3-芳基-1-(吡啶-3-基)-2-(1H-1,2,4-三唑-1-基)-2-丙烯-1-醇的合成及生物活性研究

用硼氢化钠还原3-芳基-1-(吡啶-3-基)-2-(1H-1,2,4-三唑-1-基)丙烯酮, 合成了10个新型含吡啶基的三唑醇类化合物. 所有化合物均经核磁、元素分析确证. 生物活性测试结果表明, 部分化合物具有一定的杀菌活性及植物生长调节活性.     

Bis(Cyclodisilazan-1-yl)dimethylsilane Synthese und Reaktionen

Bis(cyclodisilazane-1-yl) dimethylsilanes — Synthesis and Reactions The monolithium derivate of trisilazan-1-yl-cyclodisilazane 1 reacts with F₃SiN (SiMe₃)₂ with substitution. The silyl-bridged cyclodisilazanes 3–6 are formed in the reaction of the dilithium derivate of 1 with fluoro- and chlorosilanes. Using lithiumamide and lithiummethanolate a controlled exchange of one fluoro atom of 4 occurs ( 7,8 ). 9 and 10 are formed by hydrolysis of 4 . The aminofunctional compounds 11 und 12 are obtained in the reaction of 5 and 6 with NH₃. The dispirocyclus 13 is formed in the reaction of 8 with tert.-butyllithium. The reaction of dilithiated 1 with 4 gives the spirocyclus 14 . The crystal structure of 14 is discussed.     

HIV-1整合酶与抑制剂LCA的结合模式及抗药性研究

Ⅰ型人体免疫缺陷病毒(HIV-1)整合酶(integrase, IN)是病毒生命周期中一个重要的酶, 也是研究抗HIV新药的一个重要靶点. 运用多构象分子对接和分子动力学(molecular dynamics, MD)模拟, 研究了野生型整合酶核心区及G140S点突变的突变态整合酶核心区与抑制剂L-菊苣酸(L-chicoric acid, LCA)的结合模式, 并基于该结合模式探讨了G140S突变态整合酶对抑制剂LCA的抗药性. 结果表明: LCA结合到G140S突变态整合酶核心区中的位置与结合到野生型整合酶核心区的位置不同, 结合位置的差异导致LCA抑制作用的部分丧失; IN功能Loop区的柔性以及Mg²⁺离子与三个关键残基D64, D116和E152之间的相互作用有助于IN发挥生物学功能; G140S突变态整合酶核心区中的E152与LCA的排斥作用、K159与LCA结合能力的变弱以及Y143指向IN的口袋区是产生抗药性的重要原因. 这些模拟结果与实验结果吻合, 可为基于IN的抗HIV药物分子设计提供一些有用信息.     

Efficient chemoselective deprotection of silyl ethers using catalytic 1-chloroethyl chloroformate in methanol

Fast and chemoselective desilylation of silyl-protected alcohols was achieved using a catalytic amount of 1-chloroethyl chloroformate in methanol. With a minimal amount of 1-chloroethyl chloroformate as the source for anhydrous HCl, extremely efficient cleavage of silyl ethers of primary and secondary alcohols was accomplished, and chemoselective deprotection of one silyl ether in the presence of another silyl or other acid-labile group was possible through controlling the amount of the chloroformate and reaction time.     

Reinvestigation of the Nazarov cyclization of 1-(3-hydroxypropynyl)cyclododecan-1-ol to bicyclo[10.3.0]pentadec-1(12)-en-13-one

Reinvestigation of the acid-catalyzed cyclization of 1-(3-hydroxypropynyl)cyclododecan-1-ol under the conditions of the Nazarov reaction demonstrated that this conversion yields two isomeric bicyclic ketones, namely, bicyclo[10.3.0]pentadec-1(12)-en-13-one and bicyclo[10.3.0]pentadec-1-en-3-one. The latter compound is thermodynamically less stable. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1325–1327, July, 1997.     

The Additive Influence of Propane-1,2-Diol on SDS Micellar Structure and Properties

Micellar systems are colloids with significant properties for pharmaceutical and food applications. They can be used to formulate thermodynamically stable mixtures to solubilize hydrophobic food-related substances. Furthermore, micellar formation is a complex process in which a variety of intermolecular interactions determine the course of formation and most important are the hydrophobic and hydrophilic interactions between surfactant–solvent and solvent–solvent. Glycols are organic compounds that belong to the group of alcohols. Among them, propane-1,2-diol (PG) is a substance commonly used as a food additive or ingredient in many cosmetic and hygiene products. The nature of the additive influences the micellar structure and properties of sodium dodecyl sulfate (SDS). When increasing the mass fraction of propane-1,2-diol in binary mixtures, the c.m.c. values decrease because propane-1,2-diol is a polar solvent, which gives it the ability to form hydrogen bonds, decreasing the cohesivity of water and reducing the dielectric constant of the aqueous phase. The values of ΔGm0 are negative in all mixed solvents according to the reduction in solvophobic interactions and increase in electrostatic interaction. With the rising concentration of cosolvent, the equilibrium between cosolvent in bulk solution and in the formed micelles is on the side of micelles, leading to the formation of micelles at a lower concentration with a small change in micellar size. According to the ¹H NMR, with the addition of propylene glycol, there is a slight shift of SDS peaks towards lower ppm regions in comparison to the D₂O peak. The shift is more evident with the increase in the amount of added propane-1,2-diol in comparison to the NMR spectra of pure SDS. Addition of propane-1,2-diol causes the upfield shift of the protons associated with hydrophilic groups, causing the shielding effect. This signifies that the alcohol is linked with the polar head groups of SDS due to its proximity to the SDS molecules.     

Glycosylation site analysis of human alpha-1-acid glycoprotein (AGP) by capillary liquid chromatography-electrospray mass spectrometry

A new anionic surfactant (RapiGest SF) was successfully used for site-specific analysis of glycosylation in human alpha-1-acid glycoprotein (AGP). By means of this analytical approach combined with capillary HPLC-mass spectrometry (and tandem mass spectrometry), the N-linked glycosylation pattern of AGP was explored. On the basis of mass matching and MS/MS experiments ca 80 different AGP-derived glycopeptides were identified. Glycosylation shows a markedly different pattern for the various glycosylation sites. At sites I and II, triantennary complex-type oligosaccharides predominate and at sites III, IV and V, tetra-antennary complex-type oligosaccharides predominate. Sites IV and V show the presence of additional N-acetyl lactosamine (Gal-GlcNAc) units (even higher degree of branching and/or longer antennae are also present).     

Thermochromism of bithiophenes and internal aromatic chain rotation

The relation between thermochromism and thermal motion of aromatic rings on model bithiophene and 3-butylbithiophene molecules was studied by molecular dynamics (MD) simulations based on semiempirical AM1 hamiltonian. Theoretical optical spectra at various temperatures are generated from the conformations obtained from MD calculations. Alkyl chains have a tendency to tilt bithiophene fragments from co-planarity (connected with blue shift) whereas the unsubstituted systems prefer the higher degree of planarity (connected with red shift) upon the temperature increase. The slope of the linear temperature dependence of the reciprocal maximal wavelengths consists of the above electronic and of the vibrational contribution that (according to Wien’s displacement law) causes always the increase of the above mentioned slope by reciprocal Wien’s constant. This model explains the temperature dependence of experimental UV–vis spectra for dibutylheptathiophene and 3′,3,4′,4-tetrahexylhexathiophene.     

Kinetics, selectivity, and mechanism of the reactions of arenes with adamantyl carbocations in sulfuric acid

Data on the kinetics, selectivity, kinetic isotope effect, and the effect of the acidity of the medium on the rate of the reactions of benzene and alkylbenzenes in sulfuric acid (59–78 wt.% H₂SO₄) solutions of 1-adamantanol at 30 °C indicate that the direct reagents are the adamantyl carbocations (Ad⁺) that alkylate the arenes. The ortho positions of the benzene ring are not accessible on account of steric hindrances. The rate of attack by the Ad⁺ cation on the accessible para and meta positions of the ring is controlled by the formation of a σ complex. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 1, pp. 14–18, January–February, 2006.     

新型尼龙214,414,614,814,1014和1214的合成与表征

用熔融缩聚法基于十四碳二酸合成了一系列偶偶尼龙，包括尼龙2 14，4 14， 6 14，8 14，10 14，12 14。用红外光谱、元素分析、核磁共振、差示扫描热分析 、热失重分析、热机械分析、粘度法对合成尼龙的结构与性能进行了表征。同时还 初步研究了尼龙12 14的物理性能，发现其物理性能介于尼龙66和聚乙烯之间。