Effects of catalyst pretreatment and additives on the hydrogen incorporation during the catalytic deuteration of N-acetyl-di-iodotyrosineamide

The influence of the mode of presaturating the catalyst and of different inhibiting agents on the catalytic deuteration of N‐acetyl‐3,5‐di‐iodo‐L‐tyrosineamide was investigated in order to derive conclusions for optimizing peptide tritiations. Reactions of the activated catalyst with solvent and substrate can be inhibited independently. The exchange of the catalyst‐bound deuterium against hydrogen from solvent is inhibited by the substrate itself and by addition of 1,3‐di‐chlorobenzene. The dehalogenation reaction and the unspecific exchange of carbon‐bound hydrogen of the substrate are inhibited preferably by thioglycolic acid, iodide and by the triethyl‐ammonium ion.