Synthesis of a novel heterocyclic ring system by way of highly regio- and chemoselective 1,3-dipolar cycloaddition of nitrilimines to 1,3,4-benzotriazepin-5-one derivatives

The 1,3-dipolar cycloaddition reaction of nitrilimines to 3,4-dihydro-4-methyl-5H-1,3,4-benzotriazepin-5-ones 1 led, with complete regio- and chemoselectivity, to [1,2,4]triazolo[1,3,4]benzotriazepines 3, the structures of which were assigned by spectral methods and X-ray crystallographic analysis.