Epibisdehydroneotuberostemonine J

Abstract

The title compound, C22H29NO4, a stemona alkaloid, is composed of two lactone rings (A and E), a six-membered ring (B), a pyrrole ring (C) and a seven-membered ring (D). The five-membered rings A and E exhibit envelope conformations (C atoms as flaps) while ring C is planar. Ring B exhibits a twist-chair conformation due to fusion with pyrrole ring C while ring D adopts a chair conformation. The junction between rings A and B is cis. In the crystal, weak C—H...O interactions involving the two carbonyl groups, a methylene and a methyl group give rise to a three-dimensional network.