SYNTHESIS OF NEW ACETAMIDE-CONJUGATED MONOBACTAM ANTIBIOTICS

In the present work, we have synthesized a new analoges of monocyclic β-lactam (2-(3-(2, 4-dichlorophenoxy)-2-(substituted aryl) – 4-oxoazetidin – 1 – ylamino) – N – (pyridin-2-yl) acetamide) derivatives in the presence of triethyl amine (TEA) and phosphorus oxychloride (POCl₃) under classical method by using Dichloromethane (DCM) as a solvent. The designed compounds 4(a-l) were prepared by Staudinger reaction ([2+2] ketene-imine cycloaddition reactions). In which an azetidin-2-one motif connects with pyridine-2-acetamide nucleus with two aromatic rings. The target compounds were screened for in vitro antibacterial activity against clinically relevant Gram-negative (Escherichia coli and Klebsiella pneumonia) and Gram-positive species (Bacillus subtilis, Proteus vulgaris and Staphylococcus aureus). The obtained results have demonstrated that all the synthesized imidazole-conjugated monocyclic β-lactam derivatives showed good antibacterial activity. Particularly the compounds 4e and 4l found to be effective in P.vulgaris as equal to reference ampicillin and other compounds showed moderate to good activity against five human bacterial pathogens. All these compounds have been characterized by IR, ¹H-NMR, ¹³C-NMR, Mass spectrometry and Elemental data.