Dimethylformamide → 2,3-Dichloropyridine-4-carbaldehyde

Temperature

-78 °C

To a solution of 2,3-dichloropyridine [C.A.S. 2402-77-9] (10 g, 67.57 mmol) in dry THF (200 ml) cooled at −78° C. under a nitrogen atmosphere, was added dropwise n-butyllithium (37.165 ml, 74 mmol, 2 M in hexanes). The resulting reaction mixture was stirred at −78° C. for 20 min. Then dry DMF (6.28 ml, 81.087 mmol) was added dropwise. After 15 min. stirring at −78° C., the mixture was allowed to warm to r.t., quenched with water and extracted with DCM. The combined organic extracts were dried (Na2SO4) and concentrated in vacuo. The crude residue was purified by short open column chromatography (DCM as eluent). The desired product fractions were collected and concentrated in vacuo to give a residue that was further purified by column chromatography (silica gel; DCM/heptane up to 50% as eluent). The desired fractions were collected and concentrated in vacuo to yield intermediate compound D36 (4.15 g, 34.9%) as a white solid.

1. customThe resulting reaction mixture
2. stirringAfter 15 min. stirring at −78° C.
3. temperatureto warm to r.t.
4. customquenched with water
5. extractionextracted with DCM
6. dry with materialThe combined organic extracts were dried (Na2SO4)
7. concentrationconcentrated in vacuo
8. customThe crude residue was purified by short open column chromatography (DCM as eluent)
9. customThe desired product fractions were collected
10. concentrationconcentrated in vacuo
11. customto give a residue that
12. customwas further purified by column chromatography (silica gel; DCM/heptane up to 50% as eluent)
13. customThe desired fractions were collected
14. concentrationconcentrated in vacuo
15. customto yield intermediate compound

ORD record

ord-ba085b82c861475889e63a79692680fa

Source dataset

uspto-grants-2015_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08937060B2