Hydrochloric Acid → 2-Chloro-3-pyridinecarboxaldehyde

Temperature

-95 °C

To a solution of diisopropyl amine (110 mL, 780 mmol) in THF (500 mL) was added a 2.5 M hexanes solution of n-BuLi (300 mL, 750 mmol) at −40° C. After 5 min, the reaction mixture was cooled to −95° C. then DMPU (15 mL) and 2-chloropyridine (50 mL, 532 mmol) were successively added. The resulting mixture was then warmed and stirred at −78° C. for 4 h. After this time, the yellow suspension was cooled again to −95° C. before DMF (70 mL) was added. The final reaction mixture was warmed to −78° C. and stirred at that temperature for 1.5 h. The reaction mixture was poured into cold aqueous HCl (3N, 800 mL) and stirred for 5 min. Aqueous concentrated NH4OH was added to adjust pH to 7.5. The aqueous layer was extracted three times with EtOAc. The combined organic layer was washed with aqueous NH4Cl and brine, dried over anhydrous Na2SO4, filtered and concentrated. The crude material was further purified by a pad of silica gel by eluting with a gradient from 100% hexanes to 100% EtOAc and the product was crystallized in cold hexanes to yield the title compound as a pale yellow solid.

1. temperatureThe resulting mixture was then warmed
2. additionwas added
3. customThe final reaction mixture
4. temperaturewas warmed to −78° C.
5. stirringstirred at that temperature for 1.5 h
6. stirringstirred for 5 min
7. extractionThe aqueous layer was extracted three times with EtOAc
8. washThe combined organic layer was washed with aqueous NH4Cl and brine
9. dry with materialdried over anhydrous Na2SO4
10. filtrationfiltered
11. concentrationconcentrated
12. customThe crude material was further purified by a pad of silica gel
13. washby eluting with a gradient from 100% hexanes to 100% EtOAc
14. customthe product was crystallized in cold hexanes

ORD record

ord-d508963803e743329ff2dd2146a74da9

Source dataset

uspto-grants-2009_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07618979B2