Abstract
The 4,5,6,7-tetrahydrobenzo[b]thiophene derivative 1 reacted with benzoylisothiocyanate to give N-benzoylthiourea derivative 3. The latter underwent ready cyclization to give the tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivative 4 which was used as the key starting compound for a series of heterocyclization reactions to produce thiophene, pyridine, pyrimidine and pyran derivatives. The cytotoxicity of the newly synthesized products was evaluated using six cancer and one normal cell lines. The toxicity of compounds with the optimal cytotoxicity was measured using shrimp larvae.