藏红T褪色分光光度法测定微量肝素

在pH 5.02的Britton-Robinson缓冲溶液中,肝素与碱性吩嗪染料藏红T形成离子缔合物,染料发生明显的褪色,体系吸光度的降低与肝素钠质量浓度成正比,0~2μg/mL范围内符合比耳定律,比吸光系数为0.36×103L.g-1.cm-1。研究了表面活性剂和共存物质的影响,表明方法选择性好。用于肝素钠注射液效价的测定。     

某些碱性吩嗪染料与肝素相互作用的共振瑞利散射光谱研究

在pH为6．6—7．2,6．0—7．0和5．2—6．4的介质中,中性红(NR)、藏红T(ST)和酚藏花红(PS)等碱性吩嗪染料与肝素反应形成复合物,使溶液共振瑞利散射(RRS)增强,并出现新的RRS光谱。其最大散射峰分别位于600nm(NR体系)、568nm(ST体系)和560nm(PS体系),其中以NR体系灵敏度最高。它对肝素的检出限(3σ)为0．80μg/L。研究了适宜的反应条件和影响因素,并以中性红体系为例,考察了共存物质的影响,表明方法有较好的选择性,用于肝素钠注射液效价的测定,结果较好。     

硫堇褪色光度法测定微量肝素

在pH 4.10的Britton-Robinson缓冲溶液中,肝素与碱性吩噻嗪染料硫堇形成离子缔合物时,染料发生明显的褪色。体系吸光度的降低与肝素钠浓度成正比,肝素的质量浓度在0~60μg/25 mL范围内符合比耳定律,摩尔吸光系数为3.58×106L.mol-1.cm-1。研究了表面活性剂和共存物质的影响,表明方法选择性好。用于肝素钠注射液效价的测定,相对标准偏差小于3%,回收率为96.5%~101.9%。     

苯唑西林与维多利亚蓝B的共振瑞利散射光谱及应用

在pH 9.54时,苯唑西林的水解产物与维多利亚蓝B形成紫红色的离子缔合物,使体系的共振瑞利散射(RRS)急剧增强并产生新的RRS光谱,在最大散射波长366 nm处,苯唑西林的浓度在0~6.0μg/mL范围内与散射强度(△IRRS)成良好的线性关系,据此建立了测定苯唑西林的共振瑞利散射法,检出限为0.039μg/mL。该方法可用于苯唑西林药物及人体尿液中苯唑西林含量的测定。     

硫酸耐而蓝-肝素体系的共振瑞利散射光谱及其分析应用

提出了共振瑞利散射法(RRS)测定肝素的新方法.在pH为5.7～7.5的B-R缓冲溶液中,硫酸耐而蓝与肝素结合生成离子缔合物,使溶液共振瑞利散射(RRS)增强,其最大散射峰位于738 nm,另在536、 395、 305 nm有3个较弱的散射峰.肝素的质量浓度在0.01～0.5 mg/L范围内,与RRS强度有良好的线性关系,对肝素的检出限(3σ)达0.42 μg/L.研究了适宜的反应条件和影响因素,该方法用于肝素钠注射液的测定,回收率为98.6%～102.5%.     

散射背景下激光热透镜光谱分析法测定人体血清中锌量

建立了散射背景下测定人体血清中Zn^2＋含量的激光热透镜光谱分析方法。比较了蛋白质微粒散射对于分光光度法和激光热透镜光谱分析法测定的影响。结果表明，激光热透镜光谱分析方法能够避免溶液中存留蛋白质微粒散射的影响。Zn^2＋量在0～1．6μg/mL范围内呈线性关系（r=0．9986），检出限为1ng/mL。应用于人体血清中Zn^2＋含量的测定，与原子吸收法测定结果基本一致。     

反相高效液相色谱法同时测定血清、尿液中尿酸、肌酐的含量

建立了同时测定人体血清、尿液中肌酐、尿酸含量的高效液相色谱分析方法。采用Hypersil ODS C18色谱柱,甲醇(A)-20 mmol/L乙酸铵(B)为流动相,梯度洗脱,流速1.0 mL/min,UV检测,检测波长235 nm。血清中肌酐、尿酸含量在2~20μg/mL范围内线性关系良好,尿液中肌酐、尿酸在5~1000μg/mL范围内线性关系良好;平均加标回收率在86.7%~99.0%,RSD小于5%。选择甲醇-乙酸铵作为流动相进行血清/尿液中肌酐、尿酸含量测定具有快速简便的特点,方法应用于健康人和糖尿病病人血清/尿液样本的测定,可以对临床病人进行快速监测。     

罗丹明6G-阴离子表面活性剂体系的共振瑞利散射光谱及分析应用

在pH2．00～3．42的B—R缓冲溶液中,罗丹明6G与十二烷基苯磺酸钠（SD—BS）、十二烷基硫酸钠（SDS）阴离子表面活性剂反应形成离子缔合物,导致共振瑞利散射（RRS）增强,并产生新的RRS光谱,最大RRS峰位于375nm,方法对SDBS、SDS的检出限分别为6ng／mL、5ng／mL,其线性范围分别为0．02～5．6μg／mL、0．02～14．0μg／mL。研究了适宜的反应条件,方法具有较高的灵敏度,用于合成水样和环境水样中阴离子表面活性剂含量的测定,结果满意。     

甲基蓝与血红蛋白相互作用的共振瑞利散射光谱研究及小分子的影响

在弱酸性条件下,甲基蓝(MB)可以通过静电和疏水作用聚集到血红蛋白(Hb)上并形成离子缔合物,不仅使得吸收光谱发生变化,而且使得共振瑞利散射增强。据此发展了一种测定Hb的RRS便捷方法,其线性范围和检出限分别为0.2~20μg/mL和0.012μg/mL。与RRS法相比,分光光度法的线性范围和检出限分别为8~60μg/mL和0.688μg/mL(344 nm),5~60μg/mL和0.398μg/mL(408 nm)。此RRS法可用于尿样中Hb的痕量检测。实验考察了体系的吸收、散射光谱性质和最佳聚合条件,并在最佳条件下研究了分析参数及作用机理。并初步讨论了有机小分子对体系的影响,结果表明分子间氢键是主要作用力不容忽视。     

共振瑞利散射法测定痕量银的研究

在聚乙烯醇存在的硫酸介质中,银与过量的I^-形成配阴离子,并进一步与罗丹明B反应形成离子缔合物[AgI2]^-时,共振瑞利散射（RRS）强度明显增强并与银离子含量成正比,其最大RRS波长位于331．5nm处。研究了体系的共振瑞利散射光谱特征、主要影响因素和反应的最佳条件。结果表明,银离子质量浓度在0．06-2．0μg／mL范围内与RRS增强程度呈良好的线性关系（r=0．9973）。方法检出限为0．05仙g／mL,RSD4．78％,样品加标回收率为98．0％-102．0％。该法具有较高的灵敏度,操作简便,用于环境水样中痕量银的测定,结果令人满意。     

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.     

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.     

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.