联吡啶-铜(Ⅱ)络合物荧光增强法测定核酸

利用联吡啶-Cu(Ⅱ)络合物作为荧光探针测定脱氧核糖核酸(DNA),实验发现加入天然和变性DNA均能使联吡啶-Cu(n)络合物(Cu(bpy)2^2 )体系的荧光强度大幅度增强。测定体系的最大激发和发射波长分别为304和334nm。在最佳实验条件下,测定的线性范围分别为：小牛胸腺(CT-DNA)0．09—9mg／L;鱼精DNA(FS—DNA)0．01—12.5mg／L;酵母DNA(yeastDNA)0．30—35mg／L。检出限分别为0.003、0．002和0．02mg／L。实验结果推测该络合物与DNA之间通过静电作用结合。     

溴代十六烷基三甲基铵敏化吡罗红B-核酸作用的共振光散射增强法测定核酸

基于表面活性剂溴代十六烷基三甲基铵（CTMAB）对吡罗红B-核酸作用的共振光散射增强效应有敏化作用,建立了一种高灵敏测定核酸的新方法。在pH7．4时,吡罗红B在328nm处的共振光散射的增强与核酸浓度有良好的线性关系。在最佳实验条件下,对小牛胸腺DNA（ct-DNA）、鲱鱼精DNA（fs-DNA）、酵母RNA（yeast—RNA）测定的线性范围分别为0．0～1．2mg／L、0．0～0．8mg／L和0．04～1．4mg／L。检出限分别为6．1μg／L、11．2μg／L和8．6μg／L。该法简便、快捷、重现性好,对合成样品进行了测定,结果令人满意。     

十六烷基溴化吡啶与脱氧核糖核酸作用的共振光散射光谱及其分析应用

在碱性条件下，十六烷基溴化吡啶(CPB)与脱氧核糖核酸(DNA)共存时，体系产生较强的共振光散射，其强度与DNA浓度呈线性关系，据此提出了基于阳离子表面活性剂的共振光散射法定量测定DNA。在最佳实验条件下，测得小牛胸腺DNA(ctDNA)和鱼精子DNA(fsDNA)的线性范围分别为0．2-2．0mg／L和0．2—1．25mg／L，检出限分别为0．07mg／L和0．05mg／L。该方法已应用于合成样品及实际样品中DNA含量的测定。     

甲基紫6B共振光散射法测定脱氧核糖核酸

基于甲基紫6B与脱氧核糖核酸在酸性条件下共振光散射的增强效应,建立了测定DNA的共振光散射法。在pH值为2．0～3．0的三羟甲基氨基甲烷一盐酸缓冲溶液中,甲基紫6B与fsDNA、ctDNA分子作用后共振光散射增强,其强度增加值与DNA的浓度呈线性关系,线性范围分别为0～1．0、0～1．5mg／L,相关系数分别为0．9993、0．9997,检出限分别为15．3、12．2ug／L,用于DNA合成样品的测定,测定结果的精密度、准确度较高。     

十六烷基三甲基溴化铵增敏砂罗铬花青R共振光散射法检测DNA

在pH=3．92的三羟甲基氨基甲烷-HCl缓冲溶液中,阳离子表面活性剂十六烷基三甲基溴化铵对砂罗铬花青R与脱氧核糖核酸(DNA)的共振光散射(RLS)有协同增强作用。考察了影响因素,研究了在优化条件下RLS强度与DNA浓度之间的关系,鱼精DNA和小牛胸腺DNA的线性范围均为0．05—3．00mg／L,检出限分别31．03、35．98μg/L,回收率为97．9％～99．6％,测定结果的相对标准偏差为0．5％-2．1％。     

碱性品红荧光法测定脱氧核糖核酸及其机理的研究

以三苯甲烷类阳离子染料碱性品红(RL)为荧光探针建立脱氧核糖核酸(DNA)的定量分析方法。在近中性范围内碱性品红与DNA有较强的结合,生成复合物的荧光强度与DNA的量呈线性上升关系;线性响应范围为0．05—33．0mg／L(r=0．9904),检出限39μg／L。方法用于样品中DNA含量的测定,取得满意的结果;对作用机理进行了探讨,认为RL与DNA相互作用存在插入结合形式。     

模拟酶催化荧光反应测定核酸

痕量核酸对meso-四-(3-N-甲基吡啶基)卟啉合锰(Mn-TMPyP)催化H2O2氧化对-羟基苯乙酸(p-HPA)的荧光反应产生增强作用,且增强程度与核酸浓度之间有良好韵线性关系,据此建立了测定核酸的高灵敏的荧光分析方法。在最佳条件下,测定小牛胸腺DNA和酵母RNA的线性范围分别是2．0-150μg/L和5．0-100μg／L;检出限分别为0．6和1．6μg/L。对50μg／L CT DNA作7次平行测定,相对标准偏差为1．6％。本法已应用于锯缘青蟹样品中核酸含量的测定,所得结果与紫外吸收法一致。     

铬形态离子的毛细管电泳分离测定

利用1,2-环己二胺四乙酸（CDTA）将Cr^3＋络合成络阴离子[CrC]^-,以甲酸盐为背景电解质溶液,毛细管区带电泳同时分析了[CrC]^-和CrO4^2-。重复性实验结果（n=9）：[CrC]^-和CrO4^2-的迁移时间相对标准偏差（RSD）分别为0．5％和0．8％,峰面积的RSD分别为4．6％和3．0％,峰高的RSD分别为2．5％和2．3％。当信噪比（S／N）为2时,CrO4^2-和[CrC]^-的检出限分别为0．3和0．08mg／L。峰面积对CrO4^2-及[CrC]^-质量浓度线性范围分别为0．625—20mg／L及0．15—10mg／L。相关系数分别为0．9986及0．9997。该分析方法简单实用。     

吖啶橙-罗丹明6G荧光共振能量转移及其罗丹明6G荧光猝灭法测定蛋白质

研究了吖啶橙(AO)与罗丹明6G(R6G)之间能量转移的最佳条件。在pH=7．20的Tirs-HCl缓冲溶液,十二烷基苯磺酸钠介质中,AO-R6G能够发生有效能量转移,使R6G荧光增强。蛋白质的加入使R6G荧光猝灭,以此建立了利用AO-R6G荧光共振能量转移间接测定蛋白质的新方法。牛血清白蛋白、人血清白蛋白工作曲线线性范围分别为1．0～31和1．0—30mg／L;检出限分别为0．32和0．33mg／L;平行6次测定相对标准偏差为1．1％～2．0％;回收率为96．7％～103．2％。此方法的稳定性好,选择性高,用于人血清试样中总蛋白含量的测定,与常用的双缩脲法基本一致。     

碱性品红共振光散射法测定DNA研究

基于脱氧核糖核酸（DNA）对有机染料碱性品红的共振光散射增强效应，拟订了一种测定DNA的共振光散射法。在pH=6．75～7．25的范围内，碱性品红在594nm处的共振光散射增强与yDNA和ctDNA的浓度呈线性关系，线性范围分别为0．20～1．60μg／mL和0～1．50μg／mL，相关系数分别为0．9997和0．9994，检出限可达26．5μg／L。该方法简便、快速，用于合成样品中DNA的测定，结果满意。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.