The constitution of ergothioneine : a betaine related to histidine / by George Barger and Arthur James Ewins.

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

Licence: In copyright

Credit: The constitution of ergothioneine : a betaine related to histidine / by George Barger and Arthur James Ewins. Source: Wellcome Collection.

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    It is only moderately soluble in pyridine, and almost insoluble in all other ordinary organic solvents. The acid was crystallised for analysis by making a very dilute solution (OT per cent.) of the sodium salt, and acidifying. After three or four hours the acid began to separate, and precipitation was complete in about thirty- six hours. The acid obtained in this way separated in clusters of small prisms, which did not melt below 275°: 0-1179 gave 01805 C02 and 0-0420 H^O. 0=41-8; H = 3 9. C6H502N2S requires C' = 423; H = 3'5 per cent. By oxidation by means of dilute nitric acid as described below, 90 per cent, of the theoretical amount of sulphur was obtained from the filtrate as barium sulphate. The Action of Boiling Dilute Nitric Acid on fi-2-Thiolglyoxaline- k-acrylic A cid. 0*4 Gram of amorphous /3-2-thiolglyoxaline-4-acrylic acid was added in small portions to 20 c.c. of 10 per cent, aqueous nitric acid. The mixture was kept gently boiling on a sand-bath for some minutes after solution was complete, and then allowed to cool. The crystalline nitrate of fi-glyoxalineA(ox h)-acrylic acid separated out, which after washing and drying melted at 198° with explosive decomposition. The yield was O'28 gram: 0-1114 gave 0-1470 C02 and 0’0404 H2G. 0=36 0; H = 4 0. C6H602N2,HN03 requires 0 = 35*8; H = 3‘5 per cent. $-Glyoxaline-4:(orb)-acrylic acid was most readily obtained from the nitrate by the addition of one equivalent of sodium carbonate (solid) to a concentrated aqueous solution of the salt, when the acid separates at once as a crystalline solid, which after recrystal¬ lisation from dilute acetone was quite pure, and melted at 235—236°: 0-1776 gave 0'3474 C02 and 0'0712 H20. 0 = 53-3; H = 4*4. C6H6Na02 requires 0=52*2; H = 43 per cent. /3-Glyoxaline-4(or 5)-acrylic acid is moderately soluble in cold, but very readily so in hot, water. Its solutions give an intense red colour with sodium p-diazobenzenesulphonate. The phosphotung state is readily soluble in hot water or cold acetone, and crystallises in small, rectangular plates from dilute acetone. The pier ate forms golden-yellow prisms, melting at 213—214°, and sparingly soluble in cold water. The melting point of this picrate