Constituents of the leaves of Helinus ovatus / by John Augustus Goodson.

  • Goodson, John Augustus.
Date:
1920.]
Catalogue details

Licence: Public Domain Mark

Credit: Constituents of the leaves of Helinus ovatus / by John Augustus Goodson. Source: Wellcome Collection.

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    quantity of potassium chloride separated. The filtrate yielded eT-phenylglucosazone on treatment with phenylhydrazine. Examination of the Aqueous Extract. The aqueous extract was treated successively with lead acetate and basic lead acetate, and the two precipitates were collected. Isolation of A coni tie Acid. The lead acetate precipitate was suspended in water and decom¬ posed by hydrogen sulphide. The filtrate was concentrated under diminished pressure and extracted with ether, which removed 12*6 grams of a crystalline substance, corresponding with 1*9 per cent, in the leaves. This, on recrystallisation from water, formed minute prisms melt¬ ing at 191°, and gave all the reactions of aconitic acid, including that described by Taylor (T., 1919, 115, 886). (Found: C = 41-3, 41*4; H = 3'9, 3-6. Aconitic acid, C6HGOc, requires C = 41*4; H = 3-5 per cent.) Isolation of Scyllitol. The basic lead acetate precipitate was decomposed in the usual manner, and the filtrate concentrated under diminished pressure, when slightly brown crystals separated. Two crops of the crude substance, amounting to 3 grams and corresponding with 0'46 per cent, in the leaves, were obtained. The product was purified by recrystallisation from hot water, from which it separated in anhydrous, monoclinic rhombs. (Found: C = 39‘7, 40*1; H = 6'8, 6'9. Scyllitol, CgH12Og, requires C = 40-0; H = 6*7 per cent.) The properties of the substance agreed closely with those recorded for scyllitol (J. Muller, Ber., 1907, 40, 1821, and H. Muller, T., 1907, 91, 1767; 1912, 101, 2383). When recrystallised slowly from cold water, it separated in transparent, hexagonal prisms, which, on removal from the solvent, became opaque and friable owing to loss of water of crystallisation. Crystals freed as rapidly as possible from adhering mother liquor lost, on exposure to air, 24*9 per cent, of water. C6H1206,3H20 requires H20 = 23,l per cent. H. Muller noted this change in crystal habit and transparency, but did not establish the fact that it is due to loss of water of crystallisation (T., 1907, 91, 1772).