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, and the mixture was stirred. Diphenylphosphoryl azide (3.13 ml) was then added at room temperature and stirring was continued for 30 minutes at room temperature under a nitrogen atmosphere. Heated stirring was then carried out at 90° C. for 30 minutes and at 100° C. for 4 hours. The reaction mixture was cooled to room temperature. Ethyl acetate (25 ml) was added, and the reaction mixture was stirred for 30 minutes while cooling on ice. The precipitated crystals were collected by filtration and washed with diethyl ether. The crystals were then dried under aeration for 1 hour at room temperature to give the title compound as colorless crystals (3.92 g; 65.5%).

Provenance & Evidence