AN IMPROVED PROCEDURE FOR THE PREPARATION OF N-ARYL SUBSTITUTED 4H-1,4-BENZOTHIAZINE 1,1-DIOXIDE DERIVATIVES

Abstract

An improved procedure for the synthesis of N-aryl substituted 4H-1,4-benzothiazine 1,1-dioxide 2-carboxylic acid-esters derivatives is reported. In this new, efficient methodology. silver nitrate was used as a catalyst for the cyclization of N-aryl-phenylsulfonyl-acrylates 6–11 using potassium carbonate in dimethylformamide to the corresponding title compounds in high yields.

Key Words:

• 4H-1,4-Benzothiazine-1,1-dioxide
• N-aryl-phenylsulfonylacrylates
• silver nitrate
• cyclization reaction