Nadeem Qaisar, Shen Yunjun, Warsi Muhammad Farooq, Nasar Gulfam, Qadir Muhammad Abdul, Alberto Roger
Department of Chemistry, Baghdad-ul-Jadeed Campus, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan.
Department of Chemistry, Zhejiang University, 38, 310027, Hangzhou, P. R. China.
J Labelled Comp Radiopharm. 2017 Jul;60(9):394-400. doi: 10.1002/jlcr.3515. Epub 2017 May 30.
The present study reports the syntheses of half-sandwich complexes of the type [M(η -C H CONH-R)(CO) ] (M═Re, Tc;R═cyclic RGD peptide (cRGDyK) for potential imaging of α β integrin expression. The Tc complex was prepared directly from the reaction of [ Tc(OH ) (CO) ] with cRGDyK, doubly conjugated to Thiele's acid [(C H COOH) ] in water. This approach extends the viability of metal-mediated retro Diels-Alder reactions for the preparation of small molecules such as linear tripeptides to a more complex cyclic peptide carrying a [(η -C H ) Tc(CO) ] tag. The Diels-Alder product [(C H CONH-cRGDyK) ] was prepared from Thiele's acid via double peptide coupling. The Re-complex [Re(η -C H CONH-cRGDyK)(CO) ] was obtained by attaching [Re(η -C H COOH)(CO) ] directly to the N-terminus of cRGDyK. The identity of the Tc-complex is confirmed by chromatographic comparison with the corresponding rhenium complex, fully characterized by spectroscopic techniques.
本研究报道了[M(η⁵-C₅H₄CONH-R)(CO)₃]类型的半夹心配合物（M = Re、Tc；R = 环状RGD肽（cRGDyK））的合成，用于αβ整合素表达的潜在成像。锝配合物是通过[⁹⁹ᵐTc(OH)₃(CO)₃]与在水中与蒂勒酸[(C₅H₄COOH)₂]双共轭的cRGDyK直接反应制备的。这种方法将金属介导的逆狄尔斯-阿尔德反应用于制备小分子（如线性三肽）的可行性扩展到携带[(η⁵-C₅H₄)Tc(CO)₃]标签的更复杂的环状肽。狄尔斯-阿尔德产物[(C₅H₄CONH-cRGDyK)₂]是通过蒂勒酸经双肽偶联制备的。铼配合物[Re(η⁵-C₅H₄CONH-cRGDyK)(CO)₃]是通过将[Re(η⁵-C₅H₄COOH)(CO)₃]直接连接到cRGDyK的N端获得的。锝配合物的身份通过与相应铼配合物的色谱比较得到证实，铼配合物通过光谱技术进行了充分表征。
