Water → 5-Chloro-6-methoxypicolinaldehyde

Beteiligte Stoffe

Reaktionsschritte

Lithium aluminum hydride (2.54 g) was added in small portions to a solution of ethyl 5-chloro-6-methoxypyridine-2-carboxylate (22.3 g) in tetrahydrofuran (223 mL) under ice-cooling, and the mixture was stirred at the same temperature for 10 minutes. Water was added to the reaction solution under ice-cooling. After filtration through celite, the filtrate was concentrated under reduced pressure. Brine was added to the residue, followed by extraction with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate and filtered, after which the filtrate was concentrated under reduced pressure. Manganese dioxide (116.4 g) was added to a solution of the residue in chloroform (223 mL), and the mixture was stirred at 60° C. for one hour. The reaction solution was filtered through celite, and the filtrate was concentrated under reduced pressure. The resulting residue was suspended with hexane, stirred and then filtered. The filtrate was concentrated under reduced pressure. The same operation was further repeated three times. The resulting solids were combined and dried under reduced pressure to give the title compound as a white solid (14.7 g, 83%).

Herkunft & Nachweise