Oxygen analogues of the benzodiazepine alkaloids sclerotigenin and circumdatin F

A new type of fused oxazepinones 9a and 9b , which are analogues of sclerotigenin and circumdatin F, were obtained in a two step synthesis from 2‐(2‐amino‐benzoylamino)‐benzoic acid or the corresponding methyl ester. Secondly a new synthesis of circumdatin F arose from this work, where 2‐(2‐propionylamino‐benzoylamino)‐benzoic acid methyl ester was used as an intermediate.