Photooxidative dehydrogenation of Δ8-drimen-and Δ8-11-homodrimen-7-ones into α,α ′-dienones

An efficient two-step procedure for photooxidative dehydrogenation of drimane and 11-homodrimane compounds containing an 8-en-7-one structural unit into α,α′-dienones was elaborated. The method is based on the transformation of ketones into the respective enol acetates followed by photosensitized oxygenation. Methyl 7-oxo-11-homodrima-5,8-dien-12-oate, 5,6-dehydro-7-ketoisodrimenine, 11-acetoxydrima-5,8-dien-7-one and 11,12-diacetoxydrima-5,8-dien-7-one were prepared in high yields starting from methyl 7-oxo-11-homodrim-8-en-12-oate, 7-oxoisodrimenine, 11-hydroxydrim-8-en-7-one and 11,12-diacetoxydrim-8-en-7-one, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 678–682, April, 2006.     

Asymmetric addition of methyl nitroacetate to crotonaldehyde catalyzed by chiral amines

The asymmetric Michael addition of methyl nitroacetate to crotonaldehyde catalyzed by chiral amines was carried out. The maximum chemical yield of diastereomeric products amounted to 95 %. The best asymmetric induction (42 % e.e.) was achieved in the case of catalysis by (S)-prolinol. The diastereomeric mixture was converted to a mixture of stereoisomeric 3-methyl-2-methoxycarbonylpyrrolidines. Absolute configurations of (2S,3S)-and (2R,3S)-isomers formed in excess were determined using GLC by comparison with authentic samples of racemic and optically pure forms of 3-methylproline.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1591–1595, September, 1993.     

用硅烯醚型引发剂进行的基团转移聚合

本文报道了一类硅烯醚型的基团转移聚合引发剂。并以负离子和HgI_2等为催化剂,进行了甲基丙烯酸酯和丙烯酸酯的基团转移聚合。得到了实测分子量和理论分子量相近且分散性较小的浆合物。进行了甲基丙烯酸甲酯的活性聚合以及其与丙烯酸酯的A-B-A型三嵌段共聚,证实具有活性高分子的特征。探讨了该类引发剂引发基团转移聚合的机理,研究了催化剂和引发剂的配合选择性以及催化剂和引发剂的摩尔比对产物分子量和转化率的影响,发现该类引发剂引发的基团转移聚合是一恒速聚合反应。     

PIII-derivatives of methyl mercaptoacetate

Dichlorophenylphosphine and dichlorodiethylamidophosphite react with methyl (trimethylsilylthio)acetate to substitute the methoxycarbonylmethylthio group for one Cl atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2554–2555, December, 1998.     

聚甲基丙烯酸甲酯浇铸成膜的银纹形态与其成膜浓度的关系

聚甲基丙烯酸甲酯浇铸成膜的银纹形态与其成膜浓度的关系叶卫珺，沈静姝（中国科学院化学研究所高物开放实验室北京１０００８０）关键词银纹，缠结密度，均匀形变区，聚甲基丙烯酸甲酯非晶态聚合物在拉伸应力作用下，会在材料表面或内部产生能反射光线的微小而稠密的裂痕...     

钕掺杂提高TiO2光催化活性的机制

采用X射线衍射(XRD), BET吸附, X射线光电子能谱(XPS)表征了溶胶凝胶法制备的Nd掺杂TiO2光催化剂的晶体结构、表面电子结构与化学组成. 以甲基橙为有机底物, 测试Nd掺杂对光催化剂吸附性能和光催化活性的影响. 结果表明, Nd掺杂可阻碍TiO2的晶相转变, 减小光催化剂的晶粒尺寸, 比表面积增大. Nd掺杂提高光催化剂表面三价钛(TiⅢ)的含量及其对甲基橙的吸附能力是其提高TiO2光催化降解甲基橙活性的主要原因. Nd掺杂量为1.2%时, 光催化剂活性最高.     

A spectrophotometric determination of the formation constants of the inclusion complexes ofα- andβ-cyclodextrins with the azonium and ammonium tautomers of methyl orange and methyl yellow

The color fading caused by the addition of-cyclodextrin or-cyclodextrin to an aqueous solution of a tautomeric mixture of methyl orange or methyl yellow is studied spectrophotometrically at pH 1.1 and 25.0°C. A model involving 1 : 1 stoichiometry has been used to analyze the spectrophotometric data. The addition of a cyclodextrin shifts the tautomeric mixture towards the side of the ammonium tautomer. An expression allowing the calculation of the tautomeric equilibrium constant of the inclusion complexes is derived. The formation constants of the inclusion complexes of the individual tautomers are determined. Both- and-cyclodextrins bind the ammonium tautomer stronger than the azonium tautomer. The inclusion complexes of-cyclodextrin are more stable than the corresponding ones of-cyclodextrin.     

三维全息原子场作用矢量用于HEPT类抗艾滋病药物的QSAR研究

采用本实验室新近提出的三维全息原子场作用矢量表征34个1-[(2-羟乙氧)甲基]-6-苯硫基胸腺嘧啶(HEPT)类抗艾滋病药物结构并与其活性建立定量构效关系模型. 采用逐步回归对变量进行筛选后, 运用多元线性回归(multiple linear regression, MLR)建模的复相关系数(R2cum)、交互校验的复相关系数(Q2cum)和模型的标准偏差(SD)分别为R2cum=0.928、Q2cum=0.883与SD=0.43, 均优于Hancsh报道的值(R2cum=0.911、Q2cum=0.863与SD=0.45). 模型具有良好的稳定性和预测能力, 表明三维全息原子场作用矢量能较好表征该类分子结构信息, 值得进一步推广应用.     

Separation of conjugated linoleic acid methyl esters by silver-ion high performance liquid chromatography in semi-preparative mode

Silver-ion HPLC (Ag-HPLC) has been utilized to separate a variety of unsaturated fatty acid methyl esters (FAMEs) by configuration, location or number of olefinic or acetylenic bonds. Two analytical Ag-HPLC columns connected in series and an isocratic solvent system of acetonitrile (ACN) in hexane were used to fractionate 10-15 mg samples of a mixture of two deuterium-labeled isomers of conjugated linoleic acid (Z9.E11- and Z9,Z11-octadecadienoic acid-17,17,18,18-d4). "Baseline" (> 95%) resolution of the two isomers, which decreased with increasing weights of sample injected, was maintained by careful adjustment of the percentage of ACN in the ACN/hexane solvent system. Chemical purities of the isolated FAME were > 96%.