Reaction #1016

Reaction equation

3,5-Dichloropyridine

LDA

sodium hydrogen carbonate

iodomethane

→

title compound

Yield 53.0%

3,5-Dichloro-4-methylpyridine

Yield 53.0%

Solvents

THF

THF

dichloromethane

Conditions

Workup

1. 1
   workup.STIRRINGthe reaction mixture stirred for a further 1.5 h at -70° C
2. 2
   Otherthe organic phase separated
3. 3
   Dryingdried (MgSO4)
4. 4
   Concentrationconcentrated in vacuo

Procedure

3,5-Dichloropyridine (2.04 g, 13.5 mmol) in THF (5 ml) was added dropwise to a solution of LDA [prepared from diisopropylamine (1.9 ml, 13.5 mmol) and n-butyllithium (1.6M, 8.4 ml, 13.5 mmol)] in THF (25 ml) at -70° C. After stirring at this temperature for 5 min, iodomethane (0.85 ml, 13.5 mmol) was added and the reaction mixture stirred for a further 1.5 h at -70° C. Saturated sodium hydrogen carbonate solution (20 ml) and dichloromethane (20 ml) was added and the organic phase separated, dried (MgSO4), and concentrated in vacuo. The residue was subjected to chromatography (SiO2 ; Et2O-hexane, 1:3) to afford the title compound (1.16 g) as a pale yellow solid; δH (CDCl3) 2.46 (3H, s, Me), and 8.36 (2H, s, pyridine H2, H6).

Source