The title compounds were obtained from reaction of variously substituted 2(1H)pyrazinones with acetylenic derivatives. Experimental evidence points out to a two step mechanism : a DielsAlder cycloaddition followed by immediate decomposition of the adducts into the title products via two competitive retro DielsAlderreactions. The product distribution, which is shown to be highly dependent on the
acetylenic derivatives to give specifically substituted pyridones or pyridines. The observed selectivity can be explained in terms of HO-LU interactions for the reagents and two competitive retro Diels-Alderreactions of the primary bicycloadducts. With cyanotosylate as dienophile no pyrimidone derivative but a new 2(1H)-pyrazinone is obtained.
One step synthesis of 1,5-diaryl pyridin-2(1H)-ones from 2-aryl vinamidinium salts and N-aryl cyanoacetamides
作者:Jiabin Yang、Guoqiang Su、Yu Ren、Yang Chen
DOI:10.1016/j.tet.2014.09.041
日期:2014.11
A one step, direct method for the synthesis of 1,5-diaryl pyridin-2(1H)-one derivatives by condensation of 2-aryl vinamidinium salts with N-aryl cyanoacetamides has been developed. This method can conveniently provide the corresponding 1,5-diaryl pyridin-2(1H)-one derivatives with various substituents in good yields and overcome the drawbacks of existing methods such as poor substrate scope, heavy metal pollution, and low yields. The formation mechanism of the products was illustrated. (C) 2014 Elsevier Ltd. All rights reserved.