Synthesis and Analgesic and Anti‐inflammatory Activity of Some New (6‐Acyl‐2‐benzoxazolinone and 6‐Acyl‐2‐benzothiazolinone Derivatives with Acetic Acid and Propanoic Acid Residues

Abstract

Abstract In this study for developing potent analgesic and anti‐inflammatory compounds, we synthesized 6‐acyl‐2‐benzoxazolinone and 6‐acyl‐2‐benzothiazolinone derivatives with acetic acid and propanoic acid side chain, and performed preliminary screening of their in vivo analgesic and anti‐inflammatory activities at a single dose of 100 mg/kg inmice by a p ‐benzoquinone‐induced writhing test and a Carrageenaninduced hind paw edema model, respectively. We also determined their gastric ulceration effects in the tested animals. Propanoic acid derivatives were generally found to have higher analgesic and anti‐inflammatory activities, and among them, 3‐(6‐benzoyl‐2‐benzothiazolinon‐3‐yl)propanoic acid ( Compound 4 a ) exhibited the highest analgesic and anti‐inflammatory activity. However, all compounds showed lower anti‐inflammatory effects than we observed for indomethacin at 10 mg/kg dose. Consequently, 6‐acyl‐2‐benzoxazolinone/2‐benzothiazolinones having propanoic acid side chain might lead to further studies for developing better candidates with potent analgesic and anti‐inflammatory effects while acetic acid derivatives do not exhibit comparable satisfactory features.