Synthesis of 5-substituted indole derivatives. Part 3: A facile synthesis of 5-chloromethyl-1H-indole-2-carboxylates: replacement of sulfonic acid functionality by chlorine

Valuable new synthetic intermediates, 5-chloromethyl-1H-indole-2-carboxylates, were prepared by the elimination of SO2 from 2-ethoxycarbonyl-1H-indole-5-methanesulfonic acids, which are easily accessible by Fischer-type indolization.