tert-Butanol → tert-Butyl (3-Amino-1-phenyl-1H-pyrazol-4-yl)carbamate

Participants

Reaction Steps

A solution of 4-nitro-1-phenyl-1H-pyrazole-3-carboxylic acid (20.0 g, 85.8 mmol), triethylamine (36.0 mL, 257.3 mmol), and diphenylphosphoryl azide (37.8 g, 137.2 mmol) in dioxane (400 mL) and tert-butanol (200 mL) was heated to reflux for 16 hours. The reaction was evaporated to dryness in vacuo, diluted with methylene chloride (400 mL) and treated with trifluoroacetic acid (128 g, 857.7 mmol). The solution was stirred at ambient temperature for 16 hours. The reaction was evaporated in vacuo and the resulting oil diluted with hexanes (750 mL), ethyl acetate (150 mL) and methylene chloride (100 mL). The solids were filtered, washed with above solvent system (hexanes:ethyl acetate;methylene chloride 75:15:10), and dried to give the desired product as yellow solid. 1H NMR (CDCl3) δ 8.43 (s, 1H), 7.62 (m, 2H), 7.48 (m, 2H), 7.37 (m, 1H).

Provenance & Evidence