Abstract 2-(6-Azauracil-5-yl) benzoic acid (Ib) and its thio analogue Ia give new heterocyclic compounds, 1, 2-dihydro-1, 2, 4-triazino [5, 6-c] isocoumarin-3-one (IVb) and analogous 3- thione IVa, respectively, on treatment with N, N'-dicyclohexylcarbodiimide. A series of substituted 1, 2, 4-triazino [5, 6-c] isoquinolines V-XVI have been prepared from these compounds and from other functional derivatives (II, III) of the acids I.
