%0 Journal Article
%A Kolks, Niklas
%A Neumaier, Felix
%A Neumaier, Bernd
%A Zlatopolskiy, Boris D.
%T Preparation of NIn-Methyl-6-[18F]fluoro- and 5-Hydroxy-7-[18F]fluorotryptophans as Candidate PET-Tracers for Pathway-Specific Visualization of Tryptophan Metabolism
%J International journal of molecular sciences
%V 24
%N 20
%@ 1422-0067
%C Basel
%I Molecular Diversity Preservation International
%M FZJ-2023-04258
%P 15251
%D 2023
%X Abstract: Tryptophan (Trp) is an essential proteinogenic amino acid and metabolic precursor forseveral signaling molecules that has been implicated in many physiological and pathological pro-cesses. Since the two main branches of Trp metabolism—serotonin biosynthesis and kynureninepathway—are differently affected by a variety of neurological and neoplastic diseases, selective visual-ization of these pathways is of high clinical relevance. However, while positron emission tomography(PET) with existing probes can be used for non-invasive assessment of total Trp metabolism, optimalimaging agents for pathway-specific PET imaging are still lacking. In this work, we describe the prepa-ration of two 18F-labeled Trp derivatives, NIn-methyl-6-[18F]fluorotryptophan (NIn-Me-6-[18F]FTrp)and 5-hydroxy-7-[18F]fluorotryptophan (5-HO-7-[18F]FTrp). We also report feasible synthetic routesfor the preparation of the hitherto unknown boronate radiolabeling precursors and non-radioactivereference compounds. Under optimized conditions, alcohol-enhanced Cu-mediated radiofluorinationof the respective precursors afforded NIn-Me-6-[18F]FTrp and 5-HO-7-[18F]FTrp as application-readysolutions in radiochemical yields of 45 ± 7% and 29 ± 4%, respectively. As such, our work providesaccess to two promising candidate probes for pathway-specific visualization of Trp metabolism inamounts sufficient for their preclinical evaluation.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ 37894930
%U <Go to ISI:>//WOS:001094305600001
%R 10.3390/ijms242015251
%U https://juser.fz-juelich.de/record/1017642