8-Quinolinecarbaldehyde

General procedure: To a mixture of alcohol in dry DMSO (10 volume) was added 1 equiv of polymer bromide and the reaction mixture was stirred at room temperature for a given period of time (Table 1). After the completion of the reaction, the reaction mixture was filtered and the polymer bed washed with DMSO. Combined DMSO layers were quenched with ice-water mixture and extracted with ether. The ether layer was given water wash, brine wash, dried over anhydrous sodium sulphate, and concentrated to get the pure carbonyl compounds. All the products were characterized by NMR and MS analysis.A solution of 0.50 g (3.5 mmol) of 8-methylquinoline (21), 1.87 g (10.5 mmol) of N-bromosuccinamide (NBS), and 50 mg (0.3 mmol) of azobisisobutyronitrile (AIBN) in dichloroethane was refluxed under argon for 30 h. The reaction mixture was diluted with 150 mL dichloromethane, washed three times with 2 N NaOH, and brine, dried (MgSOTo a solution of 13a (100?mg, 0.48?mmol) in dry THF (1.5?mL) at -78?°C nBuLi (2.5?M in n-hexane, 300?μL, 0.72?mmol) was added dropwise. sec-Butyllithium (1.4 M in cyclohexane, 5. 0ml, 7. 0mmol) is added dropwise to a stirred solution of 8-bromoquinoline (1.29g, 6. 22mmol) and anhydrous tetrahydrofuran (22ml) at-78°C under nitrogen. The reaction is then stirred at-78°C for 10 min and then dimethylformamide (2. 5ml, 32.3mmol) is added. The reaction is then stirred for 10 min at-78°C and then quenched with water. The reaction is poured into saturated sodium bicarbonate (100ml) and extracted with ethyl acetate (100ml x3). The ethyl acetate is dried over sodium sulfate and then the sodium sulfate is filtered. The crude product is concentrated on a rotary evaporator and purified by flash chromatography on silica gel eluting with 20percent ethyl acetate/hexanes to yield (0.57g, 58percent) of quinoline-8- carboxaldehyde : mass spectrum (ion spray) : m/z=158. 0 (M+l) : 1H NMR (CDC13) : 8= 11.46 (1H, s), 9.06-9. 04 (1H, m), 8.34-8. 32 (1H, m), 8.26-8. 23 (1H, m), 8.11-8. 08 (1H, m), 7.70-7. 66 (1H, m), 7.53-7. 50 (1H, m).A solution of 0.50 g (3.5 mmol) of 8-methylquinoline (21), 1.87 g (10.5 mmol) of N-bromosuccinamide (NBS), and 50 mg (0.3 mmol) of azobisisobutyronitrile (AIBN) in dichloroethane was refluxed under argon for 30 h. The reaction mixture was diluted with 150 mL dichloromethane, washed three times with 2 N NaOH, and brine, dried (MgSO