Stereoselective Transformation of Chiral Amine: Novel Approach to the Synthesis of Optically Active Intermediate of Silodosin

A novel, economical and highly efficient synthetic approach has been developed for the synthesis of silodosin optically active intermediate and its application to facile preparation of silodosin parent compound. It involves stereoselective inversion of unwanted isomer of the silodosin key chiral amine intermediate via the nucleophilic substitution reaction with azide ion on (a) N,N-ditosylimide derivative and (b) 2,4,6-triphenyl pyridinium cation.