The photochemistry of 3β-Acetoxy-6-nitrocholest-5-ene and 6-Nitrocholest-5-ene. The mechanism of photodeconjugation of α,β-unsaturated nitro compounds

Abstract

The photochemistry of 3β-acetoxy-6-nitrocholest-5-ene (1) and 6- nitrocholest-5-ene (11) has been investigated in a number of solvents. It is suggested that for both compounds the major primary photo-product is the corresponding aci-nitro tautomer, which then undergoes further reactions depending mainly on the conditions employed. The aci-nitro compounds are believed to be formed by a 1,5-hydrogen shift from C4 to oxygen, and their intermediacy is supported by the formation of a mixture of 6α-deutero-6β-nitrocholest-4-ene and 6β-deutero-6α- nitrocholest-4-ene on irradiation of 6-nitrocholest-5-ene in Me₃COD.    Several other reactions of 3β-acetoxy-6-nitrocholest-5-ene and 6- nitrocholest-5-ene are described.