A New Precursor for the Radiosynthesis of 6-O-(2-[¹⁸F]Fluoroethyl)-6-Odesmethyl- diprenorphine ([¹⁸F]FE-DPN) by Nucleophilic Radiofluorination

We present the preparation of the new precursor 6-O-(2-tosyloxyethoxy)-6-O-desmethyl-3- O-trityl-diprenorphine (TE-TDDPN) for a one-pot, two-step nucleophilic radiosynthesis of 6-O-(2- [18F]fluoroethyl-6-O-desmethyl-diprenorphine ([18F]FE-DPN). The route to the precursor consists of a five-step synthesis starting from diprenorphine. We also provide alternative synthesis routes for the cold reference standard and the complete 1H- and 13C-NMR assignment of the prepared derivatives.