% 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”.

@INPROCEEDINGS{Hoffmann:1026459,
      author       = {Hoffmann, Chris and Bertram, Jan and Endepols, Heike and
                      Zlatopolskiy, Boris and Neumaier, Bernd},
      title        = {{P}reparation of radiolabeled sulfamoyl fluorides by
                      {S}u{FE}x 18{F}/19{F} isotopic exchange and assessment of
                      their in vivo stability},
      reportid     = {FZJ-2024-03408},
      year         = {2023},
      abstract     = {Objectives: Aryl fluorosulfates (FO 2 S-O-) and
                      disubstituted sulfa-moyl fluorides (FO 2S-N-) often possess
                      high hydrolytic stability and arewidely used in chemical
                      biology and drug design. Recently we reporteda protocol for
                      convenient preparation of radiolabeled aryl fluorosul-fates
                      with high molar activity via fast 18 F/19 F isotopic
                      exchange [1]. Theaim of the present work was to study the
                      suitability of this procedurefor radiofluorination of
                      sulfamoyl fluorides. To this end, the procedurewas applied
                      to N-sulfamoylated indole and carbazole as well as tothree
                      protected amino acids (Boc-Trp(SO2 F)-OMe 1,
                      Boc-His(SO2F)-OMe 2 and Boc-2,3-DH-Trp(SO2 F)-OMe 3).
                      Additionally, the in vivostability of the radiolabeled
                      tryptophan derivative Boc-Trp([18 F]SO2F)-OMe ([18 F]1) was
                      evaluated.Methods: Aqueous [18 F]fluoride was loaded onto an
                      anionexchange QMA cartridge and eluted with Et 4NOH (10
                      μmol) inMeOH (1 mL). MeOH was evaporated, a solution of the
                      correspondingsubstrate (31–125 nmol) in MeCN (500 μL) was
                      added and the reactionmixture was stirred for 7 min at 40
                      °C. Thereafter, H2 O (1 mL) wasadded and radiochemical
                      conversions (RCCs) were determined byradio-HPLC. [ 18 F]1
                      was isolated by solid phase extraction using aStrataX C18
                      cartridge. The tracer was formulated in Tween® 20 (200
                      μL)and 1 mm sodium phosphate buffer (2 μL; pH 7.2) and
                      subjected to apreclinical evaluation in healthy mice using
                      μPET.Results: Radiolabeled N–sulfamoyl fluorides of
                      carbazole andindole were prepared in RCCs of 72 ± $2\%$ and
                      86 ± $2\%,$ respectively.FO 2SN-functionalized protected
                      tryptophan 1 (RCC: 68 ± $5\%),$ histidine2 (RCC: 3 ±
                      $1\%)$ and 2,3-dihydroxy-tryptophan 3 (RCC: $34\%;$ 60°C,14
                      min), were also successfully radiofluorinated. Boc-Trp([18
                      F]SO2F)-OMe [18 F]1 was isolated in activity yields of 24 ±
                      $2\%$ with aradiochemical purity of $99\%$ (n = 3) within 70
                      min using 12.5 μg (31 nmol) of precursor. In μPET
                      experiments, the radiolabeled productshowed very low
                      radioactivity accumulation in bones, indicating a lackof
                      significant in vivo defluorination. The study also
                      demonstratedalmost exclusive hepatobiliary elimination of
                      the tracer, presumablyowing to its very high
                      lipophilicity.Conclusions: The SuFEx protocol developed for
                      radiolabeling offluorosulfates was successfully applied for
                      the simple and fastpreparation of 18 F-labeled sulfamoyl
                      fluorides. High metabolic stabilityof Boc-Trp(SO2 [
                      18F]F)-OMe underlines the suitability of this class
                      ofradiolabeled compounds as PET-probes for in vivo
                      imaging.Reference[1] Walter N., Bertram J., Drewes B.,
                      Bahutski V., Timmer M., SchützM. B., Krämer F., Neumaier
                      F., Endepols H., Neumaier B.,Zlatopolskiy B. D., European
                      Journal of Medicinal Chemistry2022, 237, 114383.},
      month         = {May},
      date          = {2023-05-22},
      organization  = {25th International Symposium on
                       Radiopharmaceutical Sciences, Honolulu,
                       USA (USA), 22 May 2023 - 26 May 2023},
      subtyp        = {After Call},
      cin          = {INM-5},
      cid          = {I:(DE-Juel1)INM-5-20090406},
      pnm          = {5253 - Neuroimaging (POF4-525)},
      pid          = {G:(DE-HGF)POF4-5253},
      typ          = {PUB:(DE-HGF)6},
      url          = {https://juser.fz-juelich.de/record/1026459},
}