2-Chloro-7-methylquinoline-3-carbaldehyde → (2-Chloro-7-methylquinolin-3-yl)methanol

To a stirred solution of 6.9 g (180 mmol) of sodium borohydride in 250 ml of absolute ethanol, a solution of 15 g (73 mmol) of 2-chloro-3-formyl-7-methylquinoline in 250 ml of dry tetrahydrofuran was added over 15 minutes without cooling. During the addition a slight H2 -evolution and a temperature rise to +28° C. was observed. The reaction mixture was stirred at room temperature for 4 hours and then 4 ml of the reaction mixture was evaporated in vacuo and the residue dissolved in ethyl acetate, extracted with saturated sodium hydrogen carbonate solution, dried over sodium sulfate and evaporated in vacuo to give a residue of 100 mg. 1H-NMR indicated complete conversion to the alcohol. After 5 hours the whole reaction mixture was worked up in the same way to give 14.8 g 2-chloro-3-hydroxymethyl-7-methylquinoline after evaporation.