Hydroxylamine HCl → 6-Fluoro-3-methyl-1,2-benzoxazole

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-(4-fluoro-2-hydroxyphenyl)ethanone (20 g), hydroxyammonium chloride (18.1 g), sodium acetate (16 g) and methanol (500 mL) was stirred at 60° C. for 1 hr. The reaction mixture was added to ice water, and the obtained crystallized product was collected by filtration and dissolved in tetrahydrofuran (400 mL). N,N′-carbonyldiimidazole (22.5 g) and then a solution of triethylamine (22.3 mL) in tetrahydrofuran (100 mL) were added, and the mixture was stirred at 70° C. for 1 hr. The reaction mixture was diluted with diethyl ether, washed with water and then with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure to give the title compound as colorless crystals (13.7 g, 70%).

Provenance & Evidence