A Convenient Synthesis of Some New Bioactive Diheterocylic Thioether and Thiazolopyrimidine Derivatives

2-Carbethoxymethylthiopyrimidinone derivative 1b was utilized for the synthesis of some new diheterocyclic thioethers via its reaction with some acetals followed by cyclization of the products with 2-aminoheterocyclic compounds or through the reaction of 1b with p-tolyldiazonium chloride followed by the reaction of the product with active methylene compounds. Also, some new thiazolopyrimidines were synthesized from 2-mercaptopyrimidine 1a or from 5-pyrimidinylmercaptoacetic acid derivative 1c. The molluscicidal activity of some synthesized compounds towards Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni, was investigated.