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
Methylenecholestan 3 β,5α,6β triol 1 isolated from the soft coral, Sinularia dissecia has high antifouling property and biodecomposability in natural environment, safe for human bodies. We have synthesized compound...Methylenecholestan 3 β,5α,6β triol 1 isolated from the soft coral, Sinularia dissecia has high antifouling property and biodecomposability in natural environment, safe for human bodies. We have synthesized compound 1 in seven steps starting from stigmasterol 2 in overall yield of 31 3%. The side chain of stigmasterol 2 was modified to keto containing structure of compound 3 via hydroxy group and olefin protection, ozonization, wittig reaction and hydrogenation. The A/B ring was modified by oxidation with performic acid to give stereospecific 5 α,6β diol sterol 4. The compound 1 was then obtained by methylenation of cabonyl group at the 24C of 4 through Wittig reaction in a rather strict conditions. The mp, and NMR data of synthesized 1 were in good agreement with that of the natural compound reported by Masaru . This is the first time of the synthesis of 24 methylenecholest 3 β,5α,6β triol 1.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Methylenecholestan 3 β,5α,6β triol 1 isolated from the soft coral, Sinularia dissecia has high antifouling property and biodecomposability in natural environment, safe for human bodies. We have synthesized compound 1 in seven steps starting from stigmasterol 2 in overall yield of 31 3%. The side chain of stigmasterol 2 was modified to keto containing structure of compound 3 via hydroxy group and olefin protection, ozonization, wittig reaction and hydrogenation. The A/B ring was modified by oxidation with performic acid to give stereospecific 5 α,6β diol sterol 4. The compound 1 was then obtained by methylenation of cabonyl group at the 24C of 4 through Wittig reaction in a rather strict conditions. The mp, and NMR data of synthesized 1 were in good agreement with that of the natural compound reported by Masaru . This is the first time of the synthesis of 24 methylenecholest 3 β,5α,6β triol 1.
