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off-white powder

Step 1: Synthesis of 3-nitro-4-(trifluoromethoxy)benzoic acid 4-(Trifluoromethoxy)benzoic acid (900 mg, 4.37 mmol) was dissolved in concentrated hydrochloric acid. Concentrated sulfuric acid (9 mL) was cooled at 0 °C and a concentrated sulfuric acid (4.5 mL) solution of potassium nitrate (486 mg, 4.80 mmol) was slowly added. The reaction temperature was maintained at 0°C with continuous stirring for 2 hours. After completion of the reaction, the mixture was poured into water (50 mL) and extracted with ethyl acetate (150 mL). The organic phase was washed sequentially with brine (2 x 100 mL), dried over anhydrous sodium sulfate, and concentrated to dryness under reduced pressure to afford the crude product 3-nitro-4-(trifluoromethoxy)benzoic acid (1.05 g, 4.18 mmol, 96% yield, MS/ESI+ m/z 252.1 [M+H]+). The crude product can be used directly in the next reaction without further purification.

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