Synthesis of Methyl 4-Aryl-4-oxo-2-{4-[(1,3-thiazol-2-yl)-sulfamoyl]phenylamino}but-2-enoates and Their Reactions with Ninhydrin

The reaction of methyl aroylpyruvates with 2-(4-aminobenzenesulfonamido)thiazole (norsulfazole) in acetic acid-ethanol (1: 1) afforded methyl (2Z)-4-aryl-4-oxo-2-{4-[(1,3-thiazol-2-yl)sulfamoyl]phenyl-amino} but-2-enoates which reacted with ninhydrin in glacial acetic acid to give 4-aroyl-3-{4-[(1,3-thiazol-2-yl)-sulfamoyl]phenylamino} spiro[2,5-dihydrofuran-5,2′-indane]-2,1′,3′-triones.