768-61-6

21913-84-8

The general procedure for the synthesis of 5-ethylpyridine-2-carboxaldehyde from (5-ethylpyridin-2-yl)methanol was as follows: first, MnSO4-H2O (14.5 g, 0.09 mol) was dissolved in 25 mL of water, and NaOH (7.6 g, 0.19 mol) was dissolved in 20 mL of water, and the solutions were prepared separately. Subsequently, KMnO4 (15.5 g, 0.10 mol) was dissolved in 100 mL of water to prepare a fresh potassium permanganate solution. The three solutions were mixed and the mixture was refluxed for 6 hours. Upon completion of the reaction, the mixture was filtered and dried under reduced pressure to obtain MnO2. Next, (5-ethylpyridin-2-yl)methanol (12.82 g, 93.4 mmol) was dissolved in chloroform and dried MnO2 (16.24 g, 186.8 mmol) was added. The mixture was refluxed in an ultrasonic bath for 5 days. Upon completion of the reaction, the reaction mixture was filtered and purified by column chromatography using petroleum ether and ethyl acetate (4:1) as eluents and separated on silica gel to give the final 5-ethylpyridine-2-carbaldehyde as a bright yellow liquid in 61% yield. The product was characterized by 1H NMR (500 MHz, CDCl3) and 13C NMR (126 MHz, CDCl3) to confirm the correct structure.