CH >C-COOH, is pre Benzoindolecarboxylic acid, CH¿CO·C2H2<NH pared by heating the finely powdered ethereal salt of benzophenylhydrazine-pyruvic acid with an equal weight of freshly fused zinc chloride at a temperature of 220° in an oil-bath. The mixture melts, darkens, and froths briskly after two or three minutes, at the end of which time the reaction is complete. When cool, the resulting brown mass is powdered and warmed with very dilute hydrochloric acid to remove the zinc chloride. The dark-coloured substance that remains is, with the exception of a little resin, all dissolved by repeated extraction with ether. The ethereal solution is then shaken with dilute soda, from which, on subsequent addition of hydrochloric acid, the indolecarboxylic acid is thrown down as a yellow precipitate. To purify this, it is dissolved in ammonia, and the solution boiled with animal charcoal; on addition of hydrochloric acid, it yields a less coloured precipitate which readily dissolves in alcohol and crystallises out in yellowish needles. The acid may be obtained perfectly white, though with a considerable loss of material, by boiling its alcoholic solution with animal charcoal, filtering and concentrating the filtrate. The pure acid melts at 284-285° with decomposition. The formula C6H1NO, requires— This acid is only slightly soluble in boiling water, but dissolves readily in alcohol and in ammonia. The addition of silver nitrate to the latter solution throws down the silver salt as a yellowish, flocculent precipitate. When heated at a temperature between 280-290°, it gives off carbonic acid and is transformed into benzoindole. The latter was obtained in the form of nearly white needles melting at 144-145°, by dissolving the melted product in alcohol and decolorising the alcoholic solution by animal charcoal. When dissolved in alcohol, it colours pine shavings moistened with hydrochloric acid, violet, and when acidulated with hydrochloric acid, it is coloured red by potassium nitrite. We intend to pursue the investigation of this compound. A small quantity of the ethyl salt of the benzoindolecarboxylic acid is contained in the ethereal solution of the product of the zinc chloride condensation, and may be obtained as a yellow residue by evaporating the ether after the free acid has been removed by agitation with sodium hydroxide solution. This residue, dissolved in alcohol, boiled with animal charcoal, and then concentrated, yields VOL. LV. 2 x slender needles which melt at 160-161°. The quantity obtained was, however, too small to admit of verification by analysis. Action of Chloroform and Alcoholic Potash on Benzophenylhydrazine. It was expected that chloroform and alcoholic potash would act on this hydrazine in a manner analogous to that of their action on phenylhydrazine and its homologues, leading to the formation of a tetrazine, as has been shown before (loc. cit.) and as will be further seen from a communication shortly to be made to the Society. But the desired compound could not be obtained. When an alcoholic solution of the hydrazine is treated with these agents, it becomes first green and then deep-red in colour. The ethereal extract of the latter, when shaken with dilute sulphuric acid and then evaporated, yields a red resin from which boiling water extracts a small quantity of a crystalline compound, probably formylbenzophenylhydrazine, which is easily decomposed when boiled with water; the same compound appeared also to be formed by heating the hydrazine with formamide at 140° till ammonia ceased to be evolved, but owing to its easy decomposition it could not be recrystallised. All attempts to obtain a crystalline substance from the red resin left after extraction with water entirely failed. University Laboratory, LXI. Further Study of the Thiocarbimides. By AUGUSTUS E. DIXON, M.D., Assistant Lecturer in Chemistry, Trinity College, University of Dublin. In a recent communication (Trans., 1880, 300), I described a number of substances obtained by the combination of certain thiocarbimides with primary and secondary amines, and with phenylhydrazine. I hope shortly to describe a further investigation of the hydrazine class of compounds; meanwhile, in the present paper an account will be found-(a) of a number of disubstituted thiocarbamides, hitherto wanting; (b) of the combinations of certain thiocarbimides with piperidine; and (c) of the relations between the thiocarbimides and thialdine. 1. Methylthiocarbimide and Benzylamine-Methylbenzylthiocarbamide. Pure benzylamine, dissolved in alcohol, was added to a warm alcoholic solution containing an equimolecular proportion of methylthiocarbimide. Heat was evolved, and the pungent smell of the thiocarbimide disappeared. After several days' exposure to the air, the mixture assumed the consistence of a thin syrup, from which aggregations of crystalline matter slowly separated. The latter were freed as far as possible from the syrupy mother-liquor by filtration under pressure, and then recrystallised twice from benzene. The substance is very freely soluble in this liquid when hot; but though it is somewhat sparingly so in the cold, the crystallisation is rather tedious, the solution remaining supersaturated for a considerable time. When purified as described, it forms agglomerated masses of dense, white, octahedral crystals, which melt between 74° and 74.5°. A sulphur determination, made by evaporating the substance to dryness with sodium hydroxide, in a nickel crucible, and fusing the residue with potassium nitrate, afforded 14:41 per cent. of sulphur; theory for C,H12N2S would require 17.79 per cent. This low result was rather unexpected, as the process just indicated gives with suitable compounds very satisfactory results. It was found, however, on further investigation, that this particular compound is difficult of attack by alkalis, even when the latter are concentrated; the loss was therefore due, presumably, to the decomposition at a high temperature of a little unattacked thiocarbamide with evolution of volatile sulphuretted products. This difficulty was easily met by operating as follows: 0.2034 gram was oxidised with fuming nitric acid on the water-bath; the oxidation-product evaporated to dryness, introduced into a nickel crucible, and again evaporated to dryness with sodium hydroxide. The residue, fused with potassium nitrate, gave 0-2604 gram BaSO1, Or, S 17.60 per cent. Calculated for C,H12N2S, S = 17.79 The action is thus represented : NHCH, CH ̧·NCS + CH,CH2•NH2 = CS<NH·CH2•C‚H2 Methylbenzylthiocarbamide, when heated with water, melts to somewhat dark-coloured droplets, which just sink in the liquid. These dissolve to a slight extent, and the clear solution, on cooling, becomes milky from the separation of a cloud of minute oily globules, which, after a time, solidify to octahedral crystals. It is extremely soluble in alcohol; moderately so in ether; its solubility in benzene has already been mentioned. Ammoniacal silver nitrate, added to either the aqueous or alcoholic solution, gives an immediate black precipitate; but it is curious to note that, just as in the case of the homologous ethylbenzylthiocarbamide (described in the communication before referred to), the solution, either in water or alcohol, is not desulphurised, even by prolonged boiling with alkaline lead tartrate. This resistance to desulphurisation is remarkable, and recalls Lellmann's observation (Annalen, 221, 8; 228, 248) that boiling with alkaline lead solution fails to remove sulphur from the thiocarbamide-derivatives of NH. the orthodiamines, e.g., CS<H>C,H,. I am inclined to consider that the difficulty in withdrawing the sulphur under the conditions named, is due in some way to the fatty nature of both radicles. The data necessary to warrant a general conclusion are, for the most part, only obtainable by direct experiment, but those hitherto obtained seem to point to the view that, in a symmetrical disubstituted thiocarbamide, desulphurisation by lead hydrate is not effected where both radicles are of a fatty nature. On the other hand, if either, or both, of the radicles be non-fatty, desulphurisation is easy. Thus, diethylthiocarbamide, in either aqueous or alcoholic solution, is unaffected by boiling with lead hydrate (Hofmann, Ber., 2, 601). I have also ascertained by direct experiment, that dibenzylthiocarbamide in alcoholic solution is not sensibly desulphurised by boiling with alkaline lead solution. (It is desulphurised instantly, and in the cold, by ammoniacal silver nitrate.) Again, as already recorded (Dixon, loc. cit.), ethylbenzylthiocarbamide does not yield its sulphur to alkaline lead tartrate, even at the boiling temperature. But on the substitution of either or both fatty groups by non-fatty groups, this resistance to desulphurisation seems to be removed. Thus, I have found ethylphenyl-, ethylorthotolyl-, and (loc. cit., 302) benzylphenyl-thiocarbamides all easily desulphurisable; and the same holds good (Hinterberger, Annalen, 83, 346) for ethylallylthiocarbamide. Further, diphenyl-, diorthotolyl-, and (Bizio, Jahr., 1861, 497) allylphenyl-thiocarbamides all readily give up their sulphur, under the conditions named, as does also (Zinin, Annalen, 84, 346) allyla-naphthylthiocarbamide. 2. Methylthiocarbimide and Paratoluidine-Methylparatolylthio carbamide. This substance-metameric with the preceding-was obtained by mixing equimolecular proportions of methylthiocarbimide and para toluidine, each dissolved in warm, concentrated alcohol. After some time tufts of prismatic crystals began to crystallise out; when nothing further appeared to separate, these were drained off, washed, and recrystallised from boiling alcohol. As thus obtained, the substance forms beautiful vitreous prisms, melting at 125-126° without decomposition. Sulphur was estimated, with the following result :— 0-2070 gram, evaporated to dryness with sodium hydroxide and fused with potassium nitrate, gave 0.2610 gram BaSO4, Or, S 17.81 per cent. Calculated for C9H12N2S, S = 17·79 The action is thus formulated : : NH.CH, CHJNCS + CHC%HẠNH = CS<NH CHÍCH, The yield amounted to nearly 70 per cent. of the theoretical. Methylparatolylthiocarbamide is slightly soluble in boiling water, almost insoluble in cold. It is moderately soluble in hot alcohol, and freely soluble in ether. Silver nitrate throws down a white precipitate, which soon blackens; the solution is also immediately desulphurised by boiling with alkaline lead tartrate (cf. methylbenzylthiocarbamide). 3. Methylthiocarbimide and Orthotoluidine-Methylorthotolylthio carbamide. This substance-metameric with the two preceding compoundswas prepared by mixing the theoretic quantities of base and thiocarbimide in concentrated alcoholic solution. No sensible heat was evolved, but after a couple of days the mixture had solidified to a pasty mass; this was recrystallised three times from alcohol, after which the substance separated in pearly-white, flattened, rhombic crystals. The latter melt, without decomposition, betweeen 152° and 153°, that is to say, 26° higher than the corresponding para-compound. When broken up, the dry substance forms a lustrous, flour-like, white powder, which, on friction, becomes strongly electrical, the particles flying about in all directions. : The formula was verified by a sulphur determination :0-1808 gram, fused with sodium hydroxide and potassium nitrate, afforded 0.2325 gram BaSO4, |