Study On The Method Of Efficiently Constructing N-Glycosidic Bonds And Total Synthesis Of Plicacetin And Norplicacetin

Glycosylation is the soul of sugar chemistry and the charm of sugar chemistry.The development of a universal approach,high glycosidation efficiency has always been the dream of sugar scientists.In 2017,our research group developed a novel glycosidation method using o-alkynylphenol ether as a leaving group.This donor is relatively stable and can be orthogonalized with an acyl protecting group to make up for the shortcomings of Yu's glycosidation.Moreover,the glycosidation method has high glycosidation efficiency,mild reaction conditions,simple preparation method,less side reaction,cheap and easy catalyst,sensitive to acid and alkali,large steric hindrance and low activity.The yield was obtained as a glycosidation product.Based on the advantages of our donors,we would like to use them in the study of Nglycosidic methods and in the total synthesis of two antibiotics,Plicacetin and Norplicacetin.N-glycosides are an important class of drugs which are used clinically to treat viral infectious diseases,tumors,and AIDS.The construction of N-glycosides is a critical step in chemical synthesis of such drug molecules.It has been proved by experiments that the O-alkynylphenol ether(MPEP)donors which was developed by our research group,it can efficiently construct N-glycosides and realize the efficient construction of different saccharide compounds and N-glycosides of purines and pyrimidines.The research of antibiotics is an important field in the microbiology.With the rapid development of antibiotic research,antibiotic drugs have become an indispensable part of clinical drugs.Plicacetin and Norplicacetin are two of antibiotics which were isolated from Streptomyces fermentation broth and have significant inhibitory effects on Gram-positive and mycobacteria.We synthesized the two compounds by linear synthesis strategy.In this process,we overcame three synthesis difficulties : the construction of the 2,3-di-deoxyglucose,the construction of Ngiycosidic bond,and the construction of 1,2 cis-glycosidic bond.