Sodium Hydroxide → 1-Oxo-1,3-dihydroisobenzofuran-6-carbaldehyde oxime

According to a similar procedure to that described in Example 4-(4), 1-oxo-1,3-dihydroisobenzofuran-6-carbaldehyde (2.42 g, 14.9 mmol) obtained from Example 5-(1), hydroxylamine hydrochloride (1.35 g, 19.4 mmol), and an aqueous solution of sodium hydroxide (1.0N; 19.3 ml, 19.3 mmol) were reacted, and the reaction mixture was worked up to afford 1-oxo-1,3-dihydroisobenzofuran-6-carbaldehyde oxime as a crude solid. According to a similar procedure to that described in Example 4-(4), the crude product obtained above, triethylamine (3.92 g, 39 mmol), and anhydrous trifluoroacetic acid (4.08 g, 19.4 mmol) were reacted, and the reaction mixture was worked up to afford, after extraction and concentration, a solid residue. The residue was subjected to chromatography on a silica gel (50 g) column (eluent; ethyl acetate:dichloromethane=0:1˜1:10) to afford the title compound (1.67 g, 70% yield) as a solid (mp. 195-196° C.).