纳米金催化鲁米诺化学发光体系测定甲巯咪唑

在碱性介质中,甲巯咪唑能强烈增敏纳米金-鲁米诺-硝酸银化学发光体系产生较强的化学发光信号,据此建立了一种流动注射化学发光测定甲巯咪唑的新方法。在优化实验条件下,该方法对甲巯咪唑的检测线性范围为1.0×10-9~1.0×10-8、1.0×10-8~1.0×10-7、1.0×10-7~1.0×10-6g/mL,检出限(S/N=3)为3.0×10-10g/mL,相对标准偏差为1.2%(n=11,ρ=1.0×10-8g/mL)。将该法用于药物中甲巯咪唑含量的测定,结果满意。同时,采用化学发光光谱表征技术对该体系的化学发光反应机理进行了初步探讨。     

纳米银催化的鲁米诺化学发光体系测定呋喃硫胺的研究

基于纳米银能够增强鲁米诺-H2O2-呋喃硫胺体系化学发光的现象,建立了测定呋喃硫胺的流动注射化学发光新方法.对体系的化学发光机理进行了初步探讨,发现该体系的化学发光光谱的最大发射波长为425nm,该体系的发光体为激发态的3-氨基邻苯二甲酸根离子.该方法测定呋喃硫胺的线性范围为1.0×10-8～1.0×10-5g/mL,检出限4×10-9g/mL,对1.0×10-6g/mL呋喃硫胺连续9次测定的相对标准偏差(RSD)为1.9％.方法已用于药物呋喃硫胺片中呋喃硫胺的测定.     

流动注射化学发光分析法测定利血平

研究发现在碱性介质中,利血平对Cr3 催化的Luminol-H2O2体系的化学发光有较强的抑制作用,据此建立了流动注射化学发光抑制法测定痕量利血平的新方法。该法线性范围宽,发光信号的降低值(ΔI)与利血平的质量浓度在1.0×10-8~2.0×10-5g/mL范围内呈良好的线性关系;检出限(3σ)为7.0×10-9g/mL;对于2.0~10-6g/mL利血平进行11次测定,相对标准偏差为1.8%。已用于针剂中利血平的测定。通过对化学发光光谱、紫外吸收光谱的研究,对机理进行了初步探讨。     

NCS-核黄素-盐酸曲普利啶化学发光反应及其分析应用研究

以荧光试剂核黄素为化学发光试剂,构建了N-氯代丁二酰亚胺(NCS)-核黄素-盐酸曲普利啶化学发光新体系。利用此体系建立了测定盐酸曲普利啶的化学发光分析新方法,方法的线性范围为1.0×10-8～9.0×10-7g/mL,检出限为8×10-9g/mL,对浓度为1.0×10-7g/mL盐酸曲普利啶溶液进行11次平行测定的相对...     

流动注射-化学发光方法测定盐酸萘甲唑林和盐酸氧甲唑林

H2SO4酸性条件下,甲醛对KMnO4-盐酸萘甲唑林(盐酸氧甲唑林)化学发光体系有较强的增敏作用,且强度与药物浓度呈良好的线性关系.据此,建立了采用KMnO4-甲醛体系测定制剂中盐酸萘甲唑林(盐酸氧甲唑林)的流动注射-化学发光分析法.在优化的实验条件下,盐酸萘甲唑林在1.0×10-8～7.0×10-6g/mL范围内呈良好的线性关系,检出限为8.69×10-9g/mL;盐酸氧甲唑林在5.0×10-8～1.0×10-5范围内呈线性关系,检出限为3.47×10-8g/mL.对浓度为1.0×10-6g/mL的盐酸萘甲唑林和盐酸氧甲唑林分别进行的11次平行测定,RSD分别为4.0%和4.1%.     

流动注射化学发光法测定头孢克洛

研究发现在碱性条件下,头孢克洛对Luminol-H2O2体系的化学发光有较强的增敏作用,据此建立了流动注射化学发光测定头孢克洛药物的新方法。头孢克洛在1.0×10-8~2.0×10-5g/mL范围内与发光信号的增强值(ΔI)呈良好的线性关系;检出限(3δ)为6.0×10-9g/mL;对于1.0×10-6g/mL头孢克洛进行11次测定,相对标准偏差为2.2%。应用于希刻劳颗粒中头孢克洛的测定。     

KMnO4-甲醛-茚三酮化学发光体系的研究

在甲醛存在下,KMnO4与茚三酮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,建立了一种利用KMnO4-甲醛-茚三酮化学发光体系测定茚三酮的方法.方法的检出限为3×10-8 g/mL;相对标准偏差为1.1%(4.0×10-6g/mL茚三酮,n=11);线性范围为1.0×10-7～2.0×10-4 g/mL.本法已用于样品中茚三酮的测定.     

流动注射抑制化学发光法测定盐酸多西环素和土霉素

在酸性条件下,Ce(Ⅳ)-罗丹明6G发光体系有较强的化学发光,盐酸多西环素及土霉素的存在能抑制其发光。且化学发光信号的减小值(ΔI)与盐酸多西环素及土霉素的浓度在一定的范围内有较好的线性关系。据此结合流动注射技术,建立了快速测定盐酸多西环素及土霉素的流动注射化学发光分析新方法。优化了影响化学发光的各种因素。结果表明在优化的条件下,盐酸多西环素及土霉素的线性范围分别是1.0×10-7~1.0×10-4g/mL,1.0×10-6~1.0×10-4g/mL,测定的检出限为5.0×10-8g/mL及2.7×10-7g/mL,对1.0×10-6g/mL的盐酸多西环素及1.0×10-5g/mL的盐酸土霉素分别进行了9次平行测定,其相对标准偏差分别为1.4%、1.6%。方法已用于盐酸多西环素及土霉素片剂的测定。     

高效液相色谱化学发光法测定血清中左羟丙哌嗪

在H2SO4介质中, KMnO4氧化左羟丙哌嗪产生化学发光, 甲醛可增敏上述化学发光, 在此基础上建立了反相高效液相色谱(RP-HPLC)分离, 柱后化学发光检测左羟丙哌嗪的新方法, 并成功应用于血清中左羟丙哌嗪的测定. 在优化的实验条件下, 该法测定左羟丙哌嗪的线性范围为1.0×10-7～1.0×10-5 g/mL, 检出限(3σ)为3×10-8 g/mL. 对2.0×10-6 g/mL的左羟丙哌嗪进行11次平行测定, 其相对标准偏差为2.3%.     

胶束敏化化学发光法测定赤藓红

N-氯代丁二酰亚胺在碱性条件下可氧化赤藓红产生弱的化学发光.十六烷基三甲基溴化铵胶束的存在对这一反应的化学发光信号具有显著的增强作用.基于此,结合流动注射技术,优化了化学发光反应条件,建立了测定赤藓红的化学发光新方法.赤藓红质量浓度在1.0×10-7～1.0×10-5g/mL范围内与化学发光强度具有线性关系.该方法测定赤藓红的检出限为3×10-8g/mL,相对标准偏差为3.7%(1.0×10-6g/mL赤藓红溶液,n=11).该方法已用于糖果中赤藓红含量的测定.     

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%.     

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.