Methyl iodide → 6-Ethyl-2-picoline

Participants

Reaction Conditions

Reaction Steps

In a 250-ml 3-neck jacketed reactor flask, 4.3 g (40.2 mmol) of 2,6-dimethylpyridine and 4.06 g (40.2 mmol) of triethylamine were dissolved by addition of 50 ml of anhydrous tetrahydrofuran, and the solution was cooled to −40° C., after which 28.7 ml (46 mmol) of 1.6 M butyllithium in hexane was added dropwise thereto. At the same time, the solution changed to deep red. Next, the solution was stirred for 1 hour, and then warmed to 0° C., after which 5.7 g (40.2 mmol) of methyl iodide was added dropwise thereto, followed by stirring for 1 hour. Then, the reaction product was concentrated, and the concentrate was dissolved in ethyl acetate, washed with water and saline, dried with anhydrous magnesium sulfate, and then concentrated again, thereby obtaining crude 2-ethyl-6-methylpyridine. Subsequently, 3.2 g of the obtained 2-ethyl-6-methylpyridine was placed in a 250-ml 3-neck jacketed reactor flask and dissolved by addition of 4.06 g (40.2 mmol) of triethylamine and 50 ml of anhydrous tetrahydrofuran. The solution was cooled to −40° C., and 28.7 ml (46 mmol) of 1.6 M n-butyllithium in hexane was added dropwise. At this time, the solution changed to deep red. Next, the solution was stirred for 1 hour, and then cooled to 0° C., after which 6.0 g (42 mmol) of methyl iodide was added thereto dropwise. Then, the cooling bath was removed, and the solution was stirred at room temperature for 1 hour, and then concentrated. The concentrate was dissolved in ethyl acetate, washed with water and saline, dried with anhydrous magnesium sulfate, and then concentrated again. The concentrate was purified by column chromatography (stationary phase: silicagel; eluent: n-hexane/ethyl acetate (6/1), thereby obtaining 2 g of 2,6-diethyl pyridine as liquid. The obtained 2,6-diethyl pyridine was analyzed by NMR.

Provenance & Evidence