13669-42-6

5332-24-1

68-12-2

13669-42-6

General method: n-Butyllithium (2.5 M in hexane, 300 μL, 0.72 mmol) was added slowly and dropwise to an anhydrous THF (1.5 mL) solution of 3-bromoquinoline (100 mg, 0.48 mmol) at -78 °C. The reaction solution turned red. The reaction solution then turned red, followed by the addition of N,N-dimethylformamide (192 μL, 2.49 mmol). After maintaining the reaction temperature at -78 °C for 10 min, the reaction was quenched with deionized water. The reaction mixture was transferred to saturated aqueous sodium bicarbonate solution (10 mL) and extracted with ethyl acetate (3 × 10 mL). The organic phases were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: n-hexane solution of 10% ethyl acetate) to give quinoline-3-carbaldehyde as a yellow solid in 53% yield.