Tetrahydrofuran → 4-(4-Amino-3-fluorophenoxy)pyridine-2-carboxamide

Participants

Reaction Steps

Potassium tert-butoxide (214 g) was dissolved in dimethyl sulfoxide (750 ml) and tetrahydrofuran (250 ml) under a nitrogen stream, and a solution of 4-amino-3-fluorophenol ½ naphthalene-2,6-disulfonate (242 g) and 4-chloropyridine-2-carboxamide (100 g) in dimethyl sulfoxide (1000 ml) was added dropwise to the solution with stirring and cooling on ice. The reaction mixture was stirred at room temperature for 30 minutes, then in an oil bath at 90° C. (external temperature) for 2 hours. The reaction mixture was allowed to cool down to room temperature, and water (3000 ml) was added, and the reaction mixture was stirred for 2 hours. The precipitated crystals were collected by filtration, and washed with water (500 ml, twice). The residue was suspended in water (2000 ml), stirred for 30 minutes, collected by filtration again, and washed with water (500 ml, twice). Drying by hot air at 60° C. gave the title compound (119 g, 75.3%).

Provenance & Evidence