AbstractThe site‐specific deuteration and tritiation of 1‐methylindole and benzo [b] ‐thiopheme analogs of biologically active indole derivatives has been achieved by use of the facile metalation of these heterocycles with n‐butyllithium and subsequent reaction with2H2or3H2O. Metalation occurs at the 2‐position and site and extent of deuterium incorporation was determined by N. M. K. The use of similar procedures with3H2O led to ready incorporation of tritium into these het