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.

    5/8 (page 2340)
    remained unchanged when mixed with a synthetic specimen. The latter we obtained in small quantity by the action of trimethylamine on a-chloro-/3-glyoxaline-4(or 5)-propionic acid. The Reduction of &-GlyoxalineA(ov b)-acrylic Acid to &~GlyoxalineA(or b)-propionic Acid. /3-Glyoxaline-4(or 5)~acrylic acid was dissolved in a little absolute alcohol, and the hot solution treated with five to six atomic propor¬ tions of sodium. The solution was then acidified with hydrochloric acid, and the precipitated salt collected. The filtrate and washings were evaporated to dryness, the residue dissolved in 5 per cent, aqueous sulphuric acid, and precipitated with phosphotungstic acid. The precipitate was treated with acetone, filtered from undissolved material, and the soluble phosphotungstate decomposed in the usual manner. On concentrating the final filtrate a crystalline acid separated, which after recrystallisation melted at 202°. When mixed with a specimen of synthetic /3-glyoxaline-4(or 5)-propionic acid (m. p. 202°), the melting point remained unaltered. The acid obtained on reduction was therefore proved to be /3-glyoxaline- 4(or 5)-propionic acid. The Action of Ferric Chloride on Ergothioneine. Formation of $-GlyoxalineA(or5)-propio betaine (Histidine-betaine). ■* One gram of ergothioneine was boiled for one hour with an aqueous solution containing nine molecular proportions of ferric chloride. The iron was removed from solution by sodium carbonate, the filtrate acidified with sulphuric acid (so as to give a 5 per cent, solution of the latter), and precipitated by phospho¬ tungstic acid. The precipitate, which was completely soluble in acetone, was decomposed in the usual way, and the barium and sulphuric acid removed. The filtrate was concentrated, and treated with a hot aqueous solution of picric acid. On cooling, a crystalline pier ate separated, which after recrystallisation from water was obtained in deep yellow prisms melting at 123°: 0*1340 gave 0*1908 C02 and 0*0396 H20. 0 = 38*4; H = 3*3. C0H15O2N8(C6HjO7N5)2 requires C = 38*5; EC = 3*3 per cent. The dipicrate is very sparingly soluble in cold, fairly readily so in hot, water. The picrolonate prepared in the usual way forms long, thin, orange-yellow needles, melting at 229—230°. The aurichloride separated from dilute aqueous hydrochloric acid as large, broad, deep orange-yellow prisms, melting at 171°.