Synthesis of Monoesters as Surfactants and Drugs from D-Glucose

Sugar-Based Surfactants: Effects of Structural Features on the Physicochemical Properties of Sugar Esters and Their Comparison to Commercial Octyl Glycosides

Two series of sugar esters with alkyl chain lengths varying from 5 to 12 carbon atoms, and with a head group consisting of glucose or galactose moieties, were synthesized. Equilibrium surface tension isotherms were measured, yielding critical micellar concentration (CMC) surface tensions at CMC (γcmc) and minimum areas at the air-water interface (Amin). In addition, Krafft temperatures (Tks) were measured to characterize the ability of molecules to dissolve in water, which is essential in numerous applications. As a comparison to widely used commercial sugar-based surfactants, those measurements were also carried out for four octyl d-glycosides. Impacts of the linkages between polar and lipophilic moieties, alkyl chain lengths, and the nature of the sugar head group on the measured properties were highlighted. Higher Tk and, thus, lower dissolution ability, were found for methyl 6-O-acyl-d-glucopyranosides. CMC and γcmc decreased with the alkyl chain lengths in both cases, but Amin did not appear to be influenced. Both γcmc and Amin appeared independent of the ester group orientation. Notably, alkyl (methyl α-d-glucopyranosid)uronates were found to result in noticeably lower CMC, possibly due to a closer distance between the carbonyl function and the head group.

Introducing Lipophilicity to (Polyhydroxyalkyl)thiazolidine Carboxylic Acids Via Acylation

The therapeutic efficacy of bioactive compounds is related to their bioavailability. In turn, the bioavailability depends on the equilibrium between the hydrophilicity and the lipophilicity. 2(R,S)-(Polyhydroxyalkyl)thiazolidine-4(R) carboxylic acids (TCAs), obtained from the condensation of l-cysteine and an aldose, have been recognized as nontoxic precursors of glutathione with important preventive and therapeutic effects. The bioavailability of these compounds can be improved by enhancing their lipophilicity. This can be achieved by the introduction of some acyl groups derived from fatty acids via esterification of the aldose hydroxyl groups. With this purpose four new compounds were synthesized through a selective palmitoyl acylation of d-(-)-ribose and d-(+)-glucose and subsequent condensation with l-cysteine. In addition, the log P of the new compounds was calculated as a measure of the lipophilicity, and in vitro 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) tests were performed as a measure of the antioxidant capability.

An Overview of Novel Surfactants for Formulation of Cosmetics with Certain Emphasis on Acidic Active Substances

Novel surfactants which are nowadays available for incorporation into various formulations of personal care and cosmetic products are numerous, implying a permanent need for their classification. This overview provides essential information relating to synthesis, basic physicochemical characteristics, application and other relevant data on surfactants currently used in cosmetic products. In the second part of the paper an outline of acidic active substances with significant application in cosmetic products is given, as well as the problems that arise during preparation/manufacture of the containing formulations, accompanied with the review of scientific publications and other available reliable data dealing with the incorporation of these actives in the cosmetic formulations stabilized with novel (mainly natural) surfactants.

Preparation and biological evaluation of some 1,2-O-isopropylidene-d-hexofuranose esters

The synthesis and biological evaluation of some new glycose esters bearing the 1,2-O-isopropylidene-d-hexofuranose functionality and belonging to the 3-O-acyl-d-allose and 6-O-acyl-d-glucose series are reported. When the results concerning cell growth inhibition are compared, it appears that the 6-O-acyl-d-glucose derivatives are more active than the 3-O-acyl-d-allose compounds. Within both 6-O-acyl-d-glucose and 3-O-acyl-d-allose derivatives, butyric esters displayed the highest inhibitory effects. Inhibition of cell growth is not associated with high induction levels of erythroid differentiation, despite the fact that pivaloates induce erythroid differentiation to an extent similar to that exhibited by previously reported molecules [Bioorg. Med. Chem. Lett.1999, 9, 3153-3158].

Preparation of C-3,5-Acyl Furanoses via Highly Selective Intramolecular Acyl Migration

A practical synthesis of C-3,5-acyl furanose via a base-catalyzed, highly selective intramolecular acyl migration in alcohol solvents is reported.

Direct syntheses of S-alkylthio-d-galactono-, d-mannono-1,4-lactones, S-alkylthio-l-galactitols and d-mannitols displaying amphiphilic and mesophasic properties

Alkylthio-L-galactitols and D-mannitols were obtained in good yields (70-81%) by reduction, with NaBH4, of the corresponding 6-S-alkyl-6-thio-D-hexono-1,4-lactones.

Preparation and evaluation of the in vitro erythroid differentiation induction properties of some esters of methyl 3,4-O-isopropylidene-beta-D-galactopyranoside and 2,3-O-isopropylidene-D-mannofuranose

Two series of glycide esters of short fatty acids, designed for avoiding intramolecular transesterification, were prepared and tested for in vitro erythroid differentiation induction activities using the K562 cell line as experimental system. The 6-O-isobutiryl and pivaloyl derivatives of methyl 3,4-O-isopropylidene-beta-D-galactopyranosides as well the same 1-O-esters of 2,3-O-isopropylidene-alpha- and beta-D-mannofuranose exhibit biological activities much higher that the corresponding acids and could be proposed as possible agents to modulate production of embryo-fetal hemoglobins by human erythroid cells.

Surface Activity and Critical Aggregation Concentration of Pure Sugar Esters with Different Sugar Headgroups

We have studied the surface properties of a series of enzymatically synthesized sugar monoesters of xylose, galactose, sucrose, and lactose with different hydrophobic chain lengths (C12-C16) and purified, chemically synthesized sucrose esters that, unlike the enzymatically synthesized samples, contain a mixture of isomers. Data obtained have been compared with those for dodecanoic glucoside and maltoside acetals, and also a commercial sucrose myristate. Nearly all of the sugar esters studied brought about a significant reduction of the surface tension of water (to 31.0-43.0 mN m(-1)). A reduction in the critical aggregation concentration (CAC) of the surfactants with increasing carbon chain length was observed. Surfactants with more hydrophilic headgroups exhibited higher CAC, though this trend was moderated by the alkyl chain length. Comparing the chemically synthesized sucrose esters with their enzymatically synthesized equivalents revealed only minor differences in the CAC and the surfactant efficiency, indicating that the exact point of esterification might not be critical for the surfactant's properties. The presence of 0.1 M NaCl, KCl, or CaCl(2) did not significantly alter the surface behavior of the chemically synthesized esters, indicating the absence of surface-active species with charged headgroups. Copyright 2000 Academic Press.

Carbohydrate- and related polyol-derived fluorosurfactants: an update

A short review of recent literature is presented on the synthesis, biological properties, colloid and surface chemistry, and applications of carbohydrate- and related polyol-derived amphiphiles with perfluoroalkyl hydrophobes.

Induction of erythroid differentiation of human K562 cells by 3-O-acyl-1,2-O-isopropylidene-D-glucofuranose derivatives

In this paper we report the synthesis of twelve 3-O-acyl-1,2-O-isopropylidene-D-glucofuranose derivatives and the results obtained on their effects in inducing erythroid differentiation of human leukemic K562 cells. The data obtained demonstrate that two of the newly synthetized compounds are able to induce erythroid differentiation of K562 cells. In addition, these same compounds potentiate K562 erythroid differentiation induced by cytosine arabinoside, retinoic acid and mithramycin. Inducers of erythroid differentiation stimulating fetal gamma-globin synthesis could be considered for possible use in the experimental therapy of hematological diseases associated with a failure in the expression of adult beta-globin genes.

Effects of tail alkyl chain length (n), head group structure and junction (Z) on amphiphilic properties of 1-Z-R-D,L-xylitol compounds (R = CnH2n+1)

In the family of 1-Z-R-D,L-xylitol, we have determined the main amphiphilic properties of esters (Z = OCO) as a function of alkyl chain length (R = CnH2n+1, n = 4-17). A classical decrease of critical micelle concentration with the increase in the alkyl chain has been found. With water, esters displayed lamellar phases at temperatures of 25 degrees C or higher. The extent of hydrophilic/lipophilic balance range obtained by emulsification method can be proven to be of interest for pharmaceutical applications. The results were compared with those obtained in previous investigations, i.e. for alkyl-substituted xylitol, with thioether (Z=S) and ether (Z=O) linking groups in order to discuss the role of the junction nature. Likewise, they were compiled with the results related to their D-glucose homologues, in order to put forward the effects of the head group configuration, cyclic or acyclic.

Regioselective synthesis and biological profiling of butyric and phenylalkylcarboxylic esters derivated from D-mannose and xylitol: influence of alkyl chain length on acute toxicity

Regiospecific synthesis of 12 novel n-butyric and phenylalkylcarboxylic monoesters of mannose and xylitol was achieved. The strategy adopted, avoided a tedious intramolecular transesterification step, previously described for the synthesis of analogous compounds and permitted the facile synthesis of a new generation of stable derivatives. The general tolerance of the drugs has been assayed after intravenous administration of a bolus dose into mice. Monobutyric esters showed a low toxicity commensurate with the requirements for future development. A relationship was observed between chain length and toxicity. In contrast, phenylacetic, 3-phenylpropionic and 4-phenylbutyric esters were found to be toxic. Phenylbutyric esters induced marked and specific neuromuscular damage. Preliminary biological investigations of the new series of monobutyric esters showed them to retain the benificial biological properties of butyric acid whilst remaining relatively non toxic. They induced an inhibition of in vitro proliferation of 10 human cases of de novo acute myeloid leukemia (AML) primary cultures and AML established cell lines. AML blasts growth appeared to be blocked and cell differentiation was established. Transcription and expression of maturation markers and finally apoptosis were observed. Moreover, human gamma-chain hemoglobin (HbF) synthesis in erythroleukemia cells was stimulated by monobutyric esters. Mannose and xylitol butyric derivatives would appear to have exciting potential in treatment of beta-Hemoglobinopathies, sickle cell anemia and cancer.

Nonionic surfactants regioselective synthesis of fatty acid esters of alpha- and beta-glucopyranose

Lipophilic esters of saccharides belong to the family of nonionic surfactants widely employed in pharmaceutical and cosmetics formulations. A very simple method is presented whereby 6-O-esters of alpha- and beta-glucose can be prepared and isolated. Good results have been obtained in the synthesis of 6-O-oleyl derivatives by simple acylation with appropriate oleyl chloride. The condensing agent bis(2-oxo-3-oxazolidinyl) phosphinic chloride (BOP-Cl) allows the preparations of the same esters with better regioselectivity but with yields strongly dependent on the aliphatic chain length of the carboxylic acids employed.