Electrochemical oxidation of 4-monoalkyl-substituted 1,4-dihydropyridines
摘要:
The electrochemical oxidation of 4-monoalkyl-substituted 1,4-dihydropyridines has been studied in an aprotic medium and in the presence of pyridine. In an aprotic medium the products of oxidation are both 4-alkyl-substituted and 4-unsubstituted pyridines or mixtures of them. On oxidation in acetonitrile of 4-Et-, 4-n-Pr-, and 4-i-Bu-substituted dihydropyridines, 2-methylene-1,2,3,4-tetrahydropyridines were obtained in addition to the oxidized forms. In the presence of base the products of preparative electrolysis of the studied compounds were 4-alkyl-substituted pyridines. The exception was the 4-i-Pr- substituted dihydropyridine which was dealkylated on oxidation even in the presence of base.
Synthesis of Substituted 1,4‐Dihydropyridines in Water Using Phase‐Transfer Catalyst Under Microwave Irradiation
作者:Hojatollah Salehi、Qing‐Xiang Guo
DOI:10.1081/scc-200039409
日期:2004.12.31
Abstract The synthesis of various substituted 1,4‐dihydropyridines has been achieved by the reaction of aldehydes, ethyl/methyl acetoacetates, and ammonium acetate in water using phase‐transfer catalyst undermicrowaveirradiation. Compared to the classical Hantzsch's reaction conditions, this new method consistently has the advantage of good yields and short reaction times. Bifunctionalcompounds containing
Magnetic Fe3O4 nanoparticles: Efficient and recoverable nanocatalyst for the synthesis of polyhydroquinolines and Hantzsch 1,4-dihydropyridines under solvent-free conditions
A green approach for efficient and rapid synthesis of biologically active substituted Hantzsch 1,4-dihydropyridine and polyhydroquinolinederivatives using magneticFe3O4 nanoparticles (Fe3O4 MNPs) as a recyclable catalyst undersolvent-freeconditions was reported. The catalyst was characterized by FT-IR, XRD, and TEM analysis. Compared to the classical reactions, this method consistently has the
报道了在无溶剂条件下使用磁性Fe 3 O 4纳米颗粒(Fe 3 O 4 MNPs)作为可循环利用催化剂高效,快速合成生物活性取代的Hantzsch 1,4-二氢吡啶和聚氢喹啉衍生物的绿色方法。通过FT-IR,XRD和TEM分析对催化剂进行了表征。与经典反应相比,该方法始终具有反应时间短,催化剂负载少,收率高,易于磁分离和催化剂可重复使用的优点。
LiBr as an Efficient Catalyst for One-pot Synthesis of Hantzsch 1,4-Dihydropyridines under Mild Conditions
作者:D. K. Yadav、R. Patel、V. P. Srivastava、G. Watal、L. D. S. Yadav
DOI:10.1002/cjoc.201190036
日期:2011.1
A simple, inexpensive and efficientone‐potsynthesis of 1,4‐dihydropyridines has been accomplished via lithium bromide‐catalyzed Hantzsch three‐component condensation reaction of an aldehyde, α,β‐ketoester and ammonium acetate in acetonitrile at room temperature in good to excellent yields. The present protocol is applicable to wide range of substrates including aliphatic, aromatic and heterocyclic
The electrochemical oxidation of 4-monoalkyl-substituted 1,4-dihydropyridines has been studied in an aprotic medium and in the presence of pyridine. In an aprotic medium the products of oxidation are both 4-alkyl-substituted and 4-unsubstituted pyridines or mixtures of them. On oxidation in acetonitrile of 4-Et-, 4-n-Pr-, and 4-i-Bu-substituted dihydropyridines, 2-methylene-1,2,3,4-tetrahydropyridines were obtained in addition to the oxidized forms. In the presence of base the products of preparative electrolysis of the studied compounds were 4-alkyl-substituted pyridines. The exception was the 4-i-Pr- substituted dihydropyridine which was dealkylated on oxidation even in the presence of base.