Radical synthesis of 1-bromoperfluoroalkanes from 1-iodoperfluoroalkanes or 1-hydroperfluoroalkanes

Abstract

Medical application of 1-bromoperfluoroalkanes, especially perfluorooctyl bromide, are well known. Emulsions containing perfluorooctyl bromide are used as contrast agents in magnetic resonance imaging, computed tomography or conventional X-ray procedures. Other emulsions have use as oxygen transport media, such as artificial blood. More recently, their effect on the radiosensitivity of tumor cells in cancer therapy has been studied. Different synthetic methods for these compounds have been described in the literature. 1-Iodoperfluoroalkanes react at high temperature with brominating agents and lead to 1-bromoperfluoroalkanes. A study of different parameters, such as the nature and concentration of the brominating agent, the presence or absence of solvent and radical initiator, the temperature and the reaction time was carried out. These results allow the optimal conditions for the formation of 1-bromoperfluoroalkanes to be established according to the following scheme: C nF 2n+1I+Brominating agent ▪ C nF 2n+1Br (n = 4,6,8) A similar reaction, using 1-hydroperfluoroalkanes as the starting material yields 1-bromoperfluoroalkanes under more drastic conditions: C n,F 2n+1H+Brominating agent ▪ C nF 2n+1Br (n = 6,8) The concentration of the brominating agent and the temperature have also been studied. We are grateful to the Atochem Company, Namely Mr Schirmann and Mr Lantz, for their support.