Lewis acid mediated reactions of cyclopropyl aryl ketones with alpha-ketoesters: facile preparation of 5,6-dihydropyran-2-ones

[reaction: see text] A new general method for the synthesis of 5,6-dihydropyran-2-ones from cyclopropyl aryl ketones (monoactivated cyclopropanes) and alpha-ketoesters in good to excellent yields has been developed. The process involves a cascade of reactions, including a nucleophilic ring-opening reaction of monoactivated cyclopropane by H2O, Lewis acid mediated transesterification, and an aldol type reaction.     

Highly enantioselective epoxidation of alpha,beta-unsaturated esters by chiral dioxirane

This paper describes a highly enantioselective epoxidation of alpha,beta-unsaturated esters using the fructose-derived ketone 2 as catalyst and Oxone as oxidant. High ee's have been obtained for a number of trans and trisubstituted substrates (82-98% ee). The results described show that it is feasible for dioxiranes to effectively epoxidize electron-deficient olefins with high ee's.     

金属羰基化合物的结构对氧原子转移反应速率的影响

本文研究了氧化三甲胺Ｍｅ３ＮＯ与羰基簇合物Ｍ４（ＣＯ）１２－ｎＬｎ（Ｍ＝Ｃｏ，Ｉｒ；ｎ＝１，２；Ｌ＝磷配体）的氧转移反应动力学，讨论了反应机理。反应符合二级速率方程：ｒ＝Ｋ２［Ｍｅ３ＮＯ］［Ｍ４（ＣＯ）１２－ｎＬｎ］Ｍ４（ＣＯ）１２－ｎＬｎ的氧转移反应活性呈现如下顺序：中心元素不同时Ｃｏ４（ＣＯ）１２－ｎＬｎ＜Ｉｒ４（ＣＯ）１２－ｎＬｎ；取代配体不同时Ｍ４（ＣＯ）１２－ｎ（Ｐ（ＯＭｅ）３）ｎ＞Ｍ４     

Pressurized hot water extraction of berberine, baicalein and glycyrrhizin in medicinal plants

Pressurized hot water extraction (PHWE) using a laboratory made system was applied for the extraction of thermally labile and reasonably polar components such as berberine in coptidis rhizoma, glycyrrhizin in radix glycyrrhizae/liquorice and baicalein in scutellariae radix. PHWE was carried out dynamically at a flow of 1 ml/min, temperature between 95 and 140 °C, an applied pressure of 10-20 bar and extraction time of 40 min. Extraction by PHWE was found to give efficiencies comparable to Soxhlet extraction for baicalein in scutellariae radix and sonication for berberine in coptidis rhizoma, and glycyrrhizin in radix glycyrrhizae. Effects of ethanol added into the water used in PHWE were explored. Pressurized liquid extraction (PLE) with methanol as solvent was used for extraction of baicalein in scutellariae radix. The marker compounds present in the various medicinal plant extracts were determined by gradient elution HPLC.     

头发锌含量测定的应用价值评价

以114例2－5岁儿童为对象，同时取其末梢血和头发，测定锌含量。以全血锌值为标准，评价头锌测定的应用价值。结果显示，头发锌测定的灵敏度可达86．1％，特异度为52．4％，符合率为73．7％。     

Existence of doubly charged lead monohydrate: experimental evidence and theoretical examination

Despite reports to the contrary, doubly charged lead monohydrate is a stable species against both proton and charge transfers. [Pb(H(2)O)](2+) has been observed as a minor product in the ligand-exchange reaction of [Pb(CH(3)CN)](2+) with H(2)O after collisional activation. Density functional theory has been used to examine reaction profiles of [Pb(H(2)O)(n)](2+) where n = 1, 2, and 3.     

DMF-甲醇体系粘度与核磁共振化学位移的同时关联

提出了一个基于局部组成概念上的核磁共振模型. 利用该模型和以前别人提出的局部组成型粘度方程, 成功地同时关联属于传递性质的粘度数据和属于波谱性质的核磁共振化学位移数据，关联所得到化学位移的平均绝对偏差小于0.0072，粘度的平均绝对偏差小于0.0006 mPa•s，结果表明提出的局部组成模型是合理的.     

湿热证动物模型微量元素、维生素E变化及清香散的调节作用

采用多因素造模方法复制成湿热证动物模型，观察了动物模型微量元素Zn、Cu、Fe、Se和维生素E代谢水平的变化。结果显示，模型动物血清Zn下降（P＜0．05），Cu升高（P＜0．05或P＜0．01），Fe变化不大（P＞0．05），血Se水平下降（P＜0．05），血浆维生素E含量减少（P＜0．01）。经清热祛湿的经验方清香散治疗后，治疗I组动物血清Zn、血Se、血浆维生素E明显升高（P＜0．05），血清Cu下降（P＜0．05）；治疗Ⅱ组血浆血清Cu有变化（P＜0．05）外，其余变化不大。     

Syntheses and characterizations of three-dimensional channel-like polymeric lanthanide complexes constructed by 1,2,4,5-benzenetetracarboxylic acid

The hydrothermal reaction of YbCl(3) small middle dot6H(2)O with 1,2,4,5-benzenetetracarboxylic dianhydride resulted in [[Yb((b)btec)(1/4)((d)btec)(3/6)(H(2)O)(2)](4).6H(2)O](n)() (1) (H(4)btec = 1,2,4,5-benzenetetracarboxylic acid), and the solvothermal reaction of Er(NO(3))(3) small middle dot6H(2)O or TbCl(3).6H(2)O with 1,2,4,5-benzenetetracarboxylic dianhydride in H(2)O/acetic acid gave rise to [[Er(2)((c)btec)(2/4)((e)btec)(2/4)((f)btec)(2/4)(H(2)O)(4)].4H(2)O](n)() (2) and [[Tb(H(2)btec)(2/4)((f)btec)(3/6)(H(2)O)].2H(2)O](n)() (3), respectively. Complex 1 crystallizes in monoclinic space group C2/m with a = 20.8119(5) A, b = 17.6174(1) A, c = 5.7252(2) A, beta = 92.324(1) degrees, and Z = 1. 1 possesses a three-dimensional framework consisting of eight-coordinate ytterbium centers and two kinds of channels along the c axis. Complex 2 crystallizes in triclinic space group P with a = 9.6739(5) A, b = 11.0039(5) A, c = 11.5523 A, alpha = 104.8330(10) degrees, beta = 91.0000(10) degrees, gamma = 114.2570(10) degrees, and Z = 2. 2 has a three-dimensional framework comprising both eight- and nine-coordinate erbium centers and channels along the a axis. Complex 3 crystallizes in monoclinic space group P2(1)/n with a = 10.7246(12) A, b = 7.1693(9) A, c = 17.158(2) A, beta = 97.109(2) degrees, and Z = 4. 3 shows a three-dimensional framework containing nine-coordinate terbium centers and channels along the b axis. Uncoordinated water molecules occupy the channels in the three complexes. TGA and XRPD were determined for the three complexes, and the results illustrate that the framework of 1 is retained upon removal of uncoordinated and coordinated water molecules.     

Hydrothermal Synthesis and Crystal Structure of a Cadmium（Ⅱ） Polymer with One-dimensional Chain Structure： [Cd（MDPPz）（BDC）（H2O）]n

A metal-organic coordination compound formulated as [Cd(MDPPz)(BDC)(H2O)]n 1 (MDPPz=11-methyldipyrido[3,2-a:2',3'-c]phenazine,BDC=1,4-benzenedicarboxylate) has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,fluorescence spectrum and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic system,space group C2/c,with a=30.673(8),b=9.623(3),c=20.784(6) ,β=98.646(3)o,V=6065(3)3,C27H17CdN4O5,Mr=589.85,Dc=1.292 g/cm3,μ(MoKα)=0.757 mm-1,F(000)=2360,Z=8,the final R=0.0381 and wR=0.0855 for 4191 observed reflections (I>2σ(I)). 1 exhibits blue fluorescence property at room temperature.