Anthranilic Acid → 2-(2-Oxo-propyl)-benzo[D][1,3]oxazin-4-one

Participants

Reaction Steps

To a solution of anthranilic acid (290 g, 2.1 mol) in acetone (1000 mL), diketene (460 mL, 6.0 mol) was added dropwise at room temperature. The solution was stirred at room temperature for 16 hours, and the resulting crystals were collected by filtration, washed with acetone and diethylether, and air dried (170 g yield). The crude crystals were suspended in a mixture of acetic anhydride (320 mL, 3.4 mol) and tetrahydrofuran (1000 mL), and the suspension was heated and stirred at 80° C. for 12 hours. The suspension was cooled to room temperature, and concentrated under reduced pressure, and the resulting crude crystals were collected by filtration. The crystals were washed with acetonitrile and air dried to give the title compound (244 g, 57% yield).

Provenance & Evidence