Preparation of Pickering emulsions through interfacial adsorption by soft cyclodextrin nanogels

• Shintaro Kawano,
• Toshiyuki Kida,
• Mitsuru Akashi,
• Hirofumi Sato,
• Motohiro Shizuma and
• Daisuke Ono

Beilstein J. Org. Chem. 2015, 11, 2355–2364, doi:10.3762/bjoc.11.257

• on the type of oil solvent. Our research focuses on a new class of Pickering emulsifiers based on nanometer-sized hydrogel nanoparticles composed of crosslinked CD polymers (hereafter CD nanogels), which have a surface-active property and form stable emulsions at the oil-water interface. Reports on

• CD polymer, which can be dispersed in water as well as in nonpolar solvents. This amphiphilic polymer should realize water-swellable hydrogel nanoparticles containing CDs (CD nanogels). In this paper, we describe the preparation of Pickering emulsions using CD nanogels composed of crosslinked DM-β-CD

• the oil droplets from coalescence. Conclusion Amphiphilic CD nanogels, which are a new class of soft hydrogel nanoparticles, were prepared by crosslinking DM-β-CDs with PDI followed by the immersion in water. The DLS study shows that the primary CD nanogels (30–50 nm in diameter) assemble into larger

Cu(I)-catalyzed N,N’-diarylation of natural diamines and polyamines with aryl iodides

• Svetlana P. Panchenko,
• Alexei D. Averin,
• Maksim V. Anokhin,
• Olga A. Maloshitskaya and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2015, 11, 2297–2305, doi:10.3762/bjoc.11.250

• -aryldiamines using aryl iodides in the presence of CuCl under neat conditions [28], N,N’-diarylation of the simplest propane-1,3-diamine and butane-1,4-diamine was carried out using a CuI-metformin catalyst [29], monoarylation of mono- and diamines was studied using Cu2O and CuO nanoparticles and CuO

Synthesis, structure, and mechanical properties of silica nanocomposite polyrotaxane gels

• Kazuaki Kato,
• Daisuke Matsui,
• Koichi Mayumi and
• Kohzo Ito

Beilstein J. Org. Chem. 2015, 11, 2194–2201, doi:10.3762/bjoc.11.238

• by a novel network formed using cyclodextrin-based polyrotaxanes. Covalent bond formation between the cyclic components of polyrotaxanes and the surface of silica nanoparticles (15 nm diameter) resulted in an infinite network structure without direct bonds between the main chain polymer and the

• silica. Small-angle X-ray scattering revealed that the homogeneous distribution of silica nanoparticles in solution was maintained in the gel state. Such homogeneous nanocomposite gels were obtained with at least 30 wt % silica content, and the Young’s modulus increased with silica content. Gelation did

• not occur without silica. This suggests that the silica nanoparticles behave as cross-linkers. Viscoelastic measurements of the nanocomposite gels showed no stress relaxation regardless of the silica content for <20% compression strain, indicating an infinite stable network without physical cross

Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II)-ethylenediamine precatalyst

• Redouane Beniazza,
• Natalia Bayo,
• Florian Molton,
• Carole Duboc,
• Stéphane Massip,
• Nathan McClenaghan,
• Dominique Lastécouères and
• Jean-Marc Vincent

Beilstein J. Org. Chem. 2015, 11, 1950–1959, doi:10.3762/bjoc.11.211

• -reduction processes leading to the formation of copper(0) nanoparticles occurred when prolonged irradiation times were applied [12][13]. When a deaerated solution of 1 in THF was irradiated at 365 nm, a very fast change of the solution aspect was observed, the solution becoming colourless in ≈10 min as

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• series of two electron reductions. The scope of reductive photoredox applications was significantly boosted by Scaiano and co-workers’ discovery that organic halides function as acceptors with platinized TiO2 nanoparticles [71]. They used (iPr)2NEt as the sacrificial donor and demonstrated that reductive

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• scenario magnetic or conductive materials (metal beads, nanoparticles, etc.) are placed within a reactor cartridge exposed to an oscillating magnetic field of medium (15–25 kHz) or high frequency (780–850 kHz) leading to very rapid heating of reagent streams pumped through the reactor. A powerful

Influence of length and flexibility of spacers on the binding affinity of divalent ligands

• Susanne Liese and
• Roland R. Netz

Beilstein J. Org. Chem. 2015, 11, 804–816, doi:10.3762/bjoc.11.90

• overwhelming variety of multivalent ligand architectures that range from small divalent ligands to densely packed nanoparticles, led to different approaches to describe multivalency, depending on the size and valency of the system. Several studies aimed to treat ligand–receptor systems with different

Impact of multivalent charge presentation on peptide–nanoparticle aggregation

• Daniel Schöne,
• Boris Schade,
• Christoph Böttcher and
• Beate Koksch

Beilstein J. Org. Chem. 2015, 11, 792–803, doi:10.3762/bjoc.11.89

• macrostructures. Keywords: coiled-coil peptides; α-helical fibrils; controlled aggregation; gold nanoparticles; multivalency; Introduction In the past few decades metal and semiconductor nanoparticles, including gold nanoparticles, have gained much interest due to their desirable optical, magnetic, and

• electronic properties [1]. In particular, the distinct colour of gold nanoparticles is a result of the localised surface plasmon resonance (LSPR) band caused by collective electron oscillations. The LSPR induces a certain excitation band at visible wavelengths in the absorption spectrum, the position and

• width of which is highly dependent upon nanoparticle size. However, nanoparticle aggregation induces a spectral red-shift and broadening of the band in the absorption spectrum which depends on the distance between nanoparticles, the density of the assembly and the size of the particles [2][3]. Thus the

Multivalent dendritic polyglycerolamine with arginine and histidine end groups for efficient siRNA transfection

• Fatemeh Sheikhi Mehrabadi,
• Hanxiang Zeng,
• Mark Johnson,
• Cathleen Schlesener,
• Zhibin Guan and
• Rainer Haag

Beilstein J. Org. Chem. 2015, 11, 763–772, doi:10.3762/bjoc.11.86

• dynamic light scattering (DLS). Figure 2 shows the size distribution of dPG polyplexes (at N/P ratio 10). The average size of all nanoparticles ranges from 60–100 nm. In general, the AAdPG/siRNA polyplexes were smaller than the corresponding dPG-NH2 50%/siRNA polyplexes. Moreover, AAdPG complexes have a

• broader distribution of the final nanoparticles. The size of dPG-13Arg and dPG-13His complexes was slightly smaller than the other dPG-based vectors. The surface charge of the final nanoparticles was comparable to the corresponding complexes of siRNA and dPG-NH2 50% with terminal primary amines and about

Glycodendrimers: tools to explore multivalent galectin-1 interactions

• Jonathan M. Cousin and
• Mary J. Cloninger

Beilstein J. Org. Chem. 2015, 11, 739–747, doi:10.3762/bjoc.11.84

• mediated interactions. Dynamic light scattering and fluorescence microscopy were used to study the multivalent interaction of galectin-1 with the glycodendrimers in solution, and glycodendrimers were observed to organize galectin-1 into nanoparticles. In the presence of a large excess of galectin-1

• , glycodendrimers nucleated galectin-1 into nanoparticles that were remarkably homologous in size (400–500 nm). To understand augmentation of oncologic cellular aggregation by galectin-1, glycodendrimers were used in cell-based assays with human prostate carcinoma cells (DU145). The results revealed that

• glycodendrimers would organize extracellular galectin-1 into aggregates that would influence the biological activity of galectin-1. To test this hypothesis, lactose functionalized dendrimers were used to nucleate the aggregation of galectin-1 into nanoparticles, and the sizes of the galectin-1/glycodendrimer

Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces

• Stephan Schmidt,
• Hanqing Wang,
• Daniel Pussak,
• Simone Mosca and
• Laura Hartmann

Beilstein J. Org. Chem. 2015, 11, 720–729, doi:10.3762/bjoc.11.82

• , because a potentially multivalent arrangement of mannose on AA and CA grafting units could lead to chelate- or subsite binding at the ConA receptor enhancing the affinity of individual mannose units. In contrast to other work on similar multivalent scaffolds like oligomers, dendrimers or nanoparticles [20

Synthesis of tripodal catecholates and their immobilization on zinc oxide nanoparticles

• Franziska Klitsche,
• Julian Ramcke,
• Julia Migenda,
• Andreas Hensel,
• Tobias Vossmeyer,
• Horst Weller,
• Silvia Gross and
• Wolfgang Maison

Beilstein J. Org. Chem. 2015, 11, 678–686, doi:10.3762/bjoc.11.77

• Sciences, University of Padova, INSTM, Via Marzolo 1, 35131 Padova, Italy Department of Chemistry, University of Hamburg, Institute of Physical Chemistry, Grindelallee 117, 20146 Hamburg, Germany 10.3762/bjoc.11.77 Abstract A common approach to generate tailored materials and nanoparticles (NPs) is the

• anchor groups for biomedically relevant metal surfaces and nanoparticles. We report here the synthesis of new tripodal catecholates as multivalent anchor molecules for immobilization on metal surfaces and nanoparticles. The tripodal catecholates have been conjugated to various effector molecules such as

• . Keywords: bifunctional anchors; catecholates; multivalency; poly(ethylene glycol); ZnO nanoparticles; Introduction An elegant approach to generate tailored materials and nanoparticles is the formation of molecular monolayers by chemisorption of bifunctional anchor molecules (Figure 1A) [1]. The

Synthesis of multivalent carbohydrate mimetics with aminopolyol end groups and their evaluation as L-selectin inhibitors

• Joana Salta,
• Jens Dernedde and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2015, 11, 638–646, doi:10.3762/bjoc.11.72

• as selectin inhibitors. There we have found that sulfated aminopyrans connected by amide bonds to gold nanoparticles are highly potent inhibitors of L- and P-selectin with IC50 values in the subnanomolar range [12][13]. These lectins are crucial in the inflammatory process [14][15][16][17][18] and

• smaller inhibitors than the above mentioned nanoparticles and also to examine multivalency effects [25][26]. Several of these compounds could successfully be sulfated and tested as L-selectin inhibitors. Results and Discussion Aminopyran 1 was easily available following the previously reported synthetic

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

• [69], magnetic core-shell nanoparticles (with magnetite cores and polyacrylate shells) [70], and thermoresponsive block copolymers [71]. Such catalytic systems can exhibit excellent organocatalytic activity under aqueous conditions, and many of them can be recycled and reused. A rather unique property

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45

• immobilization of an enzyme on the electrode covered with different conducting polymers often embedded with carbon nanotubes and/or metal nanoparticles [52][53][54][55][56]. Chitosan, a naturally occurring biopolymer, has also been utilized for sensor fabrication [57][58]. Cholesterol oxidase has been

• immobilized on carbon nanotubes [59], metal nanoparticles [60] or graphene [61], and additionally decorated with metal nanoparticles [62] or modified with ionic liquids [63]. The application of composite electrodes, including silica sol–gel matrix with Prussian Blue [64], carbon nanotubes with zinc oxide

• nanoparticles [65], and zinc oxide nanorods directly grown on silver [66], has also been reported on. The “cholesterol self-powered biosensor” [67], in which the cathodic process is determined by cholesterol oxidase and on an anode phenothiazine-mediated oxidation of cholesterol as well as immobilization of

Matsuda–Heck reaction with arenediazonium tosylates in water

• Ksenia V. Kutonova,
• Marina E. Trusova,
• Andrey V. Stankevich,
• Pavel S. Postnikov and
• Victor D. Filimonov

Beilstein J. Org. Chem. 2015, 11, 358–362, doi:10.3762/bjoc.11.41

• ]. In 2012, examples of the Matsuda–Heck arylation of styrene and acrylic acid esters with arenediazonium tetrafluoroborates in water and catalyzed with in situ formed Pd nanoparticles [5] or agarose-supported Pd nanoparticles [6] have been reported. Superparamagnetic Pd–ZnFe2O4 MNPs have been shown to

Formulation development, stability and anticancer efficacy of core-shell cyclodextrin nanocapsules for oral chemotherapy with camptothecin

• Hale Ünal,
• Naile Öztürk and
• Erem Bilensoy

Beilstein J. Org. Chem. 2015, 11, 204–212, doi:10.3762/bjoc.11.22

• bioavailability of anticancer drugs should be improved [10]. Nanoparticulate drug delivery systems are promising in this field [11][12]. Nanoparticles are defined as submicron colloidal systems that include both nanospheres and nanocapsules. Nanospheres are defined as matrix systems whereas nanocapsules are core

• consideration of the disadvantages that limit the effectiveness of oral chemotherapy and the advantages of nanoparticular drug delivery systems, developing a strategy with nanoparticles and even nanocapsules might be very promising for oral delivery of anticancer agents. Nanocapsules are especially beneficial

• prolong residence time in the GI tract due to the polymeric wall, and iii) enhance permeability of drugs by taking the advantages of both small size of nanoparticles and mucoadhesive properties of polymers as coating materials. The main goal of this study therefore in a first step, to design and evaluate

Properties of cationic monosubstituted tetraalkylammonium cyclodextrin derivatives – their stability, complexation ability in solution or when deposited on solid anionic surface

• Martin Popr,
• Sergey K. Filippov,
• Nikolai Matushkin,
• Juraj Dian and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2015, 11, 192–199, doi:10.3762/bjoc.11.20

• acid [26]. Similar approaches of ionic self-assembly with CDs were used for the preparation of nanoparticles with external CD trigger [27], new material nanostructures [28], polyelectrolyte-surfactant complexes which yield new types of solid mesomorphous materials [29], or membranes with size-selective

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

• -cyclodextrin polymers. In aqueous solution nanoparticles were formed from association between the (S)-camptothecin–dextran polymers and the β-cyclodextrin polymers. Keywords: (S)-camptothecin; cyclodextrins; fluorescence; nanoparticles; ITC; Introduction Cancer remains to be the major cause of mortality in

• trials simply due to limited aqueous solubility and thereby low bioavailability [2]. Hence, there is an urgent need for novel methods to overcome the solubility issue of these drugs and to ensure efficient transport to the desired site of action with limited adverse effects. In this respect nanoparticles

• have shown tremendous potential as drug-delivery vehicles due to their ability to encapsulate drugs and ensure delivery to specific tissues and organs. Nanoparticles in the size range of 50–200 nm have shown very promising results due to their ability to penetrate and accumulate in the highly porous

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• palladium nanoparticles, that were generated in situ in water with the elimination of acetone. One of the major issues is the preparation of polysubstituted phenanthridines, in particular asymmetrically positioned on one of phenyl side-rings. An intriguing approach over rhodium-catalysed alkyne [2 + 2 + 2

Organic chemistry on surfaces: Direct cyclopropanation by dihalocarbene addition to vinyl terminated self-assembled monolayers (SAMs)

• Malgorzata Adamkiewicz,
• David O’Hagan and
• Georg Hähner

Beilstein J. Org. Chem. 2014, 10, 2897–2902, doi:10.3762/bjoc.10.307

• (SAMs) are increasingly being used as a means of surface modification to alter properties in a tuneable manner [1][2][3]. The major classes of SAMs are those with adsorbed long chain alkyl thiols on gold surfaces/nanoparticles [4][5], or long chain alkylsilanes on silica surfaces [6][7]. Two general

A novel 4-aminoantipyrine-Pd(II) complex catalyzes Suzuki–Miyaura cross-coupling reactions of aryl halides

• Claudia A. Contreras-Celedón,
• Darío Mendoza-Rayo,
• José A. Rincón-Medina and
• Luis Chacón-García

Beilstein J. Org. Chem. 2014, 10, 2821–2826, doi:10.3762/bjoc.10.299

• develop a stable and efficient Pd catalyst for these reactions. Recently, palladium complexes containing imidazole-imines [12], binary nanoclusters [13], N-heterocyclic carbenes (NHCs) [14], nanoparticles [15], palladacycles [16], and Schiff bases [17] have been developed as highly effective phosphine

Detonation nanodiamonds biofunctionalization and immobilization to titanium alloy surfaces as first steps towards medical application

• Juliana P. L. Gonçalves,
• Afnan Q. Shaikh,
• Manuela Reitzig,
• Daria A. Kovalenko,
• Jan Michael,
• René Beutner,
• Gianaurelio Cuniberti,
• Dieter Scharnweber and
• Jörg Opitz

Beilstein J. Org. Chem. 2014, 10, 2765–2773, doi:10.3762/bjoc.10.293

• in Figure 4, images g and h. Especially in the field of nanoparticles, entropic and surface effects, play a meaningful role that supports the electrostatic forces and possible covalent interaction, therefore the immobilization leads to binding of more and finer nanodiamonds (Figure 4g) and the

Synthesis of nanodiamond derivatives carrying amino functions and quantification by a modified Kaiser test

• Gerald Jarre,
• Steffen Heyer,
• Elisabeth Memmel,
• Thomas Meinhardt and
• Anke Krueger

Beilstein J. Org. Chem. 2014, 10, 2729–2737, doi:10.3762/bjoc.10.288

• bound amino groups are most versatile for the grafting of larger moieties onto the surface of nanoparticles. Typically, they are used for the formation of amides using protocols from peptide chemistry or in reductive aminations [1][2]. Additionally, amino groups have an influence on the surface polarity

• surfaces, namely when only low amounts of sample are available, e.g., when using fluorescent nanodiamond as the starting material or when the material shows unfavourable properties in other analytical methods. However, care should be taken in the event of strong agglomeration of the nanoparticles. Only the

• can be used for other nanoparticles with similar adsorption properties as well and represents a useful addition to the wet-chemical analysis of functional groups on nanomaterials. Experimental General chemicals and methods Detonation diamond has been purchased from Gansu Lingyun Corp. (Lanzhou, China

A green approach to the synthesis of novel phytosphingolipidyl β-cyclodextrin designed to interact with membranes

• Yong Miao,
• Florence Djedaïni-Pilard and
• Véronique Bonnet

Beilstein J. Org. Chem. 2014, 10, 2654–2657, doi:10.3762/bjoc.10.278

• and cosmetic applications and food industry thanks to their ability to encapsulate the hydrophobic molecules by forming inclusion complexes [1]. Moreover, the modified amphiphilic CDs are able to form nanoparticles without cosolvent or surfactant which could be ideal for drug delivery systems [2]. In

• still desired to vary membrane interactions. We have thus discovered that the fatty acyl-permethylated-β-CD cannot form nanoparticles in aqueous solvent probably due to the single lipidic chain inside the CD cavity [4][8], and later we found that bicatenar compounds whose hydrophobic moiety is composed

• of two chains, can form nanoparticles giving low critical aggregation concentration (CAC) [9]. Moreover, to the best of our knowledge, only few green approaches were described to modify cyclodextrins (enzyme catalysis [8][9], green solvents [10]). The use of phytosphingosine as a sustainable