[Cl:1][CH2:2][CH2:3][O:4][C:5]1[CH:14]=[CH:13][C:8]([C:9]([O:11][CH3:12])=[O:10])=[CH:7][C:6]=1[O:15][CH3:16].[N:17]([O-:19])=[O:18].[Na+].C(O)(=O)C.[N+]([O-])(O)=O>O>[CH3:16][O:15][C:6]1[C:5]([O:4][CH2:3][CH2:2][Cl:1])=[CH:14][C:13]([N+:17]([O-:19])=[O:18])=[C:8]([CH:7]=1)[C:9]([O:11][CH3:12])=[O:10]In a 50 mL volume glass flask equipped with a stirrer, a thermometer and a dropping funnel were placed 1.02 g (4.08 mmol) of methyl 4-(2-chloroethoxy)-3-methoxybenzoate (purity: 98%) obtained in Reference Example III-1, 0.03 g (0.40 mmol) of sodium nitrite, and 1.25 mL of acetic acid. The resulting mixture was heated to 40° C. under stirring. To the reaction mixture was dropwise added slowly 1.72 g (16.5 mmol) of nitric acid (60 wt. %), and the mixture was heated to the same temperature for 5 hours. After the reaction was complete, 5 mL of water was added to the reaction mixture, and the aqueous mixture was cooled to 20° C., precipitating a crystalline product. The crystalline product was collected by filtration, washed with 5 mL of water, and dried under reduced pressure, to give 1.12 g (isolated yield: 93.0%, purity: 98% in terms of area percentage determined by high performance liquid chromatography) of methyl 5-methoxy-4-(2-chloroethoxy)-2-nitrobenzoate as a white crystalline product.
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