Boron Effect on Sugar‐Based Organogelators

Abstract

The reaction of several alkylglucosides with phenyl boronic acid permittede asya ccess to as eries of alkylglucoside phenyl boronate derivatives. This type of compound has structures similar to those of known benzylidene glucoside organogelators except for the presence of ab oronate functioni np lace of the acetalo ne. Low to very low concentrationso ft hese amphiphilic molecules produced gelation of several organic solvents. The rheological properties of the correspondings oft materials characterizedt hem as elastic solids. They were further characterized by SEMto obtain more informationo nt heir morphologies and by SAXS to determinet he type of self-assembly involved within the gels. The sensitivity of the boronate functiont owards hydrolysis was also investigated. We demonstrated that as mall amount of water (5 % v/v)w as sufficient to disrupt the organogels leadingt ot he originala lkylglucosidea nd phenyl boronic acid;a ni mportant difference with the stable benzylidene-based organogelators. Such water-sensitive boronated organogelators could be suitable substances for the preparation of smart soft material for topicald rug delivery.

Recently Developed Carbohydrate Based Gelators and Their Applications

“…Overall, the study shows that the alkyl chain length only influenced gelation at the microscopic level, but the substituents on the aniline ring affected the stability and self-assembly of the gels [43]. Ludwig et al reported a water-sensitive organogelator that is structurally similar to the successful 4,6-benzylidene protected alkyl glucoside derivatives that have been shown to be effective organogelators ( Figure 5) [44]. The resulting phenyl boronic protected alkyl glucoside derivatives 12a-h were found to be effective gelators for toluene, cyclohexane, ethyl myristate and isopropyl palmitate.…”

“…Ludwig et al reported a water-sensitive organogelator that is structurally similar to the successful 4,6-benzylidene protected alkyl glucoside derivatives that have been shown to be effective organogelators ( Figure 5 ) [ 44 ]. The resulting phenyl boronic protected alkyl glucoside derivatives 12a–h were found to be effective gelators for toluene, cyclohexane, ethyl myristate and isopropyl palmitate.…”

“…While the comparable benzylidene protected derivatives are stable in the presence of non-acidic water; the boronate functions are water sensitive. Exposure to water results in hydrolysis to reveal the deprotected glycoside, which are typically not gelators [ 44 ]. When exploring the water sensitivity of these organogels, they found that as low as 5% v / v water to organic solvent solutions were sufficient to cause enough hydrolysis to disrupt the gels [ 44 ].…”

“…Exposure to water results in hydrolysis to reveal the deprotected glycoside, which are typically not gelators [ 44 ]. When exploring the water sensitivity of these organogels, they found that as low as 5% v / v water to organic solvent solutions were sufficient to cause enough hydrolysis to disrupt the gels [ 44 ]. Within 1 h the gels were partially disrupted, and after 3 h the gel state had disappeared.…”

“…Within 1 h the gels were partially disrupted, and after 3 h the gel state had disappeared. Alternative experiments were carried out replacing the DI water with acetate buffer (pH 4.8) and carbonate buffer (pH 9.8) solutions, yielding similar results [ 44 ]. These findings suggest that this sensitivity towards water could make these organogels candidates for applications in topical drug delivery as smart soft materials.…”