1-Bromo-4-fluoro-2-nitrobenzene → 7-bromo-4-fluoro-1H-indole

Temperature

-40 °C

1.12 g (5 mmol) of 2-bromo-5-fluoro-nitrobenzene were dissolved in 50 ml THF. At a temperature of −45° C. 15 ml of a 1M vinyl magnesium bromide solution in THF were added under nitrogen in such a way that the temperature did not exceed −40° C. After complete addition the dark solution was stirred for 30 min at −40° C. The reaction mixture was quenched with 10 ml aqueous saturated ammonium chloride solution and extracted twice with diethyl ether. The combined organic layers were washed once with saturated aqueous sodium chloride solution, dried over sodium sulfate, filtered and the solvent was evaporated. The residue was dissolved in DCM and purified by column chromatography (100 g silica gel; heptane/EtOAc 9:1) to yield 501 mg (47%) 7-bromo-4-fluoro-1H-indole as an orange oil. MS (EI) 213.0 (100), 215.0 (100) (M)+.

1. customAt a temperature of −45° C
2. customdid not exceed −40° C
3. additionAfter complete addition the dark solution
4. customThe reaction mixture was quenched with 10 ml aqueous saturated ammonium chloride solution
5. extractionextracted twice with diethyl ether
6. washThe combined organic layers were washed once with saturated aqueous sodium chloride solution
7. dry with materialdried over sodium sulfate
8. filtrationfiltered
9. customthe solvent was evaporated
10. dissolutionThe residue was dissolved in DCM
11. custompurified by column chromatography (100 g silica gel; heptane/EtOAc 9:1)

ORD record

ord-3ef7120c4be4473f800c172352a35d4d

Source dataset

uspto-grants-2007_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07259183B2