A novel and efficient synthesis of pyrido[1,2-a]-fused 1,3- diazaheterocyclic compounds via a one-pot three-component reaction

摘要

An efficient one-pot synthesis of pyrido[1,2-a]-fused 1,3-diazaheterocyclic compounds by three-component reaction of diamine, nitroketene dithioacetal (=1,1-bis(methylsulfanyl)-2-nitroethene), and electron-poor itaconic anhydride (=2-methylidenesuccinic anhydride=2-methylidenebutanedioic anhydride) in aqueous EtOH is reported. This protocol has the advantages of easiness, higher yields, and shorter reaction times. The structures were corroborated spectroscopically (IR, ~1H- and ~(13)C-NMR, and EI-MS) and by elemental analyses. A plausible mechanism for this type of cyclization is proposed (Scheme2).