4-Cyano-3,5-difluoro benzaldehyde

479621-01-7

433939-88-9

2,6-Difluoro-4-[(methylsulfinyl)(methylthio)methyl]benzonitrile (2.17 g, 8.32 mmol) was used as a raw material, which was dissolved in 90 mL of tetrahydrofuran (THF), followed by the addition of 3.5 mL of concentrated sulfuric acid. The reaction mixture was stirred at room temperature for 3 days. After completion of the reaction, the mixture was slowly poured into 450 mL of water and extracted three times with ethyl acetate (EtOAc). The organic phases were combined, washed twice sequentially with aqueous sodium bicarbonate and saturated saline, dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the target product 2,6-difluoro-4-formylphenyl cyanide. Yield: 1.36 g (98%). The structure of the product was confirmed by 13C NMR, where the carbon signal at 140.7 ppm showed the expected coupling pattern with two coupling constants of 260 Hz and 6.3 Hz, corresponding to ipso and meso coupling to the fluorine atom.1H NMR (400 MHz, CDCl3) δ 10.35 (s, 1H), 7.33 (m, 2H).