A highly efficient synthetic methodology for the preparation of 2-thioxocytosine was achieved by the nucleophilic addition of thiourea to α-cyanocinnamonitrile followed by intramolecular cyclization. The reaction smoothly proceeds in the presence of K2CO3-NPs as mild basic catalyst with yield 85%. The product was annulated to new imidazo[1,2-c]pyrimidine derivatives. Besides, Schiff base and acylated pyrimidine derivatives were synthesized via condensation or acylation with triethyl orthoformate, formic acid, maleic anhydride, benzoyl chloride or acetic anhydride.