abstract |
17A-MONOESTERS OF 11B,17A,21-TRIHYDROXYSTEROIDS ARE PREPARED BY SILYLATING THE 11B-HYDROXYL GROUP OF AN 11B, 17A-DIHYDROXY-21-ACLOXY STEROID TO A SILYLOXY GROUP, ESTERIFYING THE 17A-HYDROXYL GROUP, AND THEN REMOVING THE SILYL GROUP AT THE 11B POSITION AND THE ACYL GROUP AT THE 21 POSITION BY HUDROLYSIS OR ALCOHOLYSIS. |