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The general procedure for the synthesis of 2-bromo-4-fluoro-6-nitroaniline from 4-fluoro-2-nitroaniline is as follows: 1. 4-fluoro-2-nitroaniline (10.0 g, 42.55 mmol) was dissolved in dichloromethane (DCM) to prepare a mixture. 2. a mixture of bromine (Br2, 9.9 ml, 130 mmol) in dichloromethane (110 mL, pre-cooled to 0 °C) and acetic acid (HOAc, 75 mL) was slowly added dropwise at 0 °C, with the rate of dropwise acceleration being controlled to keep the internal reaction temperature below 10 °C. 3. After titration, the reaction mixture was stirred at room temperature overnight. 4. The reaction mixture was poured into water (500 mL) to separate the organic phase. 5. The pH of the aqueous phase was adjusted to about 7 with ammonium hydroxide (NH4OH) and then the aqueous phase was extracted with dichloromethane (DCM, 100 mL x 3). 6. The organic extracts were combined, dried with magnesium sulfate (MgSO4), filtered and concentrated in vacuum to give 2-bromo-4-fluoro-6-nitroaniline as a yellow solid (14 g, 93% yield). Mass spectrum (ESI): m/z = 233 [M-1].