PROCESS FOR PRODUCING NUCLEOSIDE

摘要

An anomer mixture of a nonnatural 1-phosphorylated saccharide is reacted with a base by the action of phosphorylase activity, wherein the exchange reaction between the phosphate group of the 1-phosphorylated saccharide and the base is conducted anomer-selectively. Metal cations capable of forming a sparingly water-soluble salt with phosphate ions are caused to be present in the reaction mixture, whereby the phosphate ions which are a by-product of the reaction can be precipitated as a sparingly water-soluble salt and the reaction equilibrium can be shifted toward nucleoside synthesis. Thus, the yield of the target compound is heightened. By utilizing a difference in the rate of the exchange reaction, a mixture of optical isomers of the nucleoside can be obtained in which one of the isomers is contained in a higher proportion.