organic compounds
The Amaryllidaceae alkaloids (+)-tazettine [(+)-(3S,4aS,6aS,13bS)-3-methoxy-5-methyl-3,4,4a,5,6,6a-hexahydro-8H,11H-[1,3]dioxolo[6,7][2]benzopyrano[3,4-c]indol-6a-ol, C18H21NO5] and partially hydrated (+)-3-epimacronine [(+)-(3S,4aS,6aR,13bS)-3-methoxy-5-methyl-3,4,4a,5,6,6a-hexahydro-8H,11H-[1,3]dioxolo[6,7][2]benzopyrano[3,4-c]indol-8-one 0.066-hydrate, C18H19NO5.0.066H2O] have been extracted from Galanthus plicatus subsp. byzantinus, while (+)-3-O-demethylcriwelline [(+)-(3R,4aS,6aS,13bS)-5-methyl-3,4,4a,5,6,6a-hexahydro-8H,11H-[1,3]dioxolo[6,7][2]benzopyrano[3,4-c]indole-3,6a-diol, C17H19NO5] has been isolated from the plant Galanthus gracilis. These compounds have the ring skeleton of the tazettine or [2]benzopyrano[3,4-c]indole subgroup. (+)-3-O-Demethylcriwelline is a new alkaloid and is the 3-O-demethyl C3-epimer of (+)-tazettine. The geometrical features of the compounds differ predominantly in the conformations of the pyrrolidine and pyran rings.