Ringspaltung cyclischer Azoverbindungen, V¹⁾ 2‐Mesityl‐2H‐benzo[c]‐1.2‐thiazet‐1.1‐dioxid, ein stabiles Benzo‐β‐sultam

Novel Synthesis of N-Methyl-1,2-benzosultams, an Unsuspected Demethylative Intramolecular Cyclization Reaction

“…Alternatively, the expected dimethylamino sulfonyl chloride 15 maybe did form but underwent an internal nucleophilic attack on the sulfonyl chloride to produce intermediate 16 , which upon demethylation led to 3 . This represents a novel synthesis of such a four-membered benzosultam, the literature methods of synthesis being by extrusion of dinitrogen from a 1,1-dioxo-1,2,3,4-thiatriazole formed via intramolecular capturing of an aromatic diazonium with an ortho sulfonamide , or by intramolecular radical cyclization 2 …”