Abstract The Dieckmann condensation of alkyl 2-(N-methyl-N-(alkoxycarbonylmethyl) sulfamoyl) benzoates IIIa-IIIe with various bases affords alkyl 4-hydroxy-2-methyl-2H-1, 2- benzothiazine-3-carboxylate 1, 1-dioxides IVa-IVe which are intermediates in the synthesis of antiinflammatory drug piroxicam. The yields of benzothiazines IVa-IVe depend mostly on the nature of a base, reaction temperature and solvent used for these condensations. ...
