Investigation of the Structures of Some Natural Products From the Neem Tree

Abstract

Podocarpic acid (1) and totarol (2) have been converted into five diterpenoids reported to have been isolated from the Neem tree. The synthetic diterpenoids have been compared with the naturally occurring diterpenoids but only the structure of nimbidiol (23) has been confirmed. The structure for margosolone, which was reported as (19), has been revised to (20) after synthesis of both (19) and (20).