Synthesis of new tetraheterocyclic systems by the mixed condensation reactions on [1,2,4]triazolo[4,3-a][1,5]benzodiazepines

We report here a one step synthesis of a new series of bis-[1,2,4-triazolo][4,3-a:3',4'-d][1,5]benzodiazepines 3a-e and [1,2,4]oxadiazolo[5,4-d][1,2,4]triazolo[4,3-a][1,5]benzodiazepines 5a-c by the condensation reactions of diarylnitrilimines and arylonitrile oxides. This 1,3-dipolar cycloaddition is completely regioselective. The structure of these products has been confirmed by H-1, C-13 NMR and mass spectroscopic.