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高效毛细管电泳同时拆分外消旋头孢他啶及头孢曲松钠 总被引:3,自引:0,他引:3
用毛细管电泳β-环糊精(β-CD)添加剂法同时拆分外消旋头孢他啶及头孢曲松钠,主要考察了影响分离和测定的因素:(β-CD浓度,背景电解质的pH值,分离电压和毛细管的柱温。通过优化得到了毛细管电泳手性分离头孢他啶及头孢曲松钠对映体的实验方法,在280nm处进行紫外检测,分离温度为25℃,压力进样6s,分离电压为28kV,背景缓冲液含50mmol/L磷酸二氢钠、0.4mmol/Lβ-环糊精(β-CD)、3.0mmol/L(三羟甲基)氨基甲烷(Tirs),pH为7.15的条件下,头孢他啶及头孢曲松钠同时能达到基线分离。对其拆分机理进行了探讨。 相似文献
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卡替诺尔和氟西汀对映体的高效毛细管电泳分离 总被引:2,自引:2,他引:0
考察了以羧甲基-β-(环糊精-β-CD)、β-环糊清(β-CD)、羟丙基-β-环糊精(HP-β-CD)、二甲基-β-环糊精(DM-β-CD)为手性选择剂,在50mmol/L醋酸三乙胺缓冲溶液中分离卡替诺尔和氟西汀对映体。该文还通过考察手性选择剂的浓度、背景电解质的酸度、背景电解质的类型等因素对映体手性分离的影响,对分离条件进行了优化,初步探讨了手性识别机理。实验结果表明:用约4mmol/L的CM-β-CD分离氟西汀和卡替诺尔对映体,能使对映体达到良好分离,不仅节约了分析成本,也简化了分析过程。 相似文献
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毛细管区带电泳对手性药物盐酸美西律和盐酸异博定的对映体分离 总被引:1,自引:0,他引:1
应用环糊精-毛细管区带电泳体系对手性药物盐酸美西律和盐酸异博定的对映体分离进行了研究。结果表明, 在所研究的手性选择剂α-环糊精, β-环糊精, 二甲基-β-环糊精, 羟丙基β-环糊精和γ-环糊精中, 羟丙基β-环糊精对所研究的手性药物分离效果较好。对盐酸美西律和盐酸异博定的最佳羟丙基-β-环糊精浓度分别为30mmol/L和9mmol/L, 最佳缓冲溶液浓度为100mmol/L Tris-H3PO4(pH2.3)。向缓冲溶液中加入0.05%羟丙基纤维素(HPLC)可改善分离。盐酸美西律获得了接近基线的手性分离, 而盐酸异博定亦获得了较好的分离。 相似文献
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以环糊精及其衍生物为手性选择剂,通过优化缓冲液的浓度、酸度以及采用环糊精的种类和浓度等,建立了罗格列酮钠对映体的水介质和非水介质两种毛细管电泳拆分方法.最佳条件为:150 mmol/LTris-H3PO4缓冲液,pH=2.0,含有1 mmol/Lβ-CD或DM-β-CD,10%(ψ)甲醇的运行液,分离电压为25 kV,检测波长215 nm.也可以使用含有9 mmol/L HDMS-β-CD,20 mmol/L磷酸和10 mmol/L NaOH的甲醇电泳液.两种拆分体系均实现了罗格列酮钠对映体的基线分离,而且拆分效率基本相当.方法简便、快速,可作为罗格列酮钠的手性分离方法. 相似文献
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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%. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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. 相似文献
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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. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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. 相似文献
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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. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
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. 相似文献
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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. 相似文献
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《Tetrahedron》2014,70(21):3377-3384
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. 相似文献
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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. 相似文献