Synthesis of a delta opioid agonist in [2H6], [2H4], [11C], and [14C] labeled forms

In support of a program to develop a treatment for depression, four labeled forms of a delta opioid agonist were prepared. The [2H4] labeled form was prepared using a relatively straightforward conversion of [2H4]bromoethanol to [2H4]N-methyl-2-hydroxyethylamine. The key step in the synthesis of the [2H6] labeled form involved the Pd-catalyzed exchange in D2O of 8-quinolin-8-ol to give [2H6] 8-quinolin-8-ol. The C-14 labeled form was synthesized in one step using [14C]carbonylation, and the C-11 labeled form was prepared in two steps from 11CH3I. Copyright © 2011 John Wiley & Sons, Ltd.