薄层扫描法测定利喉乐含片中没食子酸的含量

应用薄层扫描法测定了利喉乐含片中没食子酸的含量。以甲苯－醋酸乙酯－甲酸（Ｖ甲苯∶Ｖ醋酸乙酯∶Ｖ甲酸＝３∶５．４∶０．６）为展开剂,１０ｇ／ＬＦｅＣｌ３显色后,用Ｃｓ－９２０薄层扫描仪扫描,扫描波长为５２０ｎｍ。没食子酸在１．２４～６．２０μｇ之间线性关系良好,该法的加样回收率为９５．９３％,板内精密度为２．７８％,板间精密度为３．３０％,为利喉乐含片的质量控制提供了一种简便而准确的含量测定方法     

同时测定体液中咖啡因和茶碱的薄层色谱扫描法

研究了同时测定血清、尿样中的咖啡因和茶碱的薄层色谱定量法。在ＧＦ２５４硅胶板上，用乙酸乙酯－氨水（Ｖ乙酸乙酯∶Ｖ氨水＝９６∶４）的二元展开体系能将这两种生物碱有效地分离。其Ｒｆ值为咖啡因０．４６，茶碱０．１６。分离后的试样用薄层色谱扫描仪进行扫描定量，测定波长２７２ｎｍ，线性范围咖啡因０．００９７～１．９４μｇ，茶碱０．００９０～１．８０μｇ。血清及尿样的加标回收率在９５．８％～１０６．５％之间，相对标准偏差２．９５％～３．５０％。本法较为简便、快速、准确     

单扫描极谱法连续测定人发中的微量元素锌铁锰铜

本提出在０．１５ｍｏｌ／Ｌ乙二胺－７．５×１０＾－３ｍｏｌ／Ｌ三乙醇胺－２．５×１０＾－２ｍｏｌ／Ｌ硫氰酸钾底液中单扫描极谱法测定锌、铁、锰，续加硫酸（０．３ｍｏｌ／Ｌ）测定铜的方法，峰电位分别为－１．４２Ｖ，－１．６３Ｖ，－１．７１Ｖ，－０．４８Ｖ（ｖｓ．ＳＣＥ），线性范围：０．０５～１．４μｇ／ｍＬＭｎ，０．０４～１μｇ／ｍＬＣｕ，最低检出浓度．０３，０．０５，０．０２，０．０４μｇ／ｍＬＭ     

氯化三辛基甲基胺萃取原子吸收法测定微量锑的研究

本文在ＫＩ－Ｈ２ＳＯ４体系中，研究了锑的碘络阴离子的萃取行为，并结合火焰原子吸收法测定了微量锑，萃取体积比（Ｖ水／Ｖ有）为２０，线性范围为０－２μｇ／ｍｌ，锑的特征浓度为０．５μｇ／ｍｌ／１％吸收，检出限为０．１μｇ／ｍｌ。     

铜—2,3,4—三羟基—4‘—磺基—偶氮苯配合物吸附波的研究

在０．０６５ｍｏｌ．Ｌ＾－１柠檬酸钠－０．０４６ｍｏｌ．Ｌ＾１ＨＣｌ（ｐＨ６．６）介质中，２，３，４－三羟基－４’－磺基－偶氮苯和铜形成配合物，在单扫描示波极谱仪上于－０．２Ｖ处产生灵敏的吸附峰，测定铜的浓度范围为０．００５－０．３μｇ．ｍｌ＾－１，检出限为０．００２５μｇ．ｍｌ＾－１，本法已成功地用于人发及硫酸镍中铜的测定，并进行了电极反应机理研究。     

催化动力学光度法测定痕量钒（V）的研究

研究了在ｐＨ９．２的硼矽介质中，痕量钒（Ｖ）催化Ｈ２Ｏ２氧化桑色素褪色反应体系的新催化光度法，测定范围为０～７．５μｇ／５０ｍＬ，加标回收率为９５％～９８．５％，测定２μｇ钒（Ｖ）ＲＳＤ为１．６８％，用于水样中痕量钒（Ｖ）的测定。     

空气－C_2H_2火焰原子吸收光谱法测定中草药（鸦胆子、补骨脂）中的铁、锰

用空气－Ｃ２Ｈ２火焰原子吸收光谱法测定了中草药（鸦胆子、补骨脂）中的Ｆｅ、Ｍｇ含量，讨论了测定条件，结果令人满意，方法的回收率：Ｆｅ９８．２０％～１０４．９％，ＣＶ＝１．０６％～１．０７％，Ｍｎ９９．４％～１０１％，ＣＶ＝０．５２％～１．９４％。     

催化动力学法测定化探样品中的痕量铬

本对在弱酸性介质中铬（ＶＩ）强烈催化Ｈ２Ｏ２氧化铬蓝黑Ｒ褪色反应进行了一系列研究，拟定了用催化动力学法测定铬（ＶＩ）的最佳条件。该法检出限为３．２×１０＾－９ｇ／ｍＬ，测定线性范围０～１．５μｇ／２５ｍＬ铬（ＶＩ），用于化探样品中痕量铬的测定，结果良好。     

流动注射－化学发光分析测定矿石中痕量铌

利用铌对鲁米诺－Ｈ_２Ｏ_２－Ｋ_３Ｆｅ（ＣＮ）_６化学发光体系的抑制作用，建立了痕量Ｎｂ（Ｖ）的流动注射－化学发光测定法。方法的检出限是２．３ｎｇ／ｍＬＮｂ（Ｖ）。线性范围为０．０１～１μｇ／ｍＬＮｂ（Ｖ），测定的相对标准偏差为３．０％（０．０１μｇ／ｍＬＮｂ（Ｖ）（ｎ＝１１），方法已应用于矿石中Ｎｂ的测定。     

单扫示波极谱法测定茶叶中铜

在ＰＨ６．８磷酸盐缓冲体系中，Ｃｕ（Ⅱ）－乙酰丙酮产生一灵敏的极谱波，峰电位为－０．２５Ｖ，检出下限为０．０００６４μｇ．ｇ＾－１，线性范围为０．００１３－３．２μｇ．ｇ＾－１，用单扫示波极谱法测定茶叶中铜，具有灵敏、准确、快速、简便、选择性好的特点。     

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.