Highly effective and recyclable dendritic ligands for the enantioselective aryl transfer reactions to aldehydes

[reaction: see text] A series of chiral pyrrolidinylmethanol-based dendritic ligands were synthesized for application in enantioselective aryl transfer reactions to aldehydes with the (ArBO)3/ZnEt2 system in up to 98% ee.     

Synthesis and reactions of 2-(alkylthio)-4,4-dimenthyl-1,3-thiazole-5(4H)-thiones

Six 2-(alkylthio)-substituted 4,4-dimethyl-1,3-thiazole-5(4H)-thiones were synthesized according to a new method. The reactions of these compounds with allyl- and benzyllithium reagents, 1,3-dipoles, and dimethyl acetylenedicarboxylate proceeded in a similar manner to 2-alkyl-substituted analogues, while methyllithium reacted in a different way yielding trithio-orthoester derivatives.     

介体型乳酸脱氢酶生物传感器的研制及应用

本报道了能对丙酮酸产生良好响应的电流型乳酸脱氢酶生物传感器。该传感器以耐尔兰Ａ修饰浸石墨电极为基体电极，将酶直接固化在蚕丝蛋白膜上。在ＰＨ７．４的ＮａＨ２ＰＯ４－ＮａＯＨ介质中，当２．４×１０＾－４ｍｏｌ／Ｌ的辅酶Ｉ（ＮＡＤＨ）存在下，该传感器的响应电流与丙酮酸浓度在３．２×１０＾－５ｍｏｌ／Ｌ范围内有良好的线性关系。响应时间为６０ｓ．本讨论了影响传感器响应的各种因素，用此传感器测定了人血清中     

Synthesis of a novel 18β-glycyrrhetinic acid derivative

A novel compound, biotinylated 18β-glycyrrhetinic acid (BGA), was synthesized. It is a compound of 18β-glycyrrhetinic acid linked with biotin. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 266–267, May–June, 2006. An erratum to this article is available at .     

α－葡萄糖基甜菊糖的酶促合成反应（Ⅱ）

研究了以球形纤维素弱阴离子交换剂作载体，固定化葡萄糖基转移酶ＧＴ－１转化甜菊糖为α－葡萄糖基甜菊糖反应的各种影响因素。结果表明，甜菊糖的酶促转化到达一定程度后，继续增大酶用量及淀粉用量，对转化结果没有太多改善，固定化酶重复使用８次，活力下降较少，说明固定化效果良好。     

Preparation of polymer-supported phosphine from ferrocene for palladium-catalyzed Suzuki-Miyaura cross-coupling reactions

Polymer-supported phosphine ligand 3b derived from ferrocene was prepared,and applied in palladium-catalyzed Suzuki- Miyaura reactions.A range of aryl bromides can couple with phenylboronic acid to obtain corresponding biaryls in excellent yields. The recycling of the polymer-bound catalyst was tested without adding palladium.     

一种新型两性表面活性剂的合成

两性表面活性剂分子既含有阳离子亲水基,又含有阴离子亲水基,因而有其它表面活性剂所不具备的优异性能。本文将月桂酸和N-(2-羟乙基)乙二胺热缩合脱水,得到2-十一烷基-1-(2-羟乙基)-2-咪唑啉(1)。接着在还原剂的作用下,咪唑啉环碳氮双键还原并开环得到一般方法难以合成的N,N-二取代乙二胺(2)。(2)通过甲酰化(3)季铵化,引入两性离子,得到     

Stöber synthesis of monodispersed luminescent silica nanoparticles for bioanalytical assays

We have developed a simple method to prepare bright and photostable luminescent silica nanoparticles of different sizes and narrow size distribution in high yield. The method is based on the use of St?ber synthesis in the presence of a fluorophore to form bright silica nanoparticles. Unlike micro-emulsion-based methods often used to prepare luminescent silica particles, the St?ber method is a one-pot synthesis that is carried out at room temperature under alkaline conditions in ethanol:water mixtures and avoids the use of potentially toxic organic solvents and surfactants. Our luminescent particles contained the transition metal complex tris(1,10-phenanthroline) ruthenium(II) chloride, [Ru(phen)3]Cl2. They showed higher photostability and a longer fluorescence lifetime compared to free Ru(phen)3 solutions. Leakage of dye molecules from the silica particles was negligible, which was attributed to strong electrostatic attractions between the positively charged ruthenium complex and the negatively charged silica. To demonstrate the utility of the highly luminescent silica nanoparticles in bioassays, we further modified their surface with streptavidin and demonstrated their binding to biotinylated glass slides. The study showed that digital counting of the luminescent nanoparticles could be used as an attractive alternative to detection techniques involving analogue luminescence detection in bioanalytical assays.     

Highly efficient aza-Baylis-Hillman reaction of N-tosylated imines with MVK, acrolein, and phenyl acrylate or alpha-naphthyl acrylate: Lewis base effects and a convenient method to synthesize alpha,beta-unsaturated beta-amino carbonyl compounds

This paper describes several highly efficient aza-Baylis-Hillman reactions of N-tosylated imines with MVK, acrolein, and phenyl acrylate or alpha-naphthyl acrylate in the presence of a Lewis base. In most cases, the reaction can be completed within 1 h using the appropriate Lewis base catalyst. An efficient method to synthesize beta-amino ketones, aldehydes and esters in high yields and short reaction time has been developed.     

Simultaneous determination of noradrenaline and dopamine in Portulaca oleracea L. by capillary zone electrophoresis

A simple and rapid capillary electrophoretic method was developed for the simultaneous determination of noradrenaline (NA) and dopamine (DA) in Portulaca oleracea L. The buffer solution used in this method was 40 mM tris (hydroxymethyl) aminomethane (Tris)-H3PO4 at pH 2.00 containing 15% methanol. The effects of pH value, organic modifier, and applied voltage were investigated. The linear ranges of NA and DA were 0.5-100 microg/mL (r=0.9952) and 6.25-200 microg/mL (r=0.9992), respectively. The relative standard deviations of the corrected peak area were 6.73% and 4.26%, respectively. NA and DA in Portulaca oleracea L. were simultaneous determined successfully within 5.6 min. In this way, the contents of NA and DA in different parts (stem, leaves, and seeds) of P. oleracea L. and in different extracts of leaves with different solvents (distilled water, 50% methanol, and methanol) were studied.