Even though benzodiazepines have a strong position in medicinal chemistry, very few synthetic routes to 1 H-1, 4-benzodiazepine-3, 5 (2 H, 4 H)-diones have ever been published and the claimed products have often been poorly characterized. Through the present work several 1 H-1, 4-benzodiazepine-3, 5 (2 H, 4 H)-diones have become available from N-carbamoylmethylanthranilic acids. The required ring closures were ...