تفاعل #5216

معادلة التفاعل

acetic acid

dimethylformamide

tert-butyllithium

6-chloro-2-methoxypyridine

→

6-chloro-2-methoxy-3-pyridinecarboxaldehyde

المردود 75.0%

المذيبات

ether

THF

ظروف التفاعل

المعالجة

1. 1
   workup.STIRRINGthe mixture was stirred at this temperature for 1.5 h
2. 2
   درجة الحرارةto warm to room temperature over a 30- min period
3. 3
   غسيلThe organic phase was washed with saturated aqueous NaHCO3 (100 mL) and brine (100 mL)
4. 4
   تجفيفwas dried over MgSO4
5. 5
   تركيزConcentration
6. 6
   أخرىafforded the crude product as a light yellow solid which
7. 7
   أخرىwas recrystallized from hexanes

الإجراء التجريبي

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.

المصدر