流动注射化学发光抑制法测定吡罗昔康

基于吖啶橙在氢氧化钠介质中能被高锰酸钾氧化产生较强的化学发光,吡罗昔康能强烈抑制其化学发光,建立了高锰酸钾-吖啶橙-吡罗昔康化学发光抑制测定吡罗昔康的新方法。吡罗昔康在1.0×10-5~7.0×10-4g/mL范围内与化学发光强度呈良好线性关系,方法的检出限为4.5×10-6g/mL,对1.0×10-5g/mL吡罗昔康连续进行6次测定的相对标准偏差为3.6%。     

利用鲁米诺-过氧化氢-铬(Ⅲ)化学发光体系测定痕量砷

本法与原子吸收法相比,检测下限由1.0×10-9g/mL降至6.0×10-12g/mL,线性范围由1.0×10-9～1.0×10-6g/mL扩大至1.0×10-10～1.0×10-5g/mL,且具有灵敏度高,选择性好,设备简单,操作简便等诸多优点,同时,在操作中不会产生ASH3这样的有毒气体,避免了分析工作人员的健康受到损害.方法目前尚未见文献报道.     

鲁米诺-铁氰化钾化学发光体系测定富马酸酮替芬

在碱性条件下, 铁氰化钾与鲁米诺产生化学发光, 富马酸酮替芬对该发光有显著的增强作用。基于此,结合流动注射技术, 建立了测定富马酸酮替芬的新方法。该方法具有较高的灵敏度, 检出限为5.7×10-9 g/mL(IUPAC), 线性范围为1.0×10-8~1.0×10-6 g/mL, 对1.0×10-7 g/mL富马酸酮替芬平行测定11次, 其相对标准偏差为2.6%。该方法已成功用于片剂中富马酸酮替芬的测定。     

化学发光法测定I-的研究

研究了高锰酸钾-Ⅰ--甲醛体系化学发光,从而建立了一种测定微量Ⅰ-的新方法.讨论了各种反应物浓度、酸度、干扰离子等因素对测定结果的影响.Ⅰ-浓度在1.0×10-6～4.0×10-5g/mL范围内与化学发光强度有较好的线性关系.对1.0×10-5g/mL的Ⅰ-进行了11次平行测定,相对标准偏差为2.8%,方法的检出限为2.4×10-8g/mL.结果令人满意.     

高锰酸钾-亚硫酸钠-氨基比林化学发光体系的研究

采用流动注射技术,研究了高锰酸钾-亚硫酸钠-氨基比林体系的化学发光行为,对影响化学发光强度的诸因素进行了实验和探讨,建立了化学发光法测定氨基比林的新方法.方法的检出限为3×10-8 g/mL,线性范围为1.0 ×10-7～8.0×10-5 g/mL.对4.0×10-6 g/mL的氨基比林进行11次平行测定,得方法的相对标准偏差为1.7%.方法用于药剂中氨基比林含量的测定,结果与分光光度法测得值一致.     

高锰酸钾-甲醛-巯嘌呤化学发光体系的研究

在酸性条件下,甲醛与高锰酸钾能够产生较弱的化学发光,而巯嘌呤的存在能够大大地增强该化学发光强度。在一定浓度范围内,增加的发光强度与巯嘌呤的浓度呈良好的线性关系,由此建立了一种测定巯嘌呤的流动注射化学发光方法。方法的检出限为8.7×10-9 g/mL,线性范围为1.0×10-8~1.0×10-6 g/mL,相对标准偏差为3.1%(c=5.0×10-7 g/mL,n=11)。     

鲁米诺-铁氰化钾化学发光体系测定甲基多巴

本文研究发现,铁氰化钾在碱性条件能氧化鲁米诺产生微弱的化学发光,而甲基多巴能大大增强该体系的发光强度.基于此,结合流动注射技术,建立起一种直接测定甲基多巴的流动注射化学发光新方法.该方法的检出限为5.7×10-10g/mL,甲基多巴浓度在1.0×10-9～1.0×10-7g/mL范围内与发光强度呈良好的线性关系.对1.0×10-9g/mL的甲基多巴平行测定11次,其相对标准偏差为2.3%.利用该方法对甲基多巴片剂含量的测定,结果令人满意.     

流动注射化学发光分析法测定三类磺胺类药物

研究发现可溶性锰(Ⅳ)氧化磺胺类药物(磺胺甲基异口恶唑、磺胺嘧啶和磺胺脒)可以产生弱的化学发光,甲醛对这一化学发光反应有较强的增敏作用,据此建立了一种测定磺胺类药物的流动注射化学发光分析法。该方法对3种磺胺类药物磺胺甲基异口恶唑、磺胺嘧啶、磺胺脒的检出限分别为2×10-8、3×10-8、2×10-8g/mL;线性范围分别为6.0×10-8~1.0×10-5、1.0×10-7~8.0×10-6、4.0×10-8~8.0×10-6g/mL。对6.0×10-6g/mL磺胺甲基异口恶唑、4.0×10-6g/mL磺胺嘧啶和4.0×10-6g/mL磺胺脒的相对标准偏差分别为1.1%、1.2%和2.2%(n=11)。此法已用于复方新诺明片剂中磺胺甲基异口恶唑的测定,结果与药典方法测定值一致。并对化学发光反应的机理进行了探讨。     

动力学光度法测定维生素B2的研究

在乙酸介质中,室温下微量维生素B2对高碘酸钾氧化茜素绿褪色反应有明显的催化作用,据此建立了测定维生素B2的动力学光度分析法.方法的线性范围为1.0×10-8～1.0×10-7g/mL,检出限为1.0×10-8g/mL.方法用于维生素B2片剂和黄豆面粉中维生素B2含量的测定,结果满意.     

反向流动注射化学发光法测定五氟利多

基于五氟利多对 KIO4- Luminol体系化学发光有强烈的增敏作用, 结合反向流动注射技术, 首次建立了测定五氟利多的流动注射化学发光的方法; 在优化的实验条件下, 测定五氟利多的线性范围为 4.0× 10- 8～ 1.0× 10- 5 g/mL, 检出限为 9.2× 10- 9 g/mL, 对 4.0× 10- 7 g/mL的五氟利多进行 11次平行测定, 方法的相对标准偏差为 2.1%; 该法用于片剂五氟利多的含量测定, 结果满意.     

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.