Cyclic Oxalylation of Primary N-Substituted Anthranilamides: 1H-Benzo[e][1,4]diazepine-2,3,5(4H)-triones and 11a-Chloro- benzo[e]oxazolo[3,2-a][1,4]diazepine-2,3,5,11(10H,11aH)-tetraones

The anthranilic scaffold plays an important role as a pharmacophore and toxophore in medicinal and agricultural chemistry and contributes to a variety of biological activities [1 – 9]. Although ring-closure reactions of N-unsubstituted anthranilic acid derivates have been extensively elaborated, investigations towards the corresponding chemistry of N-alkyl(aryl)-anthranilic acids remained fragmentary until hitherto. Recent results from our studies directed to bioactive seven-membered heterocycles with the anthranilic skeleton disclosed a facile access to novel and stable 1,4-benzodiazepine-triones 1 and 2 by oxalylation of anthranilic hydroxamates and hydrazides in the presence of imidazole [10, 11] (Fig. 1).