Dimethylformamide → 4,5-Dichloropyridine-3-carbaldehyde

Temperatur

-78 °C

To a solution of diisopropylamine (9.7 mL, 69.1 mmol) in THF (60 mL) at −30° C. was added n-butyllithium (2.5 M in hexanes, 27.6 mL, 69.1 mmol). The reaction mixture was stirred for 15 minutes then cooled to −78° C. A solution of 3,4-dichloropyridine (8.53 g, 57.6 mmol) in THF (20 mL) was added dropwise over 20 minutes then the mixture was stirred at −78° C. for 2.5 hours. DMF (5.4 mL, 69.1 mmol) was added and the reaction was warmed to room temperature. The reaction mixture was quenched with ammonium chloride (sat. aq., 300 mL) and extracted with ethyl acetate (3×100 mL). The combined organic extracts were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography (0-30% ethyl acetate in pentane) to afford the title compound as a white solid (6.78 g, 67% yield). 1H NMR (400 MHz, CDCl3): δ 10.49 (s, 1H), 8.92 (s, 1H), 8.82 (s, 1H).

1. stirringthe mixture was stirred at −78° C. for 2.5 hours
2. temperaturethe reaction was warmed to room temperature
3. customThe reaction mixture was quenched with ammonium chloride (sat. aq., 300 mL)
4. extractionextracted with ethyl acetate (3×100 mL)
5. dry with materialThe combined organic extracts were dried over anhydrous sodium sulfate
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by silica gel flash chromatography (0-30% ethyl acetate in pentane)

ORD-Eintrag

ord-9d288b9272684a8698e3c0daaa33f49b

Quelldatensatz

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09309240B2