Tricyclic aryl-substituted anticoccidial azauracils.

Syntheses of tricyclic aryl-substituted 6-azauracils are described. These compounds showed anticoccidial activity when tested against Eimeria tenella and E. necatrix. Compound activity was correlated with the chemical shift of the azauracil ring proton. No correlation existed between activity and compound lipophilicity. One of the compounds, 2-(11-oxo-6,11-dihydrodibenzo[b,e]thiepin-3yl)-as-triazine-3,5(2H,4H)-dione (23), was tested extensively against E. tenella and E. brunetti both in vivo and in vitro. Compound 23 controlled mortality due to E. tenella at 62 ppm, and it afforded protection as measured by weight gain at 31 ppm. Compound 23 afforded little protection against E. brunetti. In vitro experiments with 23 showed that it exerted a coccidiostatic effect.