title: Ganglioside GQ1b: efficient total synthesis and the expansion to synthetic derivatives to elucidate its biological roles.
abstract: The convergent total synthesis of ganglioside GQ1b based on the "cassette approach" between the nonreducing end GQ1b-core heptasaccharide and glucosylceramide building blocks was accomplished in high overall yield. The use of a sialylalpha(2-->8)sialylalpha(2-->3)galactose sequence as the key building block enhanced the efficiency of the glycan assembly and led to preparative-scale synthesis readily applicable for large-scale preparation. In addition, a judicious choice of p-methoxybenzyl protecting groups on glucosylceramide provided a solution to the previous synthetic problems, including a decrease in the yield of the deprotection steps, and led to elevation of the total yield. Furthermore, unnatural-type GQ1b derivatives were synthesized systematically in good yields by capitalizing on a similar approach in order to elucidate their biological roles.
authors.affiliation: Department of Applied Bioorganic Chemistry, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan. aimamura@ualberta.ca
authors.forename: Akihiro
authors.initials: A
authors.lastname: Imamura
authors.forename: Hiromune
authors.initials: H
authors.lastname: Ando
authors.forename: Hideharu
authors.initials: H
authors.lastname: Ishida
authors.forename: Makoto
authors.initials: M
authors.lastname: Kiso
mesh_terms: D002240:Carbohydrate Sequence; D002850:Chromatography, Gel; D018360:Crystallography, X-Ray; D005690:Galactose / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D005732:Gangliosides / Q000138:chemical synthesis*; D005963:Glucosylceramides / Q000737:chemistry; D006028:Glycosphingolipids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D005732:Gangliosides; D005963:Glucosylceramides; D006028:Glycosphingolipids; D009844:Oligosaccharides; C542734:sialylalpha(2-3)galactose; C039129:GQ1b ganglioside; D005690:Galactose