RUHEMANN AND STAPLETON : TETRAZOLINE, 1131 CXV.- Tetmzoline. By SIEGFRIED RUHEMANN and H. E. STAPLETON, Scholar of St. John’s College, Oxford. SEVERAL years ago, it was shown by one of the authors (Trans., 1889, 65, 242 ; 1890, 57, 50 ; see also Ruhemann and Elliot, Trans., 1888, 53, 850) that by the action of chloroform and alcoholic potash on phenylhydrazine a compound of the formula,1132 RUEEMANN AND STAPLETON : 'fETRAZOLINB!, resulted, which he called diphenyl tetrazi ne, Analogous substanees have been produced from ortho- and para-tolylhydrazine. The term tetrazines for this class of compounds has had to be altered to di- bydrotetrazines, since Pinner (Bey., 1894, 27, 987) obtained some members of a similar type with two hydrogen atoms less in the mole- cule. Besides these bases, the formyl derivatives of the hydrazines are also formed in the above reaction, and this fact led to the view that the latter are the first products, which in the second phase of the reaction lose water and condense to the cyclic compounds.Indeed, as shown by Pellizznri (Gaxxettcz, 1896, 26, ii, 430) and Bamberger (Bey., 1897, 30, 1263), formylphenylhydrazine, on heating, is transformed into dihydrodiphenyltetrazine, for which Pellizznri proposed the suitable name diphenyltetrazoline. The yield, however, according to these authors, is unsatisfactory, as is also the case when the base is pre- pared by the action of chloroform and alcoholic potash on phenyl- hydrazine. Lately, Pellizzari ( A t t i R. Accnd. Lincei, [v], 1899,8, 327, has found that dimethyltetrazolina and monacetyldimethyltetrizzoline me formed on heating mono- and di-acetyl hydrazine respectively, and that diformylhydrazine yields a non-crystallisable product, which, on treatment with hydrochloric acid, is transformed into tetrnzoline hydrochloride.Our attempts t o prepare tetrazoline by digesting hydrazine hydrate with chloroform and alcoholic potash have been unsuccessful, since hydr- azine seems hardly to be acted on by these substances. We find, how- ever, that it can readily be obtained by heating monoformylhydrazine, prepared by Schofer and Schwan's method (J. pr. Chem., [ii], 1895,51, 180) from hydrazine hydrate and ethylic formate. When monoformyl- hydrazine is heated for 3 hours in an oil-bath, the temperature of which is gradually raised from 150' to 210°, it loses water, and the residue, when cold, solidifies to a mass of crystals.These are fairly soluble in alcohol, but only sparingly so in chloroform or light petr- oleum. On dissolving the substance in a boiling mixture of chloroform and absolute alcohol and cooling the solution by ice-water, it separates i n exceedingly deliquescent, colourless needles which melt at 82-83'. The yield is very satisfactory. The following analytical data were obtained : 0.2003 gave 0.2085 CO, and 0.0980 H20. 0.1052 C = 25.37 ; H = 5.43. ,, 61.8 C.C. moist nitrogen a t 24' and 766 mm. N = 66.37. C,H4N, requires C = 28.57 ; H = 4.76 ; N = 66-66 per ceht. The aqueous solution of tetrazoline is not alkaline towards litmus ; itRUHEMANN AND STAPLETON : TETRAZOLINE. 1133 gives, with copper sulphate, a blue, and with ferric chloride a red coloration. Tetrazoline is very soluble in hydrochloric acid, and the hydrochloride, obtained by evaporation of the solution, crystallises from boiling ab- solute alcohol in long, transparent leaflets which melt at 151-152O (at 150°, according to Pellizzari) and are very soluble in water.On analysis, the hydrochloride gave the following numbers : 0.1 112 gave 46 C.C. moist nitrogen a t 26' and 767 mm. X = 46.30. 0*3065 ,, 0.3618 AgCl. C1=29*20. C,H,N,,HCl requires N = 46.47 ; C1= 29.46 per cent, The picrate, C,H,N,,C,H,(NO,),OH, is precipitated on mixing alcoholic solutions of the base and picric acid. It dissolves only sparingly in alcohol, and crystallises in yellow needles, which melt and decompose at 194-195'.0.1550 gave 42.5 C.C. moist nitrogen at 22' and 767 mm. N = 31.33. Tetrazoline forms, with platinic chloride, a yellow, crystalline com- CsH,0,N7 requires N = 31.50 per cent. pound which has the composition (U,H,N,)2,PtC14. 0.3680 gave 0.0945 CO, and 0.0445 H,O. 0,1642 ,, 31 C.C. moist nitrogen at 17O and 764 mm. N=22*63. C,H,N,,PtCl, requires C = 9.51 ; H = 1.58 ; N = 22.20 ; Pt = 38.53 per cent. Mercuric chloride, even in a dilute aqueous solution of tetrazoline, produces a turbidity which may disappear if the quantity of chloride is small, but is permanent if a sufficient excess is used, The com- pound, which separates in bunches of colourless needles, is sparingly soluble in water, but dissolves readily in hydrochloric acid, and has the formula 2C,H,X4,3RgC1,. 0.4127 p v e 0.2930 IlgI. H g = 61.20. 0.3550 ,, 0.2520 HgS. Hg=61*19. C4HsN,,3HgC1, requires Hg = 61-16 per cent. The aqueous solution of tetrazoline gives a yellowish, crystalline precipitate with zruric chloride, and with silver nitrate yields colourless needles of a silver compound which explodes on heating. We are engaged in the further study of tetrszoline, and shall shortly lay the results before the Society. C: = 9.61 ; H = 1.84. 0.3504 ,, 0*0960 Pt. Pt = 38.34. 0.2326 gave 0.0893 Pt. Pt = 38.35. GONVILLX ASD CAIUS COLLEGE, CAMBKIDOE. VOL. LXXV. 4 G