Sodium Carbonate → 4-bromo-1-cyclopentyl-1H-pyrazole

Participants

Reaction Steps

To a suspension of Na2CO3 (13 g, 124 mmol) in CH2OH2 (100 mL) was added 1-cyclopentyl-1 H-pyrazole (8.35 g, 62 mmol) and Br2 (3.2 mL). The resulting mixture was stirred at RT overnight. The solid was removed by filtration and the filter cake was washed with DCM. The combined filtrates were washed with water, brine and dried over anhydrous MgSO4. The solvent was concentrated to dryness to give 4-bromo-1-cyclopentyl-1 H-pyrazole (14 g, 93%). 1H NMR (300 MHz, CDCl3): δ7.46 (s, 1 H), 7.44 (s, 1 H), 4.64 (m, 1 H), 2.18-1.67(m, 8 H); MS (ESI) m/z: 215.0 [M+H]+.

Provenance & Evidence