Tf<sub>2</sub>O-Mediated Cyclization of α-Acyl-β-(2-aminopyridinyl)acrylamides: Access to N-Substituted 4<i>H</i>-Pyrido[1,2-<i>a</i>]pyrimidin-4-imines
Chitturi Bhujanga Rao, Ning Zhang, Jiana Hu, Yu Wang, Yongjiu Liang, Rui Zhang, Jingwen Yuan, Dewen Dong
Abstract
A facile and efficient direct synthesis of N-substituted 4H-pyrido[1,2-a]pyrimidin-4-imines is developed from α-acyl-β-(2-aminopyridinyl)acrylamides mediated by triflic anhydride (Tf2O) in the presence of 2-chloropyridine. This amide activation protocol features mild reaction conditions, simple execution, excellent yields, and high chemoselectivity, and is also applied to the synthesis of substituted 4H-pyrido[1,2-a]pyrimidin-4-ones via a practical one-pot procedure.
Topics & Concepts
ChemoselectivityChemistryAmideTriflic acidCombinatorial chemistryAcylationReaction conditionsMedicinal chemistryOrganic chemistryCatalysisAdvanced Synthetic Organic ChemistryChemical synthesis and alkaloidsQuinazolinone synthesis and applications