反应详情

The procedure of Example 17 was repeated except that 44.6 mg (0. 0798 mmole) of 7α-(N,N-dimethylcarbamoyloxy)-20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α-epoxypregn-5-en-3β-yl acetate was used in lieu of 43.6 mg of 20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α-epoxy-7α-methoxycarbonyloxypregn-5-en-3β-yl acetate to give 16.6 mg of 20-(5,5-dimethyl-1,3 -dioxan-2-yl)-1α,2α-epoxypregna-5,7-dien-3β-yl acetate. In addition, 16.0 mg of 7α-(N,N-dimethylcarbamolyoxy)-20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α-epoxypregn-5-en-3β-yl acetate was recovered. The yield of 20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α-epoxypregna-5,7-dien-3β-yl acetate was 69% based on consumed 7α-(N,N-dimethylcarbamoyloxy)-20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α-epoxypregn-5-en-3β-yl acetate. The 1H-NMR spectrum of the product 20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α-epoxypregna-5,7-dien-3β-yl acetate was in agreement with that of the 20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α-epoxypregna-5,7-dien-3β-yl acetate obtained in Example 17.