Synthesis of Substituted Thienopyrimidines and Their Evaluation as Antibacterial

We have synthesized various substituted thieno(2,3-d)pyrimidines, first by synthesizing ethyl 2-aminothiophene-3- carboxylate (3), by treatment of diethane with ethyl cynoacetate in presence of triethylamine, acetic acid and DMF. Further, the intermediate Ethyl 2-(ethoxycarbonyl)thiophene-3-carboxylate (5) was prepared by compound (3) refluxed with ethyl chloroformate. The key intermediate 3-(3-chloro-4-fluorophenyl) thieno [2, 3-d]pyrimidine-2, 4(1H, 3H)-dione (7) was prepared by cyclisation of compound (5) with 3-chloro-4-fluoro aniline. The nucleophilic substitution of compound 3-(3-chloro-4-fluorophenyl) thieno [2, 3-d]pyrimidine-2, 4(1 H, 3 H)-dione (7) with various aromatic amines(8a-m), aminophenol(8n) gives substituted thienopyrimidines(8a-n). The synthesized new compounds were characterized by MP, TLC, IR and NMR spectra.