Acetyl chloride → 5-chloro-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

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Reaction Conditions

Reaction Steps

Under an atmosphere of nitrogen, isopropyl carbonochloridate (50 ml, 4.50 equiv) was added dropwise to a suspension of 2-amino-6-chlorobenzoic acid (20 g, 116.56 mmol, 1.00 equiv) in 1,4-dioxane (150 ml). The resulting solution was maintained at about 90° C. for 30 minutes, and then cooled to about 50° C. Acetyl chloride (50 ml, 6.00 equiv) was added in one portion, and the solution was maintained at about 50° C. for about 30 minutes. The resulting solids were collected by filtration and purified by silica gel chromatography (ethyl acetate/petroleum ether 10:1) to afford the title product as a gray white solid (17.6 g, yield: 76%).

Provenance & Evidence