3-Bromopyridine-4-carboxaldehyde → 1255957-49-3

Temperature

-78 °C

To a solution of methyltriphenylphosphonium bromide (2.14 g, 6.00 mmol) in THF (27 mL) at −78° C. was added n-butyllithium (2.5 M in hexanes, 1.8 mL, 4.5 mmol). The resulting yellow reaction mixture was stirred for 30 min at −78° C. In a separate flask THF (6 ml) was added to 3-bromoisonicotinaldehyde (CAS#113118-81-3, 558 mg, 3.00 mmol). The resulting 3-bromoisonicotinaldehyde solution was the transferred, via cannula, to the phosphonium ylide mixture followed by a 2 mL THF wash. The reaction was allowed to warm to room temperature over 60 minutes and then permitted to stir for an additional 30 minutes. The reaction was then quenched with saturated aqueous sodium bicarbonate and diluted with ethyl acetate. The layers were separated and the organic layer was washed with saturated aqueous sodium bicarbonate. The organic layer was concentrated to near dryness. The resulting residue was then diluted with ethyl acetate and 1M sodium bisulfate and the layers were separated. The organic layer was extracted two additional times with 1M sodium bisulfate. The aqueous layers were combined, diluted with dichloromethane, and neutralized via the careful addition of saturated aqueous sodium bicarbonate and solid sodium carbonate. The layers were separated and the now basic aqueous layer was extracted three additional times with dichloromethane. The dichloromethane layers were combined, dried over anhydrous sodium sulfate, filtered and concentrated. The resulting residue was purified by silica gel flash chromatography (ethyl acetate-dichloromethane, 0 to 16%) to furnish 3-bromo-4-vinyl-pyridine; MS: (ES+) m/z 183.9 (M+H)+

1. washwash
2. temperatureto warm to room temperature over 60 minutes
3. stirringto stir for an additional 30 minutes
4. customThe reaction was then quenched with saturated aqueous sodium bicarbonate
5. additiondiluted with ethyl acetate
6. customThe layers were separated
7. washthe organic layer was washed with saturated aqueous sodium bicarbonate
8. concentrationThe organic layer was concentrated
9. additionThe resulting residue was then diluted with ethyl acetate and 1M sodium bisulfate
10. customthe layers were separated
11. extractionThe organic layer was extracted two additional times with 1M sodium bisulfate
12. additiondiluted with dichloromethane
13. additionneutralized via the careful addition of saturated aqueous sodium bicarbonate and solid sodium carbonate
14. customThe layers were separated
15. extractionthe now basic aqueous layer was extracted three additional times with dichloromethane
16. dry with materialdried over anhydrous sodium sulfate
17. filtrationfiltered
18. concentrationconcentrated
19. customThe resulting residue was purified by silica gel flash chromatography (ethyl acetate-dichloromethane, 0 to 16%)

ORD record

ord-a1637d127a64443d9796f97d5164967e

Source dataset

uspto-grants-2014_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08778972B2