Methyl iodide → 4-Bromo-1-methyl-1H-pyrazole-3-carbonitrile

Reaction equation

[H-].[Na+].[Br:3][C:4]1[C:5]([C:9]#[N:10])=[N:6][NH:7][CH:8]=1.[CH3:11]I>CN(C=O)C>[Br:3][C:4]1[C:5]([C:9]#[N:10])=[N:6][N:7]([CH3:11])[CH:8]=1

Participants

Procedure

Add sodium hydride (60 wt % oil dispersion, 700 mg, 17.5 mmol) in several portions under a nitrogen purge to a solution of 4-bromo-1H-pyrazole-3-carbonitrile (2.0 g, 11.6 mmol) in 15 mL of anhydrous DMF at 0° C. Stir the reaction at 0° C. for one hour. Add methyl iodide (0.9 mL, 14.5 mmol) to the mixture and allow to stir and come to room temperature over 1 hour. Pour into 100 mL of ice-water and stir for 15 minutes. Filter off the resulting solid and rinse with 20 mL of water. Dry the solid overnight. Chromatograph (1/9-1/3 EtOAc/hexanes) over silica gel to give the title compound as a white solid (1.38 g, 63%), along with a small amount (100 mg) of the regioisomeric bromide.