Synthesis of hordenine, the alkaloid from barley / by George Barger.

  • Barger, George, 1878-1939.
Date:
1909
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: Synthesis of hordenine, the alkaloid from barley / by George Barger. 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.

    7/8 (page 2197)
    The synthetic specimen gave Millon’s reaction very intensely; it reddened phenolplithalein, was not coloured by concentrated sulphuric acid, and reduced acid potassium permanganate in the cold and ammoniacal silver nitrate on warming; in all these respects its properties were identical with those of the natural base, as described by Leger. The amount of the synthetic substance obtained was insufficient for analysis. The natural hordenine, used for comparison, was purified by distillation, the boiling point being 173—174°/11 mm. As in the case of p-hydroxyphenylethylamine, distillation is by far the most convenient method of purification. Preparation of Hordenine Methiodide from p-IIydroxyphenylethyl- amine. Two grams of p-hydroxyphenylethylamine were dissolved in a little methyl alcohol, and boiled for a few minutes with a large excess (20 c.c.) of methyl iodide. After two days, glassy prisms separated, which were up to 4 cm. in length; the weight was 045 gram, much being left in the mother liquor. On recrystallisation from water, the quaternary iodide gave stout crystals, melting at 230—231°, and closely resembling natural hordenine methiodide, a specimen of which melted at 229—230°; on mixing the two, the melting point was 229—230° : 0-1444 gave 0-1110 Agl. 1 = 41-5. CnH18ONI requires I = 413 per cent. Benzoylhordenine methiodide, C6H5-C0-0-C6H4-CH2-CH2-N(CH8)3I, was prepared from both specimens of hordenine methiodide; in each case hexagonal leaflets were obtained, sparingly soluble in hot water, and melting at 252—254°; this was also the melting point of the mixture of the synthetic and natural substance. Although hordenine methiodide can thus be readily prepared from p-hydroxyphenylethylamine, numerous attempts to synthesise the alkaloid itself by this method were unsuccessful, and the other method, described above, had to be employed. Wellcome Physiological Research Laboratories, Herne Hill, London, S.E. p. CLAY AND SONS, I.TD. BKEAD ST. RILL, E.C., AND PUNGAY, SUFFOLK.