Reaktion #680751

Reaktionsgleichung

4-methoxypyridine

tert-butyllithium

pentane

dimethylformamide

2-Bromomesitylene

→

4-methoxy-pyridine-3-carbaldehyde

Lösungsmittel

brine

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture is warmed to −23° C.
2. 2
   workup.STIRRINGstirred for 3 h
3. 3
   TemperaturThe mixture is cooled again to −78° C.
4. 4
   workup.WAITAfter 1 h
5. 5
   Temperaturwarmed to room temperature
6. 6
   ExtraktionThe mixture is extracted with ether
7. 7
   Trocknenthe combined organic layer is dried over Na2SO4
8. 8
   EinengenConcentration
9. 9
   Wascheneluting with a 0 to 6% methanol-dichloromethane gradient

Vorschrift

A flask is charged with 1.7M tert-butyllithium in pentane (47.1 mL, 80.1 mmol) and THF (20 mL), and cooled to −78° C. 2-Bromomesitylene (6.0 mL, 39 mmol) is added dropwise. The mixture is stirred for 1 h, and 4-methoxypyridine (3.0 mL, 30 mmol) is added dropwise. The mixture is warmed to −23° C. and stirred for 3 h. The mixture is cooled again to −78° C. and dimethylformamide (3.5 mL, 45 mmol) is added. After 1 h, brine (50 mL) is added to the mixture at −78° C. and warmed to room temperature. The mixture is extracted with ether and the combined organic layer is dried over Na2SO4. Concentration followed by silica gel chromatography eluting with a 0 to 6% methanol-dichloromethane gradient gives 4-methoxy-pyridine-3-carbaldehyde. 1H NMR (400 MHz, CDCl3) δ ppm 4.01 (s, 3H), 6.94 (d, J=5.8 Hz, 1H), 8.65 (d, J=5.8 Hz, 1H), 8.90 (s, 1H), 10.46 (s, 1H).

Quelle