Hydroxy-16α,17α,21-trimethyl-5-en-20-one was synthesized from 3α-acetoxypregna-5,16-dien-20-one and characterized by elemental analysis, 1H NMR, MS and IR. 16α,17α-Dimethyl steroid was formed by treatment of 3β-...Hydroxy-16α,17α,21-trimethyl-5-en-20-one was synthesized from 3α-acetoxypregna-5,16-dien-20-one and characterized by elemental analysis, 1H NMR, MS and IR. 16α,17α-Dimethyl steroid was formed by treatment of 3β-acetoxypregna-5,16-dien-20-one with methylmagnesium bromide, followed by reaction of the resulting 17(20)-enolate with methyl iodide. The main by- products were 3β-hydroxy-16α,17α-dimethyl-5-en-20-one. LHDMS([(CH 3) 3Si] 2NLi) and LDA([(CH 3) 2CH] 2NLi) were chosen as proper reagents for 21-position alkylation. The almost quantitative conversion of 16α,17α-dimethyl corticosteroid was achieved and the highest yield of the 16α,17α,21-trimethyl corticosteroid was 78%. The optimum reaction temperature was -20 ℃ for 16α,17α- dialkylation and was -50 ℃ for 21- position alkylation.展开更多
14-Noreudesma-4,11-dien-3,9-diones′ analogues were treated with DDQ in dioxane and afforded the rearranged aromatic products. The similar compounds to eudesma-4,11-dien-3,9-diones had no reaction. 9-Actoxy-14-noreude...14-Noreudesma-4,11-dien-3,9-diones′ analogues were treated with DDQ in dioxane and afforded the rearranged aromatic products. The similar compounds to eudesma-4,11-dien-3,9-diones had no reaction. 9-Actoxy-14-noreudesma-4,11-dien-3-ones, 9-actoxy-eudesma-4,11-dien-3-ones and their analogues yielded the normal 1,2-dehydro-products. The mechanism of the rearrangement was discussed.展开更多
文摘Hydroxy-16α,17α,21-trimethyl-5-en-20-one was synthesized from 3α-acetoxypregna-5,16-dien-20-one and characterized by elemental analysis, 1H NMR, MS and IR. 16α,17α-Dimethyl steroid was formed by treatment of 3β-acetoxypregna-5,16-dien-20-one with methylmagnesium bromide, followed by reaction of the resulting 17(20)-enolate with methyl iodide. The main by- products were 3β-hydroxy-16α,17α-dimethyl-5-en-20-one. LHDMS([(CH 3) 3Si] 2NLi) and LDA([(CH 3) 2CH] 2NLi) were chosen as proper reagents for 21-position alkylation. The almost quantitative conversion of 16α,17α-dimethyl corticosteroid was achieved and the highest yield of the 16α,17α,21-trimethyl corticosteroid was 78%. The optimum reaction temperature was -20 ℃ for 16α,17α- dialkylation and was -50 ℃ for 21- position alkylation.
文摘14-Noreudesma-4,11-dien-3,9-diones′ analogues were treated with DDQ in dioxane and afforded the rearranged aromatic products. The similar compounds to eudesma-4,11-dien-3,9-diones had no reaction. 9-Actoxy-14-noreudesma-4,11-dien-3-ones, 9-actoxy-eudesma-4,11-dien-3-ones and their analogues yielded the normal 1,2-dehydro-products. The mechanism of the rearrangement was discussed.
