General procedure for the synthesis of 5-fluoro-2-nitropyridine from 2-amino-5-fluoropyridine: 2-amino-5-fluoropyridine (6.0 g, 53.51 mmol, 1.0 eq.) was dissolved in concentrated H2SO4 (60 ml) and cooled to 0 °C (solution A). In another flask, hydrogen peroxide (13 ml) was slowly added to concentrated sulfuric acid at 0°C (Solution B). Solution A was added dropwise to solution B at 0°C. The reaction mixture was stirred at room temperature for 16 hours. After completion of the reaction, the mixture was poured into ice-cold water and the product was extracted with EtOAc. The organic layers were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure to give pure 5-fluoro-2-nitropyridine (3.0 g, 39.45% yield). Mass spectrum (electrospray ionization): m/z 142.09 [M + H]+.
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