Chemotherapeutic agents, XVIII: Synthesis of pi-deficient pyrimidines and fused pyrimidines as leishmanicidal agents.

Synthesis of 6-aryl-5-cyano-2-thiouracils 1a-d from the condensation-cyclization of an aromatic aldehyde, thiourea and ethyl cyanoacetate has been described. Alkylation of 1a-d under different reaction conditions with mono- and dihalo-alkanes yielded 2, 3, and 6. Interaction of 1 with POCl3 provided halopyrimidines 8a,b. Nucleophilic substitution on 8 and 3 with aromatic amines gave 9a-d and 7a-d respectively. 6-Chloro-5-nitro-3-methyluracil (11) obtained by nitration of 10 underwent nucleophilic substitution with amines providing 12. Some of the compounds screened as leishmanicides did not exhibit any significant activity.