Regioselective chlorination of fully unprotected maltotriose has given in high yield 1(I),2(I-III),3(I-III),4(III)-octa-O-acetyl-6(I-III)-trichloro-6(I-III)-trideoxymaltotriose. Moreover, regioselective ditritylation of methyl β-maltotrioside has provided the two regioselectively C(6)-disubstituted trisaccharides. Selective deprotection of these new compounds gives the corresponding diol and halogenated analogues, respectively, in good yield. All compounds have been completely characterized and the substitution pattern in the oligosaccharidic sequence has been elucidated. A new family of amphiphilic carbohydrates, namely the 6-deoxy-6-alkylthiomaltotriose derivatives, bearing either two or three thioalkyl hydrophobic chains, respectively, has been synthesized. Critical micellar concentration (CMC) values as well as the antimicrobial properties have been evaluated for amphiphilic compounds.

The amphiphilic properties of S-alkylthiopentono-1,4-lactones (d-ribono-, d-arabinono-, d-xylono-) and corresponding pentitol derivatives with the general formula Su–SR (R=CnH2n+1) are studied. It was shown that CMC, surface area, CPP, and pC20 are influenced by the following structural parameters: alkyl chain length, the number of free hydroxyls, cyclic or acyclic Su structure, and alditol configuration.

1‐O‐Alkyl and 2‐O‐alkyl‐d‐threitol enantiomers were derived from 5‐O‐alkyl and 5‐O‐benzyl‐1,2‐O‐isopropylidene‐α‐d‐xylofuranoses. The analogous erythrtol derivatives were also obtained from the same precursors via analogous d‐ribose monoacetals. Mesophasic behavior studies of these alditols and their alkylated d‐ribose and d‐xylose precursor, showed that the relative orientation of alkyl and OH groups appeared to be the main structural factor affecting the thermotropic and lyotropic phase transition temperatures.

Mesophasic properties of S-alkylthiopentonolactones (D-ribono, D-arabinono and D-xylono) and the corresponding itol derivatives with general formula Su-SR (R=n-CnH2n+1) are studied. It was shown that the thermotropic and lyotropic phase transition temperatures are influenced by the following structural parameters: alkyl chain length, free OH group number, cyclic or acyclic Su structure and itol conformation.

Following a new four-step route, we prepared a family of “extended” glucidoamphiphiles from D -glucose, D -galactose, and xylitol in which the n -dodecyl chain is attached to the glucidic moiety by the linkage Z=O-Et-O-Et-O-(α-PP-O-) n′ where-O-(α-PP-O-) n is a poly-(α-propyloxy) commercial oligomeric mixture (with average length n =6, 10, and 14). This amphiphilic behavior study showed that (i) the glucose derivative exhibits water solubility and hydrophilic-lipophilic balance values that are close to those found for the glucose compound with Z=-O-(α-PP-O-) n (without the Et-O-Et group), (ii) all these compounds are more strongly hydrophilic than the corresponding glucidic derivatives with Z=O, (iii) the increase of the poly-(α-propyloxy) chain length from ñ =6 to ñ =14 tends to reduce the hydrophilicity slightly.

Galactose, glucose, xylose and corresponding itol derivatives with the general formula Su-ZR in which Z is an amido group either NHCO (type I) or NR'CO (type II) were synthetized and their mesophasic behaviour studied. It was shown that the thermotropic and lyotropic phase transition temperatures are influenced by the following structural parameters: alkyl or perfluoroalkyl chain length, Z junction, free OH group number, cyclic or acyclic Su structure.

Novel amphiphilic cyclodextrins have been prepared by grafting a phospholipid on a modified cyclodextrin through a spacing arm to combine the selectivity in size of cyclodextrins and the transport properties of phospholipids. Synthesis and full characterization by NMR and mass spectrometry have been performed. The aggregation process in water has been characterized by light scattering, DSC and 31P NMR. This compound appears to assemble into large objects and displays a very low CMC. The detergent properties of the phospholipidyl-cyclodextrins have been evaluated.

We prepared a new nonionic surfactant, 8 , in which the n -dodecyl chain is attached at the C-3 carbon of the D -glucose-based glucopyranose moiety by the linkage Z=−O-(α-PP-O) n with −O-(α-PP-O) n being a commercial poly-(α-propyloxy) oligomeric mixture (with average ñ =6). This amphiphilic behavior study showed that, when compared to the reference compound 3-O-dodecyl- D -glucopyranose (Z=O), compound 8 exhibits (i) a water solubility that is 100-fold higher, (ii) a hydrophilic-lipophilic balance value increase from 8.5 to 12.6 units, and (iii) a slighly lower critical micelle concentration.

We synthesized a new glucose derivatives of 1,5-benzodiazepine-2,4-dione in view to study the influence of the glucidic moiety on the amphiphilic behaviour. Reaction of 1,5- benzodiazepine-2,4-dione with 3- O -alkyl-5,6-anhydro-1,2-O-isopropylidene-a-D-glucofuran-ose gave the expected N,N-bis-glucofuranosylbenzodiazepine derivatives which was deprotected to obtain the corresponding glucopyranosyl compounds. These compounds have a water solubility more higher than the starting 1,5-benzodiazepine- 2,4-diones. Morever some glucidic derivatives with an appropriate alkyl chain at the C-3 carbon of the D-glucose gave surface tension g in water at (25°C).

We prepared glucidoamphiphile derivatives from d-glucose, d-galactose and xylitol, in which the glucidic moiety and the hydrophobic alkyl chain are separated by spacer arm E (E=glyceryl, (OEt)2-α-polypropyleneglycyl and butyloxy). Their amphiphile characteristics are compared to those of the corresponding analogs 3-O-alkyl-d-glucopyranoses, 6-O-alkyl-d-galactopyranoses and 1-O-alkyl-d,l-xylitols. We discussed the spacer arm influence on hydrophobic lipophilic balance (HLB), critical micellar concentration (CMC), water solubility (Sw) and phase transition temperatures of thermotropic and lyotropic mesophases.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

In this article we examine the effect of molecular shape on the formation of thermotropic phases of alkyl-substituted poly-ols. The relationship between the cross-sectional area of the hydrophilic head group with respect to the that of the hydrophilic tails determines the type of mesophase formed. The results obtained are similar to those found for the formation of lyotropic phases.

Glycosyl-pyrrolo[2,1-c][1,4]benzodiazepin-5,11-diones have been obtained by condensing, at the N-10, different polyhydroxylated groups Su (Su = 6-deoxy-D-glucopyranos-6-yl, 6-deoxy-3-O-R-D-glucopyranos-6-yl (R = n-CnH2n+1; n = 8, 12 and 16), 1-deoxy-D,L-xylit-1-yl and 1-deoxy-D,L-glycer-1-yl). The structural variations of Su allowed us to compare amphiphilic data like water solubility (Sw), critical micelle concentration (CMC) and corresponding surface tension (gamma) values. Results of a preliminary antibacterial study are also reported.

We studied amphiphilic properties' of a large x-O-alkyl-itol range including glycerol, threitol and xylitol. Water solubility (Sw), critical micelle concentration (CMC) and hydrophilic/lipophilic balance (HLB) values are discussed in relation to the studied parameters: OH group number (P), alkyl chain length ( R = n - CnH2n+1; n = 6 to 12) and its position (x) as well as polyhydroxylated moiety configuration. Experimental results indicate that solution behaviour of these x-O-alkyl-itol series is more affected by the polar head specific structure. than by the quantitative n and p parameters.

We studied the phase transition temperatures of a series of amphiphilic D-xylopyranose and D-xylofuranose derivatives in which the lipophilic part is an alkyl chain R (n-CnH2n+1), regiospecifically linked to D-xylose, at different positions, by Z which is an atom or a functional group (O, S, O–(CH2)3–S). The alkyl chain was moved from the C-1 to the C-5 position in the xylose moiety, thereby allowing us to compare directly the phase transition temperatures of the individual materials. These compounds give thermotropic and/or lyotropic liquid crystals. In some cases, we also observed solid–solid phase transitions.

A large x-O-alkyl-itol range was studied in view to determine the influence of structural factors on both thermotropic, and lyotropic phase transition temperatures. These series include glycerol, erythritol, threitol, xylitol and ribitol derivatives as racemics, meso and corresponding pure enantiomers. The hydroxyl group number (p) varies from p = 2 to p = 4 ;, the alkyl chain length R = n-CnH2n+l varies from n = 6 to n = 12 and its x-position on the polar head changes from C-1 to C-3 carbon atoms. Experimental results show that the occurence of thermotropic mesophases requests at least p = 3, whereas lyotropic mesophases were observed from p = 2 (glycerol derivatives). Moreover, either specific polar head configuration and alkyl chain x-position can affect strongly the phase transition temperatures. Significant differences were also observed between lyotropic phase temperatures of racemics and corresponding pure enantiomers.

Glycosyl-1,4-benzodiazepin-2,5-diones were prepared by coupling polyhydroxylated groups at N-1 of the corresponding benzodiazepine. The groups include 1-deoxy-D,L-xylit-1-yl, 6-deoxy-D-glucopyranos-6-yl, and 6-deoxy-3-OR-D-glucopyranos-6-yl (R = n-CnH(2n +1); n = 8, 12, and 16). The structural variations of the sugar group allowed comparison of such amphiphilic data as water solubility (Sw), critical micelle concentration (CMC), and corresponding surface tension (gamma) values. At 25 degrees C, unsubstituted benzodiazepines have Sw values from 0.9 to 4.2 10(-3) mol L(-1), whereas xylit-1-yl and 6-deoxy-D-glucopyranos-6-yl derivatives are, respectively, 7.4-25 and 58-204 times more soluble. Also, compounds with R = n-C8H17 are more soluble than corresponding benzodiazepines (1.4-5.8 times) and give micelles with CMC from 2.7 to 5.6 10(-3) mol L(-1) and corresponding gamma from 29 to 37 mN m(-1). In contrast, compounds with R = n-C12H25 and n-C16H33 are not soluble enough to reach the critical micelle concentration.

1,2-O-Isopropylidene-3,5-O-propylidene-α-d-glucofuranose (3) was synthesized by conversion of 3-O-allyl-1,2-O-isopropylidene-α-d-glucofuranose (1) into its 3-O-prop-1-enyl isomer (2), followed by rapid acid-catalysed intramolecular acetalation in an aprotic solvent. The diacetal 3 was used as the precursor of 6-O-alkyl and 6-O-glucidyl-d-glucose amphiphiles, which show thermotropic and lyotropic liquid-crystalline properties.

Three homologous series of 6-Z-n-alkyl-alpha-D-galactopyranoses, where Z represents either a carboxy group (OCO), a sulphur atom (S) or an oxypropylthio group (OC3H6S) have been synthesised starting from 1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranose in either two or three steps. The synthesis of the fourth series of 6-O-n-alkyl-alpha-D-galactopyranoses (Z = O) has already been reported. The length of the terminal aliphatic chains has been varied systematically and the effect on the thermotropic liquid crystal transition temperatures prepared. An enantiotropic smectic A* phase was found for all of the homologues studied. The order of efficiency of the linking group Z in favouring liquid crystal formation for the same homologues of the 6-Z-n-alkyl-alpha-D-galactopyranoses is S approximate to OCO > O > OC3H6S.