HETEROCYCLES WITH A BENZOTHIADIAZEPINE MOIETY .4. SYNTHESIS OF NOVEL TETRACYCLIC RINGS BY INTRAMOLECULAR CYCLIZATION OF 10-BROMOACETYL-10,11-DIHYDRO-11-ETHOXYCARBONYLPYRROLO[1,2-B] [1,2,5] BENZOTHIADIAZEPINE 5,5-DIOXIDE AND ITS DERIVATIVES

Two novel tetracyclic derivatives, namely 5 and 8, have been synthesized by intramolecular cyclization of the 10-bromoacetyl-10,11-dihydro-11-ethoxycarbonylpyrrolo[1,2-b] [ 1,2,5]benzothiadiazepine 5,5-dioxide (3) and, respectively, the bis-methylamide of 11-carboxy-10,11-dihydropyrrolo[1,2-b] [1,2,5]benzothiadiazepine-11-acetic acid 5,5-dioxide (4). The last compound formed when treating with an excess of methylamine either the lactam 5 or the diethyl ester of 11-carboxy-10,11-dihydropyrrolo[1,2-b] [1,2,5]benzothiadiazepine-11-acetic acid 5,5-dioxide (7). An unambiguous synthesis of the diester 7 was achieved to confirm the chemical structure of derivatives 4 and 5.