Nitric Acid → 5-fluoro-1,3-dihydro-2H-indol-2-one

Temperature

0 °C

To the solution of 3-fluorophenylacetic acid (1.23 g, 8 mmol) in concentrated H2SO4 (2.0 mL, 40 mmol) at 0° C. was added HNO3 (0.374 mL, 8 mmol) slowly. The resulting reaction mixture was stirred under argon for 2 h at 0° C., and poured into ice-water. The white solid was precipitated, and the aqueous phase was extracted with ethyl acetate. The organic phase was washed with brine, dried with Na2SO4, and concentrated. The crude (5-fluoro-2-nitro-phenyl)-acetic acid was dissolved in acetic acid. To the solution was added iron power (1.79 g, 32 mmol). The reaction mixture was stirred and heated at reflux for 2 h. Then the mixture was concentrated in vacuo. The residue was extracted with ethyl acetate, and The organic layer was separated, washed by aqueous HCl (1N), brine, dried over Na2SO4, concentrated in vacuo to give the desired product (1 g, 82%).

1. customThe resulting reaction mixture
2. customThe white solid was precipitated
3. extractionthe aqueous phase was extracted with ethyl acetate
4. washThe organic phase was washed with brine
5. dry with materialdried with Na2SO4
6. concentrationconcentrated
7. dissolutionThe crude (5-fluoro-2-nitro-phenyl)-acetic acid was dissolved in acetic acid
8. additionTo the solution was added iron power (1.79 g, 32 mmol)
9. stirringThe reaction mixture was stirred
10. temperatureheated
11. temperatureat reflux for 2 h
12. concentrationThen the mixture was concentrated in vacuo
13. extractionThe residue was extracted with ethyl acetate
14. customThe organic layer was separated
15. washwashed by aqueous HCl (1N), brine
16. dry with materialdried over Na2SO4
17. concentrationconcentrated in vacuo

ORD record

ord-34c98cbce86a44fd82bebefd635f9b7c

Source dataset

uspto-grants-2009_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07495007B2