基于铽-沙拉沙星配合物的荧光增强测定人血清白蛋白

Tb3+和沙拉沙星(SRFX)反应生成二元配合物,发射Tb3+的特征荧光。人血清白蛋白(HSA)能够增强Tb3+-SRFX配合物的荧光强度,据此,建立了荧光法测定HSA的新方法。在最佳测定条件下,当HSA的浓度在0.50～90.0 mg/L时,Tb3+-SRFX-HSA体系荧光强度的增强和HSA的浓度有良好的线性关系,方法的检出限为0.13 mg/L。用该方法测定了人血清中HSA的含量,回收率在99.2%～99.6%之间。同时对荧光强度增强的机理进行了探讨。     

胶束增敏荧光法测定盐酸沙拉沙星

在pH 5.3的乙酸-乙酸钠缓冲溶液中,十二烷基苯磺酸钠能够敏化盐酸沙拉沙星的荧光,使λex=335 nnq、λem=450 nm的荧光增强.盐酸沙拉沙星质量浓度在0.10～6.99 mg/L范围内与荧光强度呈线性关系,方法检出限为9.16μg/L.6次平行测定方法回收率为91.8%～107.2%,相对标准偏差为1.6%～3.7%.常见金属离子及药物敷料对测定无干扰,不经分离直接用于兽药中盐酸沙拉沙星的测定.     

巴洛沙星-Tb3+-ATP荧光体系的建立及其分析应用

在二元配合物巴洛沙星-Tb3+中加入ATP,Tb3+在其特征波长545 nm处的荧光强度增强,据此建立了新的巴洛沙星-Tb3+-ATP荧光体系.在最优化实验条件下,增强的荧光强度与ATP的浓度呈良好的线性关系,线性范围为2.0×10-6～3.0×10-5 mol/L,检出限为8.0×10-7 mol/L.详细的机理研究表明,ATP能与巴洛沙星-Tb3+形成大的三元络合物荧光体系.新建立的荧光体系成功地应用于ATP注射液中ATP的定量检测.对不同批次ATP注射液进行加标回收试验,回收率为101％～106％,测定结果的相对标准偏差为1.1％～1.9％(n=5).     

铕敏化荧光法测定甲磺酸帕苏沙星

稀土Eu3+能与甲磺酸帕苏沙星形成络合物,并发出Eu3+的特征荧光.加入表面活性剂SDBS能大大增强体系的荧光强度,由此建立了表面活性剂敏化的Eu3+荧光探针测定甲磺酸帕苏沙星的方法.最佳测定条件为最大激发和发射波长分别是332和618 nm;pH=7.5;Eu3+浓度为1.2×10-5 mol/L,SDBS浓度为3.0×10-5 mol/L.甲磺酸帕苏沙星浓度在3.0×10-8～2.0×10-6 mol/L范围内与荧光强度线性关系良好,r=0.9993;检出限为1.0×10-9 mol/L.该方法用于甲磺酸帕苏沙星注射剂和人体血清以及尿样中的甲磺酸帕苏沙星的含量测定,结果令人满意.     

铽-敏化荧光法测定妥舒沙星

依据Tb3+和妥舒沙星 (TSLX)形成配合物并在分子内发生能量转移 ,产生Tb3+的特征荧光 ,建立了一种分析妥舒沙星含量的的新方法。方法的线性范围为 7.0× 1 0 - 8～ 5 .0× 1 0 - 6 mol·L- 1 ,检出限为 8.5× 1 0 - 9mol·L- 1 。测定了胶囊中妥舒沙星的含量和回收率 ,回收率在 99.8%～ 1 0 4 %之间。并对Tb3+ 妥舒沙星体系敏化荧光的机理进行了探讨。     

荧光偏振免疫分析方法快速检测沙拉沙星残留

以异硫氰酸荧光素(FITC)标记沙拉沙星合成荧光标记物,采用薄层色谱法提纯,优化了反应时间、标记物和抗体的工作浓度,建立了沙拉沙星的快速荧光偏振免疫分析法( FPIA).本方法测定沙拉沙星在缓冲液中的半数抑制浓度(IC50)为43.2 μg/L;检测范围为5.7～327 μg/L,可以达到国家规定的动物性食品中兽药最高残留限量(80 μg/kg)的要求.本研究考察了FPIA测定沙拉沙星的动力学过程及对其它4种喹诺酮类药物的交叉反应.结果表明,环丙沙星、恩诺沙星、加替沙星及氧氟沙星的交叉反应率分别为3.3％,1.8％,1.7％和0.7％.在牛奶和猪尿中沙拉沙星的回收率分别在71％～94％和74％～102％之间.本方法操作简单快捷,整个检测过程只需5 min、而且灵敏度较高、特异性强,适用于动物性食品中沙拉沙星残留的快速筛选检测.     

司帕沙星-铕荧光体系的研究及其在分析中的应用

研究了司帕沙星-铕体系的荧光光谱特性,在体系的最大激发波长(322 nm)和最大发射波长(616 nm)下,确定了铕的最佳浓度和体系的pH值.在最佳条件下,司帕沙星浓度在2～10 mg/L的范围内与体系的荧光强度呈线性关系,检测限为0.08 mg/L.对样品进行加标回收试验,回收率为96.5%～102.0%,RSD为2.5%～3.1%.利用该法测定了司帕沙星片剂中的司帕沙星含量.     

流动注射化学发光法测定兽药制剂中沙拉沙星

基于沙拉沙星对Ag(III)络合物-H2SO4体系化学发光信号的增敏作用,提出了一种流动注射-化学发光测定沙拉沙星的新方法。考察和优化了影响化学发光强度的条件。沙拉沙星在2.0×10-7～1.0×10-5g/mL范围内,其校准曲线具有良好的线性。方法的检出限为1.2×10-7g/mL,相对标准偏差0.5%～1.2%。该方法已用于沙拉沙星兽药制剂的质量检测,回收率为83.3%～96.3%。通过比较其荧光光谱和化学发光光谱,讨论了该体系的化学发光机理。     

曙红分光光度法测定沙拉沙星

在pH 3.0的Clark-Lubs缓冲溶液存在下,盐酸沙拉沙星溶液在可见光区无吸收,当将其加入曙红溶液中,发现曙红吸收峰有明显位移,且吸光度增加,说明盐酸沙拉沙星与曙红反应生成络合物。盐酸沙拉沙星在4.0-220.0mg/L的范围内与吸光度呈良好的线性关系,方法检出限为117.6μg/L。用于片剂中盐酸沙拉沙星的测定,6次平行测定相对标准偏差为1.4%-3.9%,回收率为92.8%-105.8%。     

表面活性剂敏化的铽离子荧光探针对氧氟沙星的测定

稀土Tb3 +能与氧氟沙星形成络合物 ,并发出Tb3 +的特征荧光 ;加入表面活性剂SDBS能大大增强体系的荧光强度 ,由此建立了表面活性剂敏化的Tb3 +荧光探针测定氧氟沙星的方法。用 1cm石英比色池在激发波长为 30 0nm ,发射波长为 5 4 5nm处测定其荧光强度。在pH =5 .5～ 6 .5 ,Tb3 +浓度为 5 .0× 10 -5mol/L ,SDBS浓度为 5 .0× 10 -4mol/L的最佳测试条件下 ,氧氟沙星的浓度与体系的荧光强度呈线性关系 ,线性范围为 5 .0× 10 -8～ 2 .0× 10 -6mol/L ;检出限为 6 .0× 10 -9mol/L。该法可用于氧氟沙星药物的测定     

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%.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.