A Convenient Synthesis of Perfluoroalkylated and Fluorinated-Aryl Nitrogen Bases by Electrochemically Induced S<sub>RN</sub>1 Substitution
作者:Maurice Médebielle、Mehmet Ali Oturan、Jean Pinson、Jean-Michel Savéant
DOI:10.1021/jo9515541
日期:1996.1.1
Indirect electrochemical reduction, by means of an aromatic anion mediator, of perfluoroalkyl halides (CF3Br, n-C4F9I, n-C6F13I, I(CF2)(4)I) in the presence of imidazole, 4(5)-nitroimidazole, 2-methyl-5-nitroimidazole, 2-(4'-methoxyphenyl)imidazole, imidazole-2-carboxaldehyde, 4(5)-nitroimidazole-2-carboxaldehyde, 5(6)-nitrobenzimidazole, purines (adenine, hypoxanthine, xanthine, theophylline, lumazine) and pyrimidine anions (uracil, cytosine, barbituric acid) yields the corresponding C-perfluoroalkylated nitrogen bases by an S(RN)1 mechanism. Aromatic nucleophilic substitution of some fluorinated aryl halides 1-iodo-2-(trifluoromethyl)benzene and 1-(4'-iodo-tetrafluorophenyl)-imidazole was also investigated and it was found that 1-iodo-2-(trifluoromethyl)benzene could react successfully under redox-catalyzed conditions with imidazole, 2-(4'-methoxyphenyl)imidazole anion, and uracil anion to give the corresponding 5-(fluorinated-aryl) nitrogen bases. In the case of 1-(4'iodo-tetrafluorophenyl)imidazole, direct electrochemical radical nucleophilic substitution with 2-methyl-5-nitroimidazole and uracil was possible in DMSO. In this way new, 4-[2',3',5',6'-tetrafluoro-4'-(imidazol-1 ''-yl)phenyl] nitrogen bases were obtained in good yields.