Carbon Dioxide → 5-methoxy-1H-indole-7-carboxylic acid

Temperature

-78 °C

A mixture of 7-bromo-5-methoxy-1H-indole (1.2 g) and THF (12 mL) was stirred at −78° C. under an argon atmosphere. To the reaction mixture was added dropwise an n-butyllithium n-hexane solution (1.65 M, 9.6 mL) at −50° C. or lower. The reaction mixture was stirred for 0.5 hour under ice-cooling. The reaction mixture was cooled to −78° C., and dry ice (10 g) was added thereto, followed by slowly warming to room temperature. The reaction mixture was poured into a 10% aqueous citric acid solution, followed by extraction with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by silica gel column chromatography (THF/hexane=20→60%) to obtain 5-methoxy-1H-indole-7-carboxylic acid (0.60 g).

1. stirringThe reaction mixture was stirred for 0.5 hour under ice-
2. temperaturecooling
3. temperatureThe reaction mixture was cooled to −78° C.
4. temperatureby slowly warming to room temperature
5. extractionfollowed by extraction with ethyl acetate
6. washThe organic layer was washed with saturated brine
7. dry with materialdried over anhydrous magnesium sulfate
8. filtrationfiltered
9. concentrationThe filtrate was concentrated under reduced pressure
10. customthe residue was purified by silica gel column chromatography (THF/hexane=20→60%)

ORD record

ord-ec1f0d8ba8b346dfb7a22c90234f4604

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08598355B2