% 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{Kgler:186482,
      author       = {Kügler, Fabian and Ermert, Johannes and Kaufholz, Peter
                      and Coenen, Heinrich Hubert},
      title        = {4-[18{F}]{F}luorophenylpiperazines by {I}mproved
                      {H}artwig-{B}uchwald {N}-{A}rylation of
                      4-[18{F}]fluoroiodobenzene, {F}ormed via {H}ypervalent
                      λ3-{I}odane {P}recursors: {A}pplication to {B}uild-{U}p
                      of the {D}opamine {D}4 {L}igand [18{F}]{FAUC} 316},
      journal      = {Molecules},
      volume       = {20},
      number       = {1},
      issn         = {1420-3049},
      address      = {Basel},
      publisher    = {MDPI75390},
      reportid     = {FZJ-2015-00556},
      pages        = {470 - 486},
      year         = {2015},
      abstract     = {Substituted phenylpiperazines are often
                      neuropharmacologically active compounds and in many cases
                      are essential pharmacophores of neuroligands for different
                      receptors such as D2-like dopaminergic, serotoninergic and
                      other receptors. Nucleophilic, no-carrier-added (n.c.a.)
                      18F-labelling of these ligands in an aromatic position is
                      desirable for studying receptors with in vivo molecular
                      imaging. 1-(4-[18F]Fluorophenyl)piperazine was synthesized
                      in two reaction steps starting by 18F-labelling of a
                      iodobenzene-iodonium precursor, followed by Pd-catalyzed
                      N-arylation of the intermediate 4-[18F]fluoro-iodobenzene.
                      Different palladium catalysts and solvents were tested with
                      particular attention to the polar solvents dimethylformamide
                      (DMF) and dimethylsulfoxide (DMSO). Weak inorganic bases
                      like potassium phosphate or cesium carbonate seem to be
                      essential for the arylation step and lead to conversation
                      rates above $70\%$ in DMF which is comparable to those in
                      typically used toluene. In DMSO even quantitative
                      conversation was observed. Overall radiochemical yields of
                      up to $40\%$ and $60\%$ in DMF and DMSO, respectively, were
                      reached depending on the labelling yield of the first step.
                      The fluorophenylpiperazine obtained was coupled in a third
                      reaction step with 2-formyl-1H-indole-5-carbonitrile to
                      yield the highly selective dopamine D4 ligand [18F]FAUC
                      316.},
      cin          = {INM-5},
      ddc          = {540},
      cid          = {I:(DE-Juel1)INM-5-20090406},
      pnm          = {573 - Neuroimaging (POF3-573) / HITEC - Helmholtz
                      Interdisciplinary Doctoral Training in Energy and Climate
                      Research (HITEC) (HITEC-20170406)},
      pid          = {G:(DE-HGF)POF3-573 / G:(DE-Juel1)HITEC-20170406},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000348319000028},
      doi          = {10.3390/molecules20010470},
      url          = {https://juser.fz-juelich.de/record/186482},
}