共查询到20条相似文献,搜索用时 31 毫秒
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Kanitskaya L. V. Elokhina V. N. Fedorov S. V. Shulunova A. M. Nakhmanovich A. S. Turchaninov V. K. Lopyrev V. A. 《Russian Journal of General Chemistry》2002,72(5):778-784
Pyridine was reacted with propargyl bromide to obtain the dibromide [C5H5NCH = CHCH = CHCH = CHC5H5N]2
+ 2Br-. The effect of the vinyl group on its UV spectrum is qualitatively interpreted using the results of nonempirical quantum-chemical calculations (basis HF/6-31G*). 相似文献
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四(4-苯乙烯基)硅烷(TVBS)和溴代二苯乙烯基吡啶(Br-DSP)通过Heck偶联反应构筑以共价键连接的具有pH响应的新型多孔材料. 材料具有良好的孔性能和热稳定性能, 其比表面积为467 m2·g-1, 孔体积为0.41 cm3·g-1. 所得的多孔材料在273 K/760 mmHg条件下的CO2吸附量为2.96 wt%. 二苯乙烯基吡啶(DSP)单元的引入, 使多孔材料具有优异的荧光性能, 其中N原子作为质子化中心, 使材料具有pH响应性. 在固体状态下, 材料的荧光最大发射波长在526 nm; 在pH=1.00~4.50范围内, 材料的荧光最大发射波长和相应的pH值成线性关系, 表明该材料可用于酸性溶液的精确地快速检测. 相似文献
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CHEN Xiao ZHANG Yong-Xin DU Da-Ming HUA Wen-Ting 《有机化学》2003,23(Z1):25-26
The enantioselective reduction of prochiral ketones with borane in the presence of a chiral ligand leading to enantiomerically pure secondary alcohols has received considerable attention in recent years. [1] Enantiomerically pure secondary alcohols are important intermediates for the synthesis of various other organic compounds such as halides, esters, ethers, ketones and amines. To the best of our knowledge, the use of pyridine prolinol derivatives in the reduction of ketones has not been reported so far. Thus, it should be of interest to investigate the catalytic a bility of such ligands. We have an ongoing project in the synthesis and application of chiral pyridine derivatives in chiral molecular recognition[2] and we want to evaluate the effect resulting from the introduction of a pyridinyl moiety onto the catalysts. We expect that the cooperation of pyridine unit and chiral prolinol unit in new ligands may result in unique properties for catalytic reaction. 相似文献
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聚苯乙烯—吡啶树脂的合成及催化水解反应 总被引:4,自引:0,他引:4
在氢氧化钠作用下,氯甲基化聚苯乙烯与吡啶反应制成聚苯乙烯-吡啶树脂,测定了其化学组成和红外光谱,并考察了在酯水解反应中的催化活性。 相似文献
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Rybachenko V. I. Schroeder G. Chotii K. Yu. Lenska B. Red'ko A. N. 《Russian Journal of Organic Chemistry》2004,40(3):412-416
The rate of formation of N- and O-acetyl and benzoyl salts of pyridines and pyridine N-oxides in acetonitrile and methylene chloride and equilibria therein were studied. The process occurs in one step following the SN2 mechanism with a small degree of bond rupture in the transition state. 相似文献
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GAO Jun-long ZHENG Liang-yu ZHANG Suo-qin ZHANG Xin-min SUN Guo-dong QIN Lin LI Yao-xian LIU Qing-wen LI Xiao-bo 《高等学校化学研究》2010,26(1):50-54
A series of proline-based amino pyridine dipeptide organocatalysts was synthesized and applied in direct asymmetric intermolecular aldol reaction. These catalysts showed good solubility in organic solvents, good yields (73%―97%) and enantioselectivitives(74%―94%). Among them, dipeptide organocatalyst(2) was found to be the most efficient one for the asymmetric aldol reaction between cyclohexanone and 4-nitrobeznaldehyde. After optimizing the catalytic reaction conditions, we found that the catalyst showed high yield(97%), enantioselectivity(e.e., up to 92%) and anti-diastereoselectivity(up to 95:5) at mild room temperature without any additives. 相似文献
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S. P. Gromov M. V. Fomina Yu. B. Grishina N. A. Kurchavov 《Russian Journal of Organic Chemistry》2005,41(11):1678-1682
Dependence of reactivity on substituents in the pyridine ring of the 4-methylpyridinium salts was studied in intermolecular reaction of ring transformation involving quaternary salts of pyridinium and isoquinolinium promoted by methylammonium sulfite. 相似文献
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XiaoCHEN YongXinZHANG DaMingDU WenTingHUA 《中国化学快报》2004,15(2):167-168
Two new chiral pyridine prolinol derivatives have been synthesized from N-alkylation of (S)-α,α-diphenyl-2-pyrrolidinemethanol with 2-bromomethylpyridine and 2, 6-dibromo-methyl-pyridine. The catalytic asymmetric borane reduction of prochiral ketones and the asymmetric addition ofdiethylzinc to benzaldehyde were investigated. 相似文献
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M. Yu. Tipugina T. N. Lomova E. V. Motorina 《Russian Journal of Coordination Chemistry》2005,31(5):357-363
The reaction of meso-tetraphenylporphyrin with Mo(VI) oxide in boiling phenol resulted in a stable complex O=Mo(OH)TPP. Thermodynamics and kinetics of the reaction between (oxo)(hydroxo)molybdenumtetraphenyporphyrin with pyridine in toluene were studied by spectrophotometric method. This reaction was found to occur in three equilibrium elementary stages: replacement of OH– by Py (K
1=9.1 × 103 l/mol, k
1=5.25 s–1 mol–1 l), the formation of dication (dipyridine)(hydroxo)molybdenumtetraphenylporphyrin as a result of cleavage of a double bond Mo=O (K
2=39.3 l/mol, k
2=1.83 × 10–2 s-1 mol–1 l), and the formation of cationic complex[Mo(Py)3TPP]3+ · 3OH– (K
3=1.0 l/mol, k
3=1.19 × 10–3 s–1 mol–1 l).__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 5, 2005, pp. 380–386.Original Russian Text Copyright © 2005 by Tipugina, Lomova, Motorina. 相似文献
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吡啶甲酸铑阳离子催化甲醇羰基化反应机理的理论计算 总被引:1,自引:0,他引:1
采用有效核近似从头算方法,在HF/LANL2DZ水平下用Berny优化法,对吡啶甲酸铑阳离子催化剂催化甲醇羰基化反应中各基元反应的中间体、过渡态和产物的几何结构进行了优化,过渡态结构通过振动分析进行了确认;计算了各反应的活化位垒.CH_3OH与CO在吡啶甲酸铑阳离子催化剂的作用下反应分4步进行:(1)CH3I氧化加成反应;(2)羰基重排反应:(3)羰基配位反应;(4)CH_3COI还原消除反应.对于各基元反应,CH3I氧化加成反应位垒最高(167.78kJ/mol),是整个反应过程的决速步骤;羰基重排反应和CH_3COI还原消除反应的活化位垒分别为110.67和62.94 kJ/mol,羰基配位反应的位垒为零.与[Rh(CO)_2I_2]-催化剂相比,吡啶甲酸铑阳离子催化剂具有相同的催化机理,但后者催化剂上各步反应的位垒较低. 相似文献
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用量热滴定法研究2,4-二氯酚与吡啶的氢键络合反应李志伟,陈爱通,胡日恒(天津大学化学系,天津,300072)(中国科学院化学研究所)关键词2,4-二氯酚,吡啶,正庚烷,氢键,量热滴定利用反应热测定样品滴定度是一种新兴的方法。在反应常数为103~10... 相似文献
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The generation of specific enolates via Michael addition of nucleophiles to unsaturated ketones has proven to be an extremely useful process in organic synthesis. With regard to this we felt that the incorporation of a phenylselenenyl group in the 2-position of an enone would (a) enhance the ability of the enone to undergo Michael addition, (b) provide, after Michael addition, a stabilized enolate for the subsequent introduction of a substituent in the 2-position and (c) allow for the eventual introduction of a new double bond via the well-known selenoxide β-elimination reaction.1 While a few 2-phenylselenenylenones have been previously reported in the literature,2 no general method currently exists for their preparation.3 We now wish to report a general method for the synthesis of these systems in good yield under extremely mild reaction conditions. In future communications we will demonstrate the versatility of this class of compounds in a variety of enone mono- and dialkylation reactions. 相似文献
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J. Luke Koniarczyk Jacob W. Greenwood Juan V. Alegre‐Requena Robert S. Paton Andrew McNally 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(42):15024-15028
A pyridine–pyridine coupling reaction has been developed between pyridyl phosphonium salts and cyanopyridines using B2pin2 as an electron‐transfer reagent. Complete regio‐ and cross‐selectivity are observed when forming a range of valuable 2,4′‐bipyridines. Phosphonium salts were found to be the only viable radical precursors in this process, and mechanistic studies indicate that the process does not proceed through a Minisci‐type coupling involving a pyridyl radical. Instead, a radical–radical coupling process between a boryl phosphonium pyridyl radical and a boryl‐stabilized cyanopyridine radical explains the C?C bond‐forming step. 相似文献
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The three-component reaction of aromatic aldehyde,malononitrile and aliphatic amine in a mixed solvent of methanol and water exhibited very interesting molecular diversity and gave the derivatives of polysubstituted N-methyldihydropyridines,2-dialkylaminopyridines and 2-methoxypyridines as main products according to the structure of aliphatic amines used. 相似文献
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Jonathan P. Markham Ban Wang Dr. Edwin D. Stevens Dr. Stuart C. Burris Dr. Yongming Deng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(26):6638-6644
A photocatalyzed ortho-alkylation of pyridine N-oxide with ynamides and arylacetylenes has been developed, which yields a series of α-(2-pyridinyl) benzyl amides/ketones. Mechanistic studies, including electrochemical studies, radical-trapping experiments, and Stern–Volmer fluorescence quenching studies demonstrate that pyridine N-oxide serves as both a redox auxiliary and radical acceptor to achieve the mild photocatalytic single-electron oxidation of carbon–carbon triple bonds with the generation of a cationic vinyl radical intermediate. 相似文献
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A series of novel conjugated molecules with two pyridine dicarboxylic acid units have been synthesized by a Wittig reaction of corresponding alkyltriphenylphosphonium salts with aromatic aldehydes. The novel pyridine dicarboxylic acid derivatives with high ligand activity were completely characterized from their mass and 1H NMR spectra. The E-configuration of these alkenes was confirmed by infrared spectroscopic data. 相似文献