620-08-6

31872-62-5

The general procedure for the synthesis of 4-methoxy-3-nitropyridine from 4-methoxypyridine was as follows: 4-methoxypyridine (0.5 mL, 4.9 mmol) was slowly added dropwise to concentrated sulfuric acid (5 mL) cooled in an ice bath, and the dropwise time was controlled to be within 20 seconds. Subsequently, fuming nitric acid (5 mL) was added to the reaction mixture and the mixture was heated and reacted at 70 °C for 2.5 days. After completion of the reaction, the mixture was cooled to room temperature and then carefully poured into ice water. The pH of the mixture was adjusted to alkaline with solid potassium carbonate (K2CO3). The mixture was partitioned between water (H2O) and ethyl acetate (EtOAc) to separate the organic and aqueous layers. The aqueous layer was extracted once more with ethyl acetate. The organic layers were combined, washed sequentially with water and brine, and then dried over anhydrous magnesium sulfate (MgSO4). The dried organic phase was filtered and concentrated in vacuum to give a yellow powdery product 4-methoxy-3-nitropyridine 0.7 g in 92% yield. The structure of the product was confirmed by 1H NMR (CDCl3, 300 MHz) and LC-MS: 1H NMR δ 9.02 (s, 1H), 8.65 (d, J = 5.8 Hz, 1H), 7.04 (d, J = 5.9 Hz, 1H), 4.05 (s, 3H); LC-MS m/z 155 (M + 1, 100%), retention time ( Rt) 0.5 min.