Novel heterocyclic systems. Synthesis of 10H-pyrrolo[1,2-b][1,2,5]-benzothiadiazocine 5,5-dioxide and related derivatives

The synthesis of 10H-pyrrolo[1,2-b][1,2,5]benzothiadiazocine 5,5-dioxide has been carried out by intramolecular cyclization of 1-(2-formamidomethylphenylsulfonyl)-1H-pyrrole, prepared from the reaction of 1-(2-aminomethylphenylsulfonyl)-1H-pyrrole with ethyl formate. Treatment of the last pyrrole derivative with triphosgene afforded 10H-pyrrolo[1,2-b][1,2,5]benzothiadiazocin-12(11H)-one 5,5-dioxide, which was also prepared by cyclization of 1-(2-methoxycarbamidomethylphenylsulfonyll)-1H-pyrrole. Methylation of the 12-one derivative furnished the corresponding N-11-methyl benzothiadiazepine dioxide. 1-(2-Aminomethylphenylsulfonyl)-1H-pyrrole has been prepared by cleavage of the phthalimido moiety of 1-(2-phthalimidomethylphenylsulfonyl)-1H-pyrrole, obtained by reacting with potassium phthalimide 1-(2 bromomethylphenylsulfonyl)-1H-pyrrole. This compound has been obtained starting from 2-bromomethylbenzensulfonamide by Clauson-Kaas procedure.