Water → 5-(5-chloro-2-difluoromethoxyphenyl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-pyrazol-4-ylamine

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-(5-chloro-2-difluoromethoxyphenyl)-4-nitro-1-(2-trimethylsilanylethoxymethyl)-1H-pyrazole (62 g, 148 mmol) in ethanol (600 mL) was added water (200 mL), ammonium chloride (32 g, 590 mmol) and iron powder (41 g, 740 mmol). The mixture was heated at 80° C. for 2 hours then allowed to cool to room temperature. The residual solid was removed by filtration through Celite®. The filtrate was evaporated under reduced pressure, diluted with water and extracted twice with DCM. The combined organic extracts were washed with water and brine, dried (MgSO4) and evaporated to afford a dark oil. The oil was purified by flash chromatography on silica eluting with 0-25% EtOAc in DCM. Appropriate fractions were collected and the solvent removed in-vacuo to afford 5-(5-chloro-2-difluoromethoxyphenyl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-pyrazol-4-ylamine as a brown oil (30.8 g, 54%). 1H NMR (400 MHz, CDCl3) δ: (ppm) 7.56 (d, 1H), 7.44 (dd, 1H), 7.34 (s, 1H), 7.30-7.25 (m, 1H), 6.37 (t, 1H), 5.29 (s, 2H), 3.56 (t, 2H), 0.88 (dd, 2H), 0.00 (s, 9H).

Provenance & Evidence