The Synthesis Of Fexofenadine

Fexofenadine is one of the second generation of anti-histamine medicament. As the efficient intermediate in human body, it has high activeness and low side-effect.Tetra-butyl benzene was used as the starting material of the total synthesis of Fexofenadine. After radical chloro-replcement, Grignard reaction, and estered by anhydride, we got 2-methyl-2-phenylpropyl acetate (intermediate A).Another intermediate diphenyl (piperidin-4-yl) methanol (intermediate C) was synthesized in two routes. One was starting with ethyl piperidine -4-carboxylate. The secondary amine was protected by benzyl. It was then released by catalyzed hydrogenation after the ester was converted into alcohol by Grignard reaction. Another route was starting with ethyl isonicotinate. The secondary amine was released by catalyzed hydrogenation after the ester was converted into alcohol by Grignard reaction.Two intermediates were then connected and modified, and the target molecule was then synthesized.