Conversion of N-Acyl-4-phenyl/benzyl-oxazolidine-2-thiones into Thiol Esters in the Presence of EtSH-K2CO3

N-Acyl-β-hydroxy-4-phenyl-oxazolidinethiones could be rapidly converted into their ethyl thiol esters in high yields by treatment with EtSH at 0 ℃ in CH3CN or 9 ： 1 （V ： V） THF-H2O in the presence of a catalytic amount of K2CO3.     

淀粉接枝丙烯酸/醋酸乙烯酯高吸水性树脂的制备

以过硫酸铵为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,淀粉与丙烯酸/醋酸乙烯酯混合单体通过接枝共聚,制备了吸水及耐盐性能均较好的淀粉接枝丙烯酸/醋酸乙烯酯高吸水性树脂(CGAV)。最佳工艺条件为:淀粉10.0 g,m(混合单体)∶m(淀粉)=4∶1,w(引发剂)=0.3%,w(交联剂)=0.05%,于45℃反应2h~3 h。在最佳工艺条件下制得的CGAV吸去离子水率760 g.g-1,吸0.9%NaC l水溶液率68 g.g-1。     

Electrochemical Preparation of Poly(Malachite Green) Film Modified Nafion‐Coated Glassy Carbon Electrode and Its Electrocatalytic Behavior Towards NADH,Dopamine and Ascorbic Acid

Poly(malachite green) film modified Nafion‐coated glassy carbon electrodes have been prepared by potentiodynamic cycling in malachite green solution. The pH of polymerisation solution has only minor effect on film formation. Electrochemical quartz crystal microbalance (EQCM) was used to monitor the growth of the poly(malachite green) film. Cyclic voltammogram of the poly(malachite green) film shows a redox couple with well‐defined peaks. The redox response of the modified electrode was found to be depending on the pH of the contacting solution. The peak potentials were shifted to a less positive region with increasing pH and the dependence of the peak potential was found to be 56 mV per pH unit. The electrocatalytic behavior of poly(malachite green) film modified Nafion‐coated glassy carbon electrodes was tested towards oxidation of NADH, dopamine, and ascorbic acid. The oxidation of dopamine and ascorbic acid occurred at less positive potential on poly(malachite green) film compared to bare glassy carbon electrode. In the case of NADH, the overpotential was reduced substantially on modified electrode. Finally, the feasibility of utilizing poly(malachite green) film electrode in analytical estimation of ascorbic acid was demonstrated in flow injection analysis.     

An ionic liquid-type carbon paste electrode and its polyoxometalate-modified properties

The replacement of a non-conductive organic binder with a conductive room temperature ionic liquid in fabricating carbon paste electrode has been made. This new electrode due to its enhanced conductivity presented very large current response from electroactive substrates. The novel carbon paste electrode was bulk-modified via the uniform dispersion of Keggin-type phospho polyoxomolybdate (PMo₁₂) in bulky carbons, which possessed excellent electrocatalytic activity for the reduction of nitrite. The pronounced multi-electron catalytic ability was ascribed to the used hydrophobic ionic liquid which constructed an excellent charge-transfer bridge in the bulk of carbon paste electrode, thus facilitated the intake of electrons from reduced PMo₁₂ mediators. In view of their prominent properties, the carbon paste electrode using ionic liquid binder and its bulk-modified electrode take on good prospects of the application in physical chemistry and electroanalytical chemistry fields.     

A Novel Dihydroflavone from the Roots of Uvaria Macrophylla

A new dihydroflavone (1), named macrophyllol A, was isolated from the roots of Uvaria macrophylla. Its structure was elucidated on the basis of spectroscopic evidence.     

聚羟基丁酯酯缓释微球的制备及性能

用溶剂蒸发法制备了以新型生物可降解材料聚羟基丁酸酯为载体、以安定为模药的缓释微球,讨论了药物与载体之比对药物含量与包封率的影响,以及制备微球条件对药物释放性能的影响;微球平均粒径为３０～４０μｍ,粒径分布在１～１．５之间,最大载药量为１９．５１％;最高包封率为６７．１１％;体外累积释放曲线呈“两相”释放特征并拌随初始的“突释效应”。扫描电镜观察微球表面呈皱缩表观形态结构,微球内部横断面具有孔道与孔     

水热法制备Sb2S3纳米棒有序阵列

以Sb(S₂CNEt₂)₃为单源前驱体，通过改变时间、温度、表面活性剂等反应条件，用水热法成功合成了各种尺寸的Sb₂S₃纳米棒及其有序阵列。X-射线衍射(XRD)、能量分散光谱(EDS)以及选区电子衍射(SAED)研究表明纳米棒由正交晶系Sb₂S₃单晶构成。扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究显示Sb₂S     

Novel synthesis of a strained para-cyclophane derivative

A [P. Rajakumar, A.M.A. Rasheed, Tetrahedron 61（22） （2005） 5351] para-cyclophane derivative was synthesized via intramolecular esterification of a dipeptide surrogate containing asparagine to form tetrahydropyrimidinone ring. The structures of the product and intermediates were characterized by 1H NMR, 13C NMR and mass spectrum.     

Tetraazadibora[3, 3]paracyclophane

Starting from the para‐phenylenediamine derivative HN(SiMe₃)‐C₆H₄‐NH(SiMe₃), a lithiation and subsequent borylation give [(MeO)₂B]N(SiMe₃)‐C₆H₄‐N(SiMe₃)[B(OMe)₂] ( 1 ), the hydridation of which yields Li₂[(H₃B)N(SiMe₃)‐C₆H₄‐N(SiMe₃)(BH₃)] ( 2 ). Applying ZrCl₄ upon 2 initiates a condensation to give the title compound [‐N(SiMe₃)‐p‐C₆H₄‐N(SiMe₃)‐BH‐]₂, a hetero[3, 3]paracyclophane with two N‐B‐N chains that connect the para‐phenylene units. The product 3 crystallizes in the orthorhombic space group P2₁2₁2₁.     

β-环糊精与非离子表面活性剂相互作用及其对显色反应的影响——Ⅰ.β-环糊精和非离子表面活性剂的相互作用

本文以TritcnⅩ-100为例,用红外光谱法、紫外可见光度法、表面张力法、浊点法等手段,研究了β-环糊精(β-CD)与非离子表面活性剂(NSF)的相互作用。证明在β-CD和NSF的混合液中,当NSF的浓度小于或近于其CMC时,两者形式1:1包合物,大于CMC时,形成两者的混合胶束。经初步探讨,认为由于β-D对NSF的包合作用,使B-CD的内腔的极性降低,增强了与显色络合物的疏水相互作用;以及混合胶束中显色剂的分配系数增大,可能是β-CD-NSF对显色反应产生协同增敏作用的重要原因。