Condensation of 3-aryl-4-formyl isoxazoles with 1,2-diamines led to the formation of 3-aryl-(6′,7′-benzo-1,5-heptadiazino)(3,2-d)-isoxazoles or isoxazolo-[5,4-b]-benzodiazepines and 3,10-diaryl-6,7,14,15-tetrhydro-13 H ,16H-diisoxazole-(4,5-b;4,5-l)(1,4,8,11)-tetra-aza-cyclo -tetra-deca-4,14-diones, the novel seven- and 14-membered heterocyclic systems. Similar compounds are of great importance in medicinal chemistry. ... Condensation of 3-aryl-4-formyl ...