Sydnone derivatives. Part VII: Synthesis of some novel thiazoles and their pharmacological properties

The synthesis of some 4‐(arylsydnonyl)‐2‐(4‐arylhydrazono‐3‐methyl‐5‐oxo‐2‐pyrazolin‐1‐yl)‐thiazoles by reacting 1‐thiocarboxamido‐3‐methyl‐4‐(arylhydrazono)‐2‐pyrazolin‐5‐ones with different 4‐bromoacetyl‐3‐arylsydnones is described. A few compounds from this series were screened for their anti‐inflammatory, analgesic, and CNS depressant activities. Among the tested compounds 6s, 6d, 6n, and 6u showed significant anti‐inflammatory activity comparable with that of standard drug Ibuprofen. Compounds containing chlorine and carboxylic substituents are more active. 6f, 6r, and 6u showed marked analgesic activity and most of the compounds tested showed promising CNS depressant activity comparable with that of standard drug pentobarbitone.