反应详情

温度

20 °C

To a suspension of 5-bromo-2-chloro-3-nitropyridine (75.0 g, 1 wt, 1 eq) in methanol (300 mL, 4 vols), is added a solution of sodium methoxide in methanol (25 wt %, 88.6 g, 1.3 eq) over approximately 1 hour so as to maintain the internal temperature at 20±5° C. The mixture is stirred at 20° C. for at least 0.5 hr, then monitored for completion by HPLC. Water (375 mL, 5 vols) is then added to the mixture at such a rate as to maintain the internal temperature below 30° C., then aged at this temperature for at least 0.5 hr. The batch is then concentrated to 6 vols in vacuo. The resulting slurry is allowed to cool to 20-25° C., then collected by vacuum filtration, washed with water and dried in vacuo with a nitrogen bleed at 20-25° C. to constant weight to afford 5-bromo-2-methoxy-3-nitropyridine as a white solid.

1. temperatureto maintain the internal temperature below 30° C.
2. waitaged at this temperature for at least 0.5 hr
3. concentrationThe batch is then concentrated to 6 vols in vacuo
4. temperatureto cool to 20-25° C.
5. filtrationcollected by vacuum filtration
6. washwashed with water
7. customdried in vacuo with a nitrogen
8. custombleed at 20-25° C. to constant weight