Sugar‐based cationic surfactants: Synthesis and aggregation of methyl 2‐acylamido‐6‐trimethylammonio‐2,6‐dideoxy‐d‐glucopyranoside chlorides

Abstract

The synthesis of the sugar-based cationic surfactants methyl 2-acylamido-6-trimethylammonio-2,6-dideoxy-Dglucopyranoside chlorides is reported here. Aggregation of these surfactants (predominantly α anomers) in water was studied at 25°C by conductivity measurements. Increasing the chain length of the amido group R decreased the critical micelle concentration (CMC) and the degree of counter-ion dissociation. The dependence of the Gibbs' free energy of micellization and CMC on the length of R is similar to that observed for other ionic surfactants. The free energy of transfer of the head group, i.e., cationic amino sugar moiety, from water to the micelle is more negative than that of other ionic surfactants, including sodium methyl 2-acylamido-2-deoxy-6-O-sulfo-D-glucopyranosides, probably due to a combination of a micellar "medium" effect and intermolecular H-bonding in the micellar pseudophase.The impetus for the intense interest in studying ionic and nonionic sugar-based surfactants stems from the fact that they are biodegradable, very mild to the skin, and are derived from renewable sources (1). Currently, these surfactants are present in commercial powder and liquid formulations (2,3) and are employed in nondenaturing extraction and purification of membrane proteins (4,5) and in increasing the colloidal stability of liposomes (6).The compound 2-amino-2-deoxy-D-glucopyranose (hereafter called 2-amino glucose) is widely present in nature, e.g., as the building block of chitin, the second-most abundant natural polymer after cellulose (7). It is also a main component of peptidoglycan, the backbone of the cell wall of numerous bacteria. Much attention has been focused on sugar-based surfactants, although amino sugars carry two different functional groups, namely, NH 2 and OH, that could, in principle, be derivatized (8). Figure 1 illustrates some recently synthesized 2-amino glucose-based ionic and nonionic surfactants (9-14). Some of the cationic surfactants shown in Figure 1 have bacteriostatic properties and are more biodegradable than currently employed quaternary ammonium compounds, e.g., cetyltrimethylammonium halides (15-17). As can be seen from Figure 1, the positive charge is present in the ring 2-position, namely, in the form of NH 3 + or N(CH 3 ) 3 + . To our knowledge, there has been no report on methyl 2-acylamido-6-trimethylammonio-2,6-dideoxy-D-glucopyranoside halides. We decided therefore to synthesize these surfactants (as chlorides) and to study effects of increasing the length of their hydrophobic moiety (acyl group = octanoyl, dodecanoyl, and hexadecanoyl) on aggregate formation in water. We were also interested in comparing their micellar properties with those of recently synthesized 2-amino glucose-based anionic surfactants that carry the same acyl groups, namely, sodium methyl 2-acylamido-2-deoxy-6-Osulfo-D-glucopyranosides (18). EXPERIMENTAL PROCEDURESMaterials. The solvents and reagents were purchased from Aldrich (Milwaukee, WI) or Merck (Darmstadt, Germany) and were purified by standard p...

Synthesis and Characterization of Chiral [3,22]‐Ionenes

“…[16,17] The [3,22]-ionene was synthesized as described elsewhere. [4,9] The melting points were determined in an Electrothermal IA 6304 melting point apparatus.…”

“…[14,15] This ionene has been used as a chiral selector in liquid membrane applications. [8] In this work, we describe the first synthesis of chiral micelle-mimetic ionenes containing pendent glucopyranosyl and b-cyclodextrin groups, the 6-O-methyl-aglucopyranosyl- [3,22]-ionene and the mono-6…”

“…A -O-b-cyclodextrin- [3,22]-ionene, respectively. These chiral micelle-mimetic [3,22]-ionenes conjugate the interesting polysoap properties with the presence of chirality, resulting in compounds potentially useful as chiral selectors in analytical separations.…”

“…

Summary: Two [3,22]-ionenes with pendent chiral groups, glucopyranosyl-[3,22]-ionene and b-cyclodextrin-[3,22]-ionene, were synthesized by the reaction between the tosyl derivatives of the carbohydrate (methyl alpha-glucopyranoside or betacyclodextrin) and the tertiary [3,22]-polyamine obtained by selective demethylation of [3,22]-ionene. The derivatives were characterized by 1 H NMR spectroscopy, presenting degrees of substitution of 30 and 45% for the glucosyl and cyclodextrin derivatives, respectively.

…”

Novos surfactantes alquil poliglicosídicos à base de amilose extraída da batata inglesa (Solanum tuberosum l.)

“…[43][44][45][46] Por isso foram utilizadas as seguintes relações: Determinação da eficiência e efetividade do surfactante na redução da tensão superficial A redução na tensão superficial resulta da adsorção das moléculas surfactantes na interface ar/solução. Estas propriedades de uma molécula surfactante são caracterizadas por sua eficiência e efetividade.…”