The alkaloids of Picralima klaineana / by T.A. Henry and T.M. Sharp.

  • Henry, Thomas Anderson, 1873-1958
Date:
[1927.]
Catalogue details

Licence: Public Domain Mark

Credit: The alkaloids of Picralima klaineana / by T.A. Henry and T.M. Sharp. Source: Wellcome Collection.

    10/16 (page 1957)
    dissolved in boiling water, from which it separated on cooling as a colourless oil. The solution in water gives a precipitate of a new oily base on addition of sodium carbonate or alkali hydroxide. Neither the base nor any of its salts, except the picrate, have so far been induced to crystallise. The picrate is precipitated on adding picric acid in methyl alcohol to a solution of the base or the hydriodide in the same solvent, and can be crystallised either from boiling water or from methyl alcohol, producing in the former case canary-yellow needles or rosettes of needles and in the latter bronze- tinted, dense rosettes of prisms, both forms melting at 205° (Found : MeO, 10-0; NMe, 6-0. O^H^OgN^CH^CgHgO^g requires 2MeO, 9-6; NMe, 4*5%). These results agree with the assumption that in this reaction the akuammine is first hydrated by the alkali (see below) and that the hydrate undergoes O-methylation either on the hydroxyl group originally present in akuammine or on a new group formed in the hydration. Acetylation of akuammine. The pure base (3-8 g.) was boiled for 5 minutes with acetic anhydride (10 c.c.), the solution left to cool, and the excess of reagent removed by distillation under reduced pressure. The residue was dissolved in water, the liquid poured into sodium carbonate solution, and the precipitate collected, sucked dry on the filter, and dissolved in the minimum quantity of boiling alcohol, from which it separated on cooling in rosettes of colourless prisms (yield, 2-4 g.), m. p. 226°. The melting point was not changed by recrystallisation. The concentrated mother-liquors, which had ceased to deposit crystals, were taken to dryness, the residue was dissolved in four times its weight of boiling N/2-hydrobromic acid, and the solution filtered hot. On cooling, it deposited a silky mass of hair-like needles, m. p. 236°, of acetylakuammine hydro¬ bromide (yield, IT g.), the melting point of wdiich remained un¬ changed on recrystallisation. This hydrobromide on solution in boiling water and precipitation with sodium carbonate solution furnished the pure base, m. p. 226°. From the mother-liquors of the hydrobromide the rest of the acetylated base was precipitated as the picrate (0-5 g.), which crystallised with difficulty from con¬ centrated solutions in methyl alcohol, in gelatinous masses of rosettes of minute, yellow needles, m. p. 168° after drying in air. The acetylated base becomes pink on exposure to air and has [a]??* — 52-08° (c = 0-64 in alcohol) (Found for the base : C, 67-5, 67-45; H, 6-9, 6-7; MeO, 9-3; NMe, 6-9; acetic acid formed on alkaline hydrolysis, 13-1. C22H2704N2*C0*CH3 requires C, 67-6; H, 7-1; MeO, 7-3 ; NMe, 6-8 ; acetic acid, 14-1%. Found for hydrobromide : C, 57-3, 57-1; H, 5-9, 6-0; Br, 15-95. C22H2704N2-C0-CH3,HBr requires C, 56-8; H, 6-2; Br, 15-75%).