Ethyl Bromide → 1-Ethyl-4-fluoro-5-nitroindoline

Temperature

60 °C

Anhydrous potassium carbonate (0.83 g, 6 mmol) was added to a solution of 4-fluoro-5-nitro-indoline (0.54 g, 3 mmol) in acetone (20 mL). The mixture was stirred at 60° C. for 10 min and ethyl bromide (0.33 mL, 4.50 mmol) added dropwise and the mixture was refluxed for a further 12 h. The mixture was concentrated in vacuo and the residue partitioned between ethyl acetate (50 mL) and water (50 mL). The organic layer was separated and the aqueous layer extracted with ethyl acetate (5×10 mL). The combined organic layers were washed with water (3×10 mL), brine (3×10 mL) and then dried over anhydrous sodium sulphate. Concentration of the organic layer afforded the crude product which was purified by column chromatography over silica gel neutral alumina mesh using 5-8% ethyl acetate in hexane as eluent to afford 1-ethyl-4-fluoro-5-nitro-indoline (0.47 g, 75%) as a yellow solid.

1. temperaturethe mixture was refluxed for a further 12 h
2. concentrationThe mixture was concentrated in vacuo
3. customthe residue partitioned between ethyl acetate (50 mL) and water (50 mL)
4. customThe organic layer was separated
5. extractionthe aqueous layer extracted with ethyl acetate (5×10 mL)
6. washThe combined organic layers were washed with water (3×10 mL), brine (3×10 mL)
7. dry with materialdried over anhydrous sodium sulphate
8. customConcentration of the organic layer afforded the crude product which
9. customwas purified by column chromatography over silica gel neutral alumina

ORD record

ord-1821f6be21de4c92b205b3d21c8b697c

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08993574B2