Synthesis and Molecular Structure of the 5-Methoxycarbonylpentyl α-Glycoside of the Upstream, Terminal Moiety of the O-Specific Polysaccharide of Vibrio cholerae O1, Serotype Inaba

Molecules

Peng Xu²  Edwin D. Stevens¹  Alfred D. French⁴  Pavol Kováč²  Marco Terreni³ 

[1] Department of Chemistry, Western Kentucky University, 1906 College Heights Blvd., Bowling Green, KY 42101-1709, USA; E-Mail:;NIDDK, LBC, National Institutes of Health, Bethesda, MD 20892-0815, USA; E-Mail:;NIDDK, LBC, National Institutes of Health, Bethesda, MD 20892-0815, USA; E-Mail;Southern Regional Research Center, US Department of Agriculture, 1100 Robert E Lee Blvd, New Orleans, LA 70124, USA; E-Mail:

关键词: Vibrio cholerae O1;    glycosylation;    glycosidation;    crystal structure;   

DOI  :  10.3390/molecules20022892

来源: mdpi

【 摘 要 】

The trimethylsilyl trifluoromethanesulfonate (TMSOTf)-catalyzed reaction of methyl 6-hydroxyhexanoate with 3-O-benzyl-4-(2,4-di-O-acetyl-3-deoxy-l-glycero-tetronamido)-4,6-dideoxy-2-O-levulinoyl-α-d-mannopyranosyl trichloroacetimidate followed by a two-step deprotection (hydrogenolysis over Pd/C catalyst and Zemplén deacylation, to simultaneously remove the acetyl and levulinoyl groups) gave 5-(methoxycarbonyl)pentyl 4-(3-deoxy-l-glycero-tetronamido)-4,6-dideoxy-α-d-mannopyranoside. The structure of the latter, for which crystals were obtained in the analytically pure state for the first time, followed from its NMR and high-resolution mass spectra and was confirmed by X-ray crystallography. The molecule has two approximately linear components; a line through the aglycon intersects a line through the mannosyl and tetronylamido groups at 120°. The crystal packing separates the aglycon groups from the tetronylamido and mannosyl groups, with only C-H…O hydrogen bonding among the aglycon groups and N-H…O, O-H…O and C-H…O links among the tetronylamido and mannosyl groups. A carbonyl oxygen atom accepts the strongest O-H…O hydrogen bond and two strong C-H…O hydrogen bonds. The geometric properties were compared with those of related molecules.

【 授权许可】

CC BY   
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