A number of new heterocyclic compounds based on the pyrimidine moiety were created, with potential antiparasitic characteristics. The starting material, 4-(4-cyanophenyl)-6-oxo-2-thioxohexahydropyrimidine-5-carbonitrile (1), was synthesized using two methods: a conventional approach involving thiourea, ethyl cyanoacetate, and 4-cyanobenzaldehyde refluxed in ethanol with triethylamine, and a more efficient nanoparticle-catalyzed method using TiO2 or Mn3O4. The chemicals were evaluated against coccidiosis, a parasite illness caused by Eimeria spp. Cytotoxicity tests using Wi38 human lung fibroblasts showed that compound 20 had the lowest IC50 (195.83 ± 1.56 µg/ml), indicating great potency, while compound 11 had the highest IC50 (934.03 ± 5.65 µg/ml), indicating a safer profile. Compounds 16 and 20 inhibited sporulation very completely (~ 98%) at 200 ppm, whereas compound 13 was also …