Preparation of 2-azetidinones by cyclocondensation of carboxylic acids and imines via diphosphorustetraiodide

Synthesis and antimicrobial activities of some novel diastereoselective monocyclic cis-β-lactams using 2-ethoxy carbonyl DCPN as a carboxylic acid activator

A series of novel monocyclic cis-β-lactams were prepared from phenoxyacetic acid as ketene source and imines derived from 1-chloro-3,4-dihydronaphthalene-2-carbaldehyde and respective amine using ethyl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylate (or 2-ethoxy carbonyl DCPN) as a carboxylic acid activator. This is the first time 2-ethoxy carbonyl DCPN has been used as an acid activator in synthesis of β-lactams. The reaction was entirely diastereoselective leading to the formation cis-β-lactam derivatives. These newly synthesized cis-β-lactam were fully characterized by FT-IR, ¹H NMR, ¹³C NMR, HRMS, CHNS and X-ray crystallography study. All this novel compound was also evaluated for their antibacterial and antifungal activities against certain strains of Gram-positive bacteria, Gram-negative bacteria and fungi. These compounds displayed moderate activity against using bacterial and fungal strains.

Recent advances in β-lactam synthesis

During the past century, β-lactams have been identified as the core of penicillin and since then several strategies have been developed for their synthesis.

Tosylimidazole-mediated one-pot synthesis of 2-azetidinones

Cyclocondensation of Schiff bases and substituted acetic acid with tosylimidazole afforded 2-azetidinones in good to excellent yields. This reaction works reliably well for monocyclic and spirocyclic 2-azetidinones. This reaction is green and efficient and the products can be purified by simple crystallisation.