The formation of O,O-isopropylidene derivatives from 16-hydroxyoleanenes

Abstract

Re-examination of the reactions of primulagenin A, longispinogenin and chichipegenin with acetone has shown that isopropylidene derivatives may be obtained in all cases. With chichipegenin two of the three possible isomeric isopropylidene derivatives were isolated. The effect of alteration of the conformation of ring v by the introduction of a Δ¹³⁽¹⁸⁾ double bond on the ease of formation of the 1,3-dioxan ring has been examined in the case of the 3β,16α,28-triol system.