A convenient synthesis of the side chain of loteprednol etabonate--an ocular soft corticosteroid from 20-oxopregnanes using metal-mediated halogenation as a key reaction.

摘要

A facile synthesis of the side chain of loteprednol etabonate, namely, chloromethyl-17alpha-[(ethoxycarbonyl))oxy]-11beta-hydro of loteprednol etabonate, viz., chloromethyl-17alpha-[(ethoxycarbonyl))oxy]-11xy-3-oxoandrosta-1,4-diene-17beta-c arboxylate--an ocular soft corticosteroid, has been described starting from a 20-oxopregnane, namely, 3beta-acetoxy-pregn-5(6),16(17)-diene-20-one (16-dehydropregnenolone acetate, i.e., 16-DPA) using our recently developed metal-mediated halogenation as a key reaction.