127861-96-5Relevant articles and documents
CONDITIONS OF THE DIECKMANN CONDENSATION OF ALKYL 2-(N-METHYL-N-(ALKOXYCARBONYLMETHYL)SULFAMOYL-BENZOATES
Patek, Marcel,Hampl, Frantisek
, p. 3267 - 3277 (2007/10/02)
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.Hitherto undescribed esters IIIb-IIIe were sythesized and their structures were confirmed by 1H and 13C NMR, and mass spectra.