Convenient synthesis of 18-hydroxylated cortisol and prednisolone

Article abstract of DOI:10.1016/0039-128X(92)90095-Q

18,20-Epoxy-11β,17α,20β,21-tetrahydroxypregn-4-en-3-one was synthesized by the application of hypoiodite reaction to the cortisol acetonide. The intermediary 18-iodo derivative was converted to the 11-oxo steroid by chromic acid prior to silver ion-assisted solvolysis. Removal of the protective group with hydrochloric acid was finally carried out to give the desired 11β,17α,18,21-tetrahydroxypregn-4-ene3,20-dione as the hemiacetal form. 18,20-Epoxy-11β-17α,20β,21-tetrahydroxypregna-1,4-dien-3-one was also prepared from prednisolone through a similar reaction sequence.