Rapid access to pyrido[1,2,5]triazepin-4-ones through intramolecular nucleophilic aromatic substitution

Several 3-substituted pyrido[1,2,5]triazepin-4-ones and their benzo counterparts have been prepared in three steps from commercial starting materials. The key step involves SNAr-type intramolecular nucleophilic aromatic substitution of the appropriate hydrazone substrates.