenyltetrazine is a weak base, and its behaviour towards sulphuric acid characterises it as such. For the base is dissolved by boiling with dilute sulphuric acid, and, on cooling, deposits long white needles of the sulphate, which may also be prepared by adding the dilute acid to an ethereal solution of the base. The sulphate is, however, only stable in the presence of the free acid, and dissociates completely on washing with water. Light is thrown on the nature of this base by the facts that it is indifferent towards nitrous acid and that it is not altered by boiling with acetyl chloride or with acetic anhydride, for it thus exhibits the characters of a tertiary base. The same conclusion follows also from the formation of an ammonium iodide produced by the Action of Methyl Iodide on Diphenyltetrazine. The base was heated in a sealed tube with methyl iodide in the presence of methyl alcohol for a few hours at a temperature of 100°; the contents of the tube were then evaporated to dryness on the water-bath, and the residue boiled with water, in which it is readily soluble. On cooling, yellow needles crystallise out, which melt at 214°, and are easily soluble in alcohol. Analysis of this substance dried at 100° proved it to be an ammonium compound the methiodide of diphenyltetrazine. The formula Ci,Hi,N,CH,I requires On adding silver chloride to a boiling aqueous solution of the iodide, silver iodide is at once formed, and the solution contains the organic ammonium chloride. On concentration, this crystallises in silky needles which melt at 244°, and are more soluble in water than the corresponding iodide. A nitrogen determination proved it to have the formula With platinic chloride, the aqueous solution of the chloride yields a light yellow, crystalline precipitate, which is nearly insoluble in water. The salt dried at 100° has the composition 2(CH2N, CH,Cl),PtCl.. The above described experiments afford, I think, a sufficient proof of the view that the compound formed from phenylhydrazine, in the manner stated above, is without doubt diphenyltetrazine. The remarkable stability which this substance exhibits towards hydrochloric acid and alcoholic potash, as was mentioned in the first note (loc. cit.), shows itself also towards reducing agents. It may be boiled in alcoholic solutions with tin and hydrochloric acid without suffering any change; even that reducing agent, sodium and alcohol, which has so often rendered good service, has here hardly any action. By using amyl alcohol and sodium, some ammonia is, indeed, given off, but the bulk of the substance remains unaltered. Bromine, however, acts very readily on the base, and leads to various Bromine-derivatives of Diphenyltetrazine. On adding bromine to a solution of the base in glacial acetic acid, there is at once formed a nearly white precipitate, consisting of one or more bromine substitution-products. I have repeatedly carried out this operation, but with varying results, owing to the varying quantity of bromine used and to the concentration of the solution, but I have not yet found the proper conditions for the preparation of the one or the other, as I had not the necessary quantity of material at my disposal. In one operation, using a considerable excess of bromine, a precipitate was formed consisting for the most part of tribromodiphenyltetrazine, as is shown by the following analyses of the product recrystallised from glacial acetic acid. The formula C1H,Br,N, requires This compound is sparingly soluble in boiling alcohol, but is readily dissolved by boiling glacial acetic acid, from which it crystallises on cooling in white needles which decompose at about 224°. When, however, more dilute solutions and a limited amount of bromine are used, the precipitate formed consists, for the most part, of a dibromoderivative mixed with some of the tribromodiphenyltetrazine, as indicated by the analysis of the product recrystallised from glacial acetic acid, which gave 14-28 per cent. of nitrogen and 42:40 (42·24) per cent. of bromine, while the formula C1H10Br2N, requires 14-21 per cent. N and 40.6 per cent. Br. Even a monobromo-derivative is produced under certain conditions by the action of bromine on acetic acid solution of the base; this was extracted from the precipitate by hot alcohol, and repeatedly crystallised from the same solvent. Its melting point was 219-220°, and on analysis it gave 17.70 per cent. nitrogen, whilst CHBгN, requires 17.95 per cent. N. 5 C&H, N⚫N.CH would give rise A compound of the constitution to three different series of bromine-derivatives, according as the substitution takes place in the phenyl-groups or in the tetrazine nucleus, or, lastly, in both at the same time. The precipitate produced by the addition of bromine to the base dissolved in acetic acid, consists |