Synthesis of Some Novel 3-Spiro Monocyclic β-Lactams and Their Antibacterial and Antifungal Investigations

A novel series of new 3-spiro monocyclic β-lactams 3a–i have been synthesized in high chemical yields from 9H-xanthene-9-carbonyl chloride 2 as ketene source in the [2+2] cycloaddition (Staudinger reaction) with different aromatic imines. These newly synthesized β-lactams were fully characterized and evaluated for their antimalarial activities against Plasmodium falciparum K14-resistant strain with moderate to excellent EC50 values varying from 8 up to 50 µM.