کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1390817 1500905 2007 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Synthesis and conformational behavior of the difluoromethylene linked C-glycoside analog of β-galactopyranosyl-(1↔1)-α-mannopyranoside
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Synthesis and conformational behavior of the difluoromethylene linked C-glycoside analog of β-galactopyranosyl-(1↔1)-α-mannopyranoside
چکیده انگلیسی
C-Glycosides in which the pseudoglycosidic substituent is a methylene group have been advertised as hydrolytically stable mimetics of their parent O-glycosides. While this substitution assures greater stability, the lower polarity and increased conformational flexibility in the intersaccharide linker brought about by this change may compromise biological mimicry. In this regard, C-glycosides, in which the pseudoanomeric methylene is replaced with a difluoromethylene group, are interesting because the CF2 group is more of an isopolar replacement for oxygen than CH2. In addition, the CF2 residue is expected to instill conformational bias into the intersaccharide torsions. Herein is described the synthesis and conformational behavior of the difluoromethylene linked C-glycoside of β-d-galactopyranosyl-(1↔1)-α-d-mannopyranoside. The synthesis centers on the formation of the galactose residue via an oxocarbenium ion-enol ether cyclization. Conformational analysis, using a combination of molecular mechanics, dynamics, and NMR spectroscopy, suggests that the difluoro-C-glycoside populates the non-exo-Gal/exo-Man conformer to a major extent (ca 50%), with a minor contribution (∼15%) from the exo-Gal/exo-Man conformer that corresponds to the ground sate of the parent O-glycoside.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Carbohydrate Research - Volume 342, Issues 12–13, 3 September 2007, Pages 1624-1635
نویسندگان
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