Baker's Yeast Mediated Reduction of Optically Active Diketone

Baker's yeast (BY) mediated reduction of synthetic substrate is a useful method for preparing chiral intermediate in synthesis chemistry1,2, because it is readily available and inexpensive. The selectivity is generally predicted by Prelog rule3, that is, a hydride is transferred to the re face of the prochiral ketone.The baker's yeast mediated reduction of bicyclic diketones was previously reported by several groups4-6, but to our knowledge, no application of this reduction to sesquiter-pene-…     

A Phenolic Glucoside from Alangium plantanifolium

Alangium, the sole genus in the family Alangiaceae, has a variety of about 20 species distributed in the tropical and subtropical area of the Eastern Hemisphere, and 13 species are known to occur in the south of China1. A. plantanifolium and A. chinense are used in chinese traditional medicine for the treatment of rheumatalgia, paralysis, cardianeuria, and wound2. Pharmacological studies of the extracts of these two species showed muscular relaxing activity, and anabasine was considered as t…     

固-液相转移催化法合成4,4′-联苯撑二芳酰基硫脲衍生物

在固—液相转移催化条件下,以 PEG-600为催化剂,通过芳酰氯与硫氰酸铵反应合成了中间体芳酰基异硫氰酸酯;后者不经分离,分别与联苯二胺和邻甲联苯二胺反应,高产率获得相应的芳酰基硫脲衍生物,用元素分析,IR 和~1HNMR 光谱确定了其结构.     

王冠高聚物担载四核钴羰基簇催化剂的醛化反应活性

本文用二苯并-18-冠-6高聚物作因相化载体,通过化学健合,合成了担载的四核钴羰基簇催化剂Crown-Co_4。,并对该催化剂进行了元素分析、红外光谱及X射线光电子能谱(XPS)等方面的测试分析;还考察了不同温度、不同极性溶剂及不同类型烯烃对醛化活性的影响。实验证明,该催化剂对直链端位烯烃的醛化活性高于均相的苯基-四核钴羰基簇催化利Ph-Co_4。。二苯并-18-冠-6高聚物载体能明显改善催化性能。     

200KV重离子加速器及其应用

本文介绍一台采用双潘宁型多电荷重离子源的200kV重离子加速器,简述它在GaP光探测器的研制、聚合物材料和金属材料的离子注入改性等方面的研究与应用。     

Investigation into the rotational bands of ~(185)Pt with the particle-rotor model

Theoretical calculations have been performed for the ν9/2+[624](i13/2) and ν7/2-[503](f7/2) bands of 185Pt in the framework of particle-rotor model. The band properties of signature splitting and configuration mixing have been analyzed. The level energy and signature splitting before the band crossing can be well interpreted by introducing triaxiality. The positive-parity yrast band is pro posed to be dominated by the ν9/2+[624](i13/2) component, while the negative-parity band shows strong mixing of ν7/2-[5...     

钐(Ⅱ)类卡宾CH_3SmCH_2X(X=Cl、Br和Ⅰ)促进乙烯环丙烷化反应途径的理论研究(英文)

用密度泛函B3LYP方法研究了过渡金属钐类卡宾与乙烯的环丙烷化反应的机理。对三种不同的钐的SS试剂CH_3SmCH_2X(其中X=Cl、Br和Ⅰ)分别和CH_2CH_2反应的各反应物、中间体、过渡态和产物构型的全部结构几何参数进行了优化,用内禀反应坐标(IRC)计算和频率分析方法,对过渡态进行了验证。结果表明：CH_3SmCH_2X(其中X=Cl、Br和Ⅰ)与CH_2CH_2环丙烷化反应按亚甲基转移通道(通道A)和卡宾金属化通道(通道B)都可以进行,与锂类卡宾的反应机理相同,只是按亚甲基转移通道(通道A)进行反应较容易一些,而且此反应在较低的温度下就可以发生。     

X射线荧光光谱法直接测定油页岩中微量元素

本文提出用微晶纤维素与GSD等国家一级系列标样按不同比例混合制备标准样品。油页岩样品不经前处理,直接粉末法压片,经验系数法校正元素间效应,直接测定油页岩中V、Co、Ni、Cr、Cu、Zn、Sr、Ba和Rb等元素的X射线荧光光谱法。样品分析结果与ICP-AES法分析结果基本一致,本法具有简单、准确、实用的特点。     

相对论和非相对论理论模型研究奇异核的性质

采用相对论和非相对论理论模型可描述奇异核的性质 .相对论平均场理论预言了2 6,2 7,2 8P存在一个质子晕 ,而27,28,29S存在两个质子晕 .最近 ,MSU的最新的实验发现了2 6,2 7,2 8P核存在一个质子晕.采用相对论 Hartree- Fock理论研究了 Fock项和矢量介子对奇异核性质的贡献,研究表明交换项和矢量介子对非常丰中子核性质的影响非常不同于对稳定线附近核性质的影响.同时,采用形变的Hartree- Fock- Bogoliubov理论研究了某些轻核同位素链的性质和形变.     

钠原子团簇的相变

采用紧密结合的分子动力学模型，对Ｎａ４、Ｎａ８、Ｎａ２０的结构特性进行了分析。通过对这些钠原子团簇的键长涨落和径向密度分布的分析，发现在２００Ｋ到２５０Ｋ的温度范围内有从类固相到类液相的改变