p-Toluenesulfonic acid → 3alpha-Hydroxy-2alpha-methyl-5alpha-pregnane-11,20-dione
Reaction equation
C1CO[C:3]([C@@H:5]2[C@:22]3([CH3:23])[C@H:8]([C@H:9]4[C@H:19]([C:20](=[O:24])[CH2:21]3)[C@:17]3([CH3:18])[C@H:12]([CH2:13][C@H:14]([OH:26])[C@H:15]([CH3:25])[CH2:16]3)[CH2:11][CH2:10]4)[CH2:7][CH2:6]2)([CH3:4])[O:2]1.C1(C)C=CC(S(O)(=O)=O)=CC=1>CC(C)=O>[OH:26][C@@H:14]1[C@H:15]([CH3:25])[CH2:16][C@@:17]2([CH3:18])[C@@H:12]([CH2:11][CH2:10][C@@H:9]3[C@@H:19]2[C:20](=[O:24])[CH2:21][C@@:22]2([CH3:23])[C@H:8]3[CH2:7][CH2:6][C@@H:5]2[C:3](=[O:2])[CH3:4])[CH2:13]1Participants
4
Procedure
A solution of 20,20-ethylenedioxy-3α-hydroxy-2α-methyl-5α-pregnane-11-one (0.38 g.) and toluene-p-sulphonic acid (30 mg.) in acetone (20 ml.) was kept at room temperature for 11/2 hr. The reaction mixture was then evaporated to low bulk and an aqueous solution of sodium hydrogen carbonate was added. The precipitated solid (0.32 g.) was collected and purified by preparative t.l.c. and crystallised from methyl acetate/petrol (b.p. 60°-80°) to give the title compound (0.175 g.), m.p. 179°-180°, [α]D + 125°.