鲁米诺-过硫酸钠体系后化学发光法测定银

邻菲罗啉存在下,银对鲁米诺-Na2S2O8体系的后化学发光具有增敏作用,建立了流动注射后化学发光测定银的新方法.在优化实验条件下,该法测定银的线性范围为1.0×10-9～4.0×10-7 mol/L,线性相关系数为0.9987(n =7),检出限为3.53×10-10mol/L(n=11),对1.0×10-7 mol/...     

流动注射化学发光增强法测定巯嘌呤的应用研究

试验发现6-巯基嘌呤对Luminol-H2O2-OH-体系的化学发光有较强的增敏作用。据此建立了一种流动注射化学发光增强法测定6-巯基嘌呤的新方法。该法测定6-巯基嘌呤的检出限为7.5×10-9mol/L,线性范围为2.0×10-8~2.5×10-6mol/L,对6.0×10-7mol/L的6-巯基嘌呤测定的相对标准偏差为1.6%(n=11),已用于合成样中6-巯基嘌呤的测定。     

流动注射-化学发光法测定河水中对苯二酚

在碱性介质中,对苯二酚的Na_2CO_3溶液对鲁米诺-KMnO_4体系的化学发光有很强的增敏作用,据此建立了流动注射化学发光法测定对苯二酚的新方法。对苯二酚溶液浓度在5×10~(-8)~5×10~(-5)mol/L范围内与化学发光强度增强值呈线性关系,方法检出限(3σ)1.75×10~(-8)mol/L,对3.0μmol/L的对苯二酚溶液进行测定,测得其相对标准偏差为1.2%(n=11)。方法已于测定河水中对苯二酚含量。     

纳米金催化Luminol-AgNO_3化学发光体系测定盐酸阿米替林

碱性条件下,纳米金对Luminol-Ag NO3化学发光体系有增敏作用,盐酸阿米替林对该化学发光体系有显著的增敏作用。基于此,在优化化学发光反应条件的基础上,提出了测定盐酸阿米替林的新方法,并对其化学发光机理进行了探讨。该法测定盐酸阿米替林的线性范围为3.0×10-9~3.0×10-7g/m L,相关系数(r)为0.999 4,检出限(S/N=3)为2.1×10-9g/m L,相对标准偏差(RSD)为2.0%(n=11,ρ盐酸阿米替林=5.0×10-8g/m L)。该法已成功用于药物制剂中盐酸阿米替林含量的测定。     

KMnO4-甲醛化学发光体系测定对乙酰氨基酚

基于对乙酰氨基酚在酸性介质下对KMnO4-甲醛化学发光体系强烈的增敏作用,建立了对乙酰氨基酚的流动注射化学发光测定方法。在最佳测试条件下,方法对对乙酰氨基酚的检出限(S/N=3)为1.0×10-10mol/L,线性范围为1.0×10-9～1.0×10-5mol/L对乙酰氨基酚,相关系数R为0.9993;对1.0×10-6mol/L的对乙酰氨基酚溶液平行测定11次,其RSD为1.1%。该方法可应用于药物中对乙酰氨基酚含量的测定。     

敏化光转化-化学发光法测定2,4-二氯苯酚的研究

基于2,4-二氯苯酚(2,4-DCP)在荧光素存在下光转化后产物与氧化剂N-溴丁二酰亚胺(NBS)反应产生化学发光的现象,建立了高灵敏度检测2,4-二氯苯酚的新方法。阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)作为增敏剂可以有效的增强体系的化学发光强度。方法对浓度为7.3×10-7~7.3×10-6mol/L及7.3×10-6~7.3×10-5mol/L的2,4-DCP分别有良好的发光响应线性关系,检出限可达4.5×10-7mol/L;通过富集浓缩可进一步降低了方法的检出限;该方法具有良好的选择性。对化学发光反应的机理做了初步探讨,认为敏化光解所产生的单线态氧与氯代酚反应生成了可发光的产物。     

流动注射化学发光法测定头孢他啶

在碱性条件下,头孢他啶对金纳米粒子催化高锰酸钾氧化鲁米诺化学发光体系的发光强度具有明显的增敏作用,基于此建立了一种测定头孢他啶的化学发光方法.在优化实验条件下,用该法测定头孢他啶的线性范围为3.0×10-5～5.0×10-2 g/L,检出限为1.0×10-5 g/L,相对标准偏差为2.0%(ρ=4.0×10-3 g/L...     

流动注射化学发光增强法测定单宁酸

发现单宁酸对Luminol KIO4 Mn2 +碱性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增强法测定单宁酸的新方法。该法简单、快速、线性范围宽 ,测定单宁酸的检出限为 9× 10 -9mol/L ;线性范围为 3× 10 -8～ 5× 10 -6mol/L ,对于 1× 10 -6mol/L单宁酸测定的相对标准偏差 1 5 % (n =11)。应用于五倍子中单宁酸的测定 ,结果满意。     

流动注射化学发光法测定3种氟喹诺酮类药物

研究发现,氟喹诺酮类药物对可溶性Mn(-甲醛化学发光体系有强烈的增敏作用,结合流动注射技术,建立了3种氟喹诺酮类药物诺氟沙星、氧氟沙星和环丙沙星的流动注射化学发光新方法。在优化的实验条件下(2×10-4molMn(-3%甲醛-3mol/L磷酸),本方法测定诺氟沙星、氧氟沙星和环丙沙星的线性范围分别为1.0×10-7～1.0×10-5mol/L,1.0×10-7～1.0×10-5mol/L和3.0×10-7～5.0×10-5mol/L;检出限分别为3×10-8mol/L,3×10-8mol/L,1×10-7mol/L;相对标准偏差(5.0×10-6mol/L氟喹诺酮类药物,n=11)分别为2.6%,1.6%和2.8%。该方法已用于诺氟沙星胶囊中诺氟沙星的含量测定。     

流动注射光化学敏化化学发光法测定斯帕沙星

斯帕沙星 (SPFX)在酸性介质中经紫外光照射发生光化学反应 ,其产物与Tb3+ 形成络合物 ,对Ce SO2 - 3化学发光体系有增敏作用。据此 ,采用流动注射技术 ,建立了光化学敏化化学发光测定SPFX的新方法。方法的检出限为 2 .5× 10 - 8mol/L ;SPFX浓度在 1.0× 10 - 7～ 1.0× 10 - 5mol/L范围内与发光强度呈良好的线性关系。对 6.0× 10 - 6 mol/LSPFX平行测定 11次 ,RSD为 3 .8%。利用该法测定了片剂和胶囊中SPFX的含量 ,并对机理进行了初步探讨     

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.