Stereoselective synthesis of the two major metabolites of spironolactone, 3α- and 3β-hydroxy-7α-methylthio-17α-pregn-4-ene-21,17-carbolactone

7α-Methylthio-3β-hydroxy-17α-pregn-4-ene-21,17-carbolactone and 7α-methylthio-3α-hydroxy-17α-pregn-4-ene-21,17-carbolactone, the two major metabolites of spironolactone, were prepared stereoselectively by exploring different types of reduction reagents. For the 3β-hydroxyl isomer, the application of NaBH4/CeCl3·7H2O gave the best result while for the 3α-hydroxyl isomer, K-selectride seemed to provide the highest stereoselectivity.