title: Synthesis of blockwise alkylated (1→4) linked trisaccharides as surfactants: influence of configuration of anomeric position on their surface activities.
abstract: New carbohydrate-based surfactants consisting of hydrophilic cellobiosyl and hydrophobic glucosyl residues, methyl β-d-glucopyranosyl-(1→4)-α-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-α-d-glucopyranoside 1 (GβGαMα, G: glucopyranosyl residue, α and β: α-(1→4)- and β-(1→4) glycosidic bonds, M: methyl group), 2 (G(β)G(β)M(α)), 3 (G(β)G(α)M(β)), 4 (G(β)G(β)M(β)), 5 (G(β)G(α)E(α), E: ethyl group), 6 (G(β)G(β)E(α)), 7 (G(β)G(α)E(β)), 8 (G(β)G(β)E(β)) and eight α-and β-glycoside mixtures (a mixture of 1 and 2: 1/2=62/38 (9), 32/68 (10); a mixture of 3 and 4: 3/4=69/31 (11), 32/68 (12); a mixture of 5 and 6: 5/6=62/38 (13), 33/67 (14); a mixture of 7 and 8: 7/8=59/41 (15), 29/71 (16)) were synthesized via combined methods consisting of acid-catalyzed alcoholysis of cellulose ethers and glycosylation of phenyl thio-cellobioside derivatives. Their surface activities in aqueous solution depended on their chemical structures: α- or β-(1→4) linkage between hydrophilic cellobiosyl and hydrophobic glucosyl blocks, methyl or ethyl groups of hydrophobic glucosyl block, and α- or β-linked ether group at the C-1 of hydrophobic glucosyl block. The mixing effect of α- and β-glycosides on surface activities was also investigated. As a result, ethyl β-d-glucopyranosyl-(1→4)-α-d-glucopyranosyl-(1→4)-2,3,6-tri-O-ethyl-β-d-glucopyranoside 7 (G(β)G(α)E(β)) had the highest surface activity, and its critical micellar concentration (CMC) and γ(CMC) (surface tension at CMC) values of compound 7 were 0.5mM (ca. 0.03wt%) and 34.5mN/m, respectively. The surface tensions of α- and β-glycoside mixtures except for compounds 9 and 10 were almost equal to those of pure compounds. The syntheses of the mixtures of α- and β-glycosides without purification process are easier than those of pure compounds. Thus, the mixtures should be more practical compounds for industrial use as a surfactant.
authors.affiliation: Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakagawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kamitakahara
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Takano
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006027:Glycosides / Q000737:chemistry; D008747:Methylcellulose / Q000737:chemistry; D008969:Molecular Sequence Data; D013501:Surface-Active Agents / Q000138:chemical synthesis* / Q000737:chemistry*; D014312:Trisaccharides / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D006027:Glycosides; D013501:Surface-Active Agents; D014312:Trisaccharides; D008747:Methylcellulose