PURPOSE: To provide a compd. useful for production of a budesonide and desonide.

CONSTITUTION: The compd. of formula I (R is H, a 1 to 8C acyl, etc.). For example, (11β.16α)-21-(acetyloxy)-11-(formyloxy-16,17-[(1-methylethylidene)bis(oxy)]pregna-1,4-diene-3,20-dione. The compd. of the formula I is obtd. by treating, for example, a compd. of formula II with a chlorinating or brominating agent (e.g.: N-chloroacetamide, N-chlorosuccinimide, etc.), and formyloxylating agent (e.g. dimethylformamide, etc.), in acidic medium to obtain the compd. of formula III (Hal is Cl, Br), treating this compd. with an acetone in the presence of a strong acid (more preferably perchloric acid, etc.), and in the presence of a dehydrating agent (more preferably isopropyl acetate) to obtain the compd. of formula IV, then subjecting this compd. to dehalogenation by the effect of tributyltin hydride in the presence of a free radical reaction initiator.