Synthesis and antibacterial activity of novel 5,6,7,8-tetrahydroimidazo[1,2-a]pyrimidine-2-carbohydrazide derivatives

BACKGROUND: The intensely increasing multi-drug resistant microbial infections have encouraged the search for new antimicrobial agents. Hydrazone derivatives are known to exhibit a wide variety of biological activities including anti-microbial. In heterocyclic moiety, imidazo[1,2-a]pyrimidines are the subject of immense interest for their antimicrobial activity and also for their analgesic, antipyretic and anti-inflammatory properties. RESULTS: Condensation of 5,6,7,8-tetrahydroimidazo[1,2-a]pyrimidine-2-carbohydrazide 7 with aromatic aldehydes a–k in ethanol at reflux led to the generation of hydrazone derivatives 8a–k in 80–92% yield. The synthesis of carbohydrazide 7 was accomplished in six steps from commercially available 2-amino pyrimidine. The structures of the synthesized compounds were confirmed by (1)H, (13)C NMR, Mass and IR spectral data. All the synthesized hydrazone derivatives 8a–k were tested in vitro for their antibacterial activity. Compounds 8d, 8e and 8f exhibited excellent antibacterial activity with zone of inhibition 30–33 mm against E. coli (Gram negative bacteria) and S. aureus (Gram positive bacteria). These compounds also exhibited excellent antibacterial activity with zone of inhibition 22–25 mm against P. aeruginosa (Gram negative bacteria) and S. pyogenes (Gram positive bacteria). CONCLUSION: Synthesized and recorded antibacterial activity of some new 5,6,7,8-tetrahydro-imidazo[1,2-a]pyrimidine-hydrazone derivatives. [Figure: see text]