Volume 1

The chemical constitution of the proteins / by R.H.A. Plimmer.

  • Robert Plimmer
Date:
1912-1913
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The chemical constitution of the proteins / by R.H.A. Plimmer. Source: Wellcome Collection.

    143/208 page 127
    A suggested synthesis of histidine in 1909 by Gerngross from a- methyl imidazole and chloral was unsuccessful. The reaction, accord- ing to Windaus, proceeds in a different manner. Histidine, and also its natural isomer, were synthesised by Pyman in 1911. By making use of Gabriel’s method of synthesising the glyoxaline or imidazole ring, which consists in the condensation of aminoketones, R. CO. CHgNHg, with potassium thiocyanate and the subsequent oxidation of the thiol group with nitric acid :— CH—NH\^ l_C — N ^ C.SH CH—NH' R_C — N ^CH and of Kalischer’s method of preparing diaminoacetone from citric acid:— HO CH„. COOH i. COOH Ho. COOH citric acid CH2.COOH CH:NOH I I CO CO CHg.COOH CH:NOH acetone di-isonitroso dicarboxylic acid acetone CH2.NH2 io CHa. NHa diamino- acetone Pyman obtained thiol-amino methyl glyoxaline. Nitric acid removed the thiol group as sulphuric acid and at the same time the nitrous acid formed in the reaction attacked the amino group replacing it by the hydroxyl group and giving hydroxymethyl glyoxaline. Chloromethyl glyoxaline was then prepared by the action of phosphorus penta- chloride:— CH2.NH2 CH—NHv^ KSCN CO CHa.NH C.SH hNO, CH2.NH2 ^ * ^ 2 thiol- diamino aminomethyl acetone glyoxaline CH—NH\^ [I - HZ' I CH2. NH, CH CH—NH \ HNO, 2C — hydroxy- methyl glyoxaline PCL CH CHg . Cl chloro- methyl glyoxaline The chlorine atom of chloromethyl glyoxaline was easily replace- able ; by exchanging it for the CN group by treatment with potassium cyanide and hydrolysing the nitrile glyoxaline acetic acid (Knoop’s imidazole-acetic acid) was obtained ; by reducing the nitrile imidazolyl- ethylamine or glyoxaline ethylamine, a base found by Barger and Dale to be one of the active principles of ergot and derived from his- tidine, was obtained: CH—NHv II > CH C — CH2.CH2.NH2 CH—NH\ i - »> I CH2.CN CH CH—NH\^ — N^ CH I CH2.COOH
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