Synthesis of 3β-methoxy-5α, 14α-card-20(22)-enolide from 3β-methoxy-5α-androstan-17-one. A method for the construction of the cardenolide slide-chain

Abstract

The Cardenolide side-chain has been constructed on the androstane skeleton via Knoevenagel condensation of the 17-oxo-derivative (2a) with ethyl cyanoacetate, three-step transformation of the resultant product (2b) to the protected hydroxy-aldehyde (4), followed by the formation of the cyanohydrin (5a), hydrolytic butenolide ring closure, and dehydration.