| 摘要 |
<p>A process for preparing a-L-aspartyl-L-phenylalanine methyl ester consisting of:
<UnorderedLists id="ula01" listStyle="none"><ListItem>- bringing N-formyl-L-aspartic anhydride and L-phenylalanine methyl ester, in a molar ratio equal or approximately equal to 1:1, into contact with a solid cation exchange resin having free sulphonic, phosphonic or carboxylic acid groups, the ratio of the acid equivalents of said resin acid groups to the number of moles of the one or other reagent being equal to or lessthan about 1:1, and operating in the liquid phase in an inert organic solvent at a temperature of about 40°C or less, until a mixture of N-formyl-a-L-aspartyl-L-phenylalanine methyl ester and N-formyl-β-L-aspartyl-L-phenylalanine methyl ester forms in which the a isomer prevails over the p isomer;</ListItem><ListItem>- deformylating said N-formyl-a-L- aspartyl-L-phenylalanine methyl ester and N-formyl -β-L- aspartyl -L-phenylalanine methyl ester; and</ListItem><ListItem>- separating and recovering the a-L- aspartyl -L-phenylalanine methyl esterfrom said deformylated products.</ListItem></UnorderedLists></p> |
