tert-Butanol → Tert-butyl [4-(4-benzyloxycarbonylamino-3-fluorophenoxy)pyridin-2-yl]carbamate

Participants

Reaction Steps

To a suspension of 4-(4-benzyloxycarbonylamino-3-fluorophenoxy)pyridine-2-carboxylic acid (5.04 g) in tert-butanol (50 ml) was added triethylamine (4.6 ml) at room temperature, followed by stirring. Diphenylphosphoryl azide (3.13 ml) was added thereto at room temperature, followed by stirring under a nitrogen atmosphere at room temperature for 30 min. Then the reaction mixture was heated and stirred at 90° C. for 30 min and at 100° C. for 4 hr. The reaction mixture was allowed to cool down to room temperature. Ethyl acetate (25 ml) was added thereto, and the reaction mixture was stirred in an ice bath for 30 min. Precipitated crystals were collected by filtration and washed with diethyl ether. These crystals were dried under aeration at room temperature for 1 hr to provide the titled compound as colorless crystals (3.92 g, 65.5%).

Provenance & Evidence