Synthesis and antimicrobial activity of novel imidazo[1,2-a]pyridinopyrimidine-2,4,6(1H,3H,5H)-triones and thioxopyrimidine-4,6(1H,5H)diones

A novel series of imidazo[1,2-a]pyridinopyrimidine-2,4,6(1H,3H,5H)-triones and thioxopyrimidine-4,6(1H,5H)diones were synthesized via multistep synthesis starting from 2-aminopyridine on cyclisation with phenacyl bromide followed by Vilsmeier–Haack and Knoevenagel condensation reactions. Structures of all the newly synthesized compounds were confirmed by their spectral and analytical studies. All the synthesized compounds were screened for their in vitro antimicrobial activity. Antibacterial activity results revealed that compounds 5f, 5i, and 5j have shown promising activity against S. pyogenes with ZOI ranging from 19 to 20 mm, compound 5g against P. aeruginosa (ZOI 19 mm) and 5f and 5h against S. aureus (ZOI 17, 18 mm) have shown good antibacterial activity. Among barbituric acid and thiobarbituric acid derivatives, thiobarbituric acid derivatives have shown maximum antibacterial activity. None of the compounds were found to be active at 150 µg/mL concentration against tested fungal strains.