Water → 2,5-Difluoro-4-formylbenzonitrile

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Reaction Steps

2,5-Difluoro-4[(methylsulfinyl)(methylthio)methyl]benzonitrile (2.8 g, 0.0107 mol; see step (i) above) was dissolved in 100 mL of THF and 6.5 g of concentrated sulfuric acid was added. The mixture was left at room temperature for 6 days and subsequently poured into 500 mL of water. Extraction three times with diethyl ether followed and the combined ethereal phase was washed several times with water, dried (Na2SO4) and evaporated. The crude product was flash chromatographed on silica gel using heptane:EtOAc (8:2). Yield: 1.2 g (67%). The position of the formyl group was established by use of 13C NMR. The carbon signals from the fluorinated carbons at 160.1 and 158.4 respectively, were doublets and not quartets, which they would have been if the formyl group had been in the 2-position.

Provenance & Evidence