Ammonium Chloride → 3-Methylthieno[3,2-b]pyridine-2-carbaldehyde

To a mixture of ethyl 3-methylthieno[3,2-b]pyridine-2-carboxylate (3.00 g) synthesized above, calcium chloride (3.02 g), ethanol (30 mL) and tetrahydrofuran (30 mL) was added sodium borohydride (2.06 g) at 0° C., and the mixture was stirred at room temperature for 5 hr. Saturated aqueous ammonium chloride solution was added to quench the reaction, and the reaction mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure to give a white solid. To a solution (50 mL) of the obtained solid in tetrahydrofuran was added active manganese dioxide (12.2 g), and the mixture was stirred at 50° C. overnight. Manganese dioxide was filtered off, and the filtrate was concentrated under reduced pressure to give the title object compound (2.24 g, 93%) as a white solid.

1. customto quench
2. customthe reaction
3. extractionthe reaction mixture was extracted with ethyl acetate
4. washThe extract was washed with saturated brine
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated under reduced pressure
7. customto give a white solid
8. stirringthe mixture was stirred at 50° C. overnight
9. filtrationManganese dioxide was filtered off
10. concentrationthe filtrate was concentrated under reduced pressure

ORD record

ord-9267e313dfb14b23ad7583e352956205

Source dataset

uspto-grants-2013_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08436043B2