Hydrochloric Acid → 2,5-Dimethylthiophene-3-carbaldehyde

To a solution (20 mL) of 2,5-dimethylthiophene-3-carboxylic acid (920 mg) in tetrahydrofuran was added 1.0M borane-tetrahydrofuran complex in tetrahydrofuran solution (7.07 mL) at 0° C., and the mixture was stirred at room temperature overnight. 1.0M Borane-tetrahydrofuran complex in tetrahydrofuran solution (14.1 mL) was added, and the mixture was further stirred at room temperature for 3 hr. 1N Hydrochloric acid was added to quench the reaction, tetrahydrofuran was evaporated using evaporator, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by NH-silica gel column chromatography (ethyl acetate:hexane=2:3, volume ratio) to give a yellow oil. To a solution of the obtained oil in tetrahydrofuran (10 mL) was added activated manganese dioxide (3.32 g), and the mixture was stirred at room temperature overnight. Manganese dioxide was filtered off, and the filtrate was concentrated under reduced pressure to give the title compound (562 mg, 68%) as a yellow oil.

1. stirringthe mixture was further stirred at room temperature for 3 hr
2. customto quench
3. customthe reaction, tetrahydrofuran
4. customwas evaporated
5. customevaporator
6. extractionthe mixture was extracted with ethyl acetate
7. washThe extract was washed with saturated brine
8. dry with materialdried over magnesium sulfate
9. concentrationconcentrated under reduced pressure
10. customThe residue was purified by NH-silica gel column chromatography (ethyl acetate:hexane=2:3, volume ratio)
11. customto give a yellow oil
12. stirringthe mixture was stirred at room temperature overnight
13. filtrationManganese dioxide was filtered off
14. concentrationthe filtrate was concentrated under reduced pressure

ORD record

ord-d45f36f8c436453abfba0f6207353c3b

Source dataset

uspto-grants-2012_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08309580B2