Hexacoordinate Ru-based olefin metathesis catalysts with pH-responsive N-heterocyclic carbene (NHC) and N-donor ligands for ROMP reactions in non-aqueous, aqueous and emulsion conditions

• Shawna L. Balof,
• K. Owen Nix,
• Matthew S. Olliff,
• Sarah E. Roessler,
• Arpita Saha,
• Kevin B. Müller,
• Ulrich Behrens,
• Edward J. Valente and
• Hans-Jörg Schanz

Beilstein J. Org. Chem. 2015, 11, 1960–1972, doi:10.3762/bjoc.11.212

• appears to be increased by several orders of magnitude by comparison, meaning the reaction environment must have changed from aqueous to organic. This means, the ROMP reaction is most likely occurring within the micelles. About the nature of the catalytic Ru species can only be speculated at this point

Terminal lipophilization of a unique DNA dodecamer by various nucleolipid headgroups: Their incorporation into artificial lipid bilayers and hydrodynamic properties

• Emma Werz and
• Helmut Rosemeyer

Beilstein J. Org. Chem. 2015, 11, 913–929, doi:10.3762/bjoc.11.103

• enhancement of the bilayer brightness (as in Figure 4 at t = 81 min) might be due to a redelivery of the lipo-oligonucleotide from (2) or (3). Transport of the oligomer through the aqueous phase most likely occurs in the form of micelles. For example, the infiltration of such micelles was demonstrated after

• /incubation step with high bilayer fluorescence and an accumulation of fluorescent aggregates/micelles above the bilayer. C) Z-direction scan of the bilayer after the ninth perfusion/incubation step, resulting in decreased bilayer brightness and an increased amount of micelles. D) After the 13th perfusion

Synthesis of carbohydrate-scaffolded thymine glycoconjugates to organize multivalency

• Anna K. Ciuk and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2015, 11, 668–674, doi:10.3762/bjoc.11.75

• other way. These processes allow to control, regulate and fine-tune the complex life of eukaryotes. We have recently focused our research dedicated to multivalency effects in carbohydrate recognition on the aspect of conformational control of multivalent assemblies, such as micelles [5] or glycoarrays

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• -load homopolymers by solution copolymerization [46][47], crosslinked polymer microspheres by dispersion copolymerization [47], crosslinked polymer beads by suspension copolymerization [47][48], catalytic core–shell micelles (nanoreactors) [68], hydrophobic nanogel particles by emulsion polymerization

Formation of nanoparticles by cooperative inclusion between (S)-camptothecin-modified dextrans and β-cyclodextrin polymers

• Thorbjørn Terndrup Nielsen,
• Catherine Amiel,
• Laurent Duroux,
• Kim Lambertsen Larsen,
• Lars Wagner Städe,
• Reinhard Wimmer and
• Véronique Wintgens

Beilstein J. Org. Chem. 2015, 11, 147–154, doi:10.3762/bjoc.11.14

• as nanoparticles and micelles. Recently, the first delivery of siRNA in humans using CD polymers was reported [14] and currently two drug-delivery systems based on CD polymers have entered clinical phase II trials in cancer treatment [6]. The advantages of CD polymers can be exploited in preparation

Articulated rods – a novel class of molecular rods based on oligospiroketals (OSK)

• Pablo Wessig,
• Roswitha Merkel and
• Peter Müller

Beilstein J. Org. Chem. 2015, 11, 74–84, doi:10.3762/bjoc.11.11

• are easier synthetically accessible, especially with different groups at each end, and remarkably better soluble, we also investigated the interaction of ARs with micelles and artificial membranes. In aqueous environments the folded conformation of 32a predominates (indicated by an IM/IEX-ratio < 1

• , see Figure 7). Upon addition of the non-ionic surfactant Triton X-100 with concentrations above the critical micelle concentration (ccmc = 0.24 mM [29]), the signal of the excimer emission completely disappears, pointing to an incorporation of the AR in micelles in the straight conformation (Figure 7

• be a versatile tool to investigate the STR/FOL equilibrium. We systematically investigated this phenomenon as a function of solvent viscosity, cyclodextrine addition and in the presence of lipids forming micelles and vesicles. In contrast to these noncovalent STR–FOL transitions we also reported on

Release of β-galactosidase from poloxamine/α-cyclodextrin hydrogels

• César A. Estévez,
• José Ramón Isasi,
• Eneko Larrañeta and
• Itziar Vélaz

Beilstein J. Org. Chem. 2014, 10, 3127–3135, doi:10.3762/bjoc.10.330

• diblock PEO–PPO copolymer chains attached to a central ethylenediamine group [8]. Their sensitivity to pH due to the central group offers interesting features as compared with the micelles of non-ionic block copolymers (such as Pluronics). Namely, with respect to the development of pharmaceutical

• by the addition of aqueous, protein-loaded α-CD to Tetronic 90R4. The outer PPO blocks of the copolymer interact forming micelles, while inner PEO blocks form inclusion complexes with α-CD. These moieties are also capable of interacting by hydrogen bonding, contributing to the stability of the

A study on the inhibitory mechanism for cholesterol absorption by α-cyclodextrin administration

• Takahiro Furune,
• Naoko Ikuta,
• Yoshiyuki Ishida,
• Hinako Okamoto,
• Daisuke Nakata,
• Keiji Terao and
• Norihiro Sakamoto

Beilstein J. Org. Chem. 2014, 10, 2827–2835, doi:10.3762/bjoc.10.300

• solubility of cholesterol in the lumen of the small intestine via the precipitation of lecithin from bile salt micelles by complex formation with α-CD. It further indicates that the lecithin precipitation effect on the bile salt micelles by α-CD addition clearly differs from addition of other water-soluble

• dietary fibers. The decrease in micellar cholesterol solubility in the FeSSIF was the strongest with α-CD addition. Keywords: α-cyclodextrin; bile salt micelles; cholesterol; lecithin; micellar solubility; Introduction α-Cyclodextrin (α-CD) is a ring molecule composed of six glucose units that has an

• removes cholesterol through formation of an inclusion complex. Because α-CD is sparingly absorbed by the body [18], it is thought that α-CD acts within the lumen of the gut. Lecithin and bile salts are major cholesterol-solubilizing agents found in gallbladder bile and form mixed micelles [19][20][21

Linear-g-hyperbranched and cyclodextrin-based amphiphilic block copolymer as a multifunctional nanocarrier

• Yamei Zhao,
• Wei Tian,
• Guang Yang and
• Xiaodong Fan

Beilstein J. Org. Chem. 2014, 10, 2696–2703, doi:10.3762/bjoc.10.284

• and quaternization reaction. The ABC then self-assembled into stable micelles with a core–shell structure in aqueous solution. These resulting micelles are multifunctional nanocarriers which possess higher drug loading capability due to the introduction of HBPCSi segments and β-CD moieties, and

• ; hyperbranched polymer; multifunctionality; polymer nanocarrier; Introduction In recent years, many nanostructured materials (such as polymeric micelles) used as pharmaceutical nanocarriers have been applied in different fields of biomedicine for controlled release, diagnostics, imaging, treatment and

• contrast properties, raising increasing attention [3][6][7][9][10][11][12][13][14]. Compared with other multifunctional nanocarriers reported in the literature, polymeric micelles formed by amphiphilic block copolymers (ABC) may possess many advantages including water-solubility, nontoxicity, selectivity

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

• Véronique Nardello-Rataj and
• Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

• . Classically, the inactivation of quaternary ammonium biocides is performed with mixtures of polyoxyethylene (20) sorbitan monooleate (Tween 80) and lecithin which trap the biocidal agents inside the micelles formed by the neutralization agents. In his paper, Simpson showed that the neutralization can be made

• alkylammonium and co-micelles do not form (Scheme 7). Moreover, this complex is also more active than the free ammonium cation against P. aeruginosa and C. albicans [73][74]. iii) Immobilization In contrast to the single biocide/CD complexes in solution that show a dissolution-controlled biocide release rate

Effect of cyclodextrin complexation on phenylpropanoids’ solubility and antioxidant activity

• Miriana Kfoury,
• David Landy,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2014, 10, 2322–2331, doi:10.3762/bjoc.10.241

• obtained from phase-solubility are generally apparent values because they combine several effects on the guest solubility: inclusion complexation, self-association of poorly soluble guests, self-aggregation of CD/guest complexes, as well as non-inclusion interaction and micelles formation [18]. Our

Specific DNA duplex formation at an artificial lipid bilayer: fluorescence microscopy after Sybr Green I staining

• Emma Werz and
• Helmut Rosemeyer

Beilstein J. Org. Chem. 2014, 10, 2307–2321, doi:10.3762/bjoc.10.240

• ability to form complex nano-architectures [5][6] as well as self-assembling aggregates such as micelles, vesicles [3] and bilayer formation of nucleolipids [7] offers numerous possibilities, e.g., for drug delivery [3]. Simultaneously, the interaction of such nanostructures with lipid membranes becomes

Supercritical carbon dioxide: a solvent like no other

• Jocelyn Peach and
• Julian Eastoe

Beilstein J. Org. Chem. 2014, 10, 1878–1895, doi:10.3762/bjoc.10.196

• fluorocarbon surfactants have been investigated and successfully solubilised in dense CO2 to form w/c reverse micelles and microemulsions; this area has been extensively reviewed [36][38][63]. In more recent years, efforts have been made to reduce fluorocarbon use due to the high expense and ensuing

• observed to have low water-CO2 interfacial tensions (Table 1, compounds 8 and 9). The presence of reversed micelles was also confirmed with small-angle neutron scattering (SANS) where the w value = 0, although phase separation occurred immediately upon water addition [59]. SANS is a non-invasive technique

• tension and therefore a higher solubilizing power in CO2. It is hypothesised that w/c microemulsions may be obtained at lower pressures and temperatures if; (i) the CO2-philicity of reversed micelles can be increased, (ii) if there are reduced attractive interactions between micelles or (iii) if the

The search for new amphiphiles: synthesis of a modular, high-throughput library

• George C. Feast,
• Thomas Lepitre,
• Xavier Mulet,
• Charlotte E. Conn,
• Oliver E. Hutt,
• G. Paul Savage and
• Calum J. Drummond

Beilstein J. Org. Chem. 2014, 10, 1578–1588, doi:10.3762/bjoc.10.163

• amphiphile library (that form normal phases) [30], we are able to achieve lyotropic phases ranging across the structural landscape of normal to inverse micelles. Upon completion of the comprehensive phase behaviour analysis of this second library, using high-throughput small-angle X-ray scattering (SAXS) at

Carbohydrate PEGylation, an approach to improve pharmacological potency

• M. Eugenia Giorgi,
• Rosalía Agusti and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 1433–1444, doi:10.3762/bjoc.10.147

• mannose to PEI via a PEG chain spacer (Figure 3B). This system was used to deliver small interfering RNA (siRNA) into a murine macrophage cell line [44]. Mannose residues as their 2-aminoethyl glycosides were attached by reductive amination to the surface of copolymer micelles of PEG with poly-ε

End-group-functionalized poly(N,N-diethylacrylamide) via free-radical chain transfer polymerization: Influence of sulfur oxidation and cyclodextrin on self-organization and cloud points in water

• Sebastian Reinelt,
• Daniel Steinke and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 680–691, doi:10.3762/bjoc.10.61

• of thermo-responsive micelles of end-group functionalized respectively block copolymers in aqueous solution have been investigated in previous studies [35][48][49]. Studies on hydrophobically PNIPAM have also demonstrated the formation of core-shell structures exhibiting a corona of PNIPAM chains [25

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• . Kabalka developed improved conditions for the trifluoromethylation of aryl halides by carrying out the reaction in sodium dodecyl sulfate (SDS) and toluene, and by using TMSCF3 as a cheaper trifluoromethylating agent [65]. The reverse micelles appear to prevent the decomposition of TMSCF3 and provide an

Influence of cyclodextrin on the solubility and the polymerization of (meth)acrylated Triton^® X-100

• Melanie Kemnitz and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2176–2183, doi:10.3762/bjoc.8.245

• ]. Accordingly, below this concentration isolated molecules can be found; above this concentration micelles are formed. Equilibrium constants of β-CD and Triton® X-100 complexes listed in the literature span a range of 145–171000 M−1. Different methods, e.g., surface tension, isothermal titration calorimetric

• ) increased from 0.7 nm at concentrations lower than 0.22 mM up to 106 nm indicating the formation of micelles above the CMC. The formation of micelles was inhibited by the addition of RAMEB-CD to the Triton® solution, because the hydrophobic component of 1 slips into the cavity of RAMEB-CD. The addition of 1

Molecular solubilization of fullerene C₆₀ in water by γ-cyclodextrin thioethers

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2012, 8, 1644–1651, doi:10.3762/bjoc.8.188

• ) investigations were performed to check for any aggregation during solubilization of C60 by γ-CD thioethers. DLS is a relatively fast method for the determination of the particle size distributions of proteins, polymers, micelles, and nanoparticles [46]. In particular, DLS is able to distinguish between a

Impact of cyclodextrins on the behavior of amphiphilic ligands in aqueous organometallic catalysis

• Hervé Bricout,
• Estelle Léonard,
• Christophe Len,
• David Landy,
• Frédéric Hapiot and
• Eric Monflier

Beilstein J. Org. Chem. 2012, 8, 1479–1484, doi:10.3762/bjoc.8.167

• increase in the catalytic performances. Keywords: amphiphilic phosphanes; biphasic system; cyclodextrins; micelles; Introduction Facing the need of developing a greener chemistry, chemists have recently focused their investigations on clean transformation processes to convert organic molecules into

• isothermal titration calorimetry (ITC), at a suitable RAME-β-CD/phosphane concentration ratio ensuring the absence of micelles during the whole experiment. Under these conditions, the values reflect the interaction between a single CD with a single phosphane only. A 1/1 stoichiometry was found whatever the

• complexes and aggregates was a consequence of the competitive equilibria of CD/phosphane complexation and phosphane self-assembly to form micelles. The surface activity of the four studied phosphanes has already been the subject of investigations [7][8]. Phosphanes 1–4 proved to be very surface active as

Design of a novel tryptophan-rich membrane-active antimicrobial peptide from the membrane-proximal region of the HIV glycoprotein, gp41

• Evan F. Haney,
• Leonard T. Nguyen,
• David J. Schibli and
• Hans J. Vogel

Beilstein J. Org. Chem. 2012, 8, 1172–1184, doi:10.3762/bjoc.8.130

• micelles was previously reported by our group [12], and it was shown that this peptide adopts a well-defined helix in the presence of detergent micelles, with four of the five Trp residues distributed in a plane along the length of the peptide. Therefore, this peptide satisfies two of the features that we

• wavelength of the emission maximum. A shift towards lower wavelengths is usually interpreted as the Trp residue residing in a more hydrophobic environment, which may be due to the gp41w peptides oligomerizing in solution. The addition of detergent micelles and large unilamellar vesicles (LUVs) to the peptide

• oligomeric state in aqueous solution. When detergent micelles or LUVs were added to the gp41w peptide, all of the calculated Ksv were lower than the values determined in buffer, indicating that gp41w binds to both micelles and LUVs with the Trp residues inserting into the membrane. All of the gp41w

Olefin metathesis in nano-sized systems

• Didier Astruc,
• Abdou K. Diallo,
• Sylvain Gatard,
• Liyuan Liang,
• Cátia Ornelas,
• Victor Martinez,
• Denise Méry and
• Jaime Ruiz

Beilstein J. Org. Chem. 2011, 7, 94–103, doi:10.3762/bjoc.7.13

• groups and other termini. In turn, water-soluble dendrimers can be used as molecular micelles as exemplified here. The implication of dendrimers in olefin metathesis reactions has mainly been focused on recovering the catalyst by loading the dendrimer with a functionalized catalyst. This strategy has

Surfactant catalyzed convenient and greener synthesis of tetrahydrobenzo[a]xanthene-11-ones at ambient temperature

• Pravin V. Shinde,
• Amol H. Kategaonkar,
• Bapurao B. Shingate and
• Murlidhar S. Shingare

Beilstein J. Org. Chem. 2011, 7, 53–58, doi:10.3762/bjoc.7.9

• the scope of water-based organic syntheses have been investigated [3]. Incorporation of surface-active agents (surfactants) in aqueous media has been proved to enhance the reactivity of water mediated reactions via the formation of micelles or vesicular cavities. The use of micellar and vesicle

• C14. It is of note to point out that the addition of TTAB converted the initially floating reaction mass into a homogeneous mixture, which on stirring became a white turbid emulsion. This observation implies, that there was formation of micelles or micelle-like colloidal aggregates. Indeed, formation

• of the micelles swiftly excludes the water molecules generated during the reaction, thus shifting the equilibrium towards the desired product that ultimately leads to an increase in the reaction yield [34][35][36]. This explanation is schematically represented in Figure 2. We next investigated the

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• additional reactive groups that do not participate in the step-growth polymerization. Polyaddition and polycondensation are probably the polyreactions for which miniemulsion systems are the most beneficial. An emulsion polymerization scenario where a mixture of micelles and monomer droplets coexist will

Insights into the mechanical properties of a silicone oil gel with a ‘latent’ gelator, 1-octadecylamine, and CO₂ as an ‘activator’

• Emiliano Carretti,
• Mathew George and
• Richard G. Weiss

Beilstein J. Org. Chem. 2010, 6, 984–991, doi:10.3762/bjoc.6.111

• some of their junction zones. Unlike non-crystalline SAFINs, such as those from giant worm-like micelles, only in exceptional cases are crystalline SAFINs able to ‘heal’ without being melted (i.e., transformed into the sol phase) and then reformed by cooling. Amplitude sweep. The stability of the