4-L-aminoethylglyoxaline (L-iminazolylethylamine) and other active principles of ergot / by George Barger and Henry Hallett Dale.

  • Barger, George, 1878-1939.
Date:
[between 1910 and 1919?]
Catalogue details

Licence: In copyright

Credit: 4-L-aminoethylglyoxaline (L-iminazolylethylamine) and other active principles of ergot / by George Barger and Henry Hallett Dale. Source: Wellcome Collection.

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    thus collecting together silver precipitates II and III of Kutscher. After washing, the silver precipitate was carefully suspended in very dilute sulphuric acid, and decomposed by hydrogen sulphide. The filtrate from the silver sulphide was freed from hydrogen sulphide, neutralised, and evaporated to dryness. The residue was extracted several times with hot ethyl alcohol, in which the active principle was found to be sparingly soluble; a large quantity of inert matter was left behind. The residue remaining on evaporating the alcoholic solution was dissolved in a little water, and a hot saturated aqueous solution of picric acid was added. After keeping for some days, a brown, imperfectly crystalline picrate was collected, washed, and recrystallised from water. This picrate was converted info a solution of the hydrochloride, which was very active physiologically, and gave an intense red coloration with sodium ^diazobenzene- sulphonate (Pauly’s reaction), suggesting a relationship to histidine. We had previously detected some activity in the crude histidine mother liquors obtained by hydrolysis of haemoglobin with hydro¬ chloric acid; histidine itself was found to be inactive, but it became so to a slight extent on heating to 300°. We were thus led to suppose that the picrate we had isolated was that of 4-/3-amino- ethylglyoxaline. After two crystallisations from water, the picrate from ergot formed dark yellow, rhombic plates, melting and decom¬ posing at 234—235°. A specimen of the picrate sent us by Dr. D Ackermann, when heated simultaneously in a tube attached to the same thermometer, also melted at 234—235°, and when recrystallised by evaporation of the solution in a desiccator, yielded rhombic plates exactly similar to those of the ergot base. Windaus and Vogt (Ber., 1907, 40, 3695) give the melting point as 239° on rapid hearting, and the same crystalline form for a synthetic specimen of 4-/3-aminoethylglyoxaline dipicrate. For analysis, the picrate was dried at 100° until constant: 0-0590 gave 0*0776 C02 and 0*0192 H20. 0 = 35*8; H = 3*6. C5H9N3(C6H307Ni3)2 requires C = 35‘8; 11 = 2*6 per cent. We also prepared the very sparingly soluble picrolonate of the ergot base; it decomposed at 261° (Windaus and Vogt give 266° for 4-/3-aminoethylglyoxaline dipicrolonate). As the physiological action of the ergot base is also the same as that of 4-/3-aminoethylglyoxaline, there is no room for doubt that the two bases are identical. The Wellcome Physiological Research Laboratories, Brockwell Hall, Herne Hill, S.E. R. CLAY AND SONS, LTD. BREAD ST. HILL, E.C.- AND BUNGAY, SUFFOLK.