Br[CH2:2][C:3](=[O:25])[C@@H:4]1[C@:21]2([CH3:22])[C@H:7]([C@H:8]3[C@H:18]([C:19](=[O:23])[CH2:20]2)[C@:16]2([CH3:17])[C@H:11]([CH2:12][C@H:13]([OH:24])[CH2:14][CH2:15]2)[CH2:10][CH2:9]3)[CH2:6][CH2:5]1.[S-:26][C:27]#[N:28].[Ba+2].[S-]C#N>CC(C)=O.O>[OH:24][C@@H:13]1[CH2:14][CH2:15][C@@:16]2([CH3:17])[C@@H:11]([CH2:10][CH2:9][C@@H:8]3[C@@H:18]2[C:19](=[O:23])[CH2:20][C@@:21]2([CH3:22])[C@H:7]3[CH2:6][CH2:5][C@@H:4]2[C:3](=[O:25])[CH2:2][S:26][C:27]#[N:28])[CH2:12]1A solution of 21-bromo-3α-hydroxy-5α-pregnane-11,20-dione (0.75 g.) in acetone (50 ml.) was treated with a solution of barium thiocyanate (2.6 g.) in water (10 ml.). The resulting mixture was refluxed for 4 hr., cooled and then partitioned between water and ether. The organic layer was washed with water, dried (Na2SO4) and evaporated. The residue (720 mg.) was purified by preparative t.l.c. (EtOAc) to afford title compound (685 mg.) as a white foam, [α]D + 67°.
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