基于季胺基修饰的核磁共振成像造影剂的合成

Synthesis of Magnetic Resonance Imaging Contrast Agent with Tethered Quaternary Ammonium Group

利用季胺基团具有高水溶性的特点,合成了一种水溶性良好且带有长烷烃链的核磁共振成像造影剂。通过在1,4,7,10-四氮杂环十二烷(cyclen)的骨架碳原子上引入季胺基团,并分别对4个仲氨基进行亲电取代,得到具有季胺基侧链的多齿配体;在不影响对钆(Ⅲ)离子的络合能力的同时,提高了配合物的弛豫率,并赋予其良好的水溶性。长烷烃链和季胺基团的同时引入为该类配合物的进一步功能化提供了可能性。

Benefited with the high water solubility of quaternary ammonium group, a magnetic resonance imaging （MRI） contrast agent with tethered quaternary ammonium group linked by long alkyl chain was synthesized. The quaternary ammonium group was introduced in the skeleton of 1,4,7,10- tetraazacyclododecane （cyclen）, and four secondary amino groups in cyclen were functionalized with carboxymethyl groups, forming a polychelating ligand with a quaternary ammonium side chain. Without affecting the conjugation ability, this ligand forms stable Gd（III） complex showing higher relaxivity than Gd（III）-DOTA. With both quaternary ammonium group and long alkyl chain installed in the same molecule, further functionalization or modification to achieve high performance MRI contrast agents is promising.