New thieno[2,3-b]pyridine-fused [1,2,4]triazolo[4,3-a]pyrimidinone hybrids as potential MRSA and VRE inhibitors

New thieno[2,3-b]pyridine-fused [1,2,4]triazolo[4,3-a]pyrimidinones were obtained by the [5+1] heterocyclization of the appropriate thieno[2,3-b]pyridines followed by the Smiles-type reaction protocol. In general, the triazoles tested exhibited better antibacterial activity against Gram-positive than against Gram-negative bacterial strains. Compoundscontaining 3-acetyl-1-(4-methoxyphenyl)[1,2,4]triazole unit demonstrated more potent inhibitory activities than the reference Linezolid.