Tetracyclic triterpenes. Part 13. A new synthesis of 4β-demethyl-24,25-dihydrolanosterol

Abstract

The reaction of 3β-hydroxy-3α-acetyl -14α-methyl-4-nor- 5α-cholest-8-ene toluene-p-sulphonylhydrazone 10 under Bamford–Stevens conditions resulted information of 4α,14α-dimethyl-5α-cholest-8-en-3-one (4β-demethyldihydrolanosterol) and a mixture of 3,14α-dimethyl-4-oxo steroids. Thermal deoxygenation of 10 leading to the ketal 11 is explained by the intramolecular reduction mechanism involving the steroidal diimide.