Max Planck Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany.
Chem Soc Rev. 2013 Nov 7;42(21):8220-36. doi: 10.1039/c3cs60153f. Epub 2013 Jul 22.
Squaric acid diesters can be applied as reagents to couple two amino-functional compounds. Consecutive coupling of two amines allows the synthesis of asymmetric squaric acid bisamides with either low molecular weight compounds but also biomolecules or polymers. The key feature of the squaric acid diester mediated coupling is the reduced reactivity of the resulting ester-amide after the first amidation step of the diester. This allows the sequential amidation and generation of asymmetric squaramides with high selectivity and in high yields. This article gives an overview of the well-established squaric acid diester mediated coupling reactions for glycoconjugates and presents recent advances that aim to expand this very versatile reaction protocol to the modification of peptides and proteins.
丁烷-1,4-二羧酸二酯可用作偶联两个氨基官能化合物的试剂。连续偶联两个胺可以合成具有低分子量化合物、生物分子或聚合物的不对称丁烷-1,4-二羧酸双酰胺。丁烷-1,4-二羧酸二酯介导的偶联的关键特征是二酯的第一次酰胺化步骤后生成的酯酰胺的反应性降低。这允许顺序酰胺化和不对称的丁烷-1,4-二羧酸双酰胺的生成具有高选择性和高产率。本文综述了用于糖缀合物的成熟的丁烷-1,4-二羧酸二酯介导的偶联反应，并介绍了旨在将这一非常通用的反应方案扩展到肽和蛋白质修饰的最新进展。
