2-Amino-4-chlorobenzoic acid → 4-Chloroisatoic anhydride

Temperature

50 °C

To a stirred solution of 2-amino-4-chloro benzoic acid (10 g, 0.058 mmol) in acetonitrile (60 mL, 1 M), was added pyridine (9.4 mL, 0.117 mmol, 2 equiv), and triphosgene (17.3 g, 0.058 mmol, 1 equiv) in dichloromethane (85 mL, 0.7 M). The orange reaction solution was heated at 50° C. for two hours then cooled to room temperature. The solution was diluted with water (50 mL), and the organic and aqueous layers were separated. The aqueous layer was washed with dichloromethane (3×50 mL), and the combined organic layers were washed once with brine (50 mL), and dried over magnesium sulfate. The solvent was removed in vacuo leaving a yellow solid. The solid was titrated with hexanes to yield 7-chloro-1H-benzo[d][1,3]oxazine-2,4-dione (9.1 g, 74%) as a yellow solid.

1. temperaturethen cooled to room temperature
2. customthe organic and aqueous layers were separated
3. washThe aqueous layer was washed with dichloromethane (3×50 mL)
4. washthe combined organic layers were washed once with brine (50 mL)
5. dry with materialdried over magnesium sulfate
6. customThe solvent was removed in vacuo
7. customleaving a yellow solid

ORD record

ord-f0a45271a648437492aa73506c7b4166

Source dataset

uspto-grants-2015_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09126978B2