C7‐Halomethylene/methyl‐C3‐thiophenyl‐spirocyclic‐β‐lactams: Synthesis, X‐ray analysis, antimicrobial evaluation, cytotoxicity profile and molecular docking interactions

The continuous evolution of new alternative antimicrobial agents in the healthcare domain, provides hope in combatting the escalating daunting problem of severe multidrug resistance. In our quest to confront drug resistance, we explored the conjugation of thiophene motif with β‐lactams into single matrix to develop a series of spirocyclic‐β‐lactams. For this, stereoselective synthesis of cis‐C3‐alkyloxy‐C4‐thiophenyl substituted monocyclic β‐lactams was achieved which were further subjected to intramolecular sulfenyl‐cyclization to furnish C7‐halomethylene/methyl‐C3‐thiophenyl substituted spirocyclic‐β‐lactams. The synthesized compounds were investigated in vitro for their potential activity against six multidrug‐resistant bacterial strains. The most promising C7‐iodomethylene‐C3‐thiophenyl‐spirocyclic‐β‐lactam 7a appended with 4ʹ‐methoxyphenyl moiety, exhibited acceptable activity against B. cereus and P. aeruginosa with MIC values of 0.75 and 6.25 μg/mL respectively, surpassing ampicillin and vancomycin. Furthermore, this compound demonstrated antifungal effectiveness against C. tropicalis (1.5 μg/mL). Active derivatives tested for their cytotoxicity on normal human hepatic (THLE‐2) cell lines confirmed their non‐toxic nature. Further, molecular docking studies predicted the favourable binding interactions of spirocycles within active sites of target proteins. Moreover, several compounds illustrate satisfactory in silico ADME profile. These outcomes provided bright prospect for development of spirocyclic‐β‐lactams as potential solution to combat evolving multidrug resistance.