Abstract:
Radiolabeled peptides are valuable tools for diagnosis or therapies; they are often radiofluorinated using an indirect approach based on an F-18 prosthetic group. Herein, we are reporting our results on the F-18 radiolabeling of three peptides using two different methods based on click reactions. The first one used the well-known CuAAC reaction, and the second one is based on our recently reported hetero-Diels-Alder (HDA) using a dithioesters (thia-Diels-Alder) reaction. Both methods have been automated, and the 18F-peptides were obtained in similar yields and synthesis time (37-39% decay corrected yields by both methods in 120-140 min). However, to obtain similar yields, the CuAAC needs a large amount of copper along with many additives, while the HDA is a catalyst and metal-free reaction necessitating only an appropriate ratio of water/ethanol. The HDA can therefore be considered as a minimalist method offering easy access to fluorine-18 labeled peptides and making it a valuable additional tool for the indirect and site-specific labeling of peptides or biomolecules.
摘要:
放射性标记的肽是用于诊断或治疗的有价值的工具;它们通常使用基于F-18辅基的间接方法进行放射性氟化。在这里,我们正在报告使用基于点击反应的两种不同方法对三种肽进行F-18放射性标记的结果.第一个使用众所周知的CuAAC反应,第二个是基于我们最近报道的异Diels-Alder(HDA)使用二硫酯(thia-Diels-Alder)反应。这两种方法都是自动化的,并且18F-肽以相似的产率和合成时间获得(通过两种方法在120-140分钟内进行37-39%衰减校正产率)。然而,为了获得相似的产量,CuAAC需要大量的铜以及许多添加剂,而HDA是催化剂和不含金属的反应,仅需要适当比例的水/乙醇。因此,HDA可以被认为是一种极简主义方法,其提供了容易获得氟-18标记的肽,并使其成为用于肽或生物分子的间接和位点特异性标记的有价值的附加工具。