1α,6β,7β,11α,15β-Pentahydroxy-7α,20-epoxy-ent-kaur-16-ene

Abstract

The title compound, C20H30O6, a natural ent-kaurane diterpenoid, named nervosanin B, was obtained from the medicinal plant Isodon serra. It is composed of four rings with the expected trans and cis junctions. One of the six-membered rings is in a chair conformation, the other two are in boat conformations and the five-membered ring adopts an evenlope conformation. The molecules stack along the a axis and are linked together by intermolecular O—H...O hydrogen bonds. Two intramolecular O—H...O interactions also occur.