The Studies On The Synthesis Of Glycyl-L-glutamine And Glycyl-L-tyrosine

L-Glutamine(Gln) is the most abundant amino acid in human body which accounts for 50% to 60% of all free amino acids. It is essential for the patients to provide them Gln when they meet trauma、infection and other critical diseases. L-Tyrosine(Tyr) is essential amino acid for newborns and liver failure body and it is helpful for people who suffer tension, cold, tired and hard work. However, L-Glutamine and L-Tyrosine have a low solubility in water and release toxic substance when they are under autoclave condition, which restrict their clinical application.Glycyl-L-glutamine and Glycyl-L-tyrosine dipeptides can decomposition for glutamine and tyrosine to meet the demand of human metabolic. Both of them have good clinical evaluation for their good solubility, stability in water. Therefore, Glycyl-L-glutamine and Glycyl-L-tyrosine have obvious advantages and broad market propects.In this paper, based on the analysis of technology and experiments, Glycyl-L-glutamine was synthesized by halide acyl method from glutamine and chloroacetyl chloride through acylation and ammonolysis reaction. In ammonolysis reaction, when we replaced ammonia water, ammonium bicarbonate with DMF/ammonia and ammonium carbonate respectively, the impurities are greatly reduced. We determined the molar ratio of N-chloroacetyl-glutamine, ammonia and ammonium carbonate is 1:16:6 by orthogonal experiments. We controlled the pH at 7.5 to 8.5 in crastallization to get product with higher purity. After optimization of the reaction conditions, the total yield of the technology is raised to 70.9%, a 3.5% increased in yield compared to the original process. The purity can be increased to 98.9% from 97.2% and the main byproduct Glycyl-L-glutamic acid can be greatly reduced. The resin column purification process can be replaced by recrystallization. This technology is more conductive to industrial production.We also researched Glycyl-L-glutamine synthesis by hydrazinolysis method. Glutamine dipeptide was synthesized from glycine through N-protection, acylating chlorination, condensation and hydrazinolysis. In condensation reaction, we promote the conversion by replaced toluene/water system with the mixed solvent of toluene/water/acetone. We used potassium carbonate as acid-binding agent to reduce the hydrolysis of chloride. By investigating the key factors of the reaction, we determined that the molar ratio of glutamine and phthalimide acetyl chloride is 1:1.2, the reaction pH is 7.5 to 8.5, the reaction temperature is 0~5℃. In the hydrazinolysis, methanol is optimal solvent, we determined the molar ratio of phthalimide acetyl glutamine, trimethylamine and hydrazine hydrate is 1:1.1:1.8. This process is more stable and controllable and the overall yield is 72.8%, a 3.5% increased in yield compared to the original process(calculated by glutamine).Based on analysis of technology and experiments, Glycyl-L-tyrosine was synthesized by halide acyl method from tyrosine and chloroacetyl chloride through acylation and ammonolysis reaction. In ammonolysis reaction, when we replaced ammonia water, ammonium bicarbonate with DMF/ammonia and ammonium carbonate respectively, the purity of the product is improved. We determined the molar ratio of N-chloroacetyl- tyrosine, ammonia and ammonium carbonate is 1:10:2 by orthogonal experiments. The product was crystallized and recrystallized in water/ethanol/ethyl acetate with higher purity. After optimization of the reaction conditions, the total yield of the technology is raised to 68.2%, a 5.8% increased in yield compared to the original process. The purity can be increased to 98.3%, so the resin column purification process can be replaced by recrystallization. This technology is more conductive to industrial production.In addition, we have analyzed and synthesized three relevant substances of Glycyl-L-glutamine and Glycyl-L-tyrosine. The structure and purity of these substances were confirmed by 1HNMR and HPLC.