Sampathkumar Srinivasa-Gopalan, Li Adrienne V, Yarema Kevin J
Department of Biomedical Engineering, The Johns Hopkins University, 3400 N Charles Street, Clark Hall Rm 106A, Baltimore, Maryland 21218, USA.
Nat Protoc. 2006;1(5):2377-85. doi: 10.1038/nprot.2006.319.
The sialic acid biosynthetic pathway in mammalian cells utilizes N-acetyl-D-mannosamine (ManNAc) as a natural metabolic precursor and has the remarkable ability to biosynthetically process non-natural ManNAc analogs. Herein, we describe a recipe-style protocol for the synthesis of the novel peracetylated analog Ac5ManNTGc (1) that contains a pendant acetylthio- group and enables incorporation of thiol functionalities into the glycocalyx of living cells. We also describe the synthesis of the oxygen analog Ac5ManNGc (2), which serves as an appropriate control compound for biological experiments with 1. Both 1 and 2 were prepared from a reported, common intermediate 8, which is selectively acetylated at the hydroxyl groups. In contrast to previous methods, this synthetic approach introduces O-acetyl groups first, followed by N-acylation. Starting from the commercially available D-mannosamine hydrochloride (5), gram quantities of both 1 and 2 can be prepared over five steps in about 2-3 weeks.
哺乳动物细胞中的唾液酸生物合成途径利用N-乙酰-D-甘露糖胺（ManNAc）作为天然代谢前体，并且具有生物合成处理非天然ManNAc类似物的显著能力。在此，我们描述了一种合成新型全乙酰化类似物Ac5ManNTGc（1）的配方式方案，该类似物含有一个侧链乙酰硫基，能够将硫醇官能团引入活细胞的糖萼中。我们还描述了氧类似物Ac5ManNGc（2）的合成，它作为与1进行生物学实验的合适对照化合物。1和2均由报道的常见中间体8制备，该中间体在羟基处被选择性乙酰化。与先前的方法不同，这种合成方法首先引入O-乙酰基，然后进行N-酰化。从市售的盐酸D-甘露糖胺（5）开始，通过五步反应，大约2 - 3周内可以制备克级量的1和2。
