title: Synthesis, surface active and antimicrobial properties of new alkyl 2,6-dideoxy-L-arabino-hexopyranosides.
abstract: Synthesis of alkyl 2,6-dideoxy-L-arabino-hexopyranosides was accomplished by the reaction of 1,5-anhydro-2,6-dideoxy-L-arabino-hex-1-enitol with fatty alcohols in dichloromethane, catalyzed by triphenylphosphine hydrobromide. Reaction with octanol and dodecanol gave the corresponding alpha-glycosides in 50% and 42% yield, the beta-glycosides in 20% and 21% yield and the alpha-anomer of the Ferrier product in 10% and 9% yield, respectively. Deacetylation of the alpha-/beta-glycosides with sodium methoxide in methanol afforded the amphiphilic L-arabino-hexopyranosides in 94-99% yield. The surface tension at the air-water interface of the octyl L-glycosides and of the dodecyl alpha-L-glycoside aqueous solutions at 35 degrees C was measured with a du Noüy ring tensiometer and surface properties such as critical micelle concentration (CMC), relative surface excess, molecular area at the interface and Gibbs micellization free energy were evaluated. The stereochemistry of the hexopyranoside ring in unimers and aggregates is correlated to the hydrophobicity and packing efficiency on the air-water interface. The antibacterial and antifungal activities of the surface-active glycosides were evaluated using the paper disk diffusion method. The dodecyl alpha-L-arabino-hexopyranoside was quite active over Bacillus cereus and Bacillus subtilis, while low activity was found for this glycoside over Enterococcus faecalis and Listeria monocytogenes. The octyl glycosides tested showed low activity over almost all the above-mentioned bacteria, and also over the fungus Candida albicans. No inhibition of Salmonella enteritidis and of the filamentous fungus Aspergillus niger was detected for any of the compounds tested.
authors.affiliation: Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Edifício C8, 5 Piso, Campo Grande, 1749 016 Lisboa, Portugal. aprauter@fc.ul.pt
authors.forename: Amélia P
authors.initials: AP
authors.lastname: Rauter
authors.forename: Susana
authors.initials: S
authors.lastname: Lucas
authors.forename: Tânia
authors.initials: T
authors.lastname: Almeida
authors.forename: Diana
authors.initials: D
authors.lastname: Sacoto
authors.forename: Verónica
authors.initials: V
authors.lastname: Ribeiro
authors.forename: Jorge
authors.initials: J
authors.lastname: Justino
authors.forename: Ana
authors.initials: A
authors.lastname: Neves
authors.forename: Filipa V M
authors.initials: FV
authors.lastname: Silva
authors.forename: Maria C
authors.initials: MC
authors.lastname: Oliveira
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Ferreira
authors.forename: Maria-Soledade
authors.initials: MS
authors.lastname: Santos
authors.forename: Ester
authors.initials: E
authors.lastname: Barbosa
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D006601:Hexoses / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D008823:Micelles; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D013329:Structure-Activity Relationship; D013499:Surface Properties
chemical_list: D000900:Anti-Bacterial Agents; D006601:Hexoses; D008823:Micelles; C020615:digitoxose