Steroids. Part XIII. Pyrolysis of maleic anhydride and maleic ester adducts of 9,11-epoxy-5,7-dienes
Abstract
Pyrolysis of the maleic anhydride or dimethyl maleate adducts of 3β-acetoxy-9α, 11α-epoxyergosta-5,7,22-triene gives 3β-acetoxy-19-norergosta-5,7,9,22-tetraen-11-one (50%), 3β-acetoxy-19-norergosta-5,7,9,11,22-pentaene (20%), 19-norergosta-3,5,7,9,22-pentaen-11-one (5%), and 19-norergosta-3,5,7,9,11,22-hexaene (5%). The major product from the pyrolysis of the maleic anhydride adduct of 3β-acetoxy-9α, 11 α-epoxypregna-5,7-dien-20-one is 3β-acetoxy- 19-norpregna-5,7,9-triene-11,20-dione.