Halogenated terpenoids. XIX. The 24,25-dibromolanosteryl acetates

Abstract

The earlier assignment of the structures of the two epimeric 24,25-dibromides of lanosteryl acetate is reversed and is now consistent with deductions made from optical rotation data. The two dibromides on heating equilibrate to an approximately equimolar mixture. The structures of the agnosteryl acetate dibromides and of the Ianosta-7,24-dien-3-yl acetate dibromides must also be revised, with the higher-rotating A isomers having the 24R configuration in all cases.