The aim of this work is to discuss the chemistry of pyrido[3,4-d]pyrimidines as one of the most important heterocyclic compounds with remarkable synthetic, biological and medical applications. In this overview, the chemistry of heterocyclic compounds incorporated the pyrido[3,4-d]pyrimidine scaffold as demonstrated by chemical reactions and different preparation processes. The anticipated compounds were synthesized from pyridine or pyrimidine compounds and a description of the reactivity of substituents attached to ring carbon and nitrogen atoms is discussed. On the other hand, the synthesis and reactions of fused heterocycles incorporated pyrido[3,4-d]pyrimidine scaffold is described. The diamine analogs included pyrido[3,4-d]pyrimidine core were reported as tyrosine kinase inhibitors. The chemical reactions of certain unexpected and chemically substantial compounds have been discussed.
Keywords: Pyrido[3, 4-d]pyrimidines, substituents’ reactivity, synthetic routes, biological applications, heterocyclic compounds, tyrosine kinase inhibitors.