Radiosynthesis of carbon-11 labeled PDE5 inhibitors as new potential PET radiotracers for imaging of Alzheimer's disease

F. Dong, Jie Du, Caihong Miao, Limeng Jia, Wei Li, Min Wang, Qi Huang Zheng, Zhidong Xu

Research output: Contribution to journalArticle


To develop PET tracers for imaging of Alzheimer's disease, new carbon-11 labeled potent and selective PDE5 inhibitors have been synthesized. The reference standards (5) and (12), and their corresponding desmethylated precursors (6) and (13) were synthesized from methyl 2-amino-5-bromobenzoate and (4-methoxyphenyl)methanamine in multiple steps with 2%, 1%, 1% and 0.2% overall chemical yield, respectively. The radiotracers ([11C]5) and ([11C]12) were prepared from their corresponding precursors 6 and 13 with [11C]CH3OTf through O–11C-methylation and isolated by HPLC combined with SPE in 40–50% radiochemical yield, based on [11C]CO2 and decay corrected to EOB. The radiochemical purity was >99%, and the molar activity (Am) at EOB was in a range of 370–740 GBq/μmol.

Original languageEnglish (US)
Article number108873
JournalApplied Radiation and Isotopes
StatePublished - Dec 2019



  • Alzheimer's disease (AD)
  • Carbon-11 labeled PDE5 inhibitors
  • Phosphodiesterase 5 (PDE5)
  • Positron emission tomography (PET)
  • Radiosynthesis

ASJC Scopus subject areas

  • Radiation

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