Reaktion #50538

Reaktionsgleichung

ammonium chloride

n-butyl lithium

4-bromo-2-(4-methylphenyl)pyridine

dimethylformamide

→

4-formyl-2-(4-methylphenyl)pyridine

Lösungsmittel

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto warm slowly to room temperature over a period of 2 hours
2. 2
   SonstigeThe mixture was partitioned between methylene chloride and water
3. 3
   Sonstigethe organic layer separated
4. 4
   Trocknendried over sodium sulfate
5. 5
   Sonstigethe solvent evaporated under reduced pressure
6. 6
   Sonstigethe residue flash-chromatographed on silica gel
7. 7
   Wascheneluting with 20% ethyl acetate in heptane

Vorschrift

A solution of 4-bromo-2-(4-methylphenyl)pyridine (3.2 g) in 30 ml of tetrahydrofuran was cooled to -70° C., and 1.6M n-butyl lithium (8.1 ml) was added. The solution was stirred for 15 minutes at -70° C., and then dimethylformamide (1.3 ml) added. The mixture was allowed to warm slowly to room temperature over a period of 2 hours, and aqueous saturated ammonium chloride solution added. The mixture was partitioned between methylene chloride and water, the organic layer separated and dried over sodium sulfate, the solvent evaporated under reduced pressure, and the residue flash-chromatographed on silica gel, eluting with 20% ethyl acetate in heptane, to yield 0.81 g of 4-formyl-2-(4-methylphenyl)pyridine, m.p. 66° C.

Quelle