2-Bromo-4-fluorobenzaldehyde → Methyl 4-bromo-6-fluoro-1H-indole-2-carboxylate

Dry methanol (5 ml) and NaOMe (0.9 ml, 3.93 mmol, 25% wt in MeOH) were added to a three-neck flask equipped with stirrer, low-temperature thermometer, and nitrogen line. The resulting solution was cooled in a dry ice/CH3CN bath to −40° C. A solution of 2-bromo-4-fluoro-benzaldehyde (195 mg, 0.96 mmol) and methyl azidoacetate (450 mg, 3.9 mmol) in dry MeOH (5 ml) was added dropwise. The mixture was allowed to stir at −40° C. for 30 minutes before warming up to room temperature. After stirring another 3 hours, the reaction solvent was removed under reduced pressure. The residue was added to xylene (15 ml), and the organic phase was washed with H2O, brine, followed by drying over MgSO4. The resulting solution was added dropwise to a flask of xylene (30 ml) and the solution was heated at reflux overnight. After cooling to room temperature, the reaction mixture was washed with H2O, and xylene was removed under reduced pressure to give 4-bromo-6-fluoro-1H-indole-2-carboxylic acid methyl ester as a white solid (178 mg, 68%). MS: 272.1 (M−H)−.

1. customequipped with stirrer
2. temperaturebefore warming up to room temperature
3. stirringAfter stirring another 3 hours
4. customthe reaction solvent was removed under reduced pressure
5. additionThe residue was added to xylene (15 ml)
6. washthe organic phase was washed with H2O, brine
7. dry with materialby drying over MgSO4
8. additionThe resulting solution was added dropwise to a flask of xylene (30 ml)
9. temperaturethe solution was heated
10. temperatureat reflux overnight
11. temperatureAfter cooling to room temperature
12. washthe reaction mixture was washed with H2O, and xylene
13. customwas removed under reduced pressure

ORD-Eintrag

ord-3f5216aaf48543b98c181b7f02cfd30d

Quelldatensatz

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07741326B2