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A theoretical study of prednisolone, 6-fluoroprednisolone, 9-fluoroprednisolone, and 6,9-difluoroprednisolone has been performed at the ab initio HF/6-31G, MP2/6-31G, and B3LYP/6-31G levels. Structural information and the electronic features of prednisolone and its derivatives and the synergistic effect of 6,9-difluoroprednisolone was examined. Contrary to the AM1 and MNDO results, we found 9-fluoroprednisolone is more stable than the 6-fluoroprednisolone. The increased corticosteroid activity of the 6,9-difluoroprednisolone is most likely due to electronic effects, mainly related to the receptor binding. 相似文献
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甾体激素往往因分子中在 C_6的α-位置加入一甲基而增强其疗效,例如6α-甲基可的松及6α-甲基可的唑(Ⅰ)均比其母体的功效大得多,黄体酮在 C_(17)上加入一乙酰氧基可使其疗效较为持久,若再在 C_6-α位置上加入甲基则不但疗效比母体大五、六十倍,并可内服,而黄体酮则只能注射,此物(Ⅺ)的已知合成方法中,似以 Babcock 等的方法较为简便。其法是用17α-羟基黄体酮(Ⅱ)为原料,即先作成 A 环上应有的不饱和酮簇,然后再加入6α-甲基,最后引入17α-乙酰氧基得Ⅺ。 相似文献
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Abstract: The synthesis of 5-iodo-5α-cholestan-6-one (6), its 3β-acetoxy-(7) and 3β-chloro-(8) analogues, 3β-acetoxy-5-iodo-5α-stigmastan-6-one (9) and its 3β-chloro-(10) analogue by the reacion of silver chromate-iodine and pyridine with the corresponding steroidal olefins (1-5) is described. The structures of these products have been established on the basis of their elemental, analytical and spectral data. 相似文献
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Evidence for the presence of 3β,6α-dihydroxy-5α-chol-9(11)-en-23-one in the aglycone mixture from the starfish Marthasterias glacialis is provided by the synthesis of 3β,6α-dihydroxy-5α-cholan-23-one (19) and its identification in the hydrogenated aglycone mixture. The side-chain is constructed from the 23,24-dinorcholanol (13) by reaction of the 22-tosylate (16) with the acetylide anion, followed by hydration of the resulting 23-yne (17). 相似文献
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It has been established that on the interaction of the 5,6-epoxysteroids (1a–c) with trifluoroacetic acid in chloroform the 6-trifluoroacetates of the 5,6-diols (2a–c) are formed in high yield. The alkaline hydrolysis of the trifluoroacetates (2a–c) leads to the corresponding diols (3a–c).Institute of Bioorganic Chemistry, Belarus' National Academy of Sciences, 220141, Belarus', Minsk, ul. Akad. Kuprevicha, 5/2. Translated from Khimiya prirodnykh Soedinenii, No. 2, pp. 201–204, March–April, 1999. 相似文献
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Ken'Ichi Takeo Kazuhiko Ueraura Hisayoshi Mitoh 《Journal of carbohydrate chemistry》2013,32(2):293-308
Abstract Regioselective silylation of α-cyclodextrin with tert-butyl-dimethylsilyl chloride in N, N-dimethylformamide in the presence of imidazole gave, in 75% yield, the hexakis(6-O-tert-butyldimethylsilyl) derivative 2, which was transformed into the hexakis(2,3-di-O-methyl, 6-O-methyl, 2,3-di-O-propyl, and 2,3-di-O-acetyl) derivatives. On methanesulfonylation and p-toluenesulfonylation, the hexakis(2,3-di-O-acetyl) derivative 16 afforded the hexakis(2,3-di-O-acetyl-6-O-methylsulfonyl 17 and 2,3-di-O-acetyl-6-O-p -tolylsulfonyl 18) derivatives, respectively. Nucleophilic displacement of 17 and 18 with iodide, bromide, chloride, and azide ions afforded the hexakis(6-deoxy-6-iodo 19, 6-bromo-6-deoxy, 6-chloro-6-deoxy, and 6-azido-6-deoxy) derivatives, respectively, of α-cyclodextrin dodeca-acetate. The hexakis (2, 3-di-O-acetyl-6-deoxy) derivative was prepared from 19. Selective glucosylation of 16 with 2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl bromide under catalysis by halide ion, followed by removal of protecting groups, furnished 6-O-α-D-glucopyranosyl-α-cyclodextrin. 相似文献
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Condensation of p-nitrophenyl 2,3,4-tri-O-benzoyl-β-D-glucopyranoside 3 with 2,3,4-tri-O-(chlorosulfonyl)-β-D-xylopyranosyl chloride by the Koenigs-Knorr method afforded the α-linked product in a high yield. Dechlorosulfation with sodium iodide and debenzoylation by the Zemplen method gave crystalline p-nitrophenyl 6-O-(α-D-xylopyranosyl)-β-D-glucopyranoside 7. Compound 3 was condensed with 2,3,4-tri-O-benzoyl-α-D-xylopyranosyl bromide in the presence of mercury (II) cyanide in acetonitrile, and after debenzoylation, crystalline p-nitrophenyl 6-O-(β-D-xylopyranosyl)-β-D-glucopyranoside 10 was obtained. 相似文献
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2,3,4,6-Tetrar-O-methyl-α-D-glucopyranosyl bromide (3) is conveniently prepared by treatment of 2,3,4,6-tetra-O-methyl-D-glucose with HBr. This procedure is easier and produces higher yields than previously reported syntheses. 相似文献
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《Tetrahedron: Asymmetry》2001,12(8):1211-1217
Eight diastereomerically pure epoxides have been prepared from cholest-4-en-3β,6β; -3β,6α-; -3α,6β- and -3α,6α-diols via a combination of steric, protecting group and oxidant effects on stereocontrolled epoxidations of a bis-alicyclic alcohol system within the steroidal skeleton. 相似文献
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Akhrem A. A. Hermanek S. Syhora K. Zavel'skaya I. G. 《Russian Chemical Bulletin》1960,9(10):1777-1778
Russian Chemical Bulletin - 相似文献
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I. S. Levina L. E. Kulikova V. V. Kachala L. L. Khemchyan 《Russian Chemical Bulletin》2013,62(9):2037-2040
On treatment with methylmagnesium iodide, 3β-acetoxy-5β,6β-epoxy-16α,17α-cyclo-hexapregnan-20-one undergoes 3-O-deacetylation along with the opening of the 5β,6β-epoxide ring to form 5α-methyl-6β-hydroxy steroid and the 6α-methyl-6β-hydroxy isomer, the 20-keto group remaining intact. 相似文献
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