七种嘧啶碱和嘌呤碱的胶束电动毛细管色谱分离研究

研究了影响七种核酸碱基－胸腺嘧啶，尿嘧啶，胞嘧啶，腺嘌呤，腺嘌呤，腺嘌呤、鸟嘌呤，黄嘌呤和次黄嘌呤毛细管电泳分离的因素。在２４．５℃下，七种碱基在４０ｍｍｏｌ／Ｌ十二烷基硫酸钠－１０ｍｍｏｌ／Ｌ硼砂－１７％－３．０ｍｍｏｌ／Ｌβ－环糊精缓冲液中电泳可得良好分离，保留时间的变异系数小于１．８％。     

THE RETENTION BEHAVIOR OF ARSENIC COMPOUNDS ON PRP-X100 COLUMN UNDER ALKALINE CONDITION

系统地研究了碱性条件下（ｐＨ８～１０．８）Ａｓ３＋，Ａｓ５＋，ＭＡ，ＤＭＡ和ＡＢ等砷化合物在ＰＲＰ－Ｘ１００阴离子交换柱上的保留行为。用火焰原子吸收光谱（ＦＡＡＳ）测定从ＨＰＬＣ分离的砷化合物，即通过一根１ｍ×０．２３ｍｍｉ．ｄ．不锈钢毛细管，将ＨＰＬＣ柱出口与ＦＡＡＳ的雾化器连接起来，采用乙炔／空气火焰，在１９３．７ｎｍ处测定。具体研究了两个流动相（２０ｍｍｏｌ／ＬＮＨ４ＨＣＯ３和２．５ｍｍｏｌ／Ｌ对－羟基苯甲酸－１．０ｍｍｏｌ／Ｌ苯甲酸水溶液），并系统研究了ｐＨ值和缓冲液浓度对上述５个砷化合物的保留时间的影响，发现对于２０ｍｍｏｌ／ＬＮＨ４ＨＣＯ３体系，在ｐＨ８．７时，ＡＢ，Ａｓ３＋，ＤＭＡ可以得到完全分离，通过梯度洗提（ｐＨ８．７到９．８，流速１．６５ｍＬ／ｍｉｎ），在１５ｍｉｎ内上述５个砷化合物可以得到良好分离；对于２．５ｍｍｏｌ／Ｌ对－羟基苯甲酸－１．０ｍｍｏｌ／Ｌ苯甲酸体系，在ｐＨ９．０及流速１．５ｍＬ／ｍｉｎ时，可以在１２ｍｉｎ内将上述５个砷化合物分离。     

泡沫塑料对贵金属—碘化亚锡—络合物的吸附分离行为研究

本文通过泡沫塑料对贵金属－碘化亚锡体系富集分离的条件，怀能和朵理的研究，建立了一种泡沫塑料同时富集分离微量铂，钯，铑，铱，金的新体系。实验结果表明，在１．０ｍｏｌ／ＬＨＣｌ，０．６ｍｏｌ／ＬＫＩ和０．０１ｍｏｌ／ＬＳｎＣｌ２的溶液中，振荡吸附３０ｍｉｎ。各元素分配系数均在１０＾５以上，吸附容量（ｍｍｏｌ／ｇ）分别为：铂０．２５，钯０．２４，铑０．１２，铱０．１０，金０．５２，回收率分别为：铂９９．     

离子色谱法测定硝基苯光降解产物中的邻,间,对硝基苯酚及硝酸根

研究了离子色谱法同时测定硝基荧光降解的中间产物邻硝基苯酚,间硝基苯酚,对硝基苯酚及硝酸根的分析方法。采用７．５ｍｍｏｌ／Ｌ的碳酸氢钠,１．５ｍｍｏｌ／Ｌ的碳酸钠混合溶液为淋洗液,紫外检测波长２１５ｎｍ,回收率在９６．８％￣１０１．３％之间,ＲＳＤ小于１．５％,检出限在８．５×１０＾－４以下。     

毛细管电泳在拮抗药物对氨基苯甲酸，对羟基苯甲酸和磺胺分析测…

本报道了一种用毛细管区带电泳法分离与测定对氨基苯甲酸、对羟基苯甲酸及磺胺类药物的新方法。电泳条件为：用２０ｍｍｏｌ／Ｌ硼砂－２０ｍｍｏｌ／ＬＨ３ＰＯ４－２０ｍｍｏｌ／Ｌβ－环糊精－４％乙醇作电泳液，Ｌ－抗坏血酸为内标，２８０ｎｍ为检测波长，样品由电进样方式１０ｋＶ／１０ｓ）引入毛细管（５１．２ｃｍ×５０μｍｉ．ｄ．，有效分离长度为３８．５ｃｍ）．在２４．５℃下，６ｍｉｎ内三可达基线分离（电泳电     

牡丹皮中丹皮酚的二阶导数差示脉冲极谱法定量研究

建立了中草药牡丹皮中丹皮酚的二阶导数差示脉冲极谱定量分析方法。丹皮酚在１ｍｍｏｌ／Ｌ－１ｍｍｏｌ／Ｌ氯化钾－水（１：１：２３）的溶液中,于－１．６．３０Ｖ（ｓ ａｇ／ＡｇＣｌ）处出现一良好的二阶导数差示脉冲极谱峰,其峰幅值与丹皮酚在０．１～０．６ｍｍｏｌ／Ｌ范围内呈非常显著的线性关系（Ｐ〈０．０１）,检测限为９．２ｍｍｏｌ／Ｌ。本法简便、快速、灵敏,且结果准确。     

增强辣根过氧化物酶催化鲁米诺化学发光反应的新型增强剂四苯硼钠

报道了新型增强剂四苯硼钠对过氧化物酶催化鲁米诺－过氧化氢发光反应的增强作用，建立了流动注射化学发光测定或辣过氧化物酶（ＨＲＰ）的新体系。用该体系测定ＨＲＰ线性范围为１．０×１０－１２×１．２×１０－１３ｍｏｌ／Ｌ；检测限为０．６×１０－１３ｍｏｌ／Ｌ。对０．６×１０－１３ｍｍｏｌ／Ｌ的 ＨＲＰ进行１１次平行测定，相对标准偏差为 １． ５％。     

以L-谷氨酰胺为手性选择剂毛细管电泳拆分几种药物旋光对映体

以Ｌ－谷氨酰胺为手性选择剂,建立了对普萘洛尔、慢心律、心律平、苯丙哌酮、异丙肾上腺素、氯胺酮、山莨菪碱、洛贝林、布比卡因、苯海索等１０种手性药物对映体的毛细管电泳快速分离方法,在含有６０ｍｍｏｌ／Ｌ Ｌ－谷氨酰胺,６０ｍｍｏｌ／Ｌ硼砂（ｐＨ＝９．２５）的缓冲溶液中,１０种手性药物在１１ｍｉｎ内达到基线分离。并对分离机理作了初步探讨。     

毛细管区带电泳法分离检测神经性毒剂降解产物

用毛细管区带电泳间接紫外检测法分离测定６种甲基膦酸单酯。以苯基膦酸为紫外添加剂 ,检测波长为２１０ｍｍ。优化后缓冲溶液组成为：２００ｍｍｏｌ／Ｌ硼酸－５ｍｍｏｌ／Ｌ苯基膦酸－０．１０ｍｍｏｌ／Ｌ ＤＤＡＢ－．２０％ＴｉｔｏｎＸ－１００（ｐＨ３．５５）。毛细管规格为７０ｃｍ＊７５μｍｉ．ｄ。以ＫＨ２ＰＯ４为内标定量,在１－３０ｍｇ／Ｌ浓度范围内６种甲基膦酸单脂标准回归曲线性关系良好,检测限为０．２５     

4—（6—甲基—2—苯并噻唑偶氮）间苯三酚反相高效液相色谱分离测定钒钴镍铬

作以新研制的４－（６－甲基－２－苯并噻唑偶氮）间苯三酚为柱前衍生试剂，用含１０ｍｍｏｌ／Ｌ的ｐＨ６．８０的ＨＡｃ－ＮａＡｃ缓冲溶液，１０ｍｍｏｌ／Ｌ ＴＢＡ．Ｂｒ和１×１０＾－４ｍｏｌ／ＬＥＤＴＡ的甲醇－水溶液（７８：２２，Ｖ／Ｖ）作流动相，在Ｃ１８柱上，１１ｍｉｎ内反相ＨＰＬＣ分离测定了Ｃｒ（Ⅵ），Ｖ（Ⅴ），Ｃｏ（Ⅱ），Ｎｉ（Ⅱ）。当Ｓ／Ｎ＝３时，其检出限分别是Ｖ（Ⅴ）５．４５ｎｇ，Ｃｏ（Ⅱ）     

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.