Facile synthesis of carbon-11-labeled sEH/PDE4 dual inhibitors as new potential PET agents for imaging of sEH/PDE4 enzymes in neuroinflammation

Limeng Jia, Caihong Miao, Fugui Dong, Wei Li, Min Wang, Qi Huang Zheng, Zhidong Xu

Research output: Contribution to journalArticle

Abstract

To develop PET tracers for imaging of neuroinflammation, new carbon-11-labeled sEH/PDE4 dual inhibitors have been synthesized. The reference standard N-(4-methoxy-2-(trifluoromethyl)benzyl)benzamide (1) and its corresponding desmethylated precursor N-(4-hydroxy-2-(trifluoromethyl)benzyl)benzamide (2) were synthesized from (4-methoxy-2-(trifluoromethyl)phenyl)methanamine and benzoic acid in one and two steps with 84% and 49% overall chemical yield, respectively. The standard N-(4-methoxy-2-(trifluoromethyl)benzyl)-1-propionylpiperidine-4-carboxamide (MPPA, 4) and its precursor N-(4-hydroxy-2-(trifluoromethyl)benzyl)-1-propionylpiperidine-4-carboxamide (5) were synthesized from methyl 4-piperidinecarboxylate, propionyl chloride and (4-methoxy-2-(trifluoromethyl)phenyl)methanamine in two and three steps with 62% and 34% overall chemical yield, respectively. The target tracers N-(4-[11C]methoxy-2-(trifluoromethyl)benzyl)benzamide ([11C]1) and N-(4-[11C]methoxy-2-(trifluoromethyl)benzyl)-1-propionylpiperidine-4-carboxamide ([11C]MPPA, [11C]4) were prepared from their corresponding precursors 2 and 5 with [11C]CH3OTf through O-[11C]methylation and isolated by HPLC combined with SPE in 25–35% radiochemical yield, based on [11C]CO2 and decay corrected to end of bombardment (EOB). The radiochemical purity was >99%, and the molar activity (AM) at EOB was 370–740 GBq/μmol with a total synthesis time of 35–40-minutes from EOB.

Original languageEnglish (US)
Pages (from-to)1654-1659
Number of pages6
JournalBioorganic and Medicinal Chemistry Letters
Volume29
Issue number13
DOIs
StatePublished - Jul 1 2019

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Keywords

  • Carbon-11-labeled sEH/PDE4 dual inhibitors
  • Neuroinflammation
  • Phosphodiesterase 4 (PDE4)
  • Positron emission tomography (PET)
  • Radiosynthesis
  • Soluble epoxide hydrolase (sEH)

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Pharmaceutical Science
  • Drug Discovery
  • Clinical Biochemistry
  • Organic Chemistry

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