Novel Amide-Based Azetidine Derivatives as Anti-Inflammatory and Antimicrobial Agents: Synthesis, Reaction Optimization, Characterization, and In Silico Pharmacokinetic Properties

Objective: To develop a highly efficient protocol for the synthesis of novel amide-based azetidine derivatives and evaluate their anti-inflammatory, antimicrobial, and in silico pharmacokinetic properties. Methods: A series of carbonyl-azetidine derivatives (PP-S1-C1­–PP-S1-C11) were synthesized via amidation of functionalized aromatic acids with an azetidine salt using oxalyl chloride and catalytic DMF at 0°C. The reaction conditions were optimized by screening various coupling reagents (HATU, HBTU, EDC·HCl, T3P, PyBOP, TBTU, DCC) and chlorinating agents. All synthesized compounds were characterized by 1H, 13C NMR, and mass spectrometry. Anti-inflammatory activity was evaluated in vitro using the bovine serum albumin denaturation assay. Antimicrobial activity was assessed by minimum inhibitory concentration (MIC) determination against Gram-positive and Gram-negative bacterial strains and fungal cultures. In silico ADME properties were predicted using SwissADME. Results and Discussion: Optimization studies revealed that amidation via acid chloride formation using oxalyl chloride with catalytic DMF afforded the target compounds in excellent yields (up to 94%), outperforming conventional coupling reagents. A library of eleven derivatives was successfully synthesized with broad functional group compatibility. Anti-inflammatory evaluation showed that all compounds exhibited >50% inhibition of protein denaturation, with PP-S1-C5 demonstrating the highest activity (96.34%) compared to the standard drug diclofenac sodium (98.81%). Antimicrobial screening revealed moderate to good inhibition against the tested bacterial and fungal strains, with MIC values ranging from 16 to 512 μg/mL. In silico ADME studies indicated favorable pharmacokinetic profiles: all compounds exhibited high gastrointestinal absorption, TPSA values within 78.69–102.7 Å2, logPo/w in the range of 2.6–3.46, and good bioavailability scores, with most compounds complying with Lipinski’s rule of five. Conclusions: A highly efficient and scalable protocol for the synthesis of carbonyl-azetidine derivatives via acid chloride-mediated amidation has been developed. The synthesized compounds demonstrated promising anti-inflammatory and antimicrobial activities, with PP-S1-C5 emerging as the most potent anti-inflammatory agent. Favorable in silico pharmacokinetic properties suggest these compounds warrant further investigation as potential therapeutic candidates for inflammatory diseases and bacterial infections.