A disaccharide repeating unit of the O-antigen from Burkholderia ambifaria, 6-deoxy-β-d-Alt-(1→4)-α-d-Rha-O(CH2)3NH2 (1), and its dimer and trimer, 6-deoxy-β-d-Alt-(1→4)-α-d-Rha-(1→3)-6-deoxy-β-d-Alt-(1→4)-α-d-Rha-O(CH2)3NH2 (2) and 6-deoxy-β-d-Alt-(1→4)-α-d-Rha-(1→3)-6-deoxy-β-d-Alt-(1→4)-α-d-Rha-(1→3)-6-deoxy-β-d-Alt-(1→4)-α-d-Rha-O(CH2)3NH2 (3), were synthesized via a convergent strategy. The key disaccharyl thioglycoside 4 as a glycosyl donor was stereoselectively assembled by glycosylation of rhammnosyl acceptor 5 with 6-deoxy-altrosyl trichloroacetimidate donor 6b. The glycosidation of 4 with 3-azidopropanol followed by global deprotection afforded the target disaccharide 1. Further elongation of the carbohydrate chain of this glycosidation product with the disaccharyl donor 4 followed by global deprotection generated rapidly the dimeric tetrasaccharide 2 and the trimeric hexasaccharide 3 in a convergent [2 + 2] and [2 + 2 + 2] manner, respectively.
Lipopolysaccharide, synthesis, O-antigen, Burkholderia ambifaria, Carbohydrate vaccine
NCBI PubMed ID: 28288346Publication DOI: 10.1016/j.carres.2017.03.004Journal NLM ID: 0043535Publisher: Elsevier
Correspondence: guofenggu@sdu.edu.cn
Institutions: Department of Chemistry, University of Florida, 214 Leigh Hall, Gainesville 32611, FL, United States, National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Jinan 250010, PR China
Methods: 13C NMR, 1H NMR, TLC, chemical synthesis, MALDI-TOF MS, UV, glycosylation
Found