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1.
本文对巴比妥酸-NO^-2-铁(Ⅱ)-CPB显色体系进行了研究,建立了一种测定巴比妥酸的分光光度法,该法巴比妥酸含量在1.0*10^-6-2.0*10^-5g/mL范围内符合比尔定律。 相似文献
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硫代巴妥酸光度法测定香草醛 总被引:2,自引:1,他引:1
香草酸在强酸性介与硫代巴比妥酸(TBA)反应生成黄绿色的化合物,建立可见光分光光度法香草醛方法。线性范围1×10^-6 ̄1.5×10^-4mol/l,检出限为4.47×10^-8mol/L。对冰淇淋,麦片等进行了其中香草醛含量测定,结果满意。 相似文献
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本文对巴比妥酸-NO-2-铁(Ⅱ)-CPB显色体系进行了研究,建立了一种测定巴比妥酸的分光光度法,该法巴比妥酸含量在1.0×10-6~2.0×10-5g/mL范围内符合比尔定律。方法简便、快速且具有良好的选择性及重现性,用于巴比妥类药物合成样中巴比妥酸的测定,回收率在90.2%~102.1% 相似文献
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以冰乙酸为催化剂,将取代吡唑甲醛和巴比妥酸或硫代巴比妥酸在无水乙醇中进行Knoevenagel缩合反应,合成了6个5-(取代吡唑基-4-次甲基)(硫代)巴比妥酸。标题化合物经IR、1^HNMR、元素分析确证结构。 相似文献
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化学修饰环糊精—胶束动电色谱法直接拆分巴比妥对映体 总被引:3,自引:0,他引:3
应用胶束动电色谱法,于移动相中直接加入环糊精作为手性选择剂,用于对4种手性巴比妥盐的对映体拆分。实验结果表明,十二烷基磺酸钠和γ-环糊精体系对戊巴比妥和戊硫巴比妥对映体具有手性识别作用,这两种巴比妥盐的手性碳位于脂肪侧链上,与巴比妥环相隔一碳原子;胆酸和α-环糊精体系可直接拆分这四对手性对映体。本文还讨论了胆酸、SDS对环糊精的手性识别作用的影响以及经甲基化修饰的环糊精的手性识别作用的变化。 相似文献
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铁(Ⅱ)—巴比妥酸—NO2^—显色反应的研究及应用 总被引:1,自引:0,他引:1
研究了Fe(Ⅱ)-巴比妥酸-NO2显色反应的适宜条件和配合物的存在形式及光度特性,并对显色机理进行了探讨。铁含量为为0 ̄2μg/ml时符合比尔定律,本方法检测限为30μg/L,用于水中微量铁的测定,结果令人满意。 相似文献
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采用氢火焰离子化检测器,5%SE-30为固定相,正二十二烷为内标,测定苯巴比妥及其制剂,手续简便快速,结果准确可靠,平均回收率(n=5)为99.1%~101.0%。 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