Epichlorohydrin → 3-(3,4-dichloro-phenyl)-1-oxiranylmethyl-1H-pyrazole

Participants

Reaction Steps

A stirred solution of 3-(3,4-dichlorophenyl)pyrazole (300 mg, 1.4 mmol) in DMF (5 mL) was treated with cesium carbonate (550 mg, 1.69 mmol) and epichlorohydrin (1.1 mL, 14.0 mmol) at room temperature for 18 h. The crude reaction mixture was then partitioned between EtOAc (50 mL) and water (35 mL). The aqueous phase was further extracted (2×50 mL) and the combined organic layers were washed with brine, dried (Na2SO4), filtered and concentrated under reduced pressure to yield crude product. Purification by column chromatography (silica, 25% EtOAc/hexanes) afforded 308 mg (82%) of the title compound. 1NMR (400 MHz, CDCl3): 7.83 (d, J=2 Hz, 1H), 7.54 (dd, J=2, 8 Hz, 1H), 7.44 (d, J=2 Hz, 1H), 7.38 (d, J=8 Hz, 1H), 6.48 (d, J=2 Hz, 1H), 4.45 (dd, J=3, 9.7 Hz, 1H), 4.12 (dd, J=6, 15 Hz, 1H), 3.31 (m, 1H), 2.81 (dd, J=4.0, 4.6 Hz, 1H), 2.47 (dd, J=2.6, 4.7 Hz, 1H).

Provenance & Evidence