tert-Butanol → 4-Benzyloxy-3-(tert-butoxycarbonyl)amino-1-(2-fluorophenyl)pyrazole

Participants

Reaction Steps

Diphenylphosphoryl azide (2.16 mL) was added to a mixture of 4-benzyloxy-1-(2-fluorophenyl)pyrazole-3-carboxylic acid (2.09 g) and triethylamine (1.39 mL) in a mixture of 1,4-dioxane (25 mL) and tBuOH (25 mL). The mixture was refluxed for 1 hour and cooled to room temperature. The mixture was diluted with EtOAc and washed with H2O, 10% aq. citric acid, sat. NaHCO3 and brine. The organic layer was dried over anhydrous magnesium sulfate and concentrated in vacuo. The residue was purified by flash chromatography on silica gel (EtOAc/hexane 1/19, 1/9, 1/4 and 1/2) to yield 1.30 g of the title compound.

Provenance & Evidence