Organoiodine(III) mediated synthesis of 3,9-diaryl- and 3,9-difuryl-bis-1,2,4-triazolo[4,3-a][4,3-c]pyrimidines as antibacterial agents

Nine 3,9-diaryl- and 3,9-difuryl-bis-1,2,4-triazolo[4,3-a][4,3-c]pyrimidines (3a–i) have been synthesized by the oxidation of bis-2,4-pyrimidinylhydrazones of various araldehydes and furfural with 2 equiv of iodobenzene diacetate (IBD) in dichloromethane and tested in vitro for their antibacterial activity. Three compounds, namely 3,9-di-(4′-fluorophenyl)-bis-1,2,4-triazolo[4,3-a][4,3-c]pyrimidine (3f), 3,9-di-(4′-nitrophenyl)-bis-1,2,4-triazolo[4,3-a][4,3-c]pyrimidine (3g) and 3,9-di-(5′-nitro-2′-furyl)-bis-1,2,4-triazolo[4,3-a][4,3-c]pyrimidine (3i), were associated with substantially higher antibacterial activity than some commercial antibiotics against Gram-positive bacteria namely Staphylococcus aureus, Staphylococcus epidermidis and Bacillus subtilis; two Gram-negative bacteria namely Salmonella typhi and Escherichia coli at MIC (minimum inhibitory concentration) 10 μg/ml.

Graphical abstractNine 3,9-diaryl- and 3,9-difuryl-bis-1,2,4-triazolo[4,3-a][4,3-c]pyrimidines (3a–i) have been synthesized by the oxidation of bis-2,4-pyrimidinylhydrazones of various araldehydes and furfural with 2 equiv of iodobenzene diacetate (IBD) in dichloromethane and tested in vitro for their antibacterial activity against some commercial antibiotics, namely linezolid and cefaclor.Figure optionsDownload full-size imageDownload as PowerPoint slide