Methyl iodide → 3,5-Dibromo-4-methylpyridine

Participants

Reaction Conditions

Reaction Steps

Under argon, an n-butyllithium solution in hexane (1.6N, 16 ml) is added dropwise to a diisopropylamine solution (3.6 ml, 1.02 equiv.) in anhydrous THF (145 ml) kept at −10° C. The reaction mixture is cooled to −78° C. and then a 3,5-dibromopyridine solution (5.92 g, 25 mmol) in THF (200 ml) cooled to −78° C. is added dropwise. The reaction mixture is stirred for 30 min and then methyl iodide (2.17 ml, 1.4 equiv.) is added dropwise. The stirring is maintained for 2 h at −78° C. A saturated aqueous NH4Cl solution (120 ml) is added. After evaporation of the solvents, the reaction mixture is extracted with AcOEt. The organic phase is washed with brine, dried over MgSO4 and evaporated. The yellow solid obtained is taken up in AcOEt. The suspension is filtered. The filtrate is evaporated and then the residue is chromatographed on silica gel, eluting with a petroleum ether/AcOEt (97.5/2.5) mixture.

Provenance & Evidence