Dimethylformamide → 4,5-Dichloropyridine-3-carbaldehyde

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

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).

Herkunft & Nachweise