Synthesis of 7-substituted saccharins and 8-substituted oxicams, and a novel saccharin to oxicam transformation

摘要

The 4-hydroxy-1,2-benzothiazine 1,1-dioxide (oxicam) ring system 1 is a common substructure of certain pharmaceutically important antiinflammatory agents. It can conveniently be derived from the 1,2-benzolisothi- Azol-3-(2H)-one-1,1-dioxide (saccharin) system 2 by ring Expansion, and when we recently required a general Access to 8-substituted oxicams we logically looked to 7-substituted saccharins as precursors.