Study On The Synthesis Of Aspartame By Lactone

The paper briefly summarizes sweet agent theory, mainly consisting chemical essence, taste mechanism and the interaction mechanism between sweet and sweetener receptor. Researching in these basal theories can lend people to synthesis some advanced sweet agents selectively and independently.The methods of synthesis aspartame can be separated of chemical method, biology method and gene zymotechnics, but chemical method is superior to others. For Lactone method shows its profound superiority with high selectivity, high yield , simple operation and inexpensive material, it is choosed to synthesis aspartame. The protecting group is easily removed and the whole synthesis processes haven't waste water, waste gas, solid wastes.The synthesis routes are showed as follows. First, L- phenylalanine methylester hydrochloric acid was obtained by using classical method of ROH-HCl which has superiority with high yield and inexpensive raws. By adding magnesium sulfuric acid to remove water of reaction in the synthesis of L-PheOH·HCl, the yield reaches 98.1%. Second, N-for-aspartic acid anhydride was obtained from the reaction of formic acid and L-aspartic acid in acetic anhydride, Which reacted with paraformaldehyde in glacial acetic acid to form 3-formyl-4-carboxymethyl-1,3-oxazolidine-5-one. After optimizing the technical conditions and got satisfied results, the yields are 90.6% and 86.1% respectively. At the same time, the crystal atmosphere of lactone was explained. Then, N-for-aspartame was obtained from the reaction of 3-formyl-4-carboxymethyl-1,3-oxazolidine-5-one and L-phenylalanine methylester hydrochloric acid under sodium acetate anhydrous in ethyl acetate, and the target product was prepared after removing formyl in the mixture system of hydrochloric acid, methanol and water, the yield of aspartame reaches 89.2%. Finally, the structure of title compounds and intermediates were characterized by elemental analysis, IR, MS and so on, which are consist with the expected structures. By optimizing the condition of every step to reduce the product cost, which make this method with good market prospect.