Carbohydrate inhibitors of cholera toxin

• Vajinder Kumar and
• W. Bruce Turnbull

Beilstein J. Org. Chem. 2018, 14, 484–498, doi:10.3762/bjoc.14.34

• restricted to organic polymers. Gold nanoparticles coated in galactosyl ligands have been shown to be effective multivalent ligands for cholera toxin [73] and E. coli heat-labile toxin [74]. In these cases the objective of the studies was not to invoke inhibition, but rather to exploit the colour changes

• induced upon crosslinking the gold nanoparticles with CTB or LTB as a strategy for detecting the bacterial toxins. Conclusion Cholera and related diseases caused by other bacterial toxins remain a substantial threat to society. This challenge, and a molecular understanding of the basis of toxin action

Stimuli-responsive oligonucleotides in prodrug-based approaches for gene silencing

• Françoise Debart,
• Christelle Dupouy and
• Jean-Jacques Vasseur

Beilstein J. Org. Chem. 2018, 14, 436–469, doi:10.3762/bjoc.14.32

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

• been successfully employed in one case [111]. A PNA-based strand displacement probe was delivered into mammalian cells by employing cationic shell cross-linked nanoparticles, whereupon its application in the imaging of cellular mRNA expression was demonstrated [112]. Related to the concept of strand

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• ). Bhaumik et al. [59] carried out a similar reaction of 5-aminopyrazole (R = H, R1 = Me, 16), isatin 54 and cyclic-1,3-diones 58 in aqueous ethanol using aluminosilicate nanoparticles catalyst to yield pyrazolo[3,4-b]pyridines 61 (Scheme 13). Dandia et al. [60] carried out the multicomponent synthesis of

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• sulfoxide. Different aryl thiols were reacted with aliphatic and aromatic alkenes, showing a reasonable functional group tolerance. In 2015, the group of Greaney substituted the transition metal photocatalysts by titanium dioxide (TiO2) nanoparticles (Scheme 7) [37]. Photoexcitation of electrons to the

Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles

• Vivek Poonthiyil,
• Thisbe K. Lindhorst,
• Vladimir B. Golovko and
• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 11–24, doi:10.3762/bjoc.14.2

• unravel the causes of, potential new detection methods for, and novel therapeutic strategies against, many disease states. In the last two decades, glyco-gold nanoparticles have emerged as one of several potential new tools for glycoscientists. Glyco-gold nanoparticles consist of the unique structural

• combination of a gold nanoparticle core and an outer-shell comprising multivalent presentation of carbohydrates. The combination of the distinctive physicochemical properties of the gold core and the biological function/activity of the carbohydrates makes glyco-gold nanoparticles a valuable tool in

• glycoscience. In this review we present recent advances made in the use of one type of click chemistry, namely the azide–alkyne Huisgen cycloaddition, for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles. Keywords: azide–alkyne Huisgen cycloaddition; carbohydrates

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

• Marco Russo,
• Daniele La Corte,
• Annalisa Pisciotta,
• Serena Riela,
• Rosa Alduina and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2751–2763, doi:10.3762/bjoc.13.271

• synthesis of noble metal nanoparticles, and systems for the complexation and cell transfection of genetic material [17][18][19][20][21][22]. In particular, the complexation and transfection of polynucleotides also have been successfully accomplished by means of polycationic cyclodextrin or calixarene

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• [20], nanoparticles [15][21], and with a wide application in the synthesis of pharmaceutical solids [22]. Furthermore, medicinal mechanochemistry, a new research discipline that provides an access to the active pharmaceutical ingredients, is anticipated to have a strong impact on the future

Superstructures with cyclodextrins: Chemistry and applications IV

• Gerhard Wenz

Beilstein J. Org. Chem. 2017, 13, 2157–2159, doi:10.3762/bjoc.13.215

• nanoparticles with the sensitizer Zn-phthalocyanine and the antineoplastic drug docetaxel. These materials might be applicable for dual cancer therapy [15]. Another self-assembled CD nanocarrier for the photoreactive dye squaraine that is useful for photodynamic therapy is described in this Thematic Series [16

• ]. The group of Ravoo also conjugated arylazopyrazoles to amphiphilic cyclodextrin derivatives that form vesicles triggered by light [17]. A star-shaped polycationic CD derivative with many breakable, intrinsic, disulfide linkages forms nanoparticles with messenger RNA and drugs and is particularly

New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

• Daily Rodríguez-Padrón,
• Alina M. Balu,
• Antonio A. Romero and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

• processes [4]. In this sense, metal oxide nanoparticles have been extensively studied in recent decades because of their high activity, specificity of interaction and advantageous properties including a high surface/volume ratio combined with their small size [5][6][7]. Moreover, metal oxide nanoparticles

• have the additional advantage of easy recycling and reuse, which is an essential and desired property in many applications such as catalysis, sensors and even medicine [2][6][8][9]. Our research group has recently prepared different types of metal and metal oxide nanoparticles which have several

• applications in heterogeneous catalysis [10][11][12][13][14]. Transition metal and metal oxide nanoparticles have been reported to be highly active and selective in several processes, such as redox [15][16][17], C–C and C–heteroatom couplings [18][19]. In particular, iron oxide nanoparticles have been the

Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C–S cross-coupling reaction

• Debasish Sengupta,
• Koushik Bhowmik,
• Goutam De and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 1796–1806, doi:10.3762/bjoc.13.174

• , Jadavpur, Kolkata 700032, India. Fax: +91 33 24730957; Tel: +91 33 23223403 10.3762/bjoc.13.174 Abstract The present work demonstrates the C–S cross-coupling reaction between aryl halides and thiols using nickel nanoparticles (Ni NPs) supported on reduced graphene oxide (Ni/RGO) as a heterogeneous

• nanocomposites [30]. Therefore, RGO is considered an excellent candidate for catalyst support [31][32]. To date, various magnetic or semiconducting nanoparticles (NPs) have been incorporated in GO surfaces and thoroughly studied in terms of their photocatalytic and electrochemical properties [33][34][35][36][37

• ) was used as a support for in situ growth of Ni nanoparticles. The synthetic protocol presumably allows initial interaction between the metal and functional groups on to the basal plane of GO [48]. The interaction could take place effectively due to the planar structure and large contact area of GO. As

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• an economic and environmental standpoint, it is highly desirable to develop more environmentally friendly synthetic methodologies. Several studies were dedicated to the design of a novel catalytic system, that are more accessible, robust, efficient and ligand-free [19]. In that sense, nanoparticles

• . Synthesis of Pd nanoparticles suspension by electrochemical reduction The electrochemical synthesis of PVP-Pd NPs was carried out as previously reported [46]. The experiments were achieved in a glass electrochemical cell equipped with a Pt disc working electrode (geometric area = 0.0746 cm2), a very large

• with tributyl(vinyl)stannane.a Supporting Information Supporting Information File 196: TEM images of Pd nanoparticles, characterization data, and NMR spectra. Acknowledgements The research was supported by CONICET, FONCyT and SECyT - UNC. C.S.G. gratefully acknowledges CONICET for the fellowships. We

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

• Sadaf Hanif,
• Bernd Oschmann,
• Dmitri Spetter,
• Muhammad Nawaz Tahir,
• Wolfgang Tremel and
• Rudolf Zentel

Beilstein J. Org. Chem. 2017, 13, 1693–1701, doi:10.3762/bjoc.13.163

• monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO2 nanoparticles

• , which are functionalized thereafter with a block of ionic-liquid polymer. Pyrolysis of these polymer functionalized inorganic nanoparticles leads to TiO2 nanoparticles coated with a thin carbonaceous shell. Such materials may, e.g., be interesting as battery materials. Keywords: block copolymer; carbon

• , thin shells of carbonaceous materials around inorganic nanoparticles have been intensively investigated recently [22][23][24][25]. This interest is related to the search for improved battery materials for the reversible storage of electricity. To further improve batteries in terms of energy and power

Synthesis and metal binding properties of N-alkylcarboxyspiropyrans

• Alexis Perry and
• Christina J. Kousseff

Beilstein J. Org. Chem. 2017, 13, 1542–1550, doi:10.3762/bjoc.13.154

• nanoparticles has enabled photomodulation of nanoparticle fluorescence [10][11]. Similarly, tagged N-alkylcarboxyspiropyrans have provided the basis for photoactive biopolymers, e.g., polypeptides with photocontrolled folding [12], light-activated enzymes [13], light-enhanced affinity chromatography using

Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

• Desirée Leistenschneider,
• Nicolas Jäckel,
• Felix Hippauf,
• Volker Presser and
• Lars Borchardt

Beilstein J. Org. Chem. 2017, 13, 1332–1341, doi:10.3762/bjoc.13.130

• designing the porosity of carbon materials involves hard or soft templates [22][23][24]. Hard-templating utilizes metal oxide nanoparticles [25] and salts [26][27][28], which have to be synthesized in advance. Soft-templating employs surfactants or other structure-directing molecules, which self-assemble to

• for the synthesis of uniform metal oxide nanoparticles to synthesize a titanium(IV) citrate-based polymer [44][45]. The Pechini method is applicable to synthesize templated mesoporous carbons [46][47][48][49], but has never been utilized for a solvent-free and rapid process based on mechanochemistry

• . After carbonization broadened reflections occur due to the conversion of the bidenated Ti atoms to TiO2 nanoparticles of the rutile and anatase modification. We calculated the average domain size of crystalline TiO2 from the reflections at 25.4°, 48.0°, and 54.5° 2θ to be 6–9 nm after background

Detection of therapeutic radiation in three-dimensions

• John A. Adamovics

Beilstein J. Org. Chem. 2017, 13, 1325–1331, doi:10.3762/bjoc.13.129

• the study of alternative treatment approaches such as the addition of nanoparticles containing metals to the dosimeter to evaluate enhanced radiation effects [57] and utilizing mice in evaluating radiation treatment plans [58]. Conclusion Over the last twelve years there has been significant progress

Sugar-based micro/mesoporous hypercross-linked polymers with in situ embedded silver nanoparticles for catalytic reduction

• Qing Yin,
• Qi Chen,
• Li-Can Lu and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 1212–1221, doi:10.3762/bjoc.13.120

• . As the prepared porous polymer SugPOP-1 is based on hemiacetal glucose, Ag nanoparticles (AgNPs) can be successfully incorporated into the polymer by an in situ chemical reduction of freshly prepared Tollens’ reagent. The obtained AgNPs/SugPOP-1 composite demonstrates good catalytic activity in the

• reduction of 4-nitrophenol (4-NP) with an activity factor ka = 51.4 s−1 g−1, which is higher than some reported AgNP-containing composite materials. Keywords: catalytic reduction; hypercross-linking; porous polymers; silver nanoparticles; sugar; Introduction Hypercross-linked polymers (HCPs) are

• functionalization of the materials. Silver nanoparticles (AgNPs) have received extensive attention because of their unique properties and applications in catalysis [18], antibacterial use [19], phase separation [20], surface-enhanced Raman scattering (SERS) [21], etc. Compared with bulk silver, AgNPs have a more

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• , Nanotechnology Lab., Via G. Fantoli 16/15, 20138 Milan, Italy 10.3762/bjoc.13.100 Abstract Glyco-gold nanoparticles combine in a single entity the peculiar properties of gold nanoparticles with the biological activity of carbohydrates. The result is an exciting nanosystem, able to mimic the natural multivalent

• : gold nanoparticles; glyco nanoparticles; glyconanomaterials; immunology; targeting; Introduction Carbohydrates are well recognized as crucial biomolecules for their capability to produce an enormous number of biocodes which are translated into their ability to promote or suppress a plethora of

• resulting biological processes [3][4]. The increasing ability to manipulate material at the nanosize allowed the development of many glyco nanoparticles helpful in a wide range of applications, from the drug delivery to the imaging [5][6][7]. Among the large number of nanomaterials, gold is one of the main

Interactions between shape-persistent macromolecules as probed by AFM

• Johanna Blass,
• Jessica Brunke,
• Franziska Emmerich,
• Cédric Przybylski,
• Vasil M. Garamus,
• Artem Feoktystov,
• Roland Bennewitz,
• Gerhard Wenz and
• Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

• persistent macromolecules with high structural rigidity are able to form stable aggregates based on multiple supramolecular interactions, which can be detected and quantified without the presence of side effects, such as self-passivation or coiling processes. Dendrimers, nanoparticles and shape-persistent

Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes

• Carmen Moreno-Marrodan,
• Francesca Liguori and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2017, 13, 734–754, doi:10.3762/bjoc.13.73

• alkadienes from alkene feedstocks [4][5]. The chemistry of these processes is dominated by heterogeneous palladium catalysts, particularly based on solid-supported Pd nanoparticles (PdNP) [6][7]. On the industrial scale, alkynes partial hydrogenations are usually carried out under batch conditions using

• to handle, easy to operate and can accommodate beds with a broad range of physical dimensions and shapes. Commonly used packed catalysts consist of metal nanoparticles (MNP) immobilized onto a variety of porous solid supports, either pellets or powders of various grain size (in the range μm to mm

• ]. In this approach, an optimized catalyst was designed by the integration of the catalyst performances at increasing length scales, from the nanoscale (active metal nanoparticles), to the mesoscale (support) and macroscale (reactor). Thus, after identification of the optimal shape and size of PdNP for

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• their in vivo applications are restricted [12]. Therefore, the development of fluorescent nanoparticles that are able to replicate QD fluorescence properties without exhibiting long term toxicity profiles, has become very relevant. The term carbon dots (CDs) has been coined to describe a new class of

• carbon-based nanomaterials which are typically discrete, quasi-spherical nanoparticles, with sizes usually less than 10 nm in diameter (although bigger sizes have recently been reported). These relatively new nanomaterials have found many applications in the fields of photo- and electrocatalysis

• : top-down or bottom-up syntheses. Top-down methods are characterised by using a bulk carbon substrate as the starting material; using conditions that remove nanoparticles from the bulk substrate such as electrochemistry, chemical oxidation, arc discharge or laser ablation, carbon-based nanoparticles

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• reaction to proceed smoothly in THF at room temperature (Scheme 4) [24]. The reaction system used CsOH as base, providing phenols in moderate to excellent yields. In 2007, the Diaconescu group described Pd/PANI, which was prepared by supporting palladium nanoparticles with polyaniline (PANI) nanofibers. Pd

• , the Xu and Feng group cooperatively reported the hydroxylation of aryl halides without ligand using CuI-nanoparticles as catalyst in the presence of (n-Bu)4NBr under very mild conditions [47]. CuI-nanoparticles could be reused with a slight loss of activity. The reaction was carried out in water at 60

• –80 °C, affording the phenols from aryl iodides and bromides in good to excellent yields (Scheme 23). In the case of aryl bromide, long reaction time (48 h) was required. 110 mol % of CuI-nanoparticles was needed for the complete conversion of aryl bromides bearing electron-donating groups. It's worth

Novel β-cyclodextrin–eosin conjugates

• Gábor Benkovics,
• Damien Afonso,
• András Darcsi,
• Szabolcs Béni,
• Sabrina Conoci,
• Éva Fenyvesi,
• Lajos Szente,
• Milo Malanga and
• Salvatore Sortino

Beilstein J. Org. Chem. 2017, 13, 543–551, doi:10.3762/bjoc.13.52

• plot as well as in the volume plot (see Figure S39 in Supporting Information File 1). The aggregation properties of 4–β-CD were further confirmed by the results obtained by nanoparticles tracking analysis (Figure S40, Supporting Information File 1). The sample, under the selected experimental

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• ]. The authors logically proposed that the decyanation occurred via the reduction of an iminium ion intermediate. The hydrogenation of α-aminonitriles catalyzed by nickel nanoparticles results in reductive decyanation and yields 29–31. The colloid solution of nickel is prepared in situ via reduction of

• reduction by NaH [81]. Reductive decyanation catalyzed by nickel nanoparticles. Yields are given in weight % from GC–MS data [85]. Decyanation of 2-cyanobenzo[b]thiophene [87]. Simplified pathways involved in transition-metal-promoted reductive decyanations [93][95]. Fe-catalyzed reductive decyanation

Stabilization of nanosized titanium dioxide by cyclodextrin polymers and its photocatalytic effect on the degradation of wastewater pollutants

• Tamás Zoltán Agócs,
• István Puskás,
• Erzsébet Varga,
• Mónika Molnár and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2016, 12, 2873–2882, doi:10.3762/bjoc.12.286

• thin layer of waste water is treated by solar light to achieve the decomposition of the organic pollutants [32]. Another way of enhancing the surface is the application of nanoparticles (nanoTiO2). Such nanosized particles can readily aggregate forming larger agglomerates of reduced surface and reduced

• the nanoparticles (with its wider secondary side, Figure 1) [34]. In addition to the improvement of the colloidal stability, also the efficiency of the photocatalytic performance of nanoTiO2 particles can be enhanced by adsorption of β-CD. The latter plays electron-donating and hole-capturing roles

• dispersions have been studied for degradation of some model organic pollutants (methylene blue and ibuprofen) under UV-A light irradiation. Results and Discussion Selection of the CD derivative for stabilizing nanoTiO2 dispersions In aqueous dispersions, in the presence of salts the nanoparticles of TiO2