A facile synthesis of 4- and 6-chloromethyl-1H-indole-2-carboxylates: replacement of a sulfonic acid functionality by chlorine

Abstract Valuable new synthetic intermediates, 4- or 6-chloromethyl-1 H -indole-2-carboxylates, were prepared by the elimination of SO 2 from 2-ethoxycarbonyl-1 H -indole-4- or 6-methanesulfonic acids, respectively, which are easily accessible by Fischer-type indolization.