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

• nanoparticles As a consequence of evolution and as a response to pressures imposed, resistance of any organism to biocides increases. In this context, the use of silver and silver-based compounds as alternative biocidal agents has emerged in the last decade. Silver nanoparticles are very attractive because of

• their high thermal stability, low toxicity to human cells and effective broad-spectrum antibacterial activity. The antibacterial activity of these nanoparticles is probably due to their rapid breakdown which releases ionic silver that interact with the thiol residues of bacterial enzymes [80]. As a

• consequence, the bacterial DNA replication is inhibited. Moreover, the bacterial cytoplasmic membranes can also be damaged leading to cell lysis [81]. In contrast to solutions of silver ions, the biocidal efficacy of the silver nanoparticles is improved because of a high specific surface-to-volume ratio

An integrated photocatalytic/enzymatic system for the reduction of CO₂ to methanol in bioglycerol–water

• Michele Aresta,
• Angela Dibenedetto,
• Tomasz Baran,
• Antonella Angelini,
• Przemysław Łabuz and
• Wojciech Macyk

Beilstein J. Org. Chem. 2014, 10, 2556–2565, doi:10.3762/bjoc.10.267

• collected, washed 3 times with water and dried in air at 60 °C. [CrF5(H2O)]2−@TiO2 was prepared by impregnation of TiO2 particles (P25, Evonik or 10 nm particles) [20] by (NH4)2[CrF5(H2O)] under ultrasonic stirring. The suspension was sonicated for 15 minutes, left for 24 hours, and the nanoparticles were

Synthesis of α-amino amidines through molecular iodine-catalyzed three-component coupling of isocyanides, aldehydes and amines

• Praveen Reddy Adiyala,
• D. Chandrasekhar,
• Jeevak Sopanrao Kapure,
• Chada Narsimha Reddy and
• Ram Awatar Maurya

Beilstein J. Org. Chem. 2014, 10, 2065–2070, doi:10.3762/bjoc.10.214

• ], ZnO nanoparticles [18] and BF3·OEt2 [19] were reported with varying degrees of success. All these reported methods for the preparation of α-amino amidines have their own limitations such as long reaction times, high catalyst loading and use of expensive and hazardous metal catalysts. Therefore, the

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

• highly CO2-philic following the successful stabilisation of silver nanoparticles using isostearic acid [74]. It was compared to TMN-6 (Table 1, compound 12), a non-ionic surfactant with highly branched alkyl tails and around eight oxyethylene units which has previously been reported as solubilising water

Improving the reactivity of phenylacetylene macrocycles toward topochemical polymerization by side chains modification

• Simon Rondeau-Gagné,
• Jules Roméo Néabo,
• Maxime Daigle,
• Katy Cantin and
• Jean-François Morin

Beilstein J. Org. Chem. 2014, 10, 1613–1619, doi:10.3762/bjoc.10.167

• π-conjugated monomers capable of hydrogen bonding to create nanowires [21][22][23], nanoparticles [24][25][26][27], nanotubes [28][29][30][31] and two-dimensional layered materials [32] from organogels. The key to success was to obtain a good balance between solubility and gelation properties

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

• products, to biomedical applications including MRI imaging agents [1][2][3], membrane-protein crystallisation media [4][5][6] and solubilising bioactive food additives (Figure 1) [7]. Furthermore, recent research has centred on the use of amphiphile nanoparticles for drug-delivery applications [8][9][10

• library of amphiphiles, with ammonium head groups and single-chain saturated tails, can be synthesised in a combinatorial approach, using this chemistry [26]. Amphiphiles and self-assembled nanoparticles have been synthesised using CuAAC chemistry previously [27][28][29], however to our knowledge, this

Multivalent scaffolds induce galectin-3 aggregation into nanoparticles

• Candace K. Goodman,
• Mark L. Wolfenden,
• Pratima Nangia-Makker,
• Anna K. Michel,
• Avraham Raz and
• Mary J. Cloninger

Beilstein J. Org. Chem. 2014, 10, 1570–1577, doi:10.3762/bjoc.10.162

• demonstrated to be important for biological interactions ranging from bacterial invasion to cancer cellular responses, the development of systems such as glycodendrimers that can aggregate galectin-3 into nanoparticles in a highly controlled fashion is an important area of research. The study of galectin-3

• has been previously determined using turbidity and precipitation assays that carbohydrate-functionalized dendrimers induce lectin aggregation, the consistent formation of large nanoparticles has to our knowledge not been previously identified and characterized. The most likely explanation for the

A promising cellulose-based polyzwitterion with pH-sensitive charges

• Thomas Elschner and
• Thomas Heinze

Beilstein J. Org. Chem. 2014, 10, 1549–1556, doi:10.3762/bjoc.10.159

• [11]. However, polybetaines are mostly not soluble in pure water. Their solubility is often limited to concentrated saline solutions or organic solvents with high hydrogen bond-donating ability (e.g., trifluoroethanol) [12]. Therefore, the processing to yield films or nanoparticles requires

• polymer and aggregates with the DLS equipment yield no useful results, but from pH 4.5 to 3.5 nanoparticles with a Z-average diameter of about 200 nm could be detected. During the titration, the zeta potential of the particles increases from −40 to −10 mV according to the protonation of the carboxylate

Multichromophoric sugar for fluorescence photoswitching

• Stéphane Maisonneuve,
• Rémi Métivier,
• Pei Yu,
• Keitaro Nakatani and
• Juan Xie

Beilstein J. Org. Chem. 2014, 10, 1471–1481, doi:10.3762/bjoc.10.151

• (photochrome and fluorophore) moieties have also been reported by other groups [5][6][7][8][9]. The fluorophore vs photochrome ratio in reported bifunctional systems is 1:1 [4][5][6][7] or 2:1 [8][9]. Other strategies to assemble interacting fluorophores and photochromes (supramolecular systems, nanoparticles

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

• been PEGylated and introduced in the surface of polystyrene nanoparticles in order to increase the interaction with galactose receptors. p-Aminophenyl β-D-galactopyranoside was coupled with a bifunctional PEG activated on one end with NHS for the combination with the aniline and a FMOC-protected amino

• group on the other end. After deprotection, the amine reacted with the carboxylic groups on the surface of the nanoparticles (Scheme 6) [42]. A similar approach was developed recently using poly(amidoamine) dendrimers for selective delivery of chemotherapeutic agents into hepatic cancer cells [43

• -caprolactone for targeting dendritic cells and macrophages (Figure 4) [45] Both mannose and galactose were attached to PEGylated nanoparticles by click-chemistry between their propargyl glycosides and a gold nanoparticles derivatized with an azide-functionalized PEG [46]. Also, several unprotected carbohydrate

Synthesis of the first examples of iminosugar clusters based on cyclopeptoid cores

• Mathieu L. Lepage,
• Alessandra Meli,
• Anne Bodlenner,
• Céline Tarnus,
• Francesco De Riccardis,
• Irene Izzo and
• Philippe Compain

Beilstein J. Org. Chem. 2014, 10, 1406–1412, doi:10.3762/bjoc.10.144

• ], β-cyclodextrin [4][5] and porphyrin [7] cores, and with nanoparticles prepared by self-assembly of iminosugar-based glycopolypetides [6]. So far, the largest multivalent effect (up to 610-fold relative inhibition potency increase on a valency-corrected basis) has been achieved on jack bean α

Glycosystems in nanotechnology: Gold glyconanoparticles as carrier for anti-HIV prodrugs

• Fabrizio Chiodo,
• Marco Marradi,
• Javier Calvo,
• Eloisa Yuste and
• Soledad Penadés

Beilstein J. Org. Chem. 2014, 10, 1339–1346, doi:10.3762/bjoc.10.136

• to improve HIV drug treatment and prevention. In this scenario, gold nanoparticles are an interesting chemical tool to design and prepare smart and efficient drug-delivery systems. Here we describe the preparation and antiviral activity of carbohydrate-coated gold nanoparticles loaded with anti-HIV

• prodrug candidates. The nucleoside reverse transcriptase inhibitors abacavir and lamivudine have been converted to the corresponding thiol-ending ester derivatives and then conjugated to ~3 nm glucose-coated gold nanoparticles by means of “thiol-for-thiol” ligand place exchange reactions. The drugs

• . Some of these nanomaterials like polymeric nanoparticles, lipid nanoparticles and nanofibers have shown the ability to improve solubility, stability and permeability of anti-HIV drugs [9][10], but also to reduce the viral load by the activation of latently infected CD4+ T-cells [11]. Gold nanoparticles

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

Organic synthesis using photoredox catalysis

• Axel G. Griesbeck

Beilstein J. Org. Chem. 2014, 10, 1097–1098, doi:10.3762/bjoc.10.107

• -coated semiconductor nanoparticles. On the substrate side, the focus is on redox-active donor/acceptor molecules, which range from all kind of aromatic, olefinic and carbonyl-type electron acceptor compounds to heteroatom-linked electron donors. The relevance of carbon–carbon bond formation for organic

Polyglycerol-functionalized nanodiamond as a platform for gene delivery: Derivatization, characterization, and hybridization with DNA

• Li Zhao,
• Yuki Nakae,
• Hongmei Qin,
• Tadamasa Ito,
• Takahide Kimura,
• Hideto Kojima,
• Lawrence Chan and
• Naoki Komatsu

Beilstein J. Org. Chem. 2014, 10, 707–713, doi:10.3762/bjoc.10.64

• ; polyglycerol; polypeptides; Introduction A variety of nanoparticles have been investigated as nonviral vectors in drug and gene delivery systems [1][2]. Among these nanoparticles, nanodiamond (ND) has attracted a great deal of attention due to its high chemical stability, low toxicity, and large specific

• further surface functionalization to add more functions to ND [14]. As for gene delivery, on the other hand, DNA was immobilized on the surface of nanoparticles mostly by electrostatic attraction between the negative charge of DNA and the positive charge on the surface of the nanoparticle [15]. In the

• . However, ND-PG-BPP still has dispersibility of >1.0 mg/mL with less stability (Figure 5). Zeta potential characterization and pDNA complexation To analyze the surface charge of the nanoparticles, we measured the zeta potential of ND50, ND50-PG and ND-PG-BPP at neutral pH in Milli-Q water. The results are

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• aldehydes and amines to give the corresponding propargylamines 1 (Scheme 1). As Li and Van der Eycken reported in their valuable reviews, some other silver salts (e.g., Ag3PW12O40 [6], AgX [7]), complexes [8], zeolites [9] and nanoparticles [10][11] have been explored to catalyze the A3-coupling, but only

• [Au(III)salen] [20] and [Au(III)(2-phenylpyridine)Cl2] [21] complexes, immobilized heterogeneous catalysts [22], and gold nanoparticles (Au NP) [23][24][25][26] have been reported until 2010, as well as recognized in two recent exhaustive reviews by Li [2] and Van der Eycken [3]. In the past three

• years the development of new and effective nanostructured catalytic systems dominated the gold-catalyzed approach to A3-coupling. For example, ultrasmall gold(0) nanoparticles embedded in a mesoporous carbon nitride stabilizer [27] proved to be a highly active, selective and recyclable heterogeneous

Synthesis of new enantiopure poly(hydroxy)aminooxepanes as building blocks for multivalent carbohydrate mimetics

• Léa Bouché,
• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 213–223, doi:10.3762/bjoc.10.17

• stereocontrol and the flexibility concerning the chain length. In 2005, Al-Harrasi synthesized the first tert-butyldimethylsilyl (TBS)-protected aminopyrans (n = 0) and aminooxepanes (n = 1) via this reaction route [23]. Several of the poly(hydroxy)aminopyrans [24] were connected to gold nanoparticles and the

Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

• Phei Li Lau,
• Ray W. K. Allen and
• Peter Styring

Beilstein J. Org. Chem. 2013, 9, 2886–2897, doi:10.3762/bjoc.9.325

• possible, for example the catalyst can present as nanoparticles, ligand-less, unsupported or supported among other forms [16]. Practically speaking, heterogeneous catalysts provide benefits such as ease of separation and recovery from the reaction mixture. In general, heterogeneous catalysts tend to be

Synthesis of enantiopure sugar-decorated six-armed triptycene derivatives

• Paola Bonaccorsi,
• Maria Luisa Di Gioia,
• Antonella Leggio,
• Lucio Minuti,
• Teresa Papalia,
• Carlo Siciliano,
• Andrea Temperini and
• Anna Barattucci

Beilstein J. Org. Chem. 2013, 9, 2410–2416, doi:10.3762/bjoc.9.278

• controlled by recognition phenomena between carbohydrates and proteins. Generally, individual sugar units exhibit weak binding affinities to complementary proteins, while systems that incorporate several carbohydrate units, attached to an appropriate scaffold or self-assembled in nanoparticles, lead to

Self-assembly of 2,3-dihydroxycholestane steroids into supramolecular organogels as a soft template for the in-situ generation of silicate nanomaterials

• Valeria C. Edelsztein,
• Andrea S. Mac Cormack,
• Matías Ciarlantini and
• Pablo H. Di Chenna

Beilstein J. Org. Chem. 2013, 9, 1826–1836, doi:10.3762/bjoc.9.213

• cyclohexane and dichloromethane also showed a good gelling ability. These remarkable properties for such a simple steroid molecule prompted us to study the gelation scope, morphology, mode of self-assembly and the potential use of the gels to prepare silica nanoparticles through a bottom-up approach. Gelation

• . In the last case the packing is tight enough to prevent the polar solvent molecules to interact with the polar head of the steroid breaking the hydrogen bonds that lead to the SAFIN. Templated preparation of silica nanoparticles Even though LMOG 1 does not gelate tetraethoxysilane (TEOS), in-situ sol

• . The SEM images of the product obtained showed spherical nanoparticles of irregular size (see Supporting Information File 1). In this solvent the templated sol–gel polymerization failed, but the formation of spherical particles indicates some control effect on the growth of the silica nucleus by the

Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

• Rajesh Munirathinam,
• Roberto Ricciardi,
• Richard J. M. Egberink,
• Jurriaan Huskens,
• Michael Holtkamp,
• Herbert Wormeester,
• Uwe Karst and
• Willem Verboom

Beilstein J. Org. Chem. 2013, 9, 1698–1704, doi:10.3762/bjoc.9.194

• channel wall. Polymer brushes have proven to provide a unique platform in supported catalysis [14][15]. Previously, we have described the successful immobilization and evaluation of catalysts (e.g., basic organocatalyst [6], metallic nanoparticles [16], and enzymatic catalyst [17]) to the microchannel

Isolation and X-ray characterization of palladium–N complexes in the guanylation of aromatic amines. Mechanistic implications

• Abdessamad Grirrane,
• Hermenegildo Garcia and
• Eleuterio Álvarez

Beilstein J. Org. Chem. 2013, 9, 1455–1462, doi:10.3762/bjoc.9.165

• catalyzed by palladium salts [19], such as PdCl2 or Pd(OAc)2 in homogenous phase. Also recently we have reported that palladium nanoparticles supported on magnesia can be a solid catalyst for this process [20]. Working with PdCl2(NCCH3)2 in dichloromethane we were able to isolate two types of palladium

A³-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

• Jian-Lin Huang,
• Derek G. Gray and
• Chao-Jun Li

Beilstein J. Org. Chem. 2013, 9, 1388–1396, doi:10.3762/bjoc.9.155

• Jian-Lin Huang Derek G. Gray Chao-Jun Li Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A0B8, Canada 10.3762/bjoc.9.155 Abstract We decorated HS-functionalized cellulose nanocrystallite (CNC) films with monodisperse Au nanoparticles (AuNPs) to form a

• for CNCs include nanocomposite formulation, polymer reinforcement, drug delivery [27], enzyme immobilization [28], biomedical applications [29] and as templates for the synthesis of nanomaterials [30]. The deposition of metal nanoparticles onto the surface of CNCs can lead to new nano-heterogeneous

• catalysts for organic synthesis. Recently, CNCs have been used as an effective support for Pd nanoparticles [31], AuNPs [32], SeNPs [33], NiNPs [34] and Au–Ag alloy NPs [35] for greener organic synthesis. However, to date, studies on combining the surface chemistry of CNCs with metal nanoparticles in

Synthesis and spectroscopic properties of 4-amino-1,8-naphthalimide derivatives involving the carboxylic group: a new molecular probe for ZnO nanoparticles with unusual fluorescence features

• Laura Bekere,
• David Gachet,
• Vladimir Lokshin,
• Wladimir Marine and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2013, 9, 1311–1318, doi:10.3762/bjoc.9.147

• (3H)-yl)benzoic acid (4) was found to be a sensitive molecular probe for ZnO nanoparticles. We investigated in detail one- and two-photon absorption properties of this fluorophore. In nonpolar solvents, the acid 4 absorbs at about 400 nm and fluoresces at 500 nm with a fluorescence lifetime of about 7

• modification of ZnO nanoparticles produced by femtosecond laser ablation was demonstrated to afford nanohybrid materials for biophotonic applications [13][14]. Results and Discussion Synthesis and characterization Yellow 4-amino-1,8-naphthalimides are usually synthesized in two steps. The first step is the

• electron-donating properties and weaker electron-accepting properties than ZnO [18]. Grafting to the surface of ZnO nanoparticles In order to investigate the behavior of acid 4 as a fluorescent molecular probe, preliminary experiments on grafting to the surface of ZnO nanoparticles (NPs) were carried out

The synthesis of well-defined poly(vinylbenzyl chloride)-grafted nanoparticles via RAFT polymerization

• John Moraes,
• Kohji Ohno,
• Guillaume Gody,
• Thomas Maschmeyer and
• Sébastien Perrier

Beilstein J. Org. Chem. 2013, 9, 1226–1234, doi:10.3762/bjoc.9.139

• (VBC) shell nanoparticles. Optimal conditions for the control of VBC polymerization by RAFT are first established, followed by the use of the “grafting from” method to yield polymeric brushes that form a well-defined shell surrounding the silica core. We obtain particles that are monodisperse in size

• preparing highly monodisperse core–shell nanoparticles, which hold great promise for a range of applications such as drug-delivery vectors or colloidal-crystal self-assemblies [10][11]. RAFT polymerization initiated from preformed inorganic nanoparticles enables the grafting of polymer shells from the

• ]. One particular motivation has been the post-polymerization functionalization of the grafted chains to yield functional nanoparticles. Therefore, monomers that allow such post-polymerization functionalization are beginning to attract greater research attention [23][24]. 4-Vinylbenzyl chloride (VBC) is