반응 #5216

반응 방정식

acetic acid

dimethylformamide

tert-butyllithium

6-chloro-2-methoxypyridine

→

6-chloro-2-methoxy-3-pyridinecarboxaldehyde

수율 75.0%

용매

ether

THF

반응 조건

후처리

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

실험 절차

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.

출처