Heterocycles with a benzothiadiazepine moiety. 5. Derivatives of pyrrolo[2,1-d][1,2,5]benzothiadiazepine, a novel tricyclic ring

The synthesis of pyrrolo[2,1-d][1,2,5]benzothiadiazepin-7(6H)-one 5,5-dioxide has been achieved by reaction between 2-(1H-pyrrol-1-yl)benzenesulfonamide and triphosgene. N-Ethylation of the tricyclic derivative afforded 6-ethylpyrrolo[2,1-d][1,2,5] benzothiadiazepin-7(6H)-one 5,5-dioxide, also obtained by the action of trifosgene on N-ethyl 2-(1H-pyrrol-1-yl)benzenesulfonamide. Preparation of pyrrole derivatives from 2-aminobenzenesulfonamide and its N-ethyl derivative by Clauson-Kaas procedure required preliminary protection of the sulfonamide function.