Hydrochloric Acid → 7-Chloro-4-methyl-1H-indole

Temperature

-50 °C

A solution of 5.21 g of 1-chloro-4-methyl-2-nitrobenzene in 150 mL of THF was cooled to −50° C. To the solution was added 95 mL of 1 M vinylmagnesium bromide solution in THF while the inner temperature was kept at −30° C. or lower, and the resulting mixture was stirred at −50° C. for 2 hours. To the solution, 100 mL of the saturated aqueous ammonium chloride solution and 100 mL of 1 M hydrochloric acid were added, then the resulting mixture was warmed to room temperature and stirred for 15 minutes, and then extracted twice with 100 mL of ethyl acetate. The extract was washed with water and saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate, and then the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate-hexane=1:9) to obtain 2.69 g of 7-chloro-4-methylindole as a brown oil.

1. customwas kept at −30° C.
2. temperaturethe resulting mixture was warmed to room temperature
3. stirringstirred for 15 minutes
4. extractionextracted twice with 100 mL of ethyl acetate
5. washThe extract was washed with water and saturated aqueous sodium chloride solution
6. dry with materialdried over anhydrous sodium sulfate
7. customthe solvent was evaporated under reduced pressure
8. customThe residue was purified by silica gel column chromatography (ethyl acetate-hexane=1:9)

ORD record

ord-4ad822b5c526400b8c9cce6fdaea0d92

Source dataset

uspto-grants-2010_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07855225B2