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Bearing grafts based on fatty esters derivatives, lipidyl-cyclodextrins (L-CDs) are compounds able to form water-soluble nano-objects. In this context, bicatenary biobased lipidic-cyclodextrins of low DS were easily synthesized from a fatty ester epoxide by means of alternative methods (ball-milling conditions, use of enzymes). The ring opening reaction of methyl oleate epoxide needs ball-milling and is highly specific of cyclodextrins in solventless conditions. L-CDs are thus composed of complex mixtures that were deciphered by an extensive structural analysis using mainly mass spectrometry and NMR spectroscopy. In addition, as part of their potential use as vectors of active drugs, these products were submitted to an integrity study on in vitro model of the blood-brain-barrier (BBB) and the intestinal epithelium. No toxicity has been observed, suggesting that applications for the vectorization of active ingredients can be expected.

A reaction platform based on a cyclodextrin dimer, which is able to simultaneously include a substrate in one cavity and an organometallic catalyst into the other, proved to be highly efficient for aqueous hydroformylation reaction of higher olefins.

The replacement of hazardous solvents and the utilization of catalytic processes are two key points of the green chemistry movement, so aqueous organometallic catalytic processes are of great interest in this context. Nevertheless, these processes require not only the use of water-soluble ligands such as phosphanes to solubilise the transition metals in water, but also the use of mass transfer agents to increase the solubility of organic substrates in water. In this context, phosphanes based on a cyclodextrin skeleton are an interesting alternative since these compounds can simultaneously act as mass transfer agents and as coordinating species towards transition metals. For twenty years, various cyclodextrin-functionalized phosphanes have been described in the literature. Nevertheless, while their coordinating properties towards transition metals and their catalytic properties were fully detailed, their mass transfer agent properties were much less discussed. As these mass transfer agent properties are directly linked to the availability of the cyclodextrin cavity, the aim of this review is to demonstrate that the nature of the reaction solvent and the nature of the linker between cyclodextrin and phosphorous moieties can deeply influence the recognition properties. In addition, the impact on the catalytic activity will be also discussed.

The synthesis of gold nanoparticles stabilized in an aqueous phase by cyclodextrins (CD) was performed. The solvent-dispersed nanoparticles were characterized by transmission electron microscopy, UV-vis spectroscopy and dynamic light scattering analysis. Nanoparticles stabilized with large-ring CD composed of 9 or more glucose units showed a broader distribution of sizes and a larger hydrodynamic diameter compared to those stabilized with α-CD, β-CD and γ-CD. Gold nanoparticles stabilized by large-ring CD efficiently reduced 4-nitrophenol to 4-aminophenol with higher reaction rates compared to those stabilized by α-CD. NMR analysis proved that no complex formation between 4-nitrophenol and the large-ring CD occurred. The catalytic activities obtained with gold nanoparticles stabilized by large-ring CD were comparable to those observed with β-CD and γ-CD confirming their suitability for an efficient stabilization of catalytically active nanoparticles. [ABSTRACT FROM AUTHOR]

Oleic succinyl β‐cyclodextrin was proved to be efficient for the stabilization of ruthenium nanoparticles (NPs) in aqueous medium. These NPs were characterized by FTIR spectroscopy and transition electron microscopy (TEM). The catalytic activity of these NPs was evaluated in the aqueous hydrogenation of petrosourced and biosourced unsaturated compounds such as benzene and furfural derivatives. The catalytic system can be easily recycled and reused up to nine runs without any loss of activity and selectivity, demonstrating its robustness. [ABSTRACT FROM AUTHOR]

Amphiphilic β‐cyclodextrins bearing various amounts of branched and cyclic oleic grafts are synthetized. The first step of this synthesis is the alkenylation of maleic anhydride by oleic acid derivatives, in the presence of a rhodium catalyst, to produce oleic succinic anhydrides with different ratios of cyclic to branched groups. The second step is the grafting of the oleic succinic anhydrides mixtures on β‐cyclodextrin. The obtained cyclodextrins are highly water‐soluble and surface active. [ABSTRACT FROM AUTHOR]

A new family of amphiphilic cyclodextrins produced from oleic acid derivatives and maleic anhydride is described. These amphiphilic cyclodextrins are synthesized in two steps. The first step is the alkenylation of maleic anhydride by oleic acid derivatives to produce the oleic succinic anhydrides. The second step is the grafting of the oleic succinic anhydrides on various cyclodextrins. A self‐inclusion of the alkyl chain or an inclusion of one alkyl chain in the cavity of another CD is showed by NMR experiments. The twelve amphiphilic cyclodextrins described possess high solubility in water (50–500 g/L at 20 °C) and low critical aggregation concentration (16–360 mg/L). A new family of amphiphilic cyclodextrins produced from methyl oleate or oleic acid and maleic anhydride is described. A self‐inclusion of the alkyl chain or an inclusion of an alkyl chain in another CD cavity is evidenced. These oleic succinyl‐CDs possess a high solubility in water, a low surface tension, and a low critical aggregation concentration. [ABSTRACT FROM AUTHOR]

The synthesis of water-soluble rhodium(I) salicylaldiminato and salicylhydrazonic complexes has been achieved employing two preparative routes. Schiff base condensation between 6A-deoxy-6A-amino-β-CD or 6A-deoxy-6A-hydrazino-β-CD and 5-sodiosulfonato-2-hydroxybenzaldehyde (sulfonated salicylaldehyde) (1) or 5-sodiosulfonato-3-tert-butyl-2-hydroxybenzaldehyde (sulfonated tBu-salicylaldehyde) (2) led to the formation of the corresponding imine or hydrazone ligands (3, 4, 5 and 6). Reaction of [Rh(COD)2+BF4−] with these new ligands in an alkaline solution formed the corresponding rhodium complexes quantitatively. These rhodium(I) complexes could also be prepared in one-pot by mixing, in stoichiometric proportions, the modified β-CDs with the sulfonated salicylaldehyde and with the rhodium precursor in an alkaline solution at room temperature. These rhodium complexes were applied as catalysts in the aqueous biphasic hydroformylation of 1-decene as a model reaction. [ABSTRACT FROM AUTHOR]

Atherosclerosis is an inflammatory disease that leads to an aberrant accumulation of cholesterol in vessel walls forming atherosclerotic plaques. During this process, the mechanism regulating complex cellular cholesterol pools defined as the reverse cholesterol transport (RCT) is altered as well as expression and functionality of transporters involved in this process, namely ABCA1, ABCG1, and SR-BI.Macrophages, arterial endothelial and smooth muscle cells (SMCs) have been involved in the atherosclerotic plaque formation. As macrophages are widely described as the major cell type forming the foam cells by accumulating intracellular cholesterol, RCT alterations have been poorly studied at the arterial endothelial cell and SMC levels. Amongst the therapeutics tested to actively counteract cellular cholesterol accumulation, the methylated β-cyclodextrin, KLEPTOSE® CRYSMEβ, has recently shown promising effects on decreasing the atherosclerotic plaque size in atherosclerotic mouse models. Therefore we investigated in vitro the RCT process occurring in SMCs and in arterial endothelial cells (ABAE) as well as the ability of some modified β-CDs with different methylation degree to modify RCT in these cells. To this aim, cells were incubated in the presence of different methylated β-CDs, including KLEPTOSE® CRYSMEβ. Both cell types were shown to express basal levels of ABCA1 and SR-BI whereas ABCG1 was solely found in ABAE. Upon CD treatments, the percentage of membrane-extracted cholesterol correlated to the methylation degree of the CDs independently of the lipid composition of the cell membranes. Decreasing the cellular cholesterol content with CDs led to reduce the expression levels of ABCA1 and ABCG1. In addition, the cholesterol efflux to ApoA-I and HDL particles was significantly decreased suggesting that cells forming the blood vessel wall are able to counteract the CD-induced loss of cholesterol. Taken together, our observations suggest that methylated β-CDs can significantly reduce the cellular cholesterol content of cells forming atherosclerotic lesions and can subsequently modulate the expression of ABC transporters involved in RCT. The use of methylated β-CDs would represent a valuable and efficient tool to interfere with atherosclerosis pathogenesis in patients, nonetheless their mode of action still needs further investigations to be fully understood and finely controlled at the cellular level. [ABSTRACT FROM AUTHOR]

New cyclodextrin-based systems have recently been developed for aqueous organometallic . Through this review, the major advances made in the field are commented upon and discussed. The role of cyclodextrins as promoters, molecular platforms, for the formation of Pickering emulsions and thermoresponsive catalytic systems is especially emphasized. The catalytic performances of these cyclodextrin-based catalytic systems are highlighted in two model reactions, namely the rhodium-catalysed of terminal olefins and the palladium-catalysed cleavage of allyl carbonates (). Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

β-Cyclodextrin series and N,N'-dimethylurea formed low melting mixtures able to immobilize organometallic species based on sulfonated phosphanes. Hydroformylation and Tsuji-Trost reactions were efficiently performed in these new solvents which led to new recyclable catalytic systems. [ABSTRACT FROM AUTHOR]

The combination between a sulfonated diphosphine (L) and a cyclodextrin (CD) allowed the preparation of very stable water-soluble ruthenium nanoparticles (RuNPs) that displayed pertinent catalytic performances in hydrogenation of unsaturated substrates with a supramolecular control effect of the cyclodextrin. For comparison purpose, the RuNPs were produced by hydrogenation of the organometallic [Ru(1,5-cyclooctadiene)(1,3,5-cyclooctatriene)] complex under mild conditions (3 bar H2; room temperature) and in the presence of L or a L/CD mixture as stabilizer leading to Ru/L and Ru/L/CD systems, respectively. The so-obtained nanoparticles were fully characterized by complementary techniques. Interestingly, NMR investigations evidenced 1) the strong coordination of the sulfonated diphosphine ligand at the metallic surface and 2) in the presence of cyclodextrin, the formation of an inclusion complex between L and CD that modified the coordination mode of the diphosphine. The investigation of both RuNPs systems in biphasic hydrogenation of unsaturated substrates pointed out relevant differences in terms of reactivity, thus evidencing the influence of the supramolecular interaction at the metallic surface on the catalytic performances of the nanocatalysts. This work took advantage of the supramolecular properties of a cyclodextrin to modulate the surface reactivity of diphosphine-stabilized ruthenium nanoparticles and may open new opportunities in the field of nanocatalysis. [ABSTRACT FROM AUTHOR]

The interaction of β-cyclodextrin (β-CD) with meta-trisulfonated triphenylphosphine derivatives bearing one or two methyl (or methoxy) groups on the aromatic rings has been investigated by PM3 calculations. The results show that phosphine molecules interact with β-CD having either an unsubstituted sulfophenyl group or a substituted sulfophenyl group at the para and/or meta-position. The presence of one methyl or methoxy group in the ortho-position on each aromatic ring prevents the formation of an inclusion complex between meta-trisulfonated triphenylphosphine derivatives and β-CD. The deeply included phosphines in the β-CD cavity show significant van der Waals interactions with β-CD. These interactions are at the origin of the high association constants between these molecules and β-CD. Phosphines exhibiting small association constants interact with β-CD by forming H-bonds and weak (or null) van der Waals interactions. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Methylated and hydroxypropylated cyclodextrins (CDs) are highly efficient mass transfer promoters in biphasic aqueous organometallic processes. The surface tension measurements demonstrated that these CDs adsorb at air–water interface and allowed to determine surface excess of CD by using Gibbs adsorption equation. Interestingly, a good correlation between surface excess and catalytic activity was obtained in the case of hydroformylation and Tsuji–Trost reactions. These results point out the importance of CD adsorption at the interface in biphasic aqueous organometallic processes. [Copyright &y& Elsevier]

Randomly hydroxypropylated and methylated cyclodextrins with different cavity size have been used as inverse phase transfer catalysts in a palladium catalyzed Tsuji-Trost reaction with water-insoluble alkylallylcarbonates and alkylallylurethanes as substrate. It has been shown that the molecular recognition ability of both α-CD and β-CD derivatives towards these substrates was responsible for an increase in the reaction rates and remarkable substrate selectivities between a linear and a branched structure. By contrast, the too wide cavity of γ-CD derivatives did not allow these carriers to be efficient in terms of substrate selectivity. Thus, the performances of a cyclodextrin carrier in this cleavage reaction strongly depended on the size of the cavity in which the substrate had to fill in as close as possible the available space. [Copyright &y& Elsevier]

Hydroformylation is an industrial process that allows for the production of aldehydes from alkenes using transition metals. The reaction can be carried out in water, and the catalyst may be recycled at the end of the reaction. The industrial application of rhodium-catalyzed aqueous hydroformylation has been demonstrated for smaller olefins (propene and butene). Unfortunately, larger olefins are weakly soluble in water, which results in very low catalytic activity. In an attempt to counteract this, we investigated the use of amphiphilic oleic succinyl-cyclodextrins (OS-CDs) synthesized from oleic acid derivatives and maleic anhydride. OS-CDs were found to increase the catalytic activity of rhodium during the hydroformylation of water-insoluble olefins, such as 1-decene and 1-hexadecene, by promoting mass transfer. Recyclability of the catalytic system was also evaluated in the presence of these cyclodextrins. [ABSTRACT FROM AUTHOR]

New sulfonated naphthylphosphanes having an average sulfonation degree around 2 have been synthetized and tested as ligand in the aqueous biphasic Rh-catalyzed hydroformylation of 1-decene assisted by randomly methylated β-cyclodextrins. All these water-soluble phosphanes associated to a rhodium precursor were able to perform aqueous hydroformylation of 1-decene. The best results in terms of catalyst recovery and recycling were obtained with sulfonated 2-naphthylphosphanes. With sulfonated 1-naphthylphosphanes, formation of low-coordinated catalytic species leading to a catalyst leaching in the organic phase was postulated. These results were rationalized by considering that sulfonated 1-naphthylphosphanes are bulkier ligands than sulfonated 2-naphthylphosphanes. [ABSTRACT FROM AUTHOR]

Abstract: Co-incubations of various β-cyclodextrins and doxorubicin have been evaluated on an in vitro model of blood–brain barrier in order to increase the delivery of this P-gp substrate to the brain. Among these cyclodextrins used, the Rame-β-cyclodextrin and Crysme-β-cyclodextrin increased the transport by a factor of 2 and 3.7, respectively. This increase was attributed to the cholesterol extraction property of these cyclodextrins from brain capillary endothelial cells leading to a modulation of the P-gp activity. [Copyright &y& Elsevier]

Abstract: Selective decarboxylation of two alkylallylurethane isomers into alkylallylamines has been performed in a biphasic system by using randomly hydroxypropylated and methylated cyclodextrins as discriminating agents. Surprisingly, the presence of small organic hydrosoluble molecules such as amine or alcohol derivatives appeared to be crucial in the discriminating process. Indeed, it was clearly proved that the presence of such additives enhances greatly the substrate selectivity. For instance, the addition of triethylamine to the reaction medium allows to improve the discriminating power of methylated-β-cyclodextrin by a factor 7. These unexpected results were explained by considering the formation of ternary cyclodextrin/substrate/additive complexes. [Copyright &y& Elsevier]