二甲氧基羟基苯基荧光酮光度法测定生物样品中锗

研究了二甲氧基羟基苯基荧光酮光度法测定锗。在H3PO4 介质中 ,TritonX 10 0存在时 ,锗与二甲氧基羟基苯基荧光酮形成 1∶2橙红色络合物 ,最大吸收在 5 0 5nm波长处 ,表观摩尔吸光系数为 1.8× 10 5L·mol- 1·cm- 1,并且具有灵敏度高、选择性好的特点。当锗含量在 0～ 7μg/2 5ml范围内符合比耳定律。已用于茶叶、党参和药物中锗的测定     

固相分光光度法测定枸杞中的痕量锗

建立了以苯基荧光酮为显色剂固相分光光度法测定痕量锗的新方法。在0 .1 5 mol/L HCl介质中 ,锗吸附于树脂上 ,再与苯基荧光酮显色 ,直接在最大吸收波长 5 35 nm处对树脂相进行测量。锗含量在 0～ 2 5 0 μg/L范围内符合比尔定律 ,表观摩尔吸光系数为 2 .6× 1 0 6L· mol-1· cm-1。该法已应用于枸杞中痕量锗的测定     

2-羟基-3-甲氧基苯基荧光酮分光光度法测定中药中痕量锗

研究了新试剂2羟基3甲氧基苯基荧光酮(HMPF)与锗的显色反应。建立了测定几种中药中锗的光度分析方法。在磷酸(2+1)介质和非离子型表面活性剂OP介质中,2羟基3甲氧基苯基荧光酮与锗发生灵敏的显色反应,其最大吸收峰为505.50nm,表观摩尔吸光系数为1.56×105L·mol-1·cm-1,锗量在0～12μg/25mL符合比耳定律。锗与试剂的显色反应有良好的选择性,绝大多数金属离子特别是钙、镁、铁、锌和钼有非常高的允许量,可直接应用于几种中药中锗的测定,结果满意。     

巯基葡聚糖凝胶分离富集-光度法测定微量有机锗和无机锗

研究了巯基葡聚糖凝胶分离富集 光度法测定微量有机锗和无机锗。在HCl介质中,在抗坏血酸(Vc)、溴化十六烷基三甲基胺存在下锗与2,4 二甲氧基苯基荧光酮形成有色络合物,其ε=1.12×105L·mol-1·cm-1,锗浓度在0～12μg/25mL范围内符合比耳定律。方法可用于多种样品中痕量有机锗和无机锗的测定,结果令人满意。     

分光光度法测定7种治疗胃炎中成药物中锗含量

用苯基荧光酮 -溴化十六烷基三甲基铵分光光度法测定了治疗胃炎中成药物中锗含量。结果表明 ,用该法测定药物中的锗含量 ,摩尔吸光系数ε =1 0 9× 10 4 L·mol-1·cm-1,线性范围0 0 50～ 0 2 50mg·L-1。 7种药物中锗含量较丰富 ,为临床合理用药提供了有用数据     

二溴羟基苯基荧光酮光度法测定铅的研究

研究了铅与二溴羟基苯基荧光酮在阳离子表面活性剂十六烷基三甲基溴化铵存在下的显色反应。在硼酸盐缓冲介质中铅与二溴羟基苯基荧光酮在十六烷基三甲基溴化铵 ( CTMAB)存在下形成红色络合物 ,最大吸收波长为 5 4 0 nm,表观摩尔吸光系数为 6.1× 1 0 4 L· mol- 1· cm- 1。铅含量在 0～ 30μg/2 5 m L符合比耳定律。本法应用于测定市售化妆品、人工湖水中的铅 ,结果准确可靠     

巯基葡聚糖凝胶分离富集吸光光度法测定微量锗的研究

研究了在溴化十六烷基三甲基铵存在下锗与邻硝基苯基荧光酮的显色反应.结果表明,在HCl介质中,锗与邻硝基苯基荧光酮形成了灵敏度很高的络合物,其ε=1.86×105L·cm-1,组成比Ge(Ⅳ)邻硝基苯基荧光酮=13,采用巯基葡聚糖凝胶(SDG)分离富集,使方法的选择性得到了提高,可用于多种样品中痕量锗的测定,结果满意.     

苯基荧光酮荧光分光光度法测定痕量锗的研究

锗具有增血、抗炎症、抗衰老等多种医疗功能 ,因此 ,越来越受到人们的关注。荧光光度法测定微量锗已有报道[1～ 4] 。用苯基荧光酮荧光度法测定锗未见报道。本文利用苯基荧光酮与锗在醋酸 醋酸钠缓冲溶液中络合物形成速度快的优势 ,使其先在缓冲溶液中显色 ,然后在 0 .3ｍｏｌ ＬＨＣｌ介质中测定其荧光强度 ,用于粉煤灰中痕量锗的测定 ,得到满意结果。1　实验部分1 1　仪器与试剂ＲＦ - 5 4 0荧光分光光度计 (日本岛津 )。锗标准溶液 ( 1ｇ Ｌ) :称取 0 .1 0 0 0ｇ纯锗粉于 5 0ｍｌ小烧杯中 ,加入 5ｍｌＮａＯＨ ,再加入几滴 30 %Ｈ2 Ｏ2…     

溴代十六烷基三甲基胺存在下铅与苯基荧光酮显色反应的研究

研究了溴代十六烷基三甲基胺 (CTMAB)存在下 ,铅与苯基荧光酮的显色反应。试验表明 ,铅与苯基荧光酮在CTMAB存在下能够形成稳定的络合物 ,该络合物的λmax=6 2 0nm ,摩尔吸光系数ε =2 .0 7× 10 5L·mol- 1·cm- 1,铅量在 0～ 6 .2 2 μg/ 10ml范围内服从比耳定律。     

二阶导数光谱峰面积法测定中草药中微量锗

在Ge 苯基荧光酮 (PF) 氯化十六烷基吡啶 (CPC)三元络合物的显色体系中 ,引入二阶导数光谱峰面积技术 ,对锗的显色体系及测定方法进行了研究。该方法有效地消除了W 、Sn 、Mo 、V 、Ti 和Fe(Ⅲ )等离子的干扰 ,提高了准确度和选择性。线性范围为 0～ 1 5mg L,检出限为 3 .3 μg L ,εGe为 1 .4× 1 0 5L·mol- 1 ·cm- 1 。用于中药材中Ge 的测定 ,标准加入试验的回收率为 1 0 1 .0 %～ 1 1 2 .0 %。     

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.