羟基新戊醛在Ti/Sb2O5-SnO2电极上的电氧化研究

在以质子交换膜为隔膜的电解槽内, 以硫酸为支持电解质, 羟基新戊醛为原料, 在Ti/Sb2O5-SnO2电极上直接电氧化制取羟基新戊酸. 线性扫描伏安曲线显示, 加入羟基新戊醛使氧化电流密度明显提高, 表明Ti/Sb2O5-SnO2电极对羟基新戊醛氧化有电催化作用. 通过恒电位电解实验研究羟基新戊醛浓度、pH、温度及阳极电位对生成羟基新戊酸选择性和电流效率的影响, 结果表明, pH对选择性和电流效率影响最大.     

Efficient synthesis of NK(1) receptor antagonist aprepitant using a crystallization-induced diastereoselective transformation

An efficient stereoselective synthesis of the orally active NK(1) receptor antagonist Aprepitant is described. A direct condensation of N-benzyl ethanolamine with glyoxylic acid yielded a 2-hydroxy-1,4-oxazin-3-one which was activated as the corresponding trifluoroacetate. A Lewis acid mediated coupling with enantiopure (R)-1-(3,5-bis(trifluoromethyl)phenyl)ethan-1-ol afforded a 1:1 mixture of acetal diastereomers which was converted into a single isomer via a novel crystallization-induced asymmetric transformation. The resulting 1,4-oxazin-3-one was converted via a unique and highly stereoselective one-pot process to the desired alpha-(fluorophenyl)morpholine derivative. Interesting and unexpected [1,2]-Wittig and [1,3]-sigmatropic rearrangements were identified during the optimization of these key steps. In the final step, a triazolinone side chain was appended to the morpholine core. The targeted clinical candidate was thus obtained in 55% overall yield over the longest linear sequence.     

Ca3Al2Ge3O12:Cr3+的光谱性质及晶场参数计算

为了解Cr3 离子在钙铝锗酸盐Ca3Al2Ge3O12石榴石中的光谱性质,合成了Ca3Al2Ge3O12:Cr3 多晶材料;测量了其X射线衍射图,漫反射光谱,激发、发射光谱等;分析了Cr3 离子在钙铝锗酸盐中的发光特性;计算了其晶场强度(Dq/B),Stokes位移(ΔEs)及黄昆-里斯因子(S)等.在450nm激发下,Ca3Al2Ge3O12:Cr3 室温发射光谱主要由三个宽带及附加其上的弱R线构成,分别对应于Cr3 离子的4T1、4T2、2T2到4A2能级跃迁.低温时R线变得强而锐.通过计算,Dq/B=2.43,ΔEs=1884cm-1,S=5.21.表明在Ca3Al2Ge3O12中Cr3 离子处于较弱的晶场强度,电子-声子耦合较强,为发展可调谐激光材料提供重要线索.     

掺杂Cu~(2+)离子水滑石[Cd_xMg_(6-x)Al_2(OH)_(16)]~(2+)[S·2H_2O]~(2-)导电性质的研究

合成了掺杂Cu2+离子水滑石[EdxMg6-xAl2(OH)16]2+[S·2H2O]2-，研究了它的导电性质及其影响因素，计算得到在383～523K时的导电活化能为7．18kJ／mol．     

Asymmetric addition reactions of Grignard reagents to chiral 2-trifluoromethyl tert-butyl (Ellman) sulfinimine-ethanol adducts

The addition of Grignard reagents to chiral trifluoromethyl tert-butyl sulfinimine-ethanol adducts affords protected trifluoromethylamines in high yields with good to excellent diastereoselectivities. The stereochemical outcome of the addition is opposite to that expected via a chelation controlled transition state.     

Synthesis,Crystal Structure and Thermal Behavior of a New Polynitrile N,N,N′,N′-tetra(2-cyanoethyl)-1,4-bis(3-aminopropyl)piperazine

Abstract  

A new polynitrile, N,N,N′,N′-tetra(2-cyanoethyl)-1,4-bis(3-aminopropyl)piperazine, was synthesized by the nucleophilic addition reaction of 1,4-bis(3-aminopropyl)piperazine and acrylonitrile for the first time. The title compound was characterized by elemental analysis, IR spectrum, and its crystal structure determined by X-ray single-crystal diffraction. The compound crystallizes in the monoclinic system with space group P2 ₁/c and a = 8.6195(12), b = 9.300(14), c = 16.221(2) ?, β = 97.824(2)°, V = 1288.2(3) ?³, D _c  = 1.064 g cm⁻³, M _r  = 412.59, Z = 2, F(000) = 448, μ = 0.067 mm⁻¹. The TG–DTA analysis revealed that the title compound possesses relatively good thermal stability under 220 °C.     

Preparation of 2,5,7-trithiabicyclo[2.2.1]heptane from 1,2-bis-triisopropylsilanylsulfanyl alkenes

[reaction: see text] The chemical behavior of 1,2-bis-triisopropylsilanylsulfanyl alkenes 1 is relatively unexplored, and the weak sulfur-silicon bonds give rise to various transformations. Under acidic conditions (HCl) and in the presence of a Lewis acid at room temperature the bicyclic adduct 2 is obtained in good yield. The structure was confirmed by X-ray crystal analysis with R = benzyl.     

On some methods for performance ranking and correspondence analysis in the DEA context

Two novel methods named performance baseline and performance correspondence matrices are proposed to evaluate the performance of decision making units (DMUs) based on the techniques of singular value decomposition (SVD). The performance baseline matrix can be used to rank all the DMUs because it provides a common basis for performance comparison. The performance correspondence matrix can be used to conduct performance cluster analysis, with which to explore the structure of input/output variables that are associated with DMUs. The analysis can reveal the performance difference of the DMUs and the key input/output variables determining the efficiency of a certain DMU, and provides valuable quantitative information for adjusting variables to improve efficiency of the DMU. Three case studies are presented to demonstrate that the proposed methods in this work are effective and easy to use and can provide insights into proper selection of input/output variables for performance comparison to avoid over manipulating DEA models in practice.