Hydrochloric Acid → 2,2,2-Trichloroethyl 1-isopropyl-3-(thiophen-2-yl)-1h-pyrazol-5-ylcarbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-isopropyl-3-(thiophen-2-yl)-1H-pyrazole-5-carboxylic acid (0.68 g, 2.9 mmol) in dioxane (10 mL) was added with triethylamine (0.44 g, 4.3 mmol), diphenylphosphorylazide (0.95 g, 3.5 mmol) and trichloroethanol (0.86 g, 5.8 mmol) and the mixture was heated to 90° C. for 4 h. The mixture was poured into 3 M HCl (40 mL) solution and the product was extracted with EtOAc (2×40 mL). The combined organics were washed with brine, dried (Na2SO4) and concentrated in vacuo. Purification by silica gel chromatography provided 2,2,2-trichloroethyl 1-isopropyl-3-(thiophen-2-yl)-1H-pyrazol-5-ylcarbamate (0.88 g, 80% yield) as a white solid. 1H NMR (400 MHz, Acetone-d6): δ 7.36-7.34 (m, 3H), 7.07 (dd, J=5.6 Hz, 4.0 Hz, 1H), 6.52 (s, 1H), 5.83 (t, J=7.2 Hz, 3H), 4.95 (s, 2H), 4.66-4.62 (m, 1H), 1.45 (d, J=6.8 Hz, 6H); MS (ESI) m/z: 382.0 (M+H+).

Provenance & Evidence