Synthesis of the β anomer of the spacer-equipped tetrasaccharide side chain of the major glycoprotein of the Bacillus anthracis exosporium

• Published in: Carbohydrate research 2005-12, Vol.340 (17), p.2579-2582
• Main Authors: Adamo, Roberto, Saksena, Rina, Kováč, Pavol
• Format: Article
• Language: English
• Subjects: Anthrax; Anthrose; Bacillus anthracis - metabolism; Carbohydrate Conformation; Carbohydrate Sequence; Exosporium glycoprotein; Membrane Glycoproteins - biosynthesis; Membrane Glycoproteins - chemistry; Models, Molecular; Molecular Sequence Data; Oligosaccharide; Oligosaccharides - biosynthesis; Oligosaccharides - chemistry; Thioglycoside
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/j.carres.2005.09.015

Synthesis of the tetrasaccharide side chain of the major glycoprotein of the Bacillus anthracis exosporium. The β glycoside of the tetrasaccharide sequence β-Ant-(1→3)-α- l-Rha p-(1→3)-α- l-Rha p-(1→2)- l-Rha p, whose aglycon allows conjugation to proteins, was synthesized for the first time. A stepwise synthetic approach was applied with thioglycosides as glycosyl donors, and the β anomer of the compound was obtained equipped with a spacer group whose further transformation allows conjugation to suitable carriers. To synthesize the β-anthrosyl linkage with high stereoselectivity, a linker-equipped rhamnotriose derivative was glycosylated with ethyl 4-azido-3- O-benzyl-2- O-bromoacetyl-4,6-dideoxy-1-thio-β- d-glucopyranoside. Further functionalization of the tetrasaccharide thus obtained, followed by deprotection, gave the target substance.