A convenient synthesis of the novel 5H-thieno[2,3-e]-4,1,2- oxathiazepine ring system via an alkoxycarbenium ion intermediate

Article abstract of DOI:10.1002/jhet.5570360111

3-(Methoxymethoxymethyl)-2-thiophenesulfonamides and 3-hydroxymethyl-N- methoxymethyl-2-thiophenesulfonamides have been shown to undergo cyclization when treated under anhydrous acidic conditions to provide the novel 2,3- dihydro-5H-thieno[2,3-e]-4,1,2-oxathiazepine ring system. Incorporation of a primary sulfonamide group into position seven of the molecule provided compounds which inhibit human carbonic anhydrase II.