β微管蛋白中紫杉醇(Taxol)结合腔的性质分析

采用多拷贝同时搜寻法(MCSS), 并结合现有微管抑制剂的SAR及3D-QSAR对β微管蛋白中Taxol(紫杉醇)结合腔的性质进行了分析. 结构研究结果表明, Taxol结合腔以疏水性质为主, 并指出官能团分布的具体位置: 在Phe270上方(Leu361-Pro272-Leu273-Leu228之间)的弧形区域、Asp26羧基下方及其与Glu22羧基之间、M-loop的中部, 以及Asp224内侧且靠近Arg276的胍基的位置. 而Asp224的内侧又是新提出的结合位点. 研究结果符合现有微管抑制剂的SAR, 为现有抗肿瘤药物的结构改造以及小分子微管抑制剂设计提供了理论依据.     

Regioselective cleavage of the bis-benzylidene acetal of d-mannitol under oxidative and reductive conditions: a new approach to C2-symmetric chiral ligands

A highly regioselective oxidative cleavage of 1,3:4,6-di-O-benzylidene-d-mannitol was carried out using NBS and the resultant product was readily converted to the C₂-symmetric chiral ligand, (R,R)-3,4-dihydroxy-1,5-hexadiene. On the other hand, reductive cleavage of 1,3:4,6-di-O-benzylidene-d-mannitol was achieved in a highly regioselective manner using BF₃·OEt₂ and Et₃SiH to give a highly functionalized benzyl ether, which was converted to a synthetically useful C₂-symmetric bis-amino alcohol derivative.     

The Efficient Synthesis of the Optically Active β‐Hydroxyl‐γ‐Butyrolactone Derivatives

The optically active β‐hydroxyl‐γ‐butyrolactones were synthesized from nonchiral starting material by employing reductive cleavage reaction, sharpless asymmetric epoxidation and dihydroxylation, and Lewis acid‐catalysed cyclization as key steps. This strategy can be used to prepare many chiral β‐hydroxyl‐γ‐butyrolactone analogues.     

纳米级TiO2粉体的制备研究——Ⅱ.絮凝剂及其浓度的影响

采用溶胶-凝胶-超临界流体干燥(SCFD)法制备纳米级TiO₂超细粉，详细考察了不同絮凝剂及其浓度对TiO₂织构和结构性质的影响。结果表明，利用强碱溶液作为絮凝剂，浓度为5 mol·L^-1是制备大孔高比表面TiO₂超细粉较为适宜的条件。     

Reductive opening of 1H,3H-benzo[de]isochromene: synthesis of 1,8-difunctionalised naphthalenes

The lithiation of 1H,3H-benzo[de]isochromene (6) with lithium and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 5% molar) in THF at −50 °C gives dianionic intermediate 7, which by reaction with different electrophiles {H₂O, D₂O, ^tBuCHO, PhCHO, Me₂CO, (CH₃CH₂)₂CO, [CH₃(CH₂)₄]₂CO, (CH₂)₅CO, (CH₂)₇CO, (−)-menthone} at the same temperature followed by hydrolysis leads to functionalised alcohols 8. If after addition of a carbonyl compound as the first electrophile [^tBuCHO, (CH₂)₅CO, (−)-menthone], the resulting dialcoholate 9 is allowed to react at 0 °C, a second lithiation takes place to give intermediate 10 which by reaction with a second electrophile [H₂O, ^tBuCHO, (CH₂)₅CO, CO₂], yields, after hydrolysis, 1,8-difunctionalised naphthalenes 11. Cyclization under acidic conditions of diols 8e-i gives oxygen-containing eight-membered heterocycles, which are homologous to the starting material 6.     

分光光度法同时测定中草药中的钼和铜

本文建立了在混合显色剂（ＰＦ＋ＰＡＮ）的胶束体系中，利用分光光度法同时测定中草药中的钼和铜。实验表明：在混合体系中，钼量在０～１０μｇ／２５ｍＬ，铜量在０～５０μｇ／２５ｍＬ的范围内符合比尔定律，ε′Ｍｏ＝９．２×１０４Ｌ·ｍｏｌ－１·ｃｍ－１；ε′Ｃｎ＝１．５×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。该法用于中草药样品的分析，结果满意，回收率可达９２～１１１％。     

Chiral resolution of diphenylalanine by high-performance liquid chromatography on a crown-ether-based chiral stationary phase and by NMR spectroscopy

Summary The enantiomers of diphenylalanine (DPA) were well separated by chiral HPLC and NMR spectroscopy on the chiral stationary phase (CSP) derived from (18-crown-6)-2,3,11,12-tetracarboxylic acid (18-C-6-TA). The chromatographic parameters such as separation factors and retention times were greatly influenced by the mobile phase conditions. The (+)-18-C-6-TA used in the CSP was also employed as a chiral solvating agent for the enantiodiscrimination of the DPA enantiomers by NMR spectroscopy. The proton of the DPA analyte showing the chemical shift nonequivalences was used in determining the enantiomeric composition of the analyte.     

Functional polymers,XL. Syntheses of mono- and di(4-methoxy)benzotriazolesubstituted 2,4-dihydroxyaceto(or benzo)phenones

Eight benzotriazoles and (4-methoxy)benzotriazoles, mono- or di-substituted derivatives of 2,4-dihydroxyaceto(or benzo)phenone were synthesized by azo coupling of (4-methoxy)2-nitrobenzenediazonium chloride with 2,4-dihydroxyaceto(or benzo)phenone followed by reductive cyclization. Pure mono-substituted compounds were very difficult to prepare. Careful selection of thepH for the azo coupling and selection of the proper reagents for the reductive cyclization were essential. All compounds were characterized by their ultraviolet, infrared¹H and¹³C NMR spectra and their elemental analysis. These compounds have both the 2(2-hydroxyphenyl)2H-benzotriazole unit and a 2-hydroxyaceto(or benzo)phenone unit in the same molecule and are effective and useful ultraviolet absorbers.Dedicated to Prof. Dr.K. Komarek, Vienna, on the occasion of his 60^th birthday with best wishes.     

Reaction of trans-[Pt(H)2(PCy3)2] with C60 reductive elimination of H2 and formation of [Pt(PCy3)2(η-C60)]

Reaction of trans-[Pt(H)₂(PCy₃)₂], 1, with [60]fullerene at room temperature affords [Pt(PCy₃)₂(η²-C₆₀)], 2, in nearly quantitative yield. The most probable reaction pattern is the insertion of a fullerene 6,6 junction onto a Pt-H bond yielding an η¹ alkyl derivative which, after hydrogen extrusion, gives 2. On the other hand, addition of 1 to different electron-deficient olefins, such as dimethyl maleate and fumarate, furnishes mixtures of both η¹ metal—alkyl and η² metal—olefin derivatives. If tetrachloroethylene is used as 2π component, trans-[PtCl(H)(PCy₃)₂] forms exclusively.