Diethylamine Dess–Martin periodinane: an efficient catalyst–oxidant combination in a sequential, one-pot synthesis of difficult to access 2-amino-3,5-dicarbonitrile-6-sulfanylpyridines at ambient temperature
Borax catalyzed domino reactions: synthesis of highly functionalised pyridines, dienes, anilines and dihydropyrano[3,2-c]chromenes
作者:Aniruddha Molla、Sahid Hussain
DOI:10.1039/c4ra03627a
日期:——
Borax, an innocuous, inexpensive, and a naturally occurring material, very efficiently catalyzes the Knoevenagel condensation and Michael addition in domino fashion for the construction of highly functionalised pyridines, dienes, anilines and dihydropyrano[3,2-c]chromenes. The present protocol offers advantages in terms of higher yields, wide scope of substrates, operational simplicity, short reaction time, no requirement of workup or column chromatography, and easy access to a wide range of structurally diverse functionalized molecules of biological importance. Recycling of the catalyst and scaling up of the reactions are important attributes of this catalytic process.
pot, three component synthesis of 2-amino-4-aryl-3,5-dicyano-6-sulfanylpyridines and the corresponding 1,4-dihydropyridines are from readily accessible starting materials is described. Simply heating of an ethanolic solution of structurally diverse aldehydes with various thiols and malononitrile in the presence of nanocrystalline magnesium oxide provides the highly substituted pyridine derivatives
An Improved Procedure for the Three-Component Synthesis of Highly Substituted Pyridines Using Ionic Liquid
作者:Brindaban C. Ranu、Ranjan Jana、S. Sowmiah
DOI:10.1021/jo070015g
日期:2007.4.1
A basicionicliquid, [bmIm]OH, efficiently promotes a one-pot, three-component condensation of aldehydes, malononitrile, and thiophenols to produce highly substituted pyridines in high yields at room temperature. This reaction does not involve any hazardous organic solvent and toxic catalyst. The ionicliquid is recovered and recycled for subsequent reactions.
Exploring Catalyst and Solvent Effects in the Multicomponent Synthesis of Pyridine-3,5-dicarbonitriles
作者:Kai Guo、Mark J. Thompson、Beining Chen
DOI:10.1021/jo901232b
日期:2009.9.18
protocol to overcome the difficulty in the directsynthesis of pyridine-3,5-dicarbonitriles via the MCR from sterically hindered aldehydes using either base was realized by changing the reaction solvent from ethanol to acetonitrile. Mechanistically, the two catalysts were found to each promote different pathways in the final oxidation step of the penultimate product, 1,4-dihydropyridine 6. A reaction