New and Efficient Synthesis of Imidazo[4,5-<i>b</i>]pyridine-5-ones
作者:M. Fernanda Proença、Magdi E. Zaki、Brian L. Booth
DOI:10.1055/s-2005-872700
日期:——
1-Aryl-5-amino-4-cyanoformimidoyl imidazoles 1 were reacted with methyl cyanoacetate, under mild experimental conditions, leading to 3-aryl-6,7-dicyanoimidazo[4,5-b]pyridine-5-ones 5, isolated after neutralization of their ammonium salts 4. A reaction intermediate, imidazole 3d, the precursor of the bicyclic structure 5d, could be isolated under carefully controlled experimental conditions and was shown to cyclize to imidazo[4,5-b]pyridine-5-one (4d, isolated as the DBU salt) after reflux in ethanol, in the presence of DBU.
The synthesis of imidazo[4,5-d]pyridines from a substituted imidazole and acyl or sulfonyl acetonitrile
作者:Magdi E.A. Zaki、M. Fernanda Proença
DOI:10.1016/j.tet.2007.02.078
日期:2007.4
1-Aryl-5-amino-4-cyanoformimidoyl imidazoles were reacted with acyl and sulfonyl acetonitriles, under mild experimental conditions, leading to imidazo[4,5-b]pyridines and imidazo[4,5-b]pyridine-5-ones. A reaction intermediate could be isolated in the reaction with methyl cyanoacetate, under carefully controlled experimental conditions. This intermediate cyclized to imidazo[4,5-b]pyridine-5-one, in
在温和的实验条件下,将1-芳基-5-氨基-4-氰基甲酰亚胺基咪唑与酰基和磺酰基乙腈反应,生成咪唑并[4,5- b ]吡啶和咪唑并[4,5 - b ]吡啶-5-酮。在小心控制的实验条件下,可以在与氰基乙酸甲酯的反应中分离出反应中间体。在DBU存在下,该中间体环化成咪唑并[4,5 - b ]吡啶-5-酮。5-氨基-4-氰基甲酰亚胺基-1-(4-氟苯基)咪唑与乙酰丙酮之间的反应通过不同的途径发生,从而得到6-氨基甲酰基嘌呤。