An efficient and eco-friendly synthesis, computational assay and antimicrobial evaluation of some novel diastereoselective monocyclic cis-β-lactams

This paper outlines the efficient and eco-friendly synthesis of twenty monocyclic cis-β-lactam derivatives, their spectral analysis, X-ray crystallographic study, computational analysis and antimicrobial activity assay. This is the first time that, 2-methoxy carbonyl DCPN has been used as an activator of acid to generate in situ ketene in synthesis of β-lactams. The synthesis of β-lactam derivatives was completely diastereoselective leading to the formation of cis-stereoisomers exclusively. All these novel cis-β-lactam derivatives were fully characterized by FT-IR, 1H NMR, 13C NMR, HRMS, CHNS and X-ray crystallography study. we use quantum chemical analysis on selected derivatives from both the series to explore their potential optical and nonlinear optical (NLO) properties by calculating their absorption energies and third-order NLO polarizability, respectively. The third-order NLO polarizability values for derivatives 5ad and 5bd (with NO2 fragments) are found to be as large as 205.05 × 10−36 and 203.88 × 10−36 esu, respectively, which are about 10 times larger than that of p-NA (a prototype NLO molecule). The calculation of frontier molecular orbitals (FMOs) and molecular electrostatic potential (MEPs) maps indicates the intramolecular charge process as origin of larger NLO amplitudes. Additionally, all this novel compound was also evaluated for their antimicrobial activities against certain strains of bacteria and fungi. These derivatives displayed, comparatively good to moderate activity against selected microbial strains. Thus, it is believed that the present newly synthesized monocyclic cis-β-lactam derivatives are multifunctional in nature and prove to be very important in material science and chemistry.