Water → 3,5-Difluoro-4-(methylthio)benzaldehyde

Reaction equation

[F:1][C:2]1[CH:3]=[C:4]([CH:7]=[C:8]([F:11])[C:9]=1F)[CH:5]=[O:6].[CH3:12][S-:13].[Na+].O>C1COCC1>[F:1][C:2]1[CH:3]=[C:4]([CH:7]=[C:8]([F:11])[C:9]=1[S:13][CH3:12])[CH:5]=[O:6]

Participants

Procedure

To a solution of 3,4,5-trifluorobenzaldehyde (30.0 g, 0.187 mol) in anhydrous THF (400 mL) cooled in a cold water bath was added sodium thiomethoxide (14.4 g, 0.20 mol) in portions over 30 minutes. The mixture was stirred at room temperature for 18 hours, then poured into water and extracted with dichloromethane (1×500 mL, 2×200 mL). The combined extracts were washed with water, dried using magnesium sulfate, and concentrated. Purification of the product by silica gel chromatography using 2% dichloromethane/5% ethyl acetate in hexanes gave the 3,5-difluoro-4-(methylthio)-benzaldehyde as a clear colorless liquid (22.0 g, 62%). 1H NMR (CDCl3/400 MHz) 9.86 (t, J=1.5, 1H), 7.34-7.39 (m, 2H), 2.55 (s, 3H). HRMS m/z 188.0099 (M+, calcd 188.0107).