Hydrochloric Acid → n-(3,4-Dimethyl-5-isoxazolyl)-5-phenylthiophen-2-sulfonamide

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Reaction Steps

HCl (3 ml of a 3N aqueous solution) was added to a solution of N-(methoxyethoxymethyl)-N-(3,4-dimethyl-5-isoxazolyl)-5-phenylthiophene-2-sulfonamide (100 mg, 0.24 mmol) in 3 ml of 95% ethanol and the resulting mixture was refluxed for 6 h. The mixture was then concentrated, diluted with 5 ml of water, neutralized with saturated aqueous sodium bicarbonate solution and acidified to pH 4 using glacial acetic acid. The mixture was extracted with ethyl acetate (2×25 ml) and the combined organic extract was washed with brine (1×5 ml), dried and evaporated. Flash chromatography of the residue on silica gel using 2% MeOH/CHCl3 and further purification by reverse phase HPLC yielded 33.4 mg (42%) of the pure sulfonamide as a white powder, m.p. 176°-178° C.

Provenance & Evidence