Microwave or conventional heating of pyrrolo and pyrido[2,1-c][1,4]benzodiazepines in boiling phosphorus oxychloride led to rearranged products like benzo[h][1,6]naphthyridine and azepino[3,2-c]quinoleine and not to cyclopenta[b] [1,6]benzodiazepin and tetrahydrodibenzo[b,f][1,4]diazepine as initially described. (C) 2000 Elsevier Science Ltd. All rights reserved.