Water → methyl 1-(2,2,2-trifluoroethyl)-1H-pyrazole-3-carboxylate

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Reaction Steps

Methyl 1H-pyrazole-3-carboxylate (1.0 g, 7.94 mmol) was dissolved in DMF (25 mL) and cesium carbonate (12.9 g, 39.7 mmol) was added. The mixture was cooled to 0 C and 2,2,2-trifluoroethyl methanesulfonate (2.4 mL, 19.8 mmol) was gradually added. The mixture was warmed to room temperature and stirred for 16 h. Water was added and the mixture was extracted with EtOAc (3×25 mL). The combined organic extracts were washed with brine (3×10 mL) and concentrated under vacuum. The residue was purified by FCC, eluting with hexane followed by 0.5% MeOH in DCM to afford the title compound as a yellow oil (0.312 g, 19%). Method D HPLC-MS: MH+ requires m/z=209 Found: m/z=209, Rt=2.08 min (98%).

Provenance & Evidence