Synthesis of a cyanoethylidene derivative of 3,6-anhydro-d-galactose and its application as glycosyl donor

Carbohydr Res. 2007 Feb 26;342(3-4):520-8. doi: 10.1016/j.carres.2006.09.015. Epub 2006 Oct 23.

Abstract

Starting from 1,2,4-tri-O-acetyl-3,6-anhydro-alpha-d-galactopyranose, 4-O-acetyl-3,6-anhydro-1,2-O-(1-cyanoethylidene)-alpha-d-galactopyranose (7) was synthesized by treatment with cyanotrimethylsilane. Additionally, 3,4-di-O-acetyl-1,2-O-(1-cyanoethylidene)-6-O-tosyl-alpha-d-galactopyranose was prepared from the corresponding bromide and both cyanoethylidene derivatives were used as donors in glycosylation reactions. The coupling with benzyl 2,4,6-tri-O-acetyl-3-O-trityl-beta-d-galactopyranoside provided exclusively the beta-linked disaccharides in approximately 30% yield. The more reactive methyl 2,3-O-isopropylidene-4-O-trityl-alpha-l-rhamnopyranoside gave with donors 3 and 7 the corresponding disaccharides in nearly 60% yield. Furthermore, the synthesis of 3,6-anhydro-4-O-trityl-1,2-O-[1-(endo-cyano)ethylidene]-alpha-d-galactopyranose, which can be used as a monomer for polycondensation reaction is described.

MeSH terms

  • Cyanides / chemical synthesis*
  • Disaccharides / chemical synthesis
  • Galactose / analogs & derivatives*
  • Galactose / chemistry
  • Glycosylation

Substances

  • Cyanides
  • Disaccharides
  • 3,6-anhydrogalactose
  • Galactose