Potassium Carbonate → Ethyl (4-chloro-2-fluoro-5-hydroxyphenyl)carbamate

The resulting ethyl N-(2-fluoro-4-chloro-5-methoxycarbonyloxyphenyl)carbamate (45.2 g, 155 mmol) was reacted with potassium carbonate (21.4 g, 155 mmol) and water (100 ml) for 2 hours while heating under refluxing. After completion of the reaction, the mixture was cooled to room temperature, the solvent was distilled off under reduced pressure. The residue was made acidic by adding 1N hydrochloric acid (300 ml), and extracted with ethyl acetate (100 ml×3 times). The organic layer was washed with water, dried, the solvent was distilled off under reduced pressure, and the precipitated solid was isolated by filtration. The solid was recrystallized from chloroform-hexane to obtain ethyl N-(2-fluoro-4-chloro-5-hydroxyphenyl)carbamate as white crystals (35.2 g, 97% yield).

1. temperaturewhile heating
2. temperatureunder refluxing
3. customAfter completion of the reaction
4. distillationthe solvent was distilled off under reduced pressure
5. additionby adding 1N hydrochloric acid (300 ml)
6. extractionextracted with ethyl acetate (100 ml×3 times)
7. washThe organic layer was washed with water
8. customdried
9. distillationthe solvent was distilled off under reduced pressure
10. customthe precipitated solid was isolated by filtration
11. customThe solid was recrystallized from chloroform-hexane

ORD record

ord-c4adfcf9658249e09ea75294f52d2e8a

Source dataset

uspto-grants-1995_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05464811