A novel and efficient palladium catalyzed method was developed for the synthesis of wide range of pyrido[2,3-d]pyrimidines, using readily available β-bromovinyl/aryl aldehydes and 6-amino-1,3-dialkyluracils as the starting materials with good yields. This reaction proceeds via cascade imination/Buchwald–Hartwig cross coupling/cycloaddition reactions under microwave irradiation and solvent free conditions.
![Graphical abstract: Cascade imination, Buchwald–Hartwig cross coupling and cycloaddition reaction: synthesis of pyrido[2,3-d]pyrimidines](http://hg.y866.cn/compound/lib/scimg/usr/1/C5RA00725A.jpg)