Potassium Carbonate → [2-(4-Bromopyrazol-1-yl)ethyl]dimethylamine

To a solution of 4-bromo-1H-pyrazole (5 g, 34 mmol) in DMF were added K2CO3 (11.75 g, 85.03 mmol, 2.5 eq.) and 2-chloro-N,N-dimethylethanamine HCl (7.35 g, 51 mmol, 1.5 eq) and the mixture was stirred at RT for 12 h. The mixture was quenched with water and extracted with DCM (3×150 ml). The combined organic layer was washed with water, brine and dried over sodium sulphate. The solvent was distilled off to afford the crude residue which was purified by column chromatography (60-120 silica gel, 1% methanol in DCM) to give the product in 86% yield (6.4 g). 1H NMR (300 MHz, DMSO-d6): δ 7.95 (s, 1H), 7.25 (s, 1H), 4.18 (t, 2H), 2.61 (t, 2H), 2.15 (s, 6H); LC-MS (ESI): Calculated mass: 218.09; Observed mass: 219.8[M+H]+ (RT: 0.439 min).