测定啤酒和白葡萄酒中有机酸的离子排斥色谱法

研究了离子排斥色谱法分离测定啤酒和白葡萄酒中有机酸；选用常见的盐酸溶液作淋洗液，以四丁基氢氧化铵为再生液，考察了淋洗液浓度、流量等因素对分离和测定的影响，对啤酒和白葡萄酒中常见有机酸在阴离子排斥色谱柱上的保留行为进行了系统的研究；通过试验确定最佳的色谱条件为盐酸浓度1．10mmol/L，流量0．80mL/min；四丁基氢氧化铵浓度5.0mmol/L，流量1.10mL/min；并在该条件下，测定了啤酒和白葡萄酒中的有机酸。     

Cover Picture: A Stepwise Annulation for the Transformation of Cyclic Ketones to Fused 6 and 7‐Membered Cyclic Enimines and Enones (Chin. J. Chem. 4/2019)

The cover picture shows a typical building within the Campus of Xiamen University displaying Chen Jiageng (Tan Kah Kee)'s style. Just like many beautiful buildings designed and constructed by human, Nature “designs and constructs” a huge number of useful molecules with fascinating structures called natural products. Many natural products possess a fused six or seven‐membered carbocyclic unity. On page 315–322, the Huang's group disclosed a three‐step “[2+n]” annulation method for the construction of fused six and seven‐membered carbocyclic enimines and enones. The method starts from simple cyclic ketones and terminal olefinic amides, and relies on both the Suzuki coupling reaction and the olefin‐amide based Friedel‐Crafts type acylating reaction, a method developed by Huang and coworkers.

     

Effect of subsurface oxygen on the reactivity of the Ag(111) surface

Periodic, self-consistent, density functional theory calculations have been performed to demonstrate that subsurface oxygen (O(sb)) dramatically increases the reactivity of the Ag(111) surface. O(sb) greatly facilitates the dissociation of H2, O2, and NO and enhances the binding of H, C, N, O, O2, CO, NO, C2H2, and C2H4 on the Ag(111) surface. This effect originates from an O(sb)-induced upshift of the d-band center of the Ag surface and becomes more pronounced at higher O(sb) coverage. Our findings point to the important role that near-surface impurities, such as O(sb), can play in determining the thermochemistry and kinetics of elementary steps catalyzed by transition metal surfaces.     

A Rapid and Convenient Synthesis of Derivatives of Imidazoles under Microwave Irradiation

An efficient and a quick microwave‐assisted synthesis of benzimidazoles and trisubstituted imidazoles was developed. Three benzimidazoles were obtained as a result of the condensation of 1,2‐phenylenediamine with carboxylic acids and acetoacetic ester without catalyst. A series of trisubstituted imidazoles were synthesized by condensation of benzil, aromatic aldehyde and ammonium acetate in the presence of glacial acetic acid.     

Quantitation of SU1 1248, an oral multi-target tyrosine kinase inhibitor, and its metabolite in monkey tissues by liquid chromatograph with tandem mass spectrometry following semi-automated liquid-liquid extraction

SU11248 is a potent inhibitor of PDGFR, VEGFR, KIT, and Flt3, and is currently under Phase I clinical evaluation as an anticancer drug. A sensitive and specific analytical method for the quantitation of SU11248 and its metabolite in several monkey tissues (liver, kidney, brain and white fat) using LC-MS-MS following semi-automated liquid-liquid extraction (LLE) was developed and validated. Amounts of 50 mg of tissue were homogenized using an ultrasonic processor. After addition of the stable labelled internal standard (IS) and ammonium hydroxide (0.3%), samples were extracted with 2.5 ml of tert-butyl methyl ether. Following centrifugation, aliquots of 1.8 ml of the organic phase were transferred into a 96-well plate. The Packard Multiprobe II robotic liquid handler was used to perform all steps mentioned above. The organic phase was dried and the residue was reconstituted with 800 microl of 15 mM ammonium formate buffer solution (pH 3.25) using a Tomtec Quadra 96 workstation. Aliquots of 10 microl of the resulting solution were injected into the LC-MS-MS system. A Symmetry Shield C8 column (50 mm x 2.1 mm, 3.5 microm) was used to perform the chromatographic analysis. The mobile phase was 15 mM ammonium formate buffer solution (pH 3.25)-acetonitrile (74:26 (v/v)) with a flow-rate of 0.35 ml/min. Retention times of the metabolite and SU11248 were about 2.5 and 3.5 min, respectively. Total cycle time was 5 min. MS detection used the Applied Biosystems-MDS Sciex API 3000 with TurbolonSpray interface and multiple reaction monitoring (MRM) operated in positive ion mode. The method was validated for both compounds over the calibration range of about 2 and 2000 ng/g. The suitability and robustness of the method for in vivo samples were confirmed by analysis of monkey tissues from animals dosed with SU11248.     

钒、铬、锰磷桥络合物中31P NMR化学位移的研究

ISSIe山和W6flSChllh山子1960年首次用pdCI。和二苯基磷合成出黄色的二聚络合物，后被H。yieY＊确认为具有pRZ的桥式结构．此后一系列该类结构的化合物被合成并引起了广泛的兴趣．磷可以和两个甚至多个金属原子络合构成多核金属络合物，在催化反应中有重要应用．磷原子存在多种电子态，其3d空轨道也能参与成键．P乃1的NMR谱是研究含磷化合物立体结构的有力工具．P－31与其它核素之间的耦合常数以及P－31的化学位移对阐明化合物的立体构象以及电子结构具有重要作用．近年来，West饲用计算机神经网络技术预测P－：if的化学位移，但仅…     

Three-component one-pot total syntheses of glyantrypine, fumiquinazoline F, and fiscalin B promoted by microwave irradiation

A microwave-promoted three-component one-pot reaction has been developed to provide access to the core pyrazino[2,1-b]quinazoline-3,6-dione (1) scaffold, which is common to several families of alkaloids with significant biological activities. By adapting this synthetic strategy through the use of selected Boc-amino acids and amino acid esters, we have accomplished highly efficient and concise total syntheses of glyantrypine (2), fumiquinazoline F (3), and fiscalin B (5), achieving overall yields of 55, 39, and 20%, respectively.     

NMR频率综合器的微机控制

为实现ＰＴＳ系列频率综合器的微机控制，设计了一种简单的控制电路。在微机的控制下，通过该电路与微机的并行通讯口，用Ｃ语言编写的控制程序可以很方便的控制频率综合器的输出频率。控制程序采用菜单操作，电路所需的＋５Ｖ电源由微机提供，整个控制系统简单实用，值得推广。     

固相膜萃取与GC/MS联用测定地下水中痕量半挥发性有机物的野外采样方法研究

C18固相萃取膜适宜处理大体积地下水样现场采样而且易于运输、贮存。利用C18固相膜萃取以及GC／MS联用的方法对地下水中痕量半挥发性有机污染物进行了萃取以及定性、定量分析。优化了固相膜萃取的地下水采样量和浓缩体积。有机氯农药和多环芳烃的平均回收率分别为85％～110．1％、90．3％～115．1％；方法检出限达到10^-9g／L；相对标准偏差均小于15％。本方法用于北京地区地下水中的有机污染物分析，并给出地下水样C18固相膜萃取的GC／MS测定结果。     

杂多酸在活性炭上的固载化Ⅲ．活性炭在酸性介质中对钨硅杂多酸（SiW_（12））的吸附

在氢离子浓度均为３ｍｏｌ／Ｌ的硫酸，盐酸，磷酸，醋酸水溶液中和冰醋酸中研究了具有Ｋｅｇｇｉｎ结构的硅钨杂多酸（ＳｉＷ＿（１２））在不同来源活性炭上的吸附作用。各活性炭对ＳｉＷ＿（１２）吸附等温线的形式是不相同的，吸附剂载体的微孔结构以及杂多酸的溶剂化起着重要的作用。并且在无机酸介质中，杂多酸的吸附量比在水溶液中成规律性地增加，且与酸强度成正比关系。在有机酸介质中，吸附作用比较复杂。根据所得结果，提出了在酸性介质中杂多酸在活性炭表面的吸附模型。