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The preparation of 2,N,N-trimethyl-5-nitrobenzamide utilized the procedure described in U.S. Pat. No. 4,942,163. The reaction mixture of 2-methyl-5-nitrobenzoic acid (5 g, 27.6 mmol) and thionyl chloride (16.4 g, 138 mmol) was refluxed overnight. The excess thionyl chloride was removed by vacuum distillation to afford 2-methyl-5-nitro-benzoyl chloride as a solid residue. This material was dissolved in methylene chloride (30 mL) and added dropwise with stirring to a commercial 40% dimethylamine solution (30 g, 270 mmol) maintaining the temperature at 0 to 12° C. After complete addition, the reaction mixture was stirred at room temperature for 2 h. The reaction mixture was diluted with water and extracted with methylene chloride. The combined organic extracts were washed with water, dried and concentrated. The residue was purified by column chromatography with n-hexane-ethyl acetate (3:1) to afford amide as a solid (5.46 g, 95%). The identity was verified by 1H NMR

1. temperaturewas refluxed overnight
2. customThe excess thionyl chloride was removed by vacuum distillation