Reaction Steps
To a solution of the product of Example 13 (21.4 g) in 250 ml dimethylformamide, potassium acetate (25 g) was added. After stirring at 105° C. under nitrogen for 6 hours, the reaction mixture was cooled down to room temperature and poured into ice water (3 L). After filtration, crystallization from acetone afforded 21-acetoxy-11β-hydroxyl-1,4,16-pregnatriene-3,20-dione (17 g, 89.8%). Recrystallization gave yellowish long cubic, m.p.=203°-205° C. NMR (CDCl3) δ 1.25 (s, 3H, 13--CH3), 1.48 (s, 3H, 10--CH3), 2.18 (s, 3H, 21--Ac), 4.40 (m, 1H, 11--H), 4.94(m, 2H, 20--CH2O--). 6.02 (S, 1H, 4--H), 6.28 (dd, 1H, J=10 and 2 Hz, 2--H), 6.74 (m, 1H, 16--H), 7.30 (d, 1H, J=10 Hz, 1--H). Upon normal saponification there was obtained 11β,21-dihydroxy-1,4,16-pregnatriene-3,20-dione. Recrystallization from acetone gave needles (VI, 50.5%). m.p.=213°-215° C.; NMR (CDCl3) δ 1.25(s, 3H, 13--CH3), 1.49 (s, 3H, 10--CH3), 4.35-4.55 (m, 3H, 20--CH2 -- and 11--H), 6.02 (S, 1H, 4--H), 6.28 (dd, 1H, J=10 and 2 Hz, 2--H), 6.73(m, 1H, 16--H), 7.32 (d, 1H, J=10 Hz, 1--H).
