A series of 6-aryl-5-cyano-2-thiouracil derivatives (1a-d) was synthesized by the reaction of ethyl cyanoacetate with thiourea and aldehydes. These products were used as intermediate compounds for the synthesis of a number of thiouracil derivatives (2a-d to 10a-d). All compounds were screened for antibacterial and antifungal activities. Some of the prepared compounds, 6-(4-fluorophenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide (2a), 4-oxo-2-thioxo-6-(3,4,5-trimethoxyphenyl)-1,2,3,4-tetrahydropyrimidine-5-carboxamide (2d), 6-(4-fluorophenyl)-4-hydrazino-2-thioxo-1,2-dihydropyrimidine-5-cabonitrile (7a) and 4-hydrazino-2-thioxo-6-(3,4,5-trimethoxyphenyl)-1,2-dihydropyrimidine-5-carbonitrile (7d) revealed promising antimicrobial activity.
