To develop PET tracers for imaging of heart disease, a new carbon-11 labeled potent and selective PDE5 inhibitor [11C]TPN171 ([11C]9) has been synthesized. The reference standard TPN171 (9) and its corresponding precursor desmethyl-TPN171 (11) were synthesized from methyl 3-oxovalerate and 2-hydroxybenzonitrile in 9 and 10 steps with 31% and 25% overall chemical yield, respectively. The radiotracer [11C]TPN171 was prepared from desmethyl-TPN171 with [11C]CH3OTf through N-11C-methylation and isolated by HPLC purification followed by SPE formulation in 45–55% 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.
- Carbon-11 labeled PDE5 inhibitor
- Heart disease
- Phosphodiesterase 5 (PDE5)
- Positron emission tomography (PET)
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