Azinoiminophosphorane mediated synthesis of 5 H , 7 H ‐1,2,4‐triazolo[1,5‐ c ][1,3]benzoxazepin‐7‐ones and 6 H ,8 H ‐1,2,4‐triazolo‐[1,5‐ c ][1,3]oxazepin‐6‐ones

The aza‐Wittig reactions of benzophenone‐, acetophenone‐ and benzaldehyde l‐[(triphenylphosphoranyl‐idene)amino]ethylidenehydrazones (4) with phthalic anhydride, 2,3‐dimethylmaleic anhydride and 7‐oxabi‐cyclo[2,2,l]hept‐5‐ene‐2,3‐dicarboxylic anhydride ( 5a ) provide a new route to 5 H ,7 H ‐1,2,4‐triazolo[1,5‐ c ]‐[1,3]benzoxazepin‐7‐ones 8a‐c or 6 H ,8 H ‐1,2,4‐triazolo[1,5‐ c ][1,3]oxazepin‐6‐ones 8d‐h via the thermal reaction of the expected azinoimine lactones 6 .