Terpenoids. Part XXV. Structures and absolute configurations of isodoacetal, nodosinin, and odonicin, novel diterpenoids of Isodon japonicus

Abstract

On the basis of spectroscopic data and chemical evidence, the structure and absolute configuration of isodoacetal (1a), nodosinin (6), and odonicin (11) have been established. The first two are B-secokaurene derivatives and the third is ent-6α, 15α-diacetoxy-7β,20-epoxy-7α-hydroxykaura-2,16-dien-1-one. Chemical interconversions between isodoacetal and nodosinin have been accomplished.