4-Alkyl and 4,4′-dialkyl 1,2-bis(4-chlorophenyl)pyrazolidine-3,5-dione derivatives as new inhibitors of bacterial cell wall biosynthesis

An efficient microwave-assisted synthesis of substituted pyrazolidinediones was developed. These compounds showed good activity against MurB and Gram-positive bacteria. Over 195 4-alkyl and 4,4-dialkyl 1,2-bis(4-chlorophenyl)pyrazolidine-3,5-dione derivatives were synthesized, utilizing microwave accelerated synthesis, for evaluation as new inhibitors of bacterial cell wall biosynthesis. Many of them demonstrated good activity against MurB in vitro and low MIC values against Gram-positive bacteria, particularly penicillin-resistant Streptococcus pneumoniae (PRSP). Derivative 7l demonstrated antibacterial activity against both Gram-positive and Gram-negative bacteria. Derivatives 7f and 10a also demonstrated potent nanomolar Kd values in their binding to MurB.