Isotope exchange of indoles with D2O over group VIII metals

Results of H - D exchange between indole and its methyl derivatives and D2O over metallic Pt, Rh, and Pd are reported. The composition of the reaction mixture after the isotopic exchange was determined by mass spectrometry. The order of reactivity of the metals was Pt>Pd>Rh. It was determined that it was only the heterocycle π-electron system that interacts with the surface and mainly the hydrogens at C2 and C3 that undergo exchange and not those bonded to the N