A novel versatile precursor suitable for<sup>18</sup>F-radiolabeling via “click chemistry”
作者:B. Lugato、S. Stucchi、S. Ciceri、M.N. Iannone、E.A. Turolla、L. Giuliano、C. Chinello、S. Todde、P. Ferraboschi
DOI:10.1002/jlcr.3529
日期:2017.8
As an effort to improve 18F-radiolabeling of biomolecules in method robustness and versatility, we report the synthesis and radiolabeling of a new azido precursor potentially useful for the so-called “click reaction,” in particular the ligand-free version of the copper(I)-catalyzed alkyne-azide cycloaddition. The new azido precursor may help to overcome problems sometimes exhibited by most of the currently used analogues, as it is safe to handle and it displays long-term chemical stability, thus facilitating the development of new radiolabeling procedures. Moreover, the formed 18F-labeled 1,2,3-triazole is potentially metabolically stable and could enhance the in vivo circulation time. The above azido precursor was successfully radiolabeled with 18F, with 51% radiochemical yield (nondecay-corrected). As a proof of concept, the 18F-labeled azide was then tested with a suitable alkyne functionalized aminoacid (l-propargylglycine), showing 94% of conversion, and a final radiochemical yield of 27% (>99% radiochemical purity), nondecay-corrected, with a total preparation time of 104 minutes.
为了提高18F标记生物分子在方法稳健性和多样性方面的表现,我们报告了一种新型叠氮前体的合成及其放射性标记,该前体可能适用于所谓的“点击反应”,特别是无配体版的铜(I)催化的炔烃-叠氮环加成反应。这种新型叠氮前体有助于克服当前使用的大多数类似物有时展现的问题,因为它易于处理且具有长期的化学稳定性,从而有助于开发新的放射性标记程序。此外,形成的18F标记的1,2,3-三唑潜在地具有代谢稳定性,并可能增强体内循环时间。上述叠氮前体成功通过18F进行了放射性标记,放射化学产率为51%(未校正衰变)。作为概念验证,随后测试了18F标记的叠氮与适当的炔基功能化氨基酸(L-丙炔甘氨酸),显示出94%的转化率,最终放射化学产率为27%(>99%放射化学纯度),未校正衰变,总制备时间为104分钟。