Studies on synthesis of novel pyrido[2,3-d]pyrimidine derivatives, evaluation of their antimicrobial activity and molecular docking.

A series of novel pyrido[2,3-d]pyrimidine derivatives 6 were prepared starting from 2-amino-3-cyano-4-trifluoromethyl-6-phenyl pyridine 3 via Grignard's reaction, cyclization followed by coupling with aliphatic and cyclic amines. All the compounds 6 were screened for antibacterial, minimum bactericidal concentration (MBC), biofilm inhibition activity as well as antifungal and minimum fungicidal concentration (MFC) activities. Among the screened compounds, the compounds 6e, 6f, and 6m which showed exhibiting promising activity have been identified. The results reveal that the compound pyrido[2,3-d]pyrimidine derivative 6e altered the sterol profile which may exert its antifungal activity through inhibition of ergosterol biosynthesis and could be an ideal candidate for antifungal therapy. The molecular docking results also validated the antifungal results.