Synthesis of 5,6-Dihydro-4H-imidazo(1,5-a)(4,1)benzoxazepin-6-ones and Their Transformation into 5,6-Dihydro-4H-imidazo(1,5-a)(1,4)benzodiazepin-6-ones.

Novel 5,6-dihydro-4H-imidazo[1,5-a][4,1]benzoxazepin-6-ones have been prepared from benzoxazepindiones by 1,3-dipolar cycloadditions. Ring opening of the oxygen analogues with amines, chlorination followed by base promoted recyclisation provided 5,6-dihydro-4H-imidazo[1,5-a][1,4] benzodiazepin-6-ones by a novel route.