synthesis of 1,2,4-triazino [3,4-c] [i ,2,4] benzotriazine, a novel heterocyclic system

3-mercapto-1,2,4 benzotriazine (1) was methylated by methyl iodide in the presence of base to afford 1,2-dihydro-3-methyhercapto-1, 2,4 benzotriazine (2). the latter was reacted with hydrazine hydrate to give the corresponding 3-hydrazine derivative (3). compound (3) on condensation with phenacyl bromide gave 3- phenacyl hydrazino l,2,4-benzotriazine (4). ppa cyclization of the ketone (4) yielded lh, 2h, 10h-4-phenyl-triazino [3,4-c]- 1,2,4-benzotriazine (5). triazino benzotriazine (5) is a novel heterocyclic system and is reported for the first time.