Total synthesis of heterocyclic steroids

Abstract

The total synthetic approach developed initially for natural steroids, and used for the preparation of A-nor compounds, has been extended to the preparation of novel heterocyclic steroids. The easily accessible 3,4-dinor-2,5-seco-9α-estrane-1,5,17-trione (9a) was treated with hydrazine hydrate, urea, and hydroxylamine hydrochloride to provide the 1-methyl-2,3-diaza steroid derivative (10a), the pyrimidone (11), and the isoxazole analogue (12a), respectively. The 17α-ethynyl steroids (10b) and (12b) were also prepared.