Hydrochloric Acid → 5-Fluoro-8-methoxychroman-6-carboaldehyde

Temperature

-74 °C

To a solution of 3.6 g of 5-fluoro-8-methoxychromane and 4.2 ml of N,N,N′,N′,N″-pentamethyldiethylenetriamine in 130 ml of THF there was added dropwise 8 ml of n-butyllithium (2.55 M, hexane solution) at −74° C. After stirring at −74° C. for 1 hour, N-formylmorpholine was added. After further stirring at room temperature for 1 hour, 1N hydrochloric acid was added to the reaction mixture while cooling on ice, and the mixture was extracted with ethyl acetate and dried over anhydrous magnesium sulfate. The desiccating agent was filtered off and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate-heptane) to give the title compound (1.50 g) as a white solid.

1. stirringAfter further stirring at room temperature for 1 hour
2. temperaturewhile cooling on ice
3. extractionthe mixture was extracted with ethyl acetate
4. dry with materialdried over anhydrous magnesium sulfate
5. filtrationThe desiccating agent was filtered off
6. concentrationthe filtrate was concentrated under reduced pressure
7. customThe residue was purified by silica gel column chromatography (ethyl acetate-heptane)

ORD record

ord-6d60e4385aca4e568c147f45ddc70db9

Source dataset

uspto-grants-2010_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07816522B2