Wang, XiaohongXu, WenzhiMiao, CaihongDong, FuguiLi, WeiWang, MinGao, MingzhangZheng, Qi-HuangXu, Zhidong2017-12-212017-12-212018-02Wang, X., Xu, W., Miao, C., Dong, F., Li, W., Wang, M., … Xu, Z. (2018). 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. Applied Radiation and Isotopes. https://doi.org/10.1016/j.apradiso.2017.11.005https://hdl.handle.net/1805/14870The 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.enPublisher PolicyN-(3-(4-[11C]methylpiperazin-1-yl)−1-(5-methylpyridin-2-yl)−1H-pyrazol-5-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamideinterleukin-1 receptor-associated kinase 4radiosynthesisArticle