Synthesis of Nitromethyl Derivatives from Sulfur-Containing Pentafluorobenzenes

The reaction of methyl- and (difluoromethyl)sulfanyl-, methane- and difluoromethanesulfinyl-, and methane- and difluoromethanesulfonylpentafluorobenzenes with nitromethane in the presence of 1,8diazabi­cyclo­[5.4.0]undec-7-ene (DBU) in diethyl ether involved replacement of fluorine at the para position of the aromatic ring with the formation of the corresponding nitromethyl derivatives. The reaction temperature decreased in parallel with increase of the electron-withdrawing power of the sulfur-containing substituent. Treatment of 1,2,4,5-tetrafluoro-3-(methylsulfanyl)-6-(nitromethyl)benzene with sodium methoxide afforded the corresponding aci -nitro salt.