20-(5,5-Dimethyl-1,3-dioxan-2-yl)-1alpha,2alpha-epoxy-7alpha-methoxycarbonyloxypregn-5-en-3beta-yl acetate → 1alpha,2alpha-Epoxy-21,21-dimethoxy-20-methylpregna-5,7-dien-3beta-yl acetate

Participants

Reaction Steps

The procedure of Example 17 was repeated except that 40.4 mg (0.0798 mmole) of 1α,2α-epoxy-21,21-dimethoxy-7α-methoxycarbonyloxy-20-methylpregn-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 15.6 mg of 1α,2α-epoxy-21,21-dimethoxy-20-methylpregna-5,7-dien-3β-yl acetate. In addition, 14.1 mg of the starting compound 1α,2α-epoxy-21,21 -dimethoxy- 7α-methoxycarbonyloxy- 20-methylpregn-5 -en-3β-yl acetate was recovered. The yield of 1α,2α-epoxy-21,21-dimethoxy-20-methylpregna-5,7-dien-3β-yl acetate was 70% based on consumed 1α,2α-epoxy-21,21-dimethoxy-7α-methoxycarbonyloxy-20-methylpregn-5-en-3β-yl acetate.

Provenance & Evidence