Iodine → 2,4-Dichloro-3-iodopyridine

Temperature

-78 °C

To a solution of 2,4-dichloropyridine (5.2 g, 35.137 mmol) and diisopropylamine (3.911 g, 38.651 mmol) in dry THF (40 ml) cooled at −78° C. under a nitrogen atmosphere, was added n-butyllithium (24.157 ml, 38.651 mmol, 1.6 M in hexanes) dropwise. The resulting reaction mixture was stirred at −78° C. for 45 min. and then a solution of iodine (9.81 g, 38.651 mmol) in dry THF (20 ml) was added dropwise. The mixture was stirred at −78° C. for 1 h., allowed to warm to r.t., diluted with EtOAc and quenched with NH4Cl (aqueous sat. solution) and Na2S2O3 (aqueous sat. solution). The organic layer was separated, washed with NaHCO3 (aqueous sat. solution), dried (Na2SO4) and concentrated in vacuo. The crude product was purified by column chromatography (silica gel; Heptane/DCM up to 20% as eluent). The desired fractions were collected and concentrated in vacuo to yield intermediate compound D24 (7.8 g, 81%).

1. customThe resulting reaction mixture
2. stirringThe mixture was stirred at −78° C. for 1 h.
3. temperatureto warm to r.t.
4. customquenched with NH4Cl (aqueous sat. solution) and Na2S2O3 (aqueous sat. solution)
5. customThe organic layer was separated
6. washwashed with NaHCO3 (aqueous sat. solution)
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated in vacuo
9. customThe crude product was purified by column chromatography (silica gel; Heptane/DCM up to 20% as eluent)
10. customThe desired fractions were collected
11. concentrationconcentrated in vacuo
12. customto yield intermediate compound

ORD record

ord-4bc86fb0c7304b929ff5289617713d4d

Source dataset

uspto-grants-2015_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08937060B2