Example 15: 4-Nitropyridine (124 mg, 1 mmol) and O-methylhydroxylamine (71 mg, 1.5 mmol) were dissolved in N,N-dimethylformamide (DMF, 2 mL) and the resultant solution was added dropwise to a DMF solution containing tert-butanol (3 mL). Potassium tert-butoxide (336 mg, 3 mmol) and zinc(II) chloride (136 mg, 1 mmol) were sequentially added to the reaction system at 25 °C. After the addition was completed, the reaction mixture was stirred at 25 °C for 1 hour. After completion of the reaction, saturated aqueous ammonium chloride solution (50 mL) was added to the mixture and then extracted with ethyl acetate (80 mL). The organic layers were combined, dried with anhydrous magnesium sulfate, filtered and concentrated. The crude product was separated and purified by silica gel thin layer chromatography (eluent: ethyl acetate/hexane=1/1, v/v) to afford 35 mg of 3-amino-4-nitropyridine in 25% yield.
