High pressure-assisted condensation reaction of acylated glucosyl bromides with complex alcohols in the presence of diisopropylethylamine and tetrabutylammonium bromide gave the corresponding 1,2-orthoesters in good to excellent yields without using heavy metal salts.
Minimally Competent<i>Lewis</i>Acid Catalysts: Indium(III) and Bismuth(III) Salts Produce Rhamnosides (=6-Deoxymannosides) in High Yield and Purity
作者:Clifford Coss、Tucker Carrocci、Raina M. Maier、Jeanne E. Pemberton、Robin Polt
DOI:10.1002/hlca.201200528
日期:2012.12
impurities in addition to the desired glycosides. Enantiomerically pure rhamnosides (R)‐1 and (S)‐1 (Fig.) were obtained from L‐rhamnose peracetate 5 and (±)‐benzyl 3‐hydroxydecanoate (9) via the diastereoisomeric rhamnosides 10 (Table 2; Scheme 3). The much weaker Lewis acids InBr3 and Bi(OTfl)3 produced purer products in highyield under a wider range of conditions (higher temperatures), and were effective
申请人:THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIVERSITY OF ARIZONA
公开号:US20140142287A1
公开(公告)日:2014-05-22
The present invention provides carbohydrate-based surfactants and methods for producing the same. Methods for producing carbohydrate-based surfactants include using a glycosylation promoter to link a carbohydrate or its derivative to a hydrophobic compound.
申请人:THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIVERSITY OF ARIZONA
公开号:US11117914B2
公开(公告)日:2021-09-14
The present invention provides carbohydrate-based surfactants and methods for producing the same. Methods for producing carbohydrate-based surfactants include using a glycosylation promoter to link a carbohydrate or its derivative to a hydrophobic compound.
Rhamnolipids are biodegradable low toxic biosurfactants which exert antimicrobial and anti-biofilm properties. They have attracted much attention recently due to potential applications in areas of bioremediation, therapeutics, cosmetics and agriculture, however, the full potential of these versatile molecules is yet to be explored. Based on the facts that many naturally occurring lipopeptides are potent antimicrobials, our study aimed to explore the potential of replacing rhamnose in rhamnolipids with amino acids thus creating lipopeptides that would mimic or enhance properties of the parent molecule. This would allow not only for more economical and greener production but also, due to the availability of structurally different amino acids, facile manipulation of physico-chemical and biological properties.Our synthetic efforts produced a library of 43 lipopeptides revealing biologically more potent molecules. The structural changes significantly increased, in particular, anti-biofilm properties against Candida albicans, although surface activity of the parent molecule was almost completely abolished. Our findings show that the most active compounds are leucine derivatives of 3-hydroxy acids containing benzylic ester functionality. The SAR study demonstrated a further increase in activity with aliphatic chain elongation. The most promising lipopeptides 15, 23 and 36 at 12.5 mu g/mL concentration allowed only 14.3%, 5.1% and 11.2% of biofilm formation, respectively after 24 h. These compounds inhibit biofilm formation by preventing adhesion of C. albicans to abiotic and biotic surfaces.