First synthesis of thia steroids from cholic acid

Heterosteroids remain interesting due to their potential biological activities. This prompted us to synthesize novel thia steroids possessing the heteroatom in the A-ring. We set out to describe a new and versatile method for preparing 3-thia steroids from cholic acid via a selective oxidation of one hydroxyl group, a Baeyer–Villiger oxidation and a photolysis as the key steps. The characteristic 1H and 13C NMR spectroscopic features of the synthesized compounds are reported.