Methyl iodide → Lithium diisopropylamide

Participants

Reaction Steps

A solution of lithium diisopropylamide was prepared as described in Example 1(i) from diisopropylamine (17.9 g) and n-butyllithium (70.4 ml of a 2.5M solution in hexane) in dry tetrahydrofuran (300 ml) under an atmosphere of dry nitrogen. To this solution at -70° was added 4-methylpyridazine, dropwise with stirring, ensuring that the temperature did not rise above -60°. Iodomethane (27.25 g) was added slowly with stirring, the solution was stirred at -70° for 1 hour and then allowed to warm to room temperature. Water was added and the solution was evaporated to low bulk. The solution was extracted three times with dichloromethane and the combined extracts were dried (Na2SO4) and evaporated. The residue was chromatographed on silica gel using ethyl acetate as eluant. The product fractions were combined and evaporated, and the residual oil was distilled to give the title compound, (10.4 g), b.p. 65°-66° at 0.1 mm.

Provenance & Evidence