Experiments on the formation of 4 (or 5)-[beta]-aminoethylglyoxaline from histidine / by Arthur James Ewins and Frank Lee Pyman.

  • Ewins, Arthur James.
Date:
1911
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Licence: In copyright

Credit: Experiments on the formation of 4 (or 5)-[beta]-aminoethylglyoxaline from histidine / by Arthur James Ewins and Frank Lee Pyman. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    weight of potassium hydrogen sulphate in sealed tubes at 265—270° for three hours, gave yields of 20 to 25 per cent, of the theoretical, as indicated by physiological estimation. The Formation of 4(or 5)-£!-.■ I mi no ethylglyo inline from Benzoyl- histidine. Monobenzoylhistidine was prepared by the Schotten-Baumann method, as indicated by Frankel (loc. cit.). It was, however, found to be quite unnecessary to carry out the precipitation with mercuric chloride described by him. On neutralising the solution after the reaction is complete, the pure benzoyl derivative separates very quickly on simply keeping. One gram of benzoylhistidine so obtained was heated in a vacuum at 240° until all frothing ceased. The black, tarry mass was dis- solved in 2 c.c. of concentrated hydrochloric acid, and hydrolysed at 180°. The contents of the tube were washed out with water, and the separated benzoic acid collected, tho filtrate extracted with ether, and the aqueous solution neutralised. An equal volume of a solution of picrolonic acid in water was added, and the bulky, amorphous, yellow precipitate collected. The filtrate was con- centrated to small bulk, and a concentrated alcoholic solution of picrolonic acid added. After some time, 0‘47 gram of 4(or 5)-j8-amino- ethylglyoxaline picrolonate was obtained, crystallising in bunched needles, and melting at 262—264° (Windaus and Vogt, loc. cit., give “ about 266° ”). # Wellcome Physiological Research Laboratories, Herne Hill, S.E. • Wellcome Chemical Works, Dartkord, Kent. R LLAV AND SONS. LTD. BKKAI) ST HILL, S.C., AND BUNGAY, SUPPOI.K