Synthesis of 3-substituted thieno [2, 3-d] pyrimidin-4(3H)-one-2-mercaptoacetic acids and their ethyl esters for pharmacological screening.

3-Substituted thieno [2, 3-d] pyrimidin-4(3H)-one-2-mercaptoacetic acids and their ethyl esters were synthesized from 2-mercaptothieno [2, 3-d] pyrimidin-4(3H]-ones, which were obtained by cyclization of thienylthioureas in acidic medium. Analgesic, anti-inflammatory, and anticonvulsant activities were found in some of these compounds. Significant antimicrobial activity was exhibited by thienylthioureas.