Reactions of trialkylalanes with cyclic acetals and orthoformates in CH2Cl2 and ClCH2CH2Cl as solvents

Under mild conditions, trialkylalanes (Et₃Al and Buⁱ ₃Al) in chlorine-containing solvents (CH₂Cl₂ or ClCH₂CH₂Cl) react with cyclic acetals and orthoformates to form glycol monoethers and dialkylacetals, respectively, in high yields. The ¹H NMR spectroscopic data demonstrate that CH₂Cl₂ or ClCH₂CH₂Cl interacts with Buⁱ ₃Al.     

Investigations of Imidazoles. 101. Synthesis of 2,3-Dihydroimidazo[1,2-a]pyrimidine from 2-Aminopyrimidine

Two novel preparative methods have been developed for the synthesis of 2,3-dihydroimidazo[1,2-a]pyrimidine from 2-aminopyrimidine. These are the reaction with 1,2-dibromoethane and also the reaction with ethylene chloro(bromo)hydrin, subsequent treatment of 1--hydroxyethyl-2-imino-1,2-dihydropyrimidine with thionyl chloride, and cyclization of the intermediate 1--chloroethyl-2-imino-1,2-dihydropyrimidine in the presence of sodium hydroxide.     

Poly(methacrylic acid-ethylene glycol dimethacrylate) monolith in-tube solid-phase microextraction applied to simultaneous analysis of some amphetamine derivatives in urine by capillary zone electrophoresis

A method based on in-tube solid-phase microextraction and capillary zone electrophoresis (CZE) was proposed for simultaneously determining four amphetamines (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, and 3,4-methylenedioxymethamphetamine) in urine. A poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column, which can provide sufficient extraction efficiency, was introduced for the extraction of amphetamines from urine samples. The hydrophobic main chains and acidic pendant groups of the monolithic column make it a superior material for extraction of basic analytes from aqueous matrix. After extraction, the samples were analyzed by CZE. The best separation was achieved using a buffer composed of 0.1 M disodium hydrogen phosphate (adjusted to pH 4.5 with 1 M hydrochloric acid) and 20% methanol v/v, with a temperature and voltage of 25 degrees C and 20 kV, respectively. By applying electrokinetic injection with field-amplified sample stacking, detection limits of 25-34 microg/L were achieved. Excellent method of reproducibility was found over a linear range of 0.1-5 mg/L. Determination of these analytes from abusers' urine sample was also demonstrated.     

联萘冠醚的合成新方法

一种用于合成含联萘基冠醚的新方法。以消旋，手性联萘酚为起始原料，先与氯乙醇反应制得2,2'-二（2－羟基乙氧基）－1,1'－联二苯，再与二甘醇或三甘醇对二对甲苯磺酸酯反应，成功制得了4种联萘冠醚。     

Preparation of poly(N‐ethyl methacrylamide) particles via an emulsion/precipitation process: The role of the crosslinker

Monodisperse, thermosensitive poly(N‐ethyl methacrylamide) microgel particles were prepared by the batch precipitation/emulsion polymerization of water‐soluble N‐ethyl methacrylamide and the hydrophobic crosslinker ethylene glycol dimethacrylate initiated by potassium persulfate. Particular attention was paid to the effect of the crosslinker agent on the polymerization process (kinetics, conversion, and water‐soluble oligomer content). Particles were characterized in terms of their size distribution and swelling capacity. A polymerization mechanism for the water‐soluble monomer and non‐water‐soluble crosslinker is proposed and discussed on the basis of a combination of both emulsion and precipitation polymerization processes. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1808–1817, 2002     

An Environmentally Benign System for Synthesis of β-Hydroxylketones： L-Histidine Asymmetrically Catalyzed Direct Aldol Reactions in Aqueous Micelle and Water-like Media

The first histidine catalyzed direct aldol reactions of ketones with nitrobenzaldehydes in water and in poly（ethylene glycol） （PEG） were reported. It reveals that histidine is a good aldol catalyst for synthesis of β-hydroxylketones in water and in PEG, giving good to excellent yields of the respective products. Better enantioand regioselectivity were achieved using low molecular weight PEG as the media. The results show that histidine and PEG-200 or -300 may constitute a promising environmentally benign system for asymmetric synthesis of β-hydroxylketones.     

高折光指数光学树脂的合成——相转移法合成不饱和硫醇酯单体的条件控制

采用正常的低温相转移催化（ＰＴＣ）和反滴碱溶液ＰＴＣ法分别合成了含硫双烯ＭＥＳＤＭＡ和单烯ＭＥＰＳＭＡ．１Ｈ ＮＭＲ分析证明ＭＥＳ中的杂质主要是由原料ＴＤＧ引入的．对含单个巯基的ＭＥＰＳ的正常ＰＴＣ酯化接枝双键，因存在巯基和不饱和双键的加成反应而导致失败．作者最终得到了折光指数在１６２５以上的ＭＥＳＤＭＡ／ＭＥＰＳＭＡ共聚物．     

聚己内酯聚醚嵌段共聚物和共混物的表面性质对其药物释放行为的影响

聚己内酯聚醚嵌段共聚物和共混物的表面性质对其药物释放行为的影响王卫华，贝建中，王智峰，王身国（中国科学院化学研究所北京１０００８０）关键词聚己内酯聚醚嵌段共聚物，共混物，电子能谱，表面性质，药物释放行为聚己内醋（ＰＣＬ）具有优良的药物通透性和生物相容...     

手性铜催化剂的制备及在环丙烷羧酯酯不对称合成中的应用

３类手性配体ｄ－１０－樟脑磺酸及其衍生物，α－（－）－羟蒎酮及其衍生物，又恶唑啉６衍生物分别与铜（Ⅱ）形成手性铜配合物，催化重氮乙酸酯与１，１－二苯乙烯或异丁烯的环丙烷化加成反应，得到光学活性环丙羧酸酯，不对称诱导最高可达９５％ｅ．ｅ．。