11 α,17 α,21-trihydroxypregnoline-4-ene-3, 20-dione, that is, epihydrocortisone, can be acetylated by (21-hydroxy) and (11-hydroxy) sulfonylated and eliminated to generate 17 α,21-dihydroxypregnoline-4, 9(11) diene -3,20-diketone -21-diacetate, then it is acetylated by (17-hydroxyl group), 9[(11)-double bond] hypobromous acid addition and epoxidation, (hydrogen fluoride on the epoxy group) addition (9-fluoro, 11-position Formation of hydroxyl group) dehydrogenation (formation of 4-position double bond), elimination (16,17-position deacetate to form double bond) to obtain this product.