Synthetic methodology of pyrimido[4,5-b]quinoline derivatives

This review discusses the synthetic pathways of an important class of quinolines known as pyrimido[4,5-b]quinoline. Due to their profound range as biologically active compounds, they attracted the attention of medical/organic researchers. The construction of pyrimido[4,5-b]quinolines involved the intermolecular cyclization of diamino chloropyrimidine carbaldehyde and intramolecular cyclization of 2-amino-3-cyanotetra/hexahydroquinoline, 2-aminoquinoline-3-carbonitriles, ester or amide. That class of organic compounds was constructed from the reaction between 2-chloro-3-formylquinoline with amidine, urea, and thiourea. Also, barbituric acid and uracil and their analogous play an important role in synthesizing pyrimidoquinolines via multicomponent reaction strategies (MCR).