HETEROCYCLES WITH A BENZOTHIADIAZEPINE MOIETY .1. SYNTHESIS OF PYRROLO[1,2-B]-SYM-TRIAZOLO[3,4-D][1,2,5]BENZOTHIADIAZEPINE 5,5-DIOXIDE

Condensation of 2-nitrobenzenesulfonyl chloride with 2-ethoxycarbonyl-1H-pyrrole in the presence of potassium tert-butoxide and 18-crown-6 furnished 2-ethoxycarbonyl-1-(2-nitrobenzenesulfonyl)-1H-pyrrole. Reduction of nitro group to amino and subsequent cyclization by heating the aminoester in the presence of 2-hydroxypyridine as a bifuctional catalyst led to 11-oxo(10H)-pyrrolo[1,2-b] [ 1,2,5]benzothiadiazepine 5,5-dioxide. Treatment of the latter compound with di-4-morpholinylphosphinic chloride gave the corresponding phosphinyloxyimine, which on reacting with formylhydrazine underwent intramolecular cyclization to afford the title tetracyclic ring.