Methyl iodide → 2,6-Dichloro-4-methylpyridine

Temperature

-78 °C

A solution of n-BuLi (21.1 mL, 33.8 mmol, 1.6 M) in THF was cooled to −78° C. before a solution of 2,6-dichloropyridine (5.0 g, 33.8 mmol) in THF (36 mL) is added dropwise over a period of 20 min. The reaction mixture is stirred at −78° C. for 30 min, and then iodomethane (4.79 g, 33.8 mmol) is added. The mixture is stirred for 30 min before it is quenched with sat. aq. NH4Cl solution at −78° C. The mixture is extracted with diethyl ether, the org. extract is dried over MgSO4, filtered and concentrated. The crude product is purified by CC on silica gel eluting with heptane:EA 19:1 to give 2,6-dichloro-4-methyl-pyridine (2.34 g) as a colourless oil containing the regio isomer 2,6-dichloro-3-methyl-pyridine; LC-MS: tR=0.89 min, [M+1]+=161.97.

1. additionis added dropwise over a period of 20 min
2. stirringThe mixture is stirred for 30 min before it
3. customis quenched with sat. aq. NH4Cl solution at −78° C
4. extractionThe mixture is extracted with diethyl ether
5. extractionextract
6. dry with materialis dried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated
9. customThe crude product is purified by CC on silica gel eluting with heptane:EA 19:1

ORD record

ord-b15b70af4145417e815d1655ce26f7bb

Source dataset

uspto-grants-2013_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08575200B2