Synthesis Of Glucosamine Peptide Mimetics Derivatives

Protein is an active substance needed by all organisms, and the glycosylation ofprotein plays a very important role in its activity, stability, immunogenicity, signaltransduction, and so on. Since the glycoprotein isolated from organisms is specificand complicated, it is difficult to study its stability and activity. Therefore, in recentyears the research has been increasingly focused on simulating and discussing theaction of glycoprotein through the synthesis of glycopeptides derivatives in vitro.Glycopeptide derivatives have a variety of potential physiological andpharmacological effects, however, the peptide bond is unstable and susceptible todegradation in vivo. Nowadays, the research has been gradually turned to thesynthesis of glycopeptide mimetics which have physiological and pharmacologicalfunctions.In the synthesis of glycopeptide and glycopeptide mimetics, the application ofglucosamine as the glycosylation ligand is increasingly significant and extensive. Onone hand,, as the ultimate degradation products of chitin, glucosamine can be obtainedfrom abundant raw materials, on the other hand, glucosamine not only possesses thefunction of treating arthritis, diminishing inflammation, stimulating the synthesis ofproteoglycan, but also could play a part in immunomodulatory effect by activatingNK and LAK cells.In this article,1,3,4,6-tetra-O-acetyl-α-D-glucosamine sulfate was prepared bydirect acetylation of D-glucosamine hydrochloride with acetic anhydride. Thestructures of1,3,4,6-tetra-O-acetyl-α-D-glucosamine sulfate was analyzed by MS,¹HNMR, and¹³C NMR spectroscopy. Then1,3,4,6-tetra-O-acetyl-α-D-glucosaminesulfate was transformed into the corresponding isocyanate by using triphosgene as theisocyanation agent in an aqueous two-phase system and four ureido glucosamineamino acid derivatives were efficiently synthesized by coupling the isocyanate withcorresponding four different amino acid methyl esters. The optimal reaction conditionwas confirmed by investigating reaction temperature and ratio of substrate on the yield. The yield of the target products was more than83%and the purity was morethan96%. Subsequently, three new glucosamine dipeptide mimetics were synthesizedby coupling the isocyanate with three kinds of dipeptide methyl esters accompaniedby discussing the relationship between the yield and the logP of correspondingdipeptide methyl ester which could forecast the synthetic yield of this class ofderivatives preliminarily. The structures of these7new compounds were analyzed byMS,¹H NMR, and¹³C NMR spectroscopy. The results proved that this method wassimple, moderate, economic and efficient with the target products owning singleconfigurations.At the same time, the pharmacological activity of these2glucosamine peptidemimetics derivatives was researched. The results showed that D-glucosaminederivatives could effectively inhibit the activity of herpes simplex virus I type in vitrowithout toxicity to vero cell in the concentration of200μg·mL^-1.