Staudinger ketene–imine [2+2] cycloaddition of novel azomethines to synthesize biologically active azetidinone derivatives and their in vitro antimicrobial studies

Abstract

AbstractSince considerable intrigue has been focused on azetidinone (β‐lactam) compounds for their wide range antimicrobial activity, the present study focuses on the synthesis of new series of azetidinone compounds. The reaction between the novel azomethine and α‐haloester in the presence of Zn impetus and benzene resulted into the formation of desired azetidinone derivative by [2+2] cycloaddition involving imine–ketene. The reaction has also been studied in the presence of diverse Lewis acids such as Zn(OTf)2, ZnCl2, Cu(OTf)2, TiCl4, and BF3.Et2O. The effect of such Lewis acids also enhance the yield of the desired product. Moreover, the structure of the isolated products was also affirmed by spectral analysis (Fourier‐transform infrared [FT‐IR] spectroscopy, proton nuclear magnetic resonance [1H NMR], carbon‐13 nuclear magnetic resonance [13C NMR], and high‐resolution mass spectrometry [HRMS]). Furthermore, the antibacterial activity of synthesized compounds has been screened in vitro against different pathogenic bacterial and fungus species. Inspection of the results uncovered that all of the newly synthesized compounds individually display varying degrees of inhibitory impacts on the development of the tested bacterial species, thus, they might be considered as medication possibility for bacterial pathogens. The azomethine exhibited an expansive range of antibacterial activity against Gram‐negative Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, and Acinetobacter baumannii and Gram‐positive Staphylococcus aureus bacterial strains and antifungal activity against Candida albicans, Candida tropicalis, and Candida parapsilosis bacterial strain. The result demonstrated that the β‐lactam subordinates have good antibacterial and antifungal activities on microscopic organisms.