Terpenoids. Part VI. The complete structure of melianone

Abstract

The structure of melianone and of melianol, two new tetracyclic triterpenes of the tirucallane type, isolated from Melia azedarach L., has been elucidated. Melianone is 24,25-epoxyflindissone. The side-chain is characterised by the presence of a hemiacetal and of an oxiran ring. Treatment with hydrobromic acid opened the latter leading to a bicyclic acetal, the stereochemisty of which contributed towards the elucidation of the configuration of the side-chain.