2-Amino-6-chlorobenzoic acid → 5-chloro-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

Temperature

50 °C

To a stirred solution of 2-amino-6-chloro benzoic acid (10 g, 0.0583 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), the combined organic layers were washed once with brine (50 mL), and dried over magnesium sulfate. The solvent was removed in vacuo leaving a light brown solid. The solid was titrated with hexanes to yield 5-chloro-1H-benzo[d][1,3]oxazine-2,4-dione (11.3 g, 97%) as a white 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 light brown solid

ORD record

ord-c6d9c11f5e6648e28c0ad61b9d5d05f6

Source dataset

uspto-grants-2015_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09126978B2