Sodium Acetate → Ethyl 5-amino-1-(4-(trifluoromethoxy)phenyl)-1H-pyrazole-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of ethyl (2E)-2-cyano-3-ethoxy-2-propenoate (113) (1.87 g, 11.1 mmol), 4-(trifluoromethoxy)phenylhydrazine hydrochloride (114) (2.286 g, 10.00 mmol) and NaOAc (0.90 g, 11.0 mmol) in AcOH (7.5 mL) and water (2.5 mL) was heated to 100° C. under N2 for 15 h. The mixture was poured onto ice, and the resulting precipitate was filtered and recrystallised (MeOH/water) to give ethyl 5-amino-1-[4-(trifluoromethoxy)phenyl]-1H-pyrazole-4-carboxylate (115) (2.965 g, 94%) as white flakes: mp 102-103° C.; 1H NMR [(CD3)2SO] δ 7.73 (s, 1H), 7.68 (d, J=9.1 Hz, 2H), 7.53 (d, J=9.1 Hz, 2H), 6.41 (br s, 2H), 4.22 (q, J=7.1 Hz, 2H), 1.27 (t, J=7.1 Hz, 3H). APCI MS m/z 316 [M+H]+.

Provenance & Evidence