反应详情

A solution of 3α-hydroxy-2β-methyl-5α-pregnane-11,20-dione (1.04 g.) in dry methanol (150 ml) was stirred at 0°-5° during the dropwise addition of a solution of bromine (0.16 ml) in dry methanol (20 ml) over a period of 2.5 hours. The reaction mixture was partitioned between ethyl acetate and water and the organic layer was separated, washed with water, dried (MgSO4) and evaporated to a white foam. Purification by preparative t.l.c. (ethyl acetate:benzene 1:2.5) gave the title compound (510 mg.), m.p. 140° dec.; [α]D + 133° (c 0.95).

1. customThe reaction mixture was partitioned between ethyl acetate and water
2. customthe organic layer was separated
3. washwashed with water
4. dry with materialdried (MgSO4)
5. customevaporated to a white foam
6. customPurification by preparative t.l.c