Synthesis of β‐Hydroxypropanoic Acid Derivatives as Potential Anti‐inflammatory, Analgesic and Antimicrobial Agents

A series of new 3‐(substituted) 3‐hydroxy‐propanoic acid ethyl esters 1a–c , hydrazides 2a–c , thiosemicarbazides 3a–f , and semicarbazides 3g , 3h has been synthesized. Cyclization of compounds 3a–d in basic medium yielded 1,2,4‐triazole‐5‐thiones 4a–d . On the other hand, reaction of hydrazides 2a–c with CS 2 in basic medium afforded 1,3,4‐oxadiazole‐5‐thiones 5a–c . All the synthesized compounds were characterized by their physical and spectral analyses data. The newly synthesized compounds were evaluated for their anti‐inflammatory, analgesic, and antimicrobial activities. Compounds 1c , 3g , 4a , 4b , 4c , and 5c exhibited comparable anti‐inflammatory activity to that of indomethacin and compounds 1c , 4c , and 5c were more analgesics than acetyl salicylic acid. Compounds 4b , 4c , and 5c showed superior GI safety profile (33.3%, 33.3% and 50.0% ulceration) than that of indomethacin (100% ulceration) at 100 mg/kg oral dose. Compounds 4b , 4c , and 5c were also non‐toxic with a median lethal dose (LD 50 ) up to 200 mg/kg. The antibacterial and antifungal screenings identified compounds 3c , 4b , 4d , 5a , and 5b as the most effective against a variety of tested microorganisms.