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
Catalogue details

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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    01570 gave 0-1555 AgCl. Cl = 24*5. 0- 1259 „ 0-1251 AgCl. Cl = 24-6. (C6H902NS)2,3HC1,H20 requires C = 32'9; H = 53; Cl = 24'3 per cent. The composition of this salt is peculiar; there is no evidence of a similar salt of the natural histidine (compare Abderhalden and Einbeck, Zeitsch. 'physiol. Chem., 1909, 62, 322). 1- Histidine monopicrate crystallises from water in large, flat plates, which are sparingly soluble in hot water and almost insoluble in alcohol. This salt decomposes at 180—181° (corr.), after sinter- ing from about 175°. It contains one molecule of water of crystallisation: 0-3983 * lost 0-0185 at 110°. H,0 = 4-6 C,2H1209N6,H20 requires H20 = 4'5 per cent. 0-1825 f gave 6-2515 C02 and 0 0531 H20. C = 37'6; H = 3'3. C12HJ209N6 requires C = 37'5; H = 32 per cent. When this salt is dissolved in a hot aqueous solution of picric acid, the dipicrate (m. p. 190°) separates on cooling. For purposes of comparison, attempts were made to prepare a mono- and di-picrate of naturally occurring histidine. Histidine appears, however, to form only a dipicrate. Histidine dipicrate crystallises from water in long, flat, clear, well- formed leaflets, which sinter at about 80° and melt at 86° (corr.). It appears to contain two molecules of water: 0-1591 * gave 0T927 C02 and 0 0452 H20. 0 = 33 0; H = 3'2. Ci8HI5016N9,2H20 requires C = 33’3; H = 3 0 per cent. The Action of Potassium Hydrogen Suphate on Histidine. Twenty-five grams of potassium hydrogen sulphate were fused in a beaker heated by an oil-bath and 1 gram of histidine monohydro- chloride was added; considerable frothing occurred, and the mixture had to be stirred frequently. After heating for various lengths of time at different temperatures, the reaction product was dissolved in water, neutralised with potassium hydroxide, digested with animal charcoal, cooled, and filtered from charcoal and potassium sulphate. The filtrate was again concentrated, separated from more potassium sulphate, made up to a known volume, and the yield of 4(or 5)-)3-aminoethylglyoxaline determined physiologically. Heating at an oil-bath temperature of 260—270° for one hour gave the best yield of the desired base, but the maximum only reached about ® per cent, of the theoretical. A modification of this method, in which histidine monohydrochloride was heated with ton times its Air-dried salt. t Dried at 110*.