Electrolytic partial fluorination of organic compounds. 35. Anodic fluorination of 2-pyrimidyl, 2-pyridyl, and 2-quinazolinonyl sulfides

Highly regioselective electrochemical fluorination of 2-pyrimidyl sulfides having an electron(EWG) withdrawing group at the position alpha to the sulf ur atom was successfully carried out using Et4NF . nHF (n = 3, 4) or Et3N . 3HF as a supporting electrolyte and a fluoride ion source in 1,2-dimethoxy ethane (DME) in an undivided cell. 2-Methylthiopyrimidine devoid of an EWG was also selectively fluorinated in DME to provide 2-(fluoromethylthio)pyri midine in a moderate yield as 63%, while corresponding 2-methylthiopyridine was less selectively fluorinated in lower yield along with alpha,alpha-dif luorinated product. In contrast, the corresponding 2-quinazolinonyl sulfide s underwent similarly alpha-fluorination along with unexpected ipso-fluorin ation through anodic desulfurization.