Into a 25 ml dry methylene chloride solution of 500 mg (2.78 mmol) of monomethyl isophthalate and 215 μl (2.78 mmol) of DMF was added under N2 atmosphere 546 μl (6.26 mmol) of oxalyl chloride at 0° C., and subsequently, the mixture was returned to room temperature and stirred for one hour. The mixture was added dropwise under an N2 atmosphere to a solution of 1.76 g (8.34 mmol) of 1-hydroxy-2-naphthylhydroxylamine hydrochloride, 2.9 ml (21 mmol) of triethylamine in THF (25 ml), and water (5 ml), followed by stirring as such at room temperature for one hour. The reaction was completed by an addition of 4N hydrochloric acid, and the mixture extracted with methylene chloride. The organic layer was washed with 4N hydrochloric acid, water, and saturated aqueous sodium chloride, and dried over anhydrous magnesium sulfate. The solvent was evaporated under a reduced pressure, and the crude product obtained was subjected to silica gel column chromatography (hexane:ethyl acetate 6:1→4:1) to give 513 mg (55%) hydroxyamic acid.
