Acetic Acid → 6-Chloro-2-methoxypyridine-3-carbaldehyde

温度

-78 °C

To a solution of tert-butyllithium (1.7M in pentane, 48.5 mL, 83.0 mmol) in 150 mL of THF at -78° C. was added 6-chloro-2-methoxypyridine (8.94 mL, 75.0 mmol) over 5 min. The reaction mixture was stirred at -78° C. for 1 h, then dimethylformamide (7.55 mL, 97 mmol) was added and the mixture was stirred at this temperature for 1.5 h. After the addition of glacial acetic acid (8.6 mL, 150 mmol), the reaction mixture was allowed to warm to room temperature over a 30- min period, then diluted with ether (200 mL). The organic phase was washed with saturated aqueous NaHCO3 (100 mL) and brine (100 mL), and was dried over MgSO4. Concentration afforded the crude product as a light yellow solid which was recrystallized from hexanes to give 9.6 g (75%) of 6-chloro-2-methoxy-3-pyridinecarboxaldehyde as a white solid: mp 80°-81° C. (mp 62°-64° C.) (See Dainter, R. S.; Suschitzky, H.; Wakefield, B. J. Tetrahedron Lett. 1984, 25, 5693.). 1H NMR (300 MHz, CDCl3) δ 10.31 (s, 1H), 8.07 (d, 1H, J=9 Hz), 7.03 (d, 1H, J=9 Hz), 4.09 (s, 3H); IR (nujol) 1685, 1580, 1565, 1270, 1140, 1090, 1005, 905, 820, 755 cm-1.

1. stirringthe mixture was stirred at this temperature for 1.5 h
2. temperatureto warm to room temperature over a 30- min period
3. washThe organic phase was washed with saturated aqueous NaHCO3 (100 mL) and brine (100 mL)
4. dry with materialwas dried over MgSO4
5. concentrationConcentration
6. customafforded the crude product as a light yellow solid which
7. customwas recrystallized from hexanes

ORDレコード

ord-909f6e9c98fd499ca582667d47b75e98

出典データセット

uspto-grants-1993_09

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US05243050