Abstract
There are four types of pyridopyrimidines namely pyrido[2,3-d], pyrido[3,4-d], pyrido[
4,3-d]pyrimidines, and pyrido[3,2-d]pyrimidines. Different methods of preparation of pyrido[2,3-
d]pyrimidines are summarized. Synthesis of pyrido[2,3-d]pyrimidines can be from pyrimidines derivatives
or pyridine derivatives. We can start from pyrimidine derivatives and build a pyridine ring.
5,7-Diphenylpyrido[2,3-d]pyrimidines 3 and 4 were obtained by the reaction of 6-aminouracil (1)
with α,β-unsaturated ketone. 6-Amino-1,3-dimethyluracil 10 was reacted with an equimolar amount
of Mannich bases 11a-c under an atmosphere of nitrogen to give pyridopyrimidines 14a-c via the
formation of the intermediates 12a-c & 13a-c. 4-Benzylamino derivative 19 could be converted to
pyrido[2,3-d]pyrimidine derivative 20 by the reaction with dimethylformamide/ dimethylacetal. In
the same way, we can start from pyridine derivatives and build a pyrimidine ring. Different reported
biological activities of pyrido[2,3-d]pyrimidines are discussed e.g. selective adenosine kinase inhibitors,
analgesic, anti-inflammatory, antimicrobial and herbicides, selective inhibitor of the tyrosine kinase
activities of the Fibroblast Growth Factor (FGF) and Vascular Endothelial Growth Factor
(VEGF) receptors.