Abstract
A novel metal‐salt‐oxidant‐free, efficient, and economical method for the oxidation of Hantzsch 1,4‐dihydropyridines that uses aerial oxygen and solvent‐grade dimethylsulfoxide is described. Also, the synthesis of pyrido[2,3‐d]pyrimidines is achieved from in situ oxidation of dihydropyrido[2,3‐d]pyrimidines that arise from the reaction of 6‐aminouracils and cyano olefins in dimethylsulfoxide.
Acknowledgment
Authors thank the Council of Scientific and Industrial Research, New Delhi, India, for financial support of this research project.