4-Ethoxy-1,1,1-trifluoro-3-buten-2-one → 3-(Trifluoromethyl)pyrazole

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Reaction Steps

To a stirred solution of hydrazine monochloride (6.62 g, 1.6 eq.) in EtOH (300 mL) was added dropwise compound 231 (10.16 g, 1 eq.) in EtOH (200 mL). The reaction mixture was refluxed for 6 hrs and evaporated to dryness. Water and EtOAc were added to the residue. The organic layer was washed with water and brine, dried over Na2SO4, filtered, and concentrated under reduced pressure to yield compound 233a as a brown solid in 86% yield. 1H NMR (CDCl3, 376 MHz) δ (ppm) 6.66 (d, J=2.30 Hz, 1H), 7.72 (d, J=2.30 Hz, 1H); 19F NMR (CDCl3, MHz) δ (ppm) 61.41 (s, 3F).

Provenance & Evidence