无机偶合流动注射化学发光测定钛的研究

基于钛(Ⅲ)对铬(Ⅵ)氧化I-产生I2的诱导作用,和I2氧化鲁米诺产生化学发光的反应,建立了无机偶合反应流动注射化学发光测定痕量钛的新方法。方法线性范围为1×10-9～1×10-5g/mL,RSD=3.0%(n=11,ρ=1×10-7g/mL),检出限为4.0×10-10g/mL。方法用于人发样品中钛的测定。     

流动注射化学发光抑制法测定痕量钒(Ⅴ)

基于钒 (Ⅴ )对罗丹明B 过氧乙酸 NaOH体系化学发光具有强烈的抑制作用 ,建立了流动注射化学发光测定痕量钒 (Ⅴ )的新方法。该方法线性范围为2 .0× 1 0 - 9～ 1 .0× 1 0 - 6g/mL ,检出限为 3.0× 1 0 - 1 0 g/mL ,对 1 .0× 1 0 - 7g/mL钒(Ⅴ ) 7次平行测定的相对标准偏差为 2 .0 %。已用于环境水样、钢样中钒 (Ⅴ )的测定 ,初步探讨了发光反应及其抑制机理     

催化动力学光度法测定微量钯

在硫酸 ( 1 + 1 )介质中 ,Pd(Ⅱ )催化过氧化氢氧化酸性铬蓝K的褪色反应。研究了反应的最佳条件 ,建立了催化光度法测定痕量钯的新方法。方法的最低检测限为 5 97× 1 0 - 4 μg/mL。线性范围为 5 97× 1 0 - 4 ～ 2 60× 1 0 - 2 μg/mL。该法用于合成样品和含钯催化剂的分析     

流动注射化学发光法测定DL-酪氨酸

在甲醛存在下 ,高锰酸钾与DL 酪氨酸能够发生化学发光反应 ,产生很强的化学发光。据此采用流动注射技术 ,建立了一种测定DL 酪氨酸的化学发光分析法。方法的检出限为 2 .9× 1 0 - 8g/mL ,相对标准偏差为 1 .5 % ( 1 .0× 1 0 - 6g/mLDL 酪氨酸 ,n =1 1 ) ,线性范围为 1 .0× 1 0 - 7g/mL～ 5 .0× 1 0 - 6g/mL。     

用铬(Ⅵ)-糗酸钾-茜素绿体系催化光度法测定痕量铬(Ⅵ)

基于酸性介质中溴酸钾氧化茜素绿的反应,提出了测定痕量铬(Ⅵ)的新催化光度法.方法检出限为 3.0×10~(-9)g/mL,可测铬(Ⅵ)量的范围为 0.01~0.24μge/mL,应用于测定电镀废水和电镀排放水中铬(Ⅵ).     

偶合化学发光法测定环境水样中的痕量亚硝酸根

将亚硝酸盐在酸性条件下氧化亚铁氰化钾为铁氰化钾的反应 ,和尿酸 铁氰化钾 鲁米诺化学发光反应偶合一起 ,建立了一种间接测定亚硝酸根离子的新方法。讨论了酸度、反应物浓度、干扰离子等因素的影响。方法的检出限为5 .0× 1 0 - 1 1 g/mL ,对环境水样样品进行了平行测定 (n =1 1 ) ,其相对标准偏差为1 .8%～ 3 2 % ,线性范围为 1 .0× 1 0 - 9g/mL～ 1 .0× 1 0 - 5g/mL ,回收率为 94.3%～ 1 0 5 3%。     

铬(Ⅵ)-亚铁氰化钾-鲁米诺体系化学发光反应的研究

本文通过对铬(Ⅵ)-亚铁氰化钾-鲁米诺体系化学发光反应的研究,建立了一个测定铬(Ⅵ)的高灵敏化学发光分析法。方法的检出限为2×10~(-11)g/ml铬(Ⅵ);相对标准偏差小于2％(对1×10~(-10)g/ml铬(Ⅵ)11次测定);校正曲线的线性范围是1×10~(-10)～6×10~6g/ml铬(Ⅵ)。此方法已用于环境水样中铬(Ⅵ)的测定。     

DCB-偶氮胂高灵敏光度法测定痕量铬(Ⅵ)

本文研究了 DCB偶氮胂与 Cr2 O2 - 7的褪色反应。结果表明 ,在硝酸介质中褪色反应具有高的灵敏度 ,拟定了反应的最佳条件 ,建立了一种新的光度法测定痕量铬( )方法。本法检出限为 4.2 2× 1 0 - 11g/m L ,线性范围为 0～ 0 .8μg/1 0 m L ,用于测定人发中的痕量铬 ( ) ,结果令人满意     

流动注射化学发光增强法测定健民咽喉片中的没食子酸

在pH 9.4的Na2 CO3 NaHCO3介质中 ,没食子酸对鲁米诺 K3Fe(CN) 6 发光体系有很强的增敏作用。据此建立了流动注射化学发光增强法测定没食子酸的方法。发光信号的增强值 (ΔI)与没食子酸的浓度在1 0× 1 0 - 6 ～ 8.0× 1 0 - 9mol L的范围内呈良好的线性关系 ,检出限为 5 .6× 1 0 - 9mol L。对于 1 .0× 1 0 - 7mol L的没食子酸测定 ,相对标准偏差为 2 .2 % (n =1 1 )。该法可用于健民咽喉片中没食子酸含量的测定     

流动注射化学发光法测定没食子酸

基于在碱性介质中,没食子酸(Gallicacid)被过氧化氢氧化能产生化学发光,而甲醛对该体系的化学发光有较强增敏作用,据此建立了流动注射化学发光法测定没食子酸的新方法。该法简单、快速、线性范围较宽。本法测定没食子酸的线性范围为2.0×10-6～2.0×10-4g/mL,检出限达5.8×10-7g/mL,采样频率为120个/小时。对4.0×10-5g/mL没食子酸溶液连续11次测定的相对标准偏差为2.52%。该方法已成功地用于橄榄中没食子酸含量的测定。     

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%.     

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.     

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.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.