Ionic liquid promoted atom economic glycosylation under Lewis acid catalysis
作者:Jacques Augé、Gwenaëlle Sizun
DOI:10.1039/b904692e
日期:——
Straightforward glycosylation of various alcohols with unprotected and non-activated monosaccharides were performed under scandium triflate catalysis. Rate and yield of glycosylation were highly improved when using 1-butyl-3-methylimidazolium trifluoromethanesulfonate as a green solvent. This ionic liquid was allowed to be recycled at least three times without loss of activity. The possibility of drastically reducing the amounts of catalyst (down to 1 mol%) and aglycone (down to 1 equiv) when performing the reaction in ionic liquid opens new perspectives in O-glycosylation, as a direct coupling between an aglycone and free sugars.
Octyl and dodecyl glycosides possessing 2-deoxy-arabino-hexopyranoside moieties belonging to the D-and L-series in their alpha- and beta-forms were synthesized by reaction of an acetyl protected glycal with octanol or dodecanol, catalyzed by triphenylphosphine hydrobromide, followed by deprotection. Their surface properties were studied and discussed in terms of the adsorption and aggregation parameters, pC(20), CMC, and gamma(CMC). The antimicrobial activities were assessed using the paper disk diffusion and broth dilution methods. Both the octyl and dodecyl 2-deoxy beta-D-glycosides inhibited significantly Enterococcus faecalis, a microbe also highly susceptible to dodecyl 2,6-dideoxy-alpha-L-arabino-hexopyranoside. This compound was particularly active against Bacillus cereus and Bacillus subtilis, presenting for both Bacillus species a minimal inhibitory concentration of the same order of magnitude and a minimal lethal concentration even smaller than that obtained for chloramphenicol, a bioactivity which remained unaltered after 1 year solution storage at 4 degrees C. In addition, activity over Listeria monocytogenes was also observed. Direct cytotoxicity and genotoxicity of the glycosides were determined by proliferative index (mitotic index) evaluation in peripheral human lymphocytes of healthy donors. All compounds induced acute toxicity effects, and the response was dose dependent for the alpha-anomer of both the alkyl 2-deoxy-arabino-hexopyranosides and for the corresponding dodecyl beta-anomer, what suggests that non-toxic but still bioactive concentrations may be found for these compounds. (C) 2008 Elsevier Ltd. All rights reserved.
Effect of the C-2 hydroxyl group on the mesomorphism of alkyl glycosides: synthesis and thermotropic behavior of alkyl 2-deoxy-d-arabino-hexopyranosides
A homologous series of alkyl 2-deoxy-alpha-D-arabino-hexopyranosides and alkyl 2-deoxy-beta-D-arabino-hexopyranosides were synthesized, upon glycosylation of 1-alkanols (from C-8 to C-18 alkanols) with ethyl 2-deoxy-3,4,6-tri-O-acetyl-1-thio-D-arabino-hexopyranoside, followed by a deprotection. The thermotropic behavior of these new types of alkyl glycosides was investigated. It was observed that the beta-anomers of these alkyl glycosides, bearing nonyl to tetradecyl alkyl chain are mesomorphic, exhibiting monotropic smectic A phase. In contrast, the alpha-anomers are all non-mesomorphic. An effort to identify the liquid crystalline behavior of binary mixtures of the alpha- and beta-anomers was undertaken and it was found that mixtures containing equimolar amounts of the anomers exhibited rnesomorphic behavior. A fine balance of the hydrophilic and hydrophobic components within the molecule is also found to be important for the alkyl 2-deoxy glycosides to form the mesophase. (C) 2008 Elsevier Ireland Ltd. All rights reserved.
The present invention provides antimicrobial solutions that in certain cases comprise a biguanide and a glycol ether and, in some cases, optionally also includes combinations of at least one an alcohol, at least one chelator, glycerol, deoxycholate, and/or at least one alkylpolyglucoside. In certain aspects the invention comprises a biguanide and deoxycholate or a combination of chelator, ethanol, and alkylpolyglucoside. Also provided are methods for rapidly killing and/or reducing bacteria, fungi, or virus from surfaces, for example, including surfaces of indwelling medical devices and organic surfaces such as skin and sutures, and inorganic surfaces such as medical equipment, pipelines etc.
Tuning the Bioactivity of Tensioactive Deoxy Glycosides to Structure: Antibacterial Activity Versus Selective Cholinesterase Inhibition Rationalized by Molecular Docking
作者:Alice Martins、Maria S. Santos、Catarina Dias、Patrícia Serra、Vasco Cachatra、João Pais、João Caio、Vítor H. Teixeira、Miguel Machuqueiro、Marta S. Silva、Ana Pelerito、Jorge Justino、Margarida Goulart、Filipa V. Silva、Amélia P. Rauter
DOI:10.1002/ejoc.201201520
日期:2013.3
enantiomer exhibited a MIC value of 50 μM. Both 2,6-dideoxy glycosides were active towards Bacillus cereus, Bacillus subtilis, Enterococcus faecalis and Listeria monocytogenes. In contrast, none of the 2-deoxy glycosides was significantly active. These results and the data on surface activity suggest that aggregation is a key issue for antimicrobialactivity. Beyond infection, Alzheimer's disease also threatens