A method of preparing a thioic acid intermediate of fluticasone propionate includes: treating a 17β-[(N,N-dimethyl carbamoyl)thio]carbonyl compound in a solution including an alcohol and an alkali metal hydroxide, an alkaline-earth metal hydroxide, or a mixture thereof to cleave an amide from the 17β-[(N,N-dimethyl carbamoyl)thio]carbonyl compound; treating the solution to separate an aqueous portion; and adding an acid to the aqueous portion to obtain the thioic acid intermediate of fluticasone propionate. A method of preparing fluticasone propionate includes preparing the thioic acid intermediate of fluticasone propionate, and alkylating the thioic acid intermediate of fluticasone propionate to prepare the fluticasone propionate.