Utility of i-Steroid-Route to Oxidized Sterol Bound to a Cross-linker: Synthesis of the Steroid Antigen

The target sterol, which was for preparation of oxidized sterol antigen to apply to a new antibody diagnostic method for circulatory disease, was successfully synthesized via i-steroid transformation as followings: 1) the Grignard reaction, 2) Barton-McCombie reaction, 3) regioselective photolytic-addition of thiolacetic acid toward 25-double bond, and 4) in situ Michael addition between the thiol and a cross-linker.