Isoamyl Nitrite → ethyl 1-[4-(trifluoromethoxy)phenyl]-1H-pyrazole-4-carboxylate

Participants

Reaction Steps

A solution of aminopyrazole 115 (1.850 g, 5.87 mmol) and isoamyl nitrite (0.83 mL, 6.18 mmol) in THF (20 mL) was refluxed for 14 h, then further isoamyl nitrite (0.83 mL, 6.18 mmol) was added and the solution was refluxed for 6 h. The solvent was removed under reduced pressure to give a solid, which was recrystallised (EtOH) to give ethyl 1-[4-(trifluoromethoxy)phenyl]-1H-pyrazole-4-carboxylate (116) (1.527 g, 87%) as white flakes: mp 114-116° C.; 1H NMR (CDCl3) δ 8.38 (d, J=0.5 Hz, 1H), 8.10 (s, 1H), 7.74 (d, J=9.1 Hz, 2H), 7.34 (d, J=9.1 Hz, 2H), 4.35 (q, J=7.1 Hz, 2H), 1.38 (t, J=7.1 Hz, 3H). APCI MS m/z 301 [M+H]+.

Provenance & Evidence