Synthesis of N-(3-(4-[11C]methylpiperazin-1-yl)−1-(5-methylpyridin-2-yl)−1H-pyrazol-5-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamide as a new potential PET agent for imaging of IRAK4 enzyme in neuroinflammation

Xiaohong Wang, Wenzhi Xu, Caihong Miao, Fugui Dong, Wei Li, Min Wang, Mingzhang Gao, Qi Huang Zheng, Zhidong Xu

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

The reference standard N-(3-(4-methylpiperazin-1-yl)−1-(5-methylpyridin-2-yl)−1H-pyrazol-5-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamide (9) and its demethylated precursor N-(1-(5-methylpyridin-2-yl)−3-(piperazin-1-yl)−1H-pyrazol-5-yl)pyrazolo[1,5-α]pyrimidine-3-carboxamide (8) were synthesized from pyrazolo[1,5-a]pyrimidine-3-carboxylic acid and ethyl 2-cyanoacetate with overall chemical yield 13% in nine steps and 14% in eight steps, respectively. The target tracer N-(3-(4-[11C]methylpiperazin-1-yl)−1-(5-methylpyridin-2-yl)−1H-pyrazol-5-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamide ([11C]9) was prepared from its precursor with [11C]CH3OTf through N-[11C]methylation and isolated by HPLC combined with SPE in 50–60% radiochemical yield, based on [11C]CO2 and decay corrected to EOB. The radiochemical purity was >99%, and the specific activity at EOB was 370–1110 GBq/μmol.

Original languageEnglish (US)
Pages (from-to)6-12
Number of pages7
JournalApplied Radiation and Isotopes
Volume132
DOIs
StatePublished - Feb 2018

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Keywords

  • Interleukin-1 receptor-associated kinase 4 (IRAK4)
  • N-(3-(4-[C]methylpiperazin-1-yl)−1-(5-methylpyridin-2-yl)−1H-pyrazol-5-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamide
  • Neuroinflammation
  • Positron emission tomography (PET)
  • Radiosynthesis

ASJC Scopus subject areas

  • Radiation

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