Tetrahydrofuran → 1-Methyl-3-bromo-5-(5-methylpyridin-2-yl)pyrazole

Participants

Reaction Conditions

Reaction Steps

A solution of 1-methyl-3-bromo-5-(nonafluorobutanesulfonyloxy)pyrazole from Step 2 (0.36 g, 0.784 mmol) and tetrakis(triphenylphosphine) palladium (0) (0.09 g, 10 mol %) in dry N,N-dimethylformamide (2 mL) was stirred under nitrogen at 60° C. for 10 min, followed by addition of a solution of 5-methylpyridin-2-ylzinc bromide in tetrahydrofuran (0.5M, 1.8 mL, 0.9 mmol). The solution was stirred at 60° C. for 18 hours then cooled, diluted with water (30 ml), and extracted with ethyl acetate (2×20 mL). The extracts were dried (Na2SO4) and concentrated. Flash column chromatography on silica, eluting with 10% ethyl acetate-isohexane, gave 1-methyl-3-bromo-5-(5-methylpyridin-2-yl)pyrazole (0.081 g, 41%) as a yellow solid. MS (ES+) 252, 254 ([MH]+).

Provenance & Evidence