21-Sulfuric acid or 21-orthophosphoric acid ester sodium salts of prednisolone or 9.alpha.-fluoro-16.beta.-methylprednisolone
Prednisolone esters I [R = (HO)2PO, (HO)SO2; R1 = H, Me; R2 = H, F]. (4 compds.) were prepd. Thus, prednisolone (I; R = R1 = R2 = H) was treated with EtO2COCl-H3PO4 in Et3N-MeCN and then with NaOMe to give 66% I [R = (HO)2PO].