Synthesis and in vitro biological evaluation of carbon-11-labeled quinoline derivatives as new candidate PET radioligands for cannabinoid CB2 receptor imaging

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Cannabinoids have been recently proposed as a new family of potential antitumor agents, and cannabinoid receptor 2 (CB2) is believed to be over-expressed in tumor cells. This study was designed to develop new radioligands for imaging of CB2 receptor in cancer using biomedical imaging technique positron emission tomography (PET). Carbon-11-labeled 2-oxoquinoline and 2-chloroquinoline derivatives, [11C]6a-d and [11C]9a-d, were prepared by O-[11C]methylation of their corresponding precursors using [11C]CH3OTf under basic conditions and isolated by a simplified solid-phase extraction (SPE) method in 40-50% radiochemical yields based on [11C]CO2 and decay corrected to end of bombardment (EOB). The overall synthesis time from EOB was 15-20 min, the radiochemical purity was >99%, and the specific activity at end of synthesis (EOS) was 111-185 GBq/μmol. Radioligand binding assays indicated compounds 6f, 6b, and 9f display potent in vitro binding affinities with nanomolar Ki values and at least 100-2000-fold selectivity for CB2.

Original languageEnglish (US)
Pages (from-to)2099-2106
Number of pages8
JournalBioorganic and Medicinal Chemistry
Issue number6
StatePublished - Mar 15 2010



  • Cancer imaging
  • Cannabinoid receptor 2 (CB2)
  • Carbon-11-labeled quinoline derivatives
  • Positron emission tomography (PET)
  • Radioligands

ASJC Scopus subject areas

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

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