[18F]T807 (also known as [18F]AV-1451) is a highly selective and specific PET (positron emission tomography) tracer for imaging of tau pathologies in Alzheimer's disease (AD), recently developed and patented by Siemens, and early clinical PET imaging results with this radioligand have been reported. The importance of this compound as a PET AD imaging agent is well recognized, and broader research investigation to fully explore and validate the utility of neuroimaging tool [18F]T807-PET is important. However, the limited commercial availability, complicated and patented synthetic procedure, and high costs of starting materials and precursor can present an obstacle to more widespread evaluation of this intriguing agent. Wishing to study this compound in our PET center, we decided to make our own material by modifying the literature methods. The authentic standard T807 was synthesized from (4-bromophenyl)boronic acid and 3-bromo-4-nitropyridine in 3 steps (Suzuki coupling, cyclization and Suzuki coupling) with 30% overall chemical yield. The cyclization reaction conditions including temperature and time were optimized. The second Suzuki coupling reaction was modified by changing the catalyst and reaction solvent. Significant improvements in the multiple-step organic synthesis of T807 included increasing the yields and enlarging the reaction scale. Following the literature method, [18F]T807 can be prepared from its either nitro-precursor or quaternary ammonium salt precursor by the nucleophilic substitution with K[18F]F/Kryptofix 2.2.2 and isolated by HPLC combined with SPE (solid-phase extraction) purification.

Synthesis of T807 for preparation of [<sup>18</sup>F]T807, a tau PET imaging agent for Alzheimer's disease

248th National Meeting (2014)

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Synthesis of T807 for preparation of [18F]T807, a tau PET imaging agent for Alzheimer's disease

Synthesis of T807 for preparation of [¹⁸F]T807, a tau PET imaging agent for Alzheimer's disease