Sterols with Cyclopropane-Containing Side Chains: Synthesis and Acid Isomerization

To test the eventual involvement of sterols with a cyclopropane containing side chain in bio-methylation processes, 24,25-methanocholest-5-en-3β-ol ( 5 ) and 24,25-methano-26-methylcholest-5-en-3β-ol ( 6 ) were synthesized. Together with the naturally occurring cyclopropane petrosterol ( 1 ), they were submitted to acid isomerization to provide chemical models for some of their potential metabolites.