Synthesis of Precursors of Two ¹⁸F Labeled Styrylpyridine Derivatives as PET Imaging Agents

¹⁸F-AV45 was the first PET imaging agent for Alzheimer’s disease approved by FDA. Its isomer ¹⁸F-YG may have better performance in the same field. To promote the localization of ¹⁸F-AV45 and the evaluation of ¹⁸F-YG, the precursors of the two ¹⁸F labeled styrylpyridine derivatives were obtained. AV105 and YGQT were synthesized using 4-aminostyrene as starting materials. First, aromatic amido was protected by carbonic acid tert-butyl and methylated by methyl iodide to obtain tert-butyl 4-vinylphenylcarbamate. Then, the hydrogen atom on the double bond of tertbutyl 4-vinylphenylcarbamate was replaced by iodopyridine which was modified by TEG. And the hydroxyl of TEG chains was protected by P-toluene sulfonic acid group. The total yields of AV105 and YGQT were 57% and 66% respectively. Their structures were confirmed to be correct by ESI-MS and ¹H NMR investigations. This work provides a basis to study the performance of ¹⁸F-AV45 and ¹⁸F-YG in the further.