% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Kolks:1017642,
      author       = {Kolks, Niklas and Neumaier, Felix and Neumaier, Bernd and
                      Zlatopolskiy, Boris D.},
      title        = {{P}reparation of {NI}n-{M}ethyl-6-[18{F}]fluoro- and
                      5-{H}ydroxy-7-[18{F}]fluorotryptophans as {C}andidate
                      {PET}-{T}racers for {P}athway-{S}pecific {V}isualization of
                      {T}ryptophan {M}etabolism},
      journal      = {International journal of molecular sciences},
      volume       = {24},
      number       = {20},
      issn         = {1422-0067},
      address      = {Basel},
      publisher    = {Molecular Diversity Preservation International},
      reportid     = {FZJ-2023-04258},
      pages        = {15251},
      year         = {2023},
      abstract     = {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.},
      cin          = {INM-5},
      ddc          = {540},
      cid          = {I:(DE-Juel1)INM-5-20090406},
      pnm          = {5253 - Neuroimaging (POF4-525)},
      pid          = {G:(DE-HGF)POF4-5253},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {37894930},
      UT           = {WOS:001094305600001},
      doi          = {10.3390/ijms242015251},
      url          = {https://juser.fz-juelich.de/record/1017642},
}