Synthesis of pyrazolo[3,4-d]pyrimidines by intramolecular cycloaddition of azahexatrienes
Abstract
Treatment of aldehyde pyrimidin-6-ylhydrazones with aromatic aldehydes (or treatment of 6-hydrazinopyrimidines with aromatic aldehydes in excess) in dimethylformamide under reflux gave 2,3-disubstituted pyrazolo[3,4-d]pyrimidines.