Studies on the derivatives of 2-amino-4-p-chlorophenylthiazole-5-acetic acid. I. Syntheses and pharmacological analysis of acylderivatives of 2-amino-4-p-chlorophenylthiazole-5-acetic acid.

A number of new acyl and imidoderivatives of 2-amino-4-p-chlorophenylthiazole-5-acetic acid (II) and its methyl ester (VII) were synthesized. Methyl ester VII heated in benzene solution with acid anhydrides was transformed into adequate acyl derivatives (VIII, IX, X, XIII, XVI). Some of them (X, XIII, XVII) by heating with acetic anhydride underwent cyclization and were transformed into the imido derivatives (XI, XIV, XVIII). Compounds XI, XIV and XVI heated with diluted aqueous solution of sodium hydroxide underwent selective hydrolysis giving the respective dicarboxylic acids XII, XV, XVII. Pharmacological analysis revealed that some of the synthesized preparations exert an anti-inflammatory effect and allow to draw limited relations between chemical structure and pharmacological activity in this group of compounds.