Seymour D. Levine

An a-nor-3-thia-5β-pregnane

Abstract The conversion of a 5β-pregnan-3-one into a 3-thia-A-nor-pregnane is described. The single epimer, characterized as the 5β-isomer by nmr spectroscopy, was obtained. A previous report [1] from this laboratory described the synthesis of the epimeric 3-oxa-A-norpregnan-20-ones 1 and 2 from A-norprogesterone. Recently, the total synthesis of the related A-nor-3-thiaestra-1,-5(10)-diene derivative 3 has been described [2]. Continuing interest [3] in A-ring-modified steroids as probes of drug-receptor interactions prompts this report of the preparation of the 3-thia-5β-A-norpregnan-20-one 4 .

A-nor oxa steroids II. A-nor oxa pregnanes

Abstract The conversion of A-norprogesterone into A-nor oxa steroids bearing a pregnane side chain is described. In this investigation, both C-5 epimers, 3-oxa-5α-A-norpregnane-2, 20-dione and 3-oxa-5β-A-norpregnane-2,20-dione were obtained.