Synthetic method of double-sialylated tetrasaccharide

Abstract

The invention discloses a synthetic method of synthesizing double-sialylated tetrasaccharide by a chemically controllable enzyme method. The invention further provides two intermediates, which are used for synthesizing and preparing the double-sialylated tetrasaccharide, are compounds respectively as shown in formulas IV and V. According to the synthetic method disclosed by the invention, the flexibility of a chemical synthetic method and the high-area selectivity and high efficiency of the enzyme synthetic method are combined together, so that synthesis of the double-sialylated tetrasaccharide by using a chemical intervention method is firstly realized, defects such as low substrate reaction activity, multiple synthetic steps and low yield facing in existing chemical synthesis of the double-sialylated tetrasaccharide are solved, as well as a problem that sialyl transferase is difficult to obtain and only glycopeptides is identified in the enzyme method is solved; the synthetic method disclosed by the invention has the advantages of high substrate reaction activity and high yield, and therefore, the synthetic method has important significance in researching biological functions of sialic acid glucoside on molecular level and developing carbohydrate drugs based on the biological functions.

Description

technical field [0001] The invention relates to a chemical enzymatic synthesis method of carbohydrates, in particular to a chemical enzymatic synthesis method of a class of tumor-associated carbohydrate antigens and disialylated tetrasaccharides that can promote nerve repair, and belongs to the field of carbohydrate drugs. Background technique [0002] Disialylated tetrasaccharide Neu5Acα(2-3)Galβ(1-3)[Neu5Acα(2-6)]GalNAc( figure 1 ) widely exists on the surface of various types of cells, and plays a vital role in many physiological and pathological processes. For example, this tetrasaccharide is the most important sugar chain on the highly glycosylated blood group glycophorin (glycophorin) on the surface of human red blood cells. This sugar chain can not only avoid the aggregation of red blood cells, but also participate in many physiological processes mediated by red blood cells (J.Parkkinen, G.N.Rogers, T.Korhonen, W.Dahr, J.Finne.Infectionandimmunity, 1986,54,37-42); th...

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Problems solved by technology

[0005] In view of the above-mentioned present situation, the technical problem to be faced by the present invention at first is to solve the problem that the bacterial source α2,6 sialyltransferase used in the enzymatic synthesis cannot distinguish the galactose (Gal) or the galactose (Gal) of the core disaccharide Galβ(1-3)GalNAc Problems with acetylgalactosamine (GalNAc), thereby introducing the second sialic acid into the correct position

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