TRANSFORMED STEROIDS. SYNTHESIS OF THE δ-LACTONE OF 3β-ACETOXY-16α-HYDROXY-6-OXO-24-NOR-5α-CHOL-17(20)-EN-23-OIC ACID

Article abstract of DOI:10.1007/BF00634732

The synthesis of the Δ¹⁷⁽²⁰⁾-16α analog of natural chiogralactone is described.Attempts to introduce a 6-oxo group directly into the δ-lactone proved unsuccessful, since the first stage - saponification - took place with the formation of three products: the 3-hydroxy-δ-lactone, the 3-hydroxy-Δ²⁰⁽²²⁾-lactone, and the 15,17(20)-dienoic acid.The synthesis of the desired compound was effected from the ethyl ester of the 5,16-dienoic acid by the scheme 3-acetate->3-tosylate->6-hydroxy-3α,5α-cyclosteroid->6-oxo-3α,5α-cyclosteroid->6-oxo-5αH-δ-lactone.It has been shown that the cyclopropane ring in the 3α,5α-cyclosteroid δ-lactone is extremely stable under the conditions of acid treatments.