19th European Organic Chemistry Congress
London, UK
Shno Omar
Newcastle University, United Kingdom
Title: Copper coil continuous flow N-Arylation of aniline derivative
Biography
Biography: Shno Omar
Abstract
The diarylamine functionality is widespread in natural products and other bioactive species,1,2 and as a result a range of synthetic methods has been developed for its preparation. We have demonstrated that diaryliodonium salts are not only selective precursors to fluoroarenes3 but that these materials are also suitable arylating agents for a range of anilines.
Although successful, this process required elevated temperatures (130 °C) and extended reaction times (24h) limiting its application. We now wish to report translation of this methodology to a continuous process (Uniqsis FlowSyn5) which has addressed these restrictions.
Initial optimization of diphenylamine production was achieved by investigation of concentration, temperature, flow-rate and choice of counter-ion. As Ullmann-type conditions have been employed in arylation reactions6 we also investigated the effect of using a copper coil as the reactor in addition to the more usual stainless steel, PTFE coils (Fig. 1). It was found that the copper coil/trifluoroacetate counter-ion combination was essential to conduct the reaction at room temperature with a residence time of only 80 min. The process was suitable for a range of anilines e.g. R = 3,4-(OMe)2 (87%, Fig. 2); 4-NO2 (70%); 2,4,6-Me3 (80%); 1-naphthylamine (68%) and a range of diaryliodonium salts