Synthesis, chemical reactivity and fungicidal activity of pyrido[1,2-b][1,2,4]triazine derivatives

the synthesis of some new pyrido[1,2-b][1,2,4]triazines (2-12) was achieved by cyclocondensation of 4-aryl-1,6-diamino-2-oxo-1,2-dihydropyridine-3,5-dicarbonitriles (1a, b) with α,β-bifunctional compounds. pyrido[1,2:2′,3′]triazino[5′,6′-f]triazines (13-14) were also prepared. the behavior of 1a, b toward interactions with indole-2,3-dione and its n-acetyl analogue have been studied under different reaction conditions. the structures of the new products have been deduced from elemental analysis and spectral data (uv, ir, 1h nmr, 13c nmr and mass spectra). the new synthesized compounds were screened for their antifungal activities.