tert-Butanol → 4-nitro-1-phenyl-1H-Pyrazol-3-amine

Participants

Reaction Steps

To a solution of 4-nitro-1-phenyl-1H-pyrazole-3-carboxylic acid (1.00 g, 4.29 mmol) in 1,4-dioxane (15 mL) were added diphenylphosphoryl azide (1.44 mL, 6.65 mmol), triethylamine (1.79 mL, 12.9 mmol) and 2-methyl-2-propanol (7.2 mL, 75.3 mmol), and the mixture was heated under reflux for 2 hours under a nitrogen atmosphere. The reaction solution was cooled down to room temperature, and ethyl acetate was added thereto. The mixture was washed successively with water, saturated aqueous sodium bicarbonate solution and saturated brine, dried over anhydrous magnesium sulfate and concentrated in vacuo. The resulting residue was dissolved in chloroform (10 mL), and then trifluoroacetic acid (5 mL) was added thereto. The solution was stirred at room temperature for 1 hour under a nitrogen atmosphere. After the reaction solution was concentrated, ethyl acetate was added to the resulting residue. The solutionwas washedwith saturatedaqueous sodiumbicarbonate solution and saturated aqueous brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo. Diisopropyl ether was added to the resulting residue, and the precipitates were collected by filtration and dried to obtain the title compound (827 mg, 94%).

Provenance & Evidence