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

HRID 889608Notes

Reaction equation

[C:1](Cl)(=O)[O:2]C(C)C.[NH2:8][C:9]1[CH:17]=[CH:16][CH:15]=[C:14]([Cl:18])[C:10]=1[C:11]([OH:13])=[O:12].C(Cl)(=O)C>O1CCOCC1>[Cl:18][C:14]1[C:10]2[C:11](=[O:13])[O:12][C:1](=[O:2])[NH:8][C:9]=2[CH:17]=[CH:16][CH:15]=1

Participants

Conditions

Temperature: 90 °C

Procedure

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%).

Workup

temperaturecooled to about 50° C
temperaturethe solution was maintained at about 50° C. for about 30 minutes
filtrationThe resulting solids were collected by filtration
custompurified by silica gel chromatography (ethyl acetate/petroleum ether 10:1)

Sources & evidence

ORD record: ord-cf399aa0ac834f38ba619f55ebec2ce2
Source dataset: uspto-grants-2012_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08252933B2

Reaction notes

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