Collect. Czech. Chem. Commun. 1990, 55, 1223-1227

Titanium-mediated Dieckmann condensation

Marcel Pátek

Research and Development Division, Spolana Chemical Works, 277 11 Neratovice


The Dieckmann condensation of alkyl 2-(N-methyl-N-(alkoxycarbonylmethyl)sulfamoyl)-benzoates Ia and Ib with titanium tetrachloride-tert-amine or butyltitanium ate complex III affords alkyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxides IIa and IIb which are the piroxicam intermediates.