Methyl iodide → Lithium diisopropylamide

Participants

Reaction Steps

A solution of lithium diisopropylamide was prepared as described in Example 1(i) from diisopropylamine (6.88 g) and n-butyllithium (27.0 ml of a 2.5M solution in hexane) in dry tetrahydrofuran (180 ml) under an atmosphere of dry nitrogen. To this solution at -70° , a solution of 4-ethylpyrimidine (7.35 g) in dry tetrahydrofuran (20 ml) was added dropwise over 0.17 hour. The solution was stirred at -70° for 0.75 hour and then iodomethane (11.60 g) was added. The mixture was stirred for a further 3 hours and then warmed to room temperature. Water was added and the solution was evaporated to low bulk, then partitioned between ethyl acetate and water. The organic layer was separated, the aqueous layer was extracted three times with ethyl acetate and the organic fractions were combined and dried (Na2SO4). Evaporation of the solvent gave an oil which was chromatographed on silica gel, using dichloromethane/ether (9:1) as eluant. The fractions containing the product were combined and evaporated, and the residual oil was distilled to give the title compound, (3.14 g), b.p. 52°-56° at 15 mm.

Provenance & Evidence