表面活性剂增稳荷移光度法测定头孢拉定

采用分光光度法研究了头孢拉定与四氯苯醌的荷移反应。以正丙醇为介质,于pH 9.00的硼砂缓冲液中,以十二烷基苯磺酸钠为增稳剂,四氯苯醌和头孢拉定形成1∶1型稳定的荷移络合物,最大吸收波长在363 nm处,线性范围为1.8×10-6~2.0×10-8mol/L,检出限为9.6×10-9mol/L。方法用于药物制剂中头孢拉定含量的测定,平均回收率为98%。     

阿替洛尔与醌茜素的荷移反应研究

研究了阿替洛尔与醌茜素之间的荷移反应。阿替洛尔作为电子给体,醌茜素作为电子受体,两者在乙醇-水介质中反应生成荷移络合物。该络合物的λmax=568nm,表观摩尔吸光系数为7.91×103L.mol-1.cm-1,阿替洛尔药物质量浓度在0～30mg/L范围内服从比耳定律,相对标准偏差为0.92%(n=6)。应用本法测定了片剂中阿替洛尔的含量,回收率为98.9%～101.6%。     

分光光度法测定替米沙坦

用分光光度法研究了替米沙坦与茜素的荷移反应,提出了测定替米沙坦的荷移分光光度法。在丙酮溶剂中,替米沙坦和茜素形成的络合物的最大吸收波长为548nm,两者的组成比为1比2。替米沙坦质量浓度在16～240mg·L-1范围内服从比耳定律,表观摩尔吸光率为2.34×103L.mol-1.cm-1。采用此法分别测定了替米沙坦胶囊和片剂中替米沙坦的含量,所得测定值与文献报道值相符。用标准加入法做方法的精密度和回收试验,测得回收率为99.5%(胶囊)和99.8%(片剂)。     

甲氧氯普胺与紫色素的荷移反应及其测定

研究了甲氧氯普胺与紫色素之间的荷移反应。确定了反应条件,建立了一种快速简便测定甲氧氯普胺的荷移分光光度法。实验表明,甲氧氯普胺与紫色素在乙醇介质中,室温条件下即可形成稳定的1∶1型荷移络合物,该络合物的λmax=540 nm,表观摩尔吸光系数为4.32×103L.mol-1.cm-1。测定结果的相对标准偏差为0.45%(n=6),回收率为98.3%~105.1%。     

司帕沙星与茜素红荷移反应的研究

采用紫外分光光度法研究了π电子受体茜素红与电子给予体司帕沙星的荷移反应。确定了反应条件,建立了一种快速简便灵敏准确测定司帕沙星的荷移分光光度法。结果表明,司帕沙星与茜素红在(4+6)乙醇-水介质中,室温条件下即可形成1∶1稳定的荷移络合物,该络合物的最大吸收波长为530 nm,表观摩尔吸光系数为4.8×103L.mol-1.cm-1,司帕沙星药物质量浓度在6~160mg/L范围内服从比尔定律,r=0.9991。当该法用于片剂中司帕沙星的测定时,回收率为99.75%~100.00%,相对标准偏差为1.4%(n=10)。     

醌茜素显色分光光度法测定奋乃静

研究了奋乃静(Perphenazine,PPH)与醌茜素(Quinalizarin,QLZ)之间的荷移光谱及其性能。奋乃静作为电子给体,醌茜素作为电子受体,两者在乙醇-水介质中反应生成荷移络合物。该络合物的λmax=568nm,表观摩尔吸光系数是3.39×103 L.mol-1.cm-1,奋乃静药物质量浓度在0～35mg/L范围内服从比耳定律,相对标准偏差为1.23%(n=6),回收率为98.9%～102.4%。     

奥硝唑与氯醌酸的荷移反应研究

研究了奥硝唑与氯醌酸在正丙醇介质的荷移反应,建立了一种快速简便测定奥硝唑的荷移分光光度法.在室温下,荷移反应生成2∶1的荷移络合物,最大吸收波长为534nm,表观摩尔吸光系数为ε=1.08×104 L·mol-1·cm-1.奥硝唑的浓度在5.0~83mg/L范围内服从比尔定律,相关系数r=0.999 3,相对标准偏差为1.3%~2.1%,回收率为99.1%~101.7%.     

荷移分光光度法测定酒石酸美托洛尔

研究了酒石酸美托洛尔与紫色素之间的荷移反应。确定了反应条件,建立了一种测定酒石酸美托洛尔的荷移分光光度法。酒石酸美托洛尔与紫色素在乙醇介质中,室温条件下即可形成稳定的1∶1型荷移络合物,该络合物的最大吸收波长为540 nm,表观摩尔吸光率为6.83×103L.mol-1.cm-1。酒石酸美托洛尔质量浓度在10~80 mg/L范围内服从比耳定律,相关系数为0.9991。相对标准偏差为1.3%(n=11),回收率为99.3%~102.7%。     

艾司唑仑荷移反应及分析应用

采用紫外分光光度法研究了π电子受体四氯对苯醌 (TCBQ)与电子给予体艾司唑仑的荷移反应 ,结果表明 ,TCBQ与艾司唑仑在pH 8.2的BR缓冲溶液中能形成稳定的荷移反应络合物 ,吸光度显著增强。据此建立了测定艾司唑仑的简单、快速、准确和灵敏的方法。艾司唑仑浓度在 0 .2～ 3 .2mg/L范围内符合比尔定律。r=0 .9992。荷移络合物在 3 1 6nm处的表观摩尔吸光系数为 8.5× 1 0 4L·mol-1·cm-1。方法用于片剂中艾司唑仑含量的测定 ,其回收率为 99.2 %～ 99.7% ;相对标准偏差为 0 .7%～2 .1 %。     

基于氯冉酸荷移分光光度法测定乙酰螺旋霉素含量

研究了乙酰螺旋霉素和氯冉酸在甲醇介质中发生的荷移络合反应,确定了最佳条件,从而建立了一种简便快速测定乙酰螺旋霉素的荷移分光光度法。荷移络合物的最大吸收波长为λ=531 nm,络合比为1∶1,该络合物的吸光度与乙酰螺旋霉素的浓度在1.2～20 mg/L范围内呈线性关系,线性相关系数r=0.9998,检出限为0.5 mg/L,相对标准偏差为1.2%,回收率为99.5%～101.2%。本方法用于对乙酰螺旋霉素片含量的测定,结果较为满意。     

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.