Ozonization of Cholesterol

Article abstract of DOI:10.1021/ja00345a052

The ozonization of cholesterol in aqueous dispersion gave minor products 5,6α-epoxy-5α-cholestan-3β-ol and 5,6β-epoxy-5β-cholestan-3β-ol and major product 5ξ,6ξ-epidioxy-5,6-secocholestane-3β,5ξ,6ξ-triol, along with 3β-hydroxy-5-oxo-5,6-secocholestan-6-al and 3β,10-dihydroxy-5,6:5,10-disecocholestan-5-oic acid lactone (5->10) derived by decomposition of the major epidioxide product.Acetic anhydride/pyridine treatment of the epidioxide resulted in rearrangement, yielding 3β-acetoxy-10-hydroxy-6-oxo-5,6:5,10-disecocholest-3-en-5-oic acid lactone (5->10), and 6,6-diacetoxy-10-hydroxy-5,6;5,10-disecocholest-3-en-5-oic acid lactone (5->10).Acetylation of homologue 5ξ,6ξ-epidioxy-6ξ-methoxy-5,6-secocholestane-3β,5ξ-diol and its 3β-acetate also involved rearrangement to disecolactones, including 3β,6ξ-diacetoxy-10-hydroxy-6ξ-methoxy-5,6:5,10-disecocholestan-5-oic acid lactone (5->10).These results establish that 5,6-secosterol formation is the major ozonization process and 5,6-epoxidation a minor independent process and that ''anomalous'' lactone products derive by rearrangement of initially formed epidioxides.