Ginkgolides

Abstract

Three bitter principles, ginkgolides A, B, and C, were isolated from the leaves of Ginkgo biloba L. Since the structure of ginkgolide A was established by X-ray analysis of its p-bromobenzoate, structures of the other two were deduced by comparison of the n.m.r. spectra of the three compounds. The structures of ginkgolides A and B were correlated by chemical methods. Owing to its complex structure, ginkgolide A gave an unusual oxidation product, the structure of which was determined.