THREE MINOR ALKALOIDS OF GELSEMIUMSEMPERVIRENS AIT.

Abstract

After the removal of gelsemine and sempervirine from the extract of the root of Gelsemiumsempervirens Ait. the residual alkaloids left in the mother liquors were benzoylated. It was thus possible to separate the tertiary bases from the secondary bases which were obtained as a mixture of the neutral benżoyl derivatives. Purification by chromatography yielded the benzoylated mixture in crystalline form. This was hydrolyzed and the recovered secondary bases were separated by fractional crystallization of the perchlorates into alkaloid A and alkaloid B. Alkaloid A was shown by direct comparison to be identical with the gelsemicine (C20H26O4N2) of Chou. Alkaloid B, now designated gelsedine, was shown to be distinct from either gelsemicine or gelsemine. It appears to be identical with the alkaloid C19H24O3N2 claimed by Janot and his co-workers to be gelsemicine. From the tertiary bases there was isolated an apparently new base, gelseverine, as its crystalline perchlorate. Whereas gelsemine is a 3,3-disubstituted oxindole, gelsedine appears to be a 1,3-disubstituted oxindole and gelseverine a 1,3,3-tri-substituted oxindole. Gelsemicine shows many of the characteristics of an indole alkaloid.