5-Bromo-1-methyl-1H-imidazole → 1-Methylimidazole

Participants

Reaction Steps

Ethylmagnesium bromide (3 M in Et2O, 1.04 mL, 3.11 mmol) was added dropwise to a solution of 5-bromo-1-methyl-1H-imidazole (500 mg, 3.11 mmol) in DCM (6 mL) under a nitrogen atmosphere. The mixture was stirred at room temperature 15 min, then was cooled in an ice bath prior to addition of N-methoxy-N-methylpyridazine-4-carboxamide (419 mg, 2.51 mmol, Intermediate 29, step a). The resulting suspension was stirred at room temperature for 2 hours. The reaction was quenched by addition of saturated aqueous NH4Cl, diluted with water, and extracted three times with EtOAc. The aqueous phase was saturated with NaCl and back-extracted with DCM (three times). The organic phase was dried (Na2SO4), filtered, and concentrated. The residue was purified by flash column chromatography (silica gel, gradient 30-100% CH3CN-DCM, followed by isocratic 5% MeOH-acetone), affording title compound contaminated with 1-methyl-1H-imidazole, the mixture of which was used in the next reaction without further purification.

Provenance & Evidence