3,4-Seco-Isopimarane Diterpenes from the Twigs and Leaves of Isodon Flavidus.

ABSTRACT: Three isopimarane diterpenes [fladins B (1), C (2), and D (3)] were isolated from the twigs and leaves of Chinese folk medicine, Isodon flavidus. The chemical structures were determined by the analysis of the comprehensive spectroscopic data, and the absolute configuration was confirmed by X-ray crystallographic analysis. The structures of 1-3 were formed from isopimaranes through the rearrangement of ring A by the bond break at C-3 and C-4 to form a new δ-lactone ring system between C-3 and C-9. This structure type represents the first discovery of a natural isopimarane diterpene with an unusual lactone moiety at C-9 and C-10. In the crystal of 1, molecules are linked to each other by intermolecular O-H···O bonds, forming chains alon

SUBMITTER: Li WF 

PROVIDER: S-EPMC9143206 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature