Imidazole → N-(4-bromo-3-methyl-5-isoxazolyl)-2-[(3,4-methylenedioxy)phenoxycarbonyl]-thiophene-3-sulfonamide

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Reaction Steps

Carbonyldiimidazole (530 mg., 3.26 mmol.) was added to a solution of N-(4-bromo-3-methyl-5-isoxazolyl)-2-carboxylthiophene-3-sulfonamide (Example 17) (1.0 g, 2.72 mmol) in dry THF (10 ml). The mixture was stirred at room temperature for 15 minutes. Sesamol (767 mg., 5.44 mmol) and imidazole (185 mg, 2.72 mmol) were added simultaneously. The resulting mixture was refluxed for 1 hour and allowed to cool to room temperature. The solvent was evaporated. The residue was partitioned between 1N HCl and EtOAc. The organic layer was dried (MgSO4). The solid was filtered and the filtrate concentrated to give a yellow oil which was recrystalized from EtOAc/Et2O/Hexane. N-(4-bromo-3-methyl-5-isoxazolyl)-2-[(3,4-methylenedioxy)phenoxycarbonyl]thiophene-3-sulfonamide was obtained as a white powder (494 mg, 37% yield), m.p. 174-176° C.

Provenance & Evidence