Dimitriou Eleni, Miller Gavin J
Lennard-Jones Laboratory, School of Chemical and Physical Sciences, Keele University, Keele, Staffordshire, ST5 5BG, U. K.
Beilstein J Org Chem. 2021 Jul 5;17:1527-1532. doi: 10.3762/bjoc.17.110. eCollection 2021.
Alginate is a biocompatible and industrially relevant polysaccharide that derives many of its important properties from the charged carboxylate groups within its polyuronic acid backbone. The design and inclusion of isosteric replacements for these carboxylates would underpin provision of new oligo-/polysaccharide materials with alternate physicochemical properties. Presented herein is our synthesis of mannuronic acid building blocks, appropriately modified at the carboxylate C6 position with a bioisosteric tetrazole. Thioglycosides containing a protected C6-tetrazole are accessed from a C6-nitrile, through dipolar cycloaddition using NaN with -BuSnO. We also demonstrate access to orthogonally C4-protected donors, suitable for iterative oligosaccharide synthesis. The development of these building blocks is showcased to access anomeric 3-aminopropyl- and 1-phosphate free sugars containing this non-native motif.
海藻酸盐是一种具有生物相容性且与工业相关的多糖，其许多重要特性源于其聚糖醛酸主链中的带电荷羧酸盐基团。对这些羧酸盐进行等排取代的设计和引入将为提供具有交替物理化学性质的新型寡糖/多糖材料奠定基础。本文介绍了我们对甘露糖醛酸结构单元的合成，该结构单元在羧酸盐C6位置用生物电子等排体四唑进行了适当修饰。含有受保护的C6-四唑的硫代糖苷可通过使用NaN与-BuSnO进行偶极环加成反应从C6-腈获得。我们还展示了获得适用于迭代寡糖合成的正交C4保护供体的方法。展示了这些结构单元的开发过程，以获得含有这种非天然基序的异头3-氨丙基和1-磷酸基游离糖。
