Synthesis of 5-arylpyrrolo[2,1-c][1,4]benzodiazepines under mild cyclodehydration conditions

The efficiency of a cyclodehydration reaction leading to benzodiazepinones is markedly improved by N-methylation of the amide link connecting the nucleophile and the electrophile, which is attributed to its favouring both the more reactive E-rotamer and the exit of the leaving group.