Synthesis of Equine Metabolites of Anabolic Steroids: Reformatsky Reactions on Estran-17-ones

Abstract

Reformatsky reactions involving ethyl bromoacetate/zinc are reported for 19-norandrosterone acetate and 19-norepiandrosterone acetate. In each case the major product was the 17β-alcohol from α-attack, although a significant amount of the 17α-alcohol from β-attack was also isolated. The ethyl 3-acetoxy-17β-hydroxy-19-nor-5α,17α-pregnan-21-oates were then hydrolysed to 3,17β-dihydroxy-19-nor-5α,17α-pregnan-21-oic acids or reduced to 19-nor-5α,17α-pregnane-3,17β,21-triols. Comparison of the synthetic products with compounds previously reported as metabolites of norethandrolone in the horse provided valuable information on the regio- and stereo-chemistry of equine steroid metabolism.