萃取催化光度法测定痕量铜

研究了在ｐＨ５．５的弱酸性介质中,利用邻菲罗啉活化铜（Ⅱ）催化过氧化氢氧化邻氨基酚显色的指示反应,用萃取平衡控制反应时间,水相中邻氨基酚的浓度和反应程度,建立了萃取催化光度法测定痕量铜的新方法。方法的线性范围为０．０００５０￣０．１０ｍｇ／Ｌ,检测限为５．０×１０＾－７ｇ／Ｌ。用于水和粮食中痕量铜的测定,结果满意。     

邻氨基酚萃取催化光度法测定痕量钒及其催化反应机理

研究了在ｐＨ３．５的弱酸性介质中，痕量钒（Ｖ）能催化溴酸钾氧化邻氨基酚的指示反应，用萃取平衡控制反应时间和水相中邻氨基酚的浓度及反应程度，通过测量４２４ｎｍ下有机相的吸光度，建立了萃取催化光度法测定钒的新方法，方法的线性范围为０．００１０～０．３０ｍｇ／Ｌ检出限为１．０×１０＾－６ｇ／Ｌ用于人发，煤和岩石中痕量钒的测定，结果满意，此外，还探讨了反应机理，建立了动力方程。     

催化褪色光度法测定痕量铁的研究

研究了在ｐＨ４．５的弱酸性介质中，利用邻菲罗啉活化过氧化氢氧化紫脲酸铵褪色的指示反应，建立了催化动力学光度法测定痕量铁的新方法，方法的检出限为６．５×１０＾－７ｇ／Ｌ线性范围为０～１．０μｇ／２５ｍＬ，用于水，粮食中痕量铁的测定，结果满意。     

萃取阻抑动力学光度法测定痕量镍

研究了在ｐＨ５．５的弱酸性介质中，利用镍（Ⅱ）阻抑邻菲罗啉活化铜（Ⅱ）催化过氧化氢氧化邻氨基酚的指示反应，用萃取手段控制反应时间、建立了萃取阻抑动力学光度法测定镍的新方法。方法的线性范围为１．０￣８０μｇ／Ｌ；检测限为９．１×１０＾－７ｇ／Ｌ。用于环境水样，铝合金和人发中镍的测定，结果满意。对反应机理谱进行了探讨。     

萃取催化晃度法测定痕量锰及其反应机理

研究了在弱酸性介质中，以氨三乙酸为活化剂，利用锰（Ⅱ）催化高碘酸钾氧化二苯卡巴肼的指示反应，用萃取平衡控制反应时间和水相中二苯卡巴肼的浓度及反应程度，建立了萃取催化光度法测定痕量锰的新方法。方法的线性范围为０．１０￣５０μｇ／Ｌ；检出限为８．７×＾－８ｇ／Ｌ。用于水、茶叶和粮食中痕量锰的测定，结果满意。探讨了反应机理，建立了动力学方程式。     

萃取催化光度法测定痕量锰及其反应机理

研究了在弱酸性介质中，以氨三乙酸为活化剂，利用锰（Ⅱ）催化高碘酸钾氧化二苯卡巴肼的指示反应，用卒取平衡控制反应时间和水相中二苯卡巴肼的浓度及反应程度，建立了萃取催化光度法测定痕量锰的新方法。方法的线性范围为０．１０～５０μｇ／Ｌ；检出限为８．７ｘ－８ｇ／Ｌ。用于水、茶叶和粮食中痕量锰的测定，结果满意。探讨了反应机理，建立了动力学方程式。     

钴—H2O2—水杨基荧光酮反应体系的新催化动力学分析方法研究

在碱性介质中，痕量钴（Ⅱ）能显著催化Ｈ２Ｏ２氧化水杨基荧光酮的指示反应，本文据此建立了测定痕量钴的新催化动力学分析法，方法线性范围为０．１～２．８μｇ／Ｌ，检测限为０．０２μｇ／Ｌ。测得反应表现活化能为５９．０３ｋＪ／ｍｏｌ。测定了人发，茶叶，土壤和水等样品中钴的含量，结果满意。     

二溴硝基偶氮氯膦催化动力学光度法测定痕量钴的研究

研究了在ｐＨ７．０磷酸盐介质中，钴催化Ｈ２Ｏ２氧化二溴硝基偶氮氯膦色反应，建立了催化光度法测定痕量钴的新方法，其检出限为５×１０＾－７ｇ／Ｌ，在０．５－３２μｇ／Ｌ范围内，钴与ｌｇ呈良好的关系。     

催化褪色光度法测定痕量钴的研究

研究了在ＰＨ１０．５的Ｎａ２Ｂ４Ｏ７－ＮａＯＨ介质中，痕量钴（Ⅱ）对过氧化氢氧化桑色素初色反应的催化作用，建立了催化动力学光度法测定痕量钴的新方法。方法的线性范围为０－１．２μ／ｍＬ检出限为４．４＊１０＾－１８ｇ／Ｌ。用于水和维生素Ｂ１２中钴的测定，结果满意。     

茚三酮缩7—氨基—8—羟基喹啉—5—磺酸催化荧光测定痕量钒（Ⅴ）及其…

合成了新型席夫碱类试剂茚三酮缩７－氨基－８－羟基喹啉－５－磺酸，建立了该剂催化荧光测定痕量钒的 新体系，反应在盐酸体系中进行，其λｅｘ／λｅｍ为３２５／４４８（ｎｍ），钒（Ⅴ）的量在０－４０．０μｇ／Ｌ、４０．０－１６０．０μｇ／Ｌ呈良好线性关系，检测下限为１．７μｇ／Ｌ，方法用于水样痕量钒的测定，结果令人 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.