Chemical Synthesis of a Key Precursor Relevant to the Tetrasaccharide Repeating Unit from Treponema medium ATCC 700293  

作　　者：Wenbin Sun Guangzong Tian Meiru Ding Chunjun Qin Xiaopeng Zou Jing Hu Jian Yin 

机构地区：[1]Key Laboratory of Carbohydrate Chemistry and Biotechnology,Ministry of Education,School of Biotechnology&School of Life Sciences and Health Engineering,Jiangnan University,Lihu Avenue 1800,Wuxi,Jiangsu,214122 China [2]Wuxi School of Medicine,Jiangnan University,Lihu Avenue 1800,Wuxi,Jiangsu,214122 China

出　　处：《Chinese Journal of Chemistry》2024年第14期1615-1622,共8页中国化学（英文版）

基　　金：the National Natural Science Foundation of China(22325803,22077052,22277042,22107037,22177041,22207042);the China Postdoctoral Science Foundation(2021M691279);the National Key R&D Program of China(2023YFC2308000).

摘　　要：Treponema is a Gram-negative anaerobic bacterium,among which the pathogenic Treponema can cause various diseases,such as venereal syphilis(Treponema pallidum),yaws(Treponema carateum),and oral diseases(Treponema denticola and Treponema medium).Although different from conventional lipopolysaccharides,the extracellular glycoconjugate of Treponema may still be a potential antigen and provide a candidate for vaccine development.Hence,we completed the first chemical synthesis of Treponema medium ATCC 700293 tetrasaccharide precursor containing L-ornithine(L-Orn)and D-aspartic acid(D-Asp)derivatives.The efficiency of non-reducing end disaccharide formation has been improved by optimizing the assembly of the protecting groups in the donors and acceptors.Our[3+1]glycosylation strategy attempted to reduce the length of the acceptor to increase the nucleophilicity of the hydroxyl group,thereby improving the efficiency of synthesizing the target tetrasaccharide.The L-Orn derivative was introduced at the final stage due to its influence on the glycosylation stereospecificity and efficiency.Therefore,the successful introduction of two amino acid derivatives and the synthesis of a tetrasaccharide precursor with complex functional-group modifications have provided valuable insights for synthesizing other complex bacterial glycans.

关 键 词：Glycosylation Total synthesis Treponema medium ATCC 700293 Tetrasaccharide precursor Protecting group OLIGOSACCHARIDES Regioselectivity Neighboring-group effects 

分 类 号：O62[理学—有机化学]