Photochemical Schiemann reaction in ionic liquids

Photochemical Schiemann reactions of imidazole derivatives 1 and 4 were carried out in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid [bmim][BF4] as solvent. The effects of temperature, co-solvent and wavelength on the rate of the reaction and product yield were examined. The use of ionic liquid increases the yield of the photochemical fluorodediazoniation reaction of 2 at 0 °C. Careful temperature control is necessary to minimize the photodecomposition of the ionic liquid in order to increase the yield of product.

In order to obviate competition between fluoride and solvent water as nucleophiles, the photochemical Schiemann reaction of imidazole derivative 1 was carried out in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid [bmim][BF4] as solvent. Figure optionsDownload as PowerPoint slide