4,582 results match your criteria Beilstein Journal of Organic Chemistry [Journal]


The nanoscaled metal-organic framework ICR-2 as a carrier of porphyrins for photodynamic therapy.

Beilstein J Nanotechnol 2018 30;9:2960-2967. Epub 2018 Nov 30.

Department of Materials Chemistry, Institute of Inorganic Chemistry of the Czech Academy of Sciences, Husinec-Řež 1001, 250 68 Řež, Czech Republic.

Nanosized porphyrin-containing metal-organic frameworks (MOFs) attract considerable attention as solid-state photosensitizers for biological applications. In this study, we have for the first time synthesised and characterised phosphinate-based MOF nanoparticles, nanoICR-2 (Inorganic Chemistry Rez). We demonstrate that nanoICR-2 can be decorated with anionic 5,10,15,20-tetrakis(4-R-phosphinatophenyl)porphyrins (R = methyl, isopropyl, phenyl) by utilizing unsaturated metal sites on the nanoparticle surface. Read More

View Article
November 2018

Investigation of CVD graphene as-grown on Cu foil using simultaneous scanning tunneling/atomic force microscopy.

Beilstein J Nanotechnol 2018 28;9:2953-2959. Epub 2018 Nov 28.

Department of Physics Engineering, İstanbul Technical University, 34469, İstanbul, Turkey.

Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) images of graphene reveal either a triangular or honeycomb pattern at the atomic scale depending on the imaging parameters. The triangular patterns at the atomic scale are particularly difficult to interpret, as the maxima in the images could be every other carbon atom in the six-fold hexagonal array or even a hollow site. Carbon sites exhibit an inequivalent electronic structure in HOPG or multilayer graphene due to the presence of a carbon atom or a hollow site underneath. Read More

View Article
November 2018

Hybrid Au@alendronate nanoparticles as dual chemo-photothermal agent for combined cancer treatment.

Beilstein J Nanotechnol 2018 27;9:2947-2952. Epub 2018 Nov 27.

Inserm U1148, LVTS, Université Paris 13, Sorbonne Paris Cité, Bobigny, France.

A gold therapeutic nanoplatform with the same molecule used as reductant, coating and therapeutic agent has been developed in a one-pot, one-phase process using alendronate, a drug from the bisphosphonate family known for its antitumor effects. In addition, the core made of gold nanoparticles (NPs) brings thermal functionalities under irradiation within the first biological window (650-900 nm). The Au@alendronate nanoplatform thus provided a combined antitumor activity through drug delivery and photothermal therapy. Read More

View Article
November 2018
1 Read

Ternary nanocomposites of reduced graphene oxide, polyaniline and hexaniobate: hierarchical architecture and high polaron formation.

Beilstein J Nanotechnol 2018 26;9:2936-2946. Epub 2018 Nov 26.

School of Materials and National Graphene Institute, The University of Manchester, Booth St E, Manchester M13 9PL, United Kingdom.

Nanostructured systems, such as nanocomposites, are potential materials for usage in different fields since synergistic effects of their components at the nanoscale domain may improve physical/chemical properties when compared to individual phases. We report here the preparation and characterisation of a new nanocomposite composed of polyaniline (PANI), reduced graphene oxide (rGO) and hexaniobate (hexNb) nanoscrolls. Atomic force microscopy images show an interesting architecture of rGO flakes coated with PANI and decorated by hexNb. Read More

View Article
November 2018

In situ characterization of nanoscale contaminations adsorbed in air using atomic force microscopy.

Beilstein J Nanotechnol 2018 23;9:2925-2935. Epub 2018 Nov 23.

Centro de Investigación en Óptica y Nanofísica (CIOyN), Departamento Física, Facultad de Química, Campus Espinardo, Universidad de Murcia, 30100 Murcia, Spain.

Under ambient conditions, surfaces are rapidly modified and contaminated by absorbance of molecules and a variety of nanoparticles that drastically change their chemical and physical properties. The atomic force microscope tip-sample system can be considered a model system for investigating a variety of nanoscale phenomena. In the present work we use atomic force microscopy to directly image nanoscale contamination on surfaces, and to characterize this contamination by using multidimensional spectroscopy techniques. Read More

View Article
November 2018

Time-resolved universal temperature measurements using NaYF:Er,Yb upconverting nanoparticles in an electrospray jet.

Beilstein J Nanotechnol 2018 21;9:2916-2924. Epub 2018 Nov 21.

Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, USA.

Hexagonal upconverting nanoparticles (UCNPs) of NaYF:Er,Yb (ca. 300 nm) have been widely used to measure the temperature at the nanoscale using luminescence ratio thermometry. However, several factors limit their applications. Read More

View Article
November 2018

Layered calcium phenylphosphonate: a hybrid material for a new generation of nanofillers.

Beilstein J Nanotechnol 2018 20;9:2906-2915. Epub 2018 Nov 20.

SYNPO, akciová společnost, S. K. Neumanna 1316, 532 07 Pardubice, Czech Republic.

The use of nanosheets of layered calcium phenylphosphonate as a filler in a polymeric matrix was investigated. Layered calcium phenylphosphonate (CaPhP), with chemical formula CaCHPO∙2HO, is a hybrid organic-inorganic material that exhibits a hydrophobic character due to the presence of phenyl groups on the surface of the layers. In this paper, various CaPhP synthesis methods were studied with the aim of obtaining a product most suitable for its subsequent exfoliation. Read More

View Article
November 2018
1 Read

The effect of flexible joint-like elements on the adhesive performance of nature-inspired bent mushroom-like fibers.

Beilstein J Nanotechnol 2018 19;9:2893-2905. Epub 2018 Nov 19.

Mechanical Engineering, Texas Tech University, Lubbock, TX 79409-1021, USA.

Many organisms rely on densely packed, tilted and curved fibers of various dimensions to attach to surfaces. While the high elastic modulus of these fibers enables an extremely large number of fibers per unit area, where each fiber stands freely without sticking to its neighbors, the tilt/curvature provides them with the compliance and the directional adhesion properties to attach strongly and efficiently to a surface. Recent studies have revealed that many of such organisms also feature materials with a graded elastic modulus that is tailored towards improving the contact area without sacrificing the fiber density. Read More

View Article
November 2018

The activity of indenylidene derivatives in olefin metathesis catalysts.

Beilstein J Org Chem 2018 30;14:2956-2963. Epub 2018 Nov 30.

Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, c/ Mª Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain.

The first turnover event of an olefin metathesis reaction using a new family of homogenous Ru-based catalysts bearing modified indenylidene ligands has been investigated, using methoxyethylene as a substrate. The study is carried out by means of density functional theory (DFT). The indenylidene ligands are decorated with -methyl and isopropyl groups at both positions of their phenyl ring. Read More

View Article
November 2018

Stereodivergent approach in the protected glycal synthesis of L-vancosamine, L-saccharosamine, L-daunosamine and L-ristosamine involving a ring-closing metathesis step.

Beilstein J Org Chem 2018 29;14:2949-2955. Epub 2018 Nov 29.

Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, 263 avenue du Général Leclerc, Campus de Beaulieu, F-35000 Rennes, France.

In this paper, a new access to several chiral 3-aminoglycals as potential precursors for glycosylated natural products is reported from a common starting material, (-)-methyl-L-lactate. The stereodivergent strategy is based on the implementation of a ring-closing metathesis of vinyl ethers as key step of reaction sequences developed. Read More

View Article
November 2018

1,8-Bis(dimethylamino)naphthyl-2-ketimines: Inside vs outside protonation.

Beilstein J Org Chem 2018 28;14:2940-2948. Epub 2018 Nov 28.

Institute of Chemistry, St. Petersburg State University, Universitetskii pr. 26, 198504 St. Petersburg, Russian Federation.

The structure and protonation behaviour of four -arylketimines of 1,8-bis(dimethylamonio)naphthalene with a different number of methoxy groups in an aromatic substituent were investigated in solution by NMR (acetone, DMSO, MeCN), in solid state by X-ray analysis and in the gas phase by DFT calculations. Both mono- and diprotonated species were considered. It has been shown that -isomers of neutral imines can be stabilised by an intramolecular C=N-H···OMe hydrogen bond with a neighbouring methoxy group. Read More

View Article
November 2018

MoO on zeolites MCM-22, MCM-56 and 2D-MFI as catalysts for 1-octene metathesis.

Beilstein J Org Chem 2018 27;14:2931-2939. Epub 2018 Nov 27.

J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, v.v.i., Dolejškova 3, 182 23 Prague 8, Czech Republic.

Highly active olefin metathesis catalysts were prepared by thermal spreading MoO and/or MoO(acac) on MWW zeolites (MCM-22, delaminated MCM-56) and on two-dimensional MFI (all in NH form). The catalysts' activities were tested in the metathesis of neat 1-octene (as an example of a longer chain olefin) at 40 °C. Catalysts with 6 wt % or 5 wt % of Mo were used. Read More

View Article
November 2018
1 Read

Green synthesis of new chiral 1-(arylamino)imidazo[2,1-]isoindole-2,5-diones from the corresponding α-amino acid arylhydrazides in aqueous medium.

Beilstein J Org Chem 2018 26;14:2923-2930. Epub 2018 Nov 26.

Laboratoire de Synthèse Organique Asymétrique et Catalyse Homogène, (UR 11ES56) Université de Monastir, Faculté des Sciences de Monastir, avenue de l'environnement, 5000 Monastir, Tunisie. ; Tel: (+216) 73.

New chiral 1-(arylamino)imidazo[2,1-]isoindole-2,5-dione derivatives were obtained in good to excellent yields via the cyclocondensation of 2-formylbenzoic acid and various α-amino acid arylhydrazides using water as the solvent in the presence of sodium dodecyl sulfate as the surfactant and under simple and minimum manipulation, without purification. The reaction is totally diastereoselective and gives access to the nitrogenated tricyclic core with a relative stereochemistry. Read More

View Article
November 2018

Copper(I)-catalyzed tandem reaction: synthesis of 1,4-disubstituted 1,2,3-triazoles from alkyl diacyl peroxides, azidotrimethylsilane, and alkynes.

Beilstein J Org Chem 2018 23;14:2916-2922. Epub 2018 Nov 23.

Key Laboratory of Coal to Ethylene Glycol and Its Related Technology, State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Center for Excellence in Molecular Synthesis, Chinese Academy of Sciences, 155 Yangqiao Road West, Fuzhou, Fujian 350002, P. R. China.

A copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction for the synthesis of 1,4-disubstituted 1,2,3-triazoles from alkyl diacyl peroxides, azidotrimethylsilane, and terminal alkynes is reported. The alkyl carboxylic acids is for the first time being used as the alkyl azide precursors in the form of alkyl diacyl peroxides. This method avoids the necessity to handle organic azides, as they are generated in situ, making this protocol operationally simple. Read More

View Article
November 2018

Synthesis of indole-cycloalkyl[]pyridine hybrids via a four-component six-step tandem process.

Beilstein J Org Chem 2018 22;14:2907-2915. Epub 2018 Nov 22.

Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625 021, Tamil Nadu, India.

The one-pot four-component reaction of 3-(1-indol-3-yl)-3-oxopropanenitriles, aromatic aldehydes, cycloalkanones and ammonium acetate occurred via a six-step tandem Knoevenagel condensation-nucleophilic addition to carbonyl-Michael addition-N-cyclization-elimination-air oxidation sequence to afford structurally intriguing indole-cycloalkyl[]pyridine-3-carbonitrile hybrid heterocycles in excellent yields. Read More

View Article
November 2018

Generation of 1,2-oxathiolium ions from (arysulfonyl)- and (arylsulfinyl)allenes in Brønsted acids. NMR and DFT study of these cations and their reactions.

Beilstein J Org Chem 2018 22;14:2897-2906. Epub 2018 Nov 22.

Department of Organic Chemistry, Institute of Chemistry, Saint Petersburg State University, Universitetskaya nab., 7/9, Saint Petersburg, 199034, Russia.

In strong Brønsted acids (CFSOH, FSOH, DSO), (arysulfonyl)allenes (ArSO-CR=C=CRR) and (arylsulfinyl)allenes (ArSO-CR=C=CRR) undergo cyclization into the corresponding stable 1,2-oxathiolium ions, which were studied by means of NMR and DFT calculations. Quenching of solutions of these cations with low nucleophilic media, aqueous HCl, leads to their deprotonation with a stereoselective formation of (arysulfonyl)butadienes (for instance, ArSO-CR=C-C(Me)=CH, for R = R = Me, yields of 87-98%). Reactions of (arysulfonyl)allenes in the system TfOH (0. Read More

View Article
November 2018

Protein-protein interactions in bacteria: a promising and challenging avenue towards the discovery of new antibiotics.

Authors:
Laura Carro

Beilstein J Org Chem 2018 21;14:2881-2896. Epub 2018 Nov 21.

School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.

Antibiotics are potent pharmacological weapons against bacterial infections; however, the growing antibiotic resistance of microorganisms is compromising the efficacy of the currently available pharmacotherapies. Even though antimicrobial resistance is not a new problem, antibiotic development has failed to match the growth of resistant pathogens and hence, it is highly critical to discover new anti-infective drugs with novel mechanisms of action which will help reducing the burden of multidrug-resistant microorganisms. Protein-protein interactions (PPIs) are involved in a myriad of vital cellular processes and have become an attractive target to treat diseases. Read More

View Article
November 2018

The influence of the cationic carbenes on the initiation kinetics of ruthenium-based metathesis catalysts; a DFT study.

Beilstein J Org Chem 2018 20;14:2872-2880. Epub 2018 Nov 20.

Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warszawa, Poland.

Cationic carbenes are a relatively new and rare group of ancillary ligands, which have shown their superior activity in a number of challenging catalytic reactions. In ruthenium-based metathesis catalysis they are often used as ammonium tags, to provide water-soluble, environment-friendly catalysts. In this work we performed computational studies on three cationic carbenes with the formal positive charge located at different distances from the carbene carbon. Read More

View Article
November 2018

Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis.

Beilstein J Org Chem 2018 19;14:2861-2871. Epub 2018 Nov 19.

Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.

This review summarizes the recent progress of Grubbs-Hoveyda (GH) type olefin metathesis catalysts incorporated into the robust fold of β-barrel proteins. Anchoring strategies are discussed and challenges and opportunities in this emerging field are shown from simple small-molecule transformations over ring-opening metathesis polymerizations to in vivo olefin metathesis. Read More

View Article
November 2018

Site-controlled formation of single Si nanocrystals in a buried SiO matrix using ion beam mixing.

Beilstein J Nanotechnol 2018 16;9:2883-2892. Epub 2018 Nov 16.

Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany.

For future nanoelectronic devices - such as room-temperature single electron transistors - the site-controlled formation of single Si nanocrystals (NCs) is a crucial prerequisite. Here, we report an approach to fabricate single Si NCs via medium-energy Si or Ne ion beam mixing of Si into a buried SiO layer followed by thermally activated phase separation. Binary collision approximation and kinetic Monte Carlo methods are conducted to gain atomistic insight into the influence of relevant experimental parameters on the Si NC formation process. Read More

View Article
November 2018

Charged particle single nanometre manufacturing.

Beilstein J Nanotechnol 2018 14;9:2855-2882. Epub 2018 Nov 14.

Oxford Scientific Consultants Ltd, 67 High Street, Dorchester-on-Thames, OX10 7HN, UK.

Following a brief historical summary of the way in which electron beam lithography developed out of the scanning electron microscope, three state-of-the-art charged-particle beam nanopatterning technologies are considered. All three have been the subject of a recently completed European Union Project entitled "Single Nanometre Manufacturing: Beyond CMOS". Scanning helium ion beam lithography has the advantages of virtually zero proximity effect, nanoscale patterning capability and high sensitivity in combination with a novel fullerene resist based on the sub-nanometre C molecule. Read More

View Article
November 2018

Nanostructure-induced performance degradation of WO·HO for energy conversion and storage devices.

Beilstein J Nanotechnol 2018 12;9:2845-2854. Epub 2018 Nov 12.

Center for Environmental and Energy Research, Ghent University Global Campus, Yeonsu-gu, Incheon 21985, South Korea.

Although 2D layered nanomaterials have been intensively investigated towards their application in energy conversion and storage devices, their disadvantages have rarely been explored so far especially compared to their 3D counterparts. Herein, WO·HO ( = 0, 1, 2), as the most common and important electrochemical and electrochromic active nanomaterial, is synthesized in 3D and 2D structures through a facile hydrothermal method, and the disadvantages of the corresponding 2D structures are examined. The weakness of 2D WO·HO originates from its layered structure. Read More

View Article
November 2018
3 Reads

Graphene-enhanced metal oxide gas sensors at room temperature: a review.

Beilstein J Nanotechnol 2018 9;9:2832-2844. Epub 2018 Nov 9.

College of Mechanical Engineering, Yangzhou University, Yangzhou 225127, China.

Owing to the excellent sensitivity to gases, metal-oxide semiconductors (MOS) are widely used as materials for gas sensing. Usually, MOS gas sensors have some common shortages, such as relatively poor selectivity and high operating temperature. Graphene has drawn much attention as a gas sensing material in recent years because it can even work at room temperature, which reduces power consumption. Read More

View Article
November 2018

Controlling surface morphology and sensitivity of granular and porous silver films for surface-enhanced Raman scattering, SERS.

Beilstein J Nanotechnol 2018 7;9:2813-2831. Epub 2018 Nov 7.

Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 12, 64287 Darmstadt, Germany.

The design of efficient substrates for surface-enhanced Raman spectroscopy (SERS) for large-scale fabrication at low cost is an important issue in further enhancing the use of SERS for routine chemical analysis. Here, we systematically investigate the effect of different radio frequency (rf) plasmas (argon, hydrogen, nitrogen, air and oxygen plasma) as well as combinations of these plasmas on the surface morphology of thin silver films. It was found that different surface structures and different degrees of surface roughness could be obtained by a systematic variation of the plasma type and condition as well as plasma power and treatment time. Read More

View Article
November 2018

Biomimetic surface structures in steel fabricated with femtosecond laser pulses: influence of laser rescanning on morphology and wettability.

Beilstein J Nanotechnol 2018 5;9:2802-2812. Epub 2018 Nov 5.

Laser Processing Group, Instituto de Óptica, IO-CSIC, Serrano 121, 28006 Madrid, Spain.

The replication of complex structures found in nature represents an enormous challenge even for advanced fabrication techniques, such as laser processing. For certain applications, not only the surface topography needs to be mimicked, but often also a specific function of the structure. An alternative approach to laser direct writing of complex structures is the generation of laser-induced periodic surface structures (LIPSS), which is based on directed self-organization of the material and allows fabrication of specific micro- and nanostructures over extended areas. Read More

View Article
November 2018
2 Reads

Variation of the photoluminescence spectrum of InAs/GaAs heterostructures grown by ion-beam deposition.

Beilstein J Nanotechnol 2018 2;9:2794-2801. Epub 2018 Nov 2.

Department of Physics and Electronics, Platov South-Russian State Polytechnic University (NPI), 346428, 132, Prosveshchenia str., Novocherkassk, Russia.

This work reports on an experimental investigation of the influence of vertical stacking of quantum dots, the thickness of GaAs potential barriers, and their isovalent doping with bismuth on the photoluminescence properties of InAs/GaAs heterostructures. The experimental samples were grown by ion-beam deposition. We showed that using three vertically stacked layers of InAs quantum dots separated by thin GaAs barrier layers was accompanied by a red-shift of the photoluminescence peak of InAs/GaAs heterostructures. Read More

View Article
November 2018
1 Read

Near-infrared light harvesting of upconverting NaYF:Yb/Er-based amorphous silicon solar cells investigated by an optical filter.

Beilstein J Nanotechnol 2018 31;9:2788-2793. Epub 2018 Oct 31.

Institute of NanoEngineering, School of Material Science and Engineering, Shandong university of Science and Technology, Qingdao, 266590, P.R. China.

The wastage of near-infrared light seriously restricts the photoelectric conversion efficiency of hydrogenated amorphous silicon (a-Si:H) thin film solar cells. Spectral upconversion is of great significance in reducing the wastage. Herein, the upconverting compound NaYF:Yb/Er was synthesized via a hydrothermal method. Read More

View Article
October 2018

Magnetic and luminescent coordination networks based on imidazolium salts and lanthanides for sensitive ratiometric thermometry.

Beilstein J Nanotechnol 2018 30;9:2775-2787. Epub 2018 Oct 30.

Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, F-67034 Strasbourg Cedex 2, France.

The synthesis and characterization of six new lanthanide networks [Ln(L)(ox)(HO)] with Ln = Eu, Gd, Tb, Dy, Ho and Yb is reported. They were synthesized by solvo-ionothermal reaction of lanthanide nitrate Ln(NO)·HO with the 1,3-bis(carboxymethyl)imidazolium [HL] ligand and oxalic acid (Hox) in a water/ethanol solution. The crystal structure of these compounds has been solved on single crystals and the magnetic and luminescent properties have been investigated relying on intrinsic properties of the lanthanide ions. Read More

View Article
October 2018
1 Read

Comparative biological effects of spherical noble metal nanoparticles (Rh, Pd, Ag, Pt, Au) with 4-8 nm diameter.

Beilstein J Nanotechnol 2018 29;9:2763-2774. Epub 2018 Oct 29.

Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, D-45117 Essen, Germany. ; Tel: +49 201 1832402; E-mail:

For a comparative cytotoxicity study, nanoparticles of the noble metals Rh, Pd, Ag, Pt, and Au (spherical, average diameter 4 to 8 nm) were prepared by reduction in water and colloidally stabilized with poly(-vinyl pyrrolidone) (PVP). Thus, their shape, size, and surface functionalization were all the same. Size and morphology of the nanoparticles were determined by dynamic light scattering (DLS), analytical disc centrifugation (differential centrifugal sedimentation, DCS), and high-resolution transmission electron microscopy (HRTEM). Read More

View Article
October 2018

Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate.

Beilstein J Org Chem 2018 16;14:2853-2860. Epub 2018 Nov 16.

Unité de Chimie et Biocatalyse, Département de Biologie Structurale et Chimie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.

We have explored here the scope of the age-old diethyl malonate-based accesses to α-amino esters involving Knoevenagel condensations of diethyl malonate on aldehydes, reductions of the resulting alkylidenemalonates, the preparation of the corresponding α-hydroxyimino esters and their final reduction. This synthetic pathway turned out to be general although some unexpected limitations were encountered. The synthetic modifications of some of the intermediates - using Suzuki-Miyaura coupling or cycloadditions - before undertaking the oximation step - provided accesses to further α-amino esters. Read More

View Article
November 2018
2 Reads

Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions.

Beilstein J Org Chem 2018 15;14:2846-2852. Epub 2018 Nov 15.

Unité de Chimie et Biocatalyse, Département de Biologie Structurale et Chimie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.

We report here on the use of ethyl nitroacetate as a glycine template to produce α-amino esters. This started with a study of its condensation with various arylacetals to give ethyl 3-aryl-2-nitroacrylates followed by a reduction (NaBH and then zinc/HCl) into α-amino esters. The scope of this method was explored as well as an alternative with arylacylals instead. Read More

View Article
November 2018

Pd-Catalyzed microwave-assisted synthesis of phosphonated 13α-estrones as potential OATP2B1, 17β-HSD1 and/or STS inhibitors.

Beilstein J Org Chem 2018 14;14:2838-2845. Epub 2018 Nov 14.

Department of Organic Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary.

Novel 2- or 4-phosphonated 13α-estrone derivatives were synthesized via the Hirao reaction. Bromo regioisomers (2- or 4-) of 13α-estrone and its 3-benzyl or 3-methyl ether were reacted with diethyl phosphite or diphenylphosphine oxide using Pd(PPh) as catalyst under microwave irradiation. The influence of the new compounds on the transport function of the organic anion transporting polypeptide OATP2B1 was investigated by measuring Cascade Blue uptake. Read More

View Article
November 2018

Enhanced single-isomer separation and pseudoenantiomer resolution of new primary rim heterobifunctionalized α-cyclodextrin derivatives.

Beilstein J Org Chem 2018 13;14:2829-2837. Epub 2018 Nov 13.

Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 43 Prague 2, Czech Republic.

The synthesis of batch-to-batch reproducible cyclodextrin (CD) derivatives often requires functionalization at specific positions of the CD skeleton. However, the regioselective preparation of this type of CD derivatives remains a challenge in synthetic chemistry. Thus, the present study aimed to prepare all positional regioisomers on the primary rim of homobifunctionalized diazido-α-CDs by selective substitution on the primary rim. Read More

View Article
November 2018
1 Read

Synthesis of pyrrolidine-based hamamelitannin analogues as quorum sensing inhibitors in .

Beilstein J Org Chem 2018 12;14:2822-2828. Epub 2018 Nov 12.

Laboratory for Medicinal Chemistry, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.

Interfering with bacterial cell-to-cell communication is a promising strategy to combat antimicrobial resistance. The natural product hamamelitannin and several of its analogues have been identified as quorum sensing inhibitors. In this paper the synthesis of pyrrolidine-based analogues of a more lead-like hamamelitannin analogue is reported. Read More

View Article
November 2018
4 Reads

Oxidative and reductive cyclization in stiff dithienylethenes.

Beilstein J Org Chem 2018 9;14:2812-2821. Epub 2018 Nov 9.

Department of Chemistry & IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany.

The electrochemical behavior of stiff dithienylethenes, undergoing double bond isomerization in addition to ring-closure, has been investigated. Electrochromism was observed in almost all cases, with the major pathway being the oxidatively induced cyclization of the open isomers. The influence of the ring size (to lock the reactive antiparallel conformation) as well as substituents (to modulate the redox potential) on the electrocyclization was examined. Read More

View Article
November 2018
2 Reads

Synthesis of α-D-GalN-(1-3)-D-GalN: α- and 3-selectivity using 3,4-diol acceptors.

Beilstein J Org Chem 2018 8;14:2805-2811. Epub 2018 Nov 8.

Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen O, Denmark.

The motif α-D-GalNAc-(1-3)-D-GalNAc is very common in Nature and hence its synthesis highly relevant. The synthesis of its azido precursor has been studied and optimized in terms of steps, yields and selectivity. It has been found that glycosylation of the 3,4-diol acceptor is an advantage over the use of a 4--protected acceptor and that both regio- and anomeric selectivity is enhanced by bulky 6--protective groups. Read More

View Article
November 2018
2 Reads

Synthesis of mono-functionalized S-diazocines via intramolecular Baeyer-Mills reactions.

Beilstein J Org Chem 2018 7;14:2799-2804. Epub 2018 Nov 7.

Otto Diels-Institute for Organic Chemistry, Christian-Albrechts-University, Otto-Hahn-Platz 4, 24118 Kiel, Germany.

Herein we report a reliable method to synthesize mono-functionalized S-diazocines in reproducible yields via intramolecular Baeyer-Mills reactions. Diazocines exhibit excellent photoswitchable properties. As opposed to azobenzenes they are more stable in their configuration. Read More

View Article
November 2018

Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1-pyrazoles.

Beilstein J Org Chem 2018 6;14:2789-2798. Epub 2018 Nov 6.

LASOL - CCQFA - Universidade Federal de Pelotas - UFPel - P.O. Box 354 - 96010-900, Pelotas, RS, Brazil.

A one-pot iodine-catalyzed multicomponent reaction has been developed for the selective preparation of 5-amino-4-(arylselanyl)-1-pyrazoles from a diverse array of benzoylacetonitriles, arylhydrazines and diaryl diselenides. The reactions were conducted in MeCN as solvent at reflux temperature under air. The methodology presents a large functional group tolerance to electron-deficient, electron-rich, and bulky substituents and gave the expected products in good to excellent yields. Read More

View Article
November 2018
1 Read

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes.

Beilstein J Org Chem 2018 5;14:2779-2788. Epub 2018 Nov 5.

Department of Organic and Polymer Materials Chemistry, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.

The alternating copolymerization of epoxides with cyclic anhydrides (CAs) is a highly diverse synthetic method for polyesters as the polymers' architectures and properties can be easily controlled depending on the combination of two monomers. Thus, a variety of catalyst designs has been reported to prepare the desired copolymers efficiently. We herein report dinuclear cobalt-salen complexes with a benzene ring as a linker and their activities in copolymerization reactions. Read More

View Article
November 2018
1 Read

DABCO- and DBU-promoted one-pot reaction of -sulfonyl ketimines with Morita-Baylis-Hillman carbonates: a sequential approach to (2-hydroxyaryl)nicotinate derivatives.

Beilstein J Org Chem 2018 2;14:2771-2778. Epub 2018 Nov 2.

Discipline of Chemistry, Indian Institute of Technology Indore, Simrol, Indore, 453552, Madhya Pradesh, India.

An intriguing DABCO-catalyzed and DBU-promoted one-pot synthesis of an important class of (2-hydroxyaryl)pyridine derivatives bearing a carboxylate or a nitrile group suitably placed at C3 position of the aza-ring has been achieved in acceptable chemical yields with a broad functional group tolerance. This sequential C-C/C-N bond making process proceeds through a regioselective allylic alkylation/aza-Michael reaction between MBH carbonates derived from an acrylate/acrylonitrile and -sulfonyl ketimines as C,N-binucleophiles catalyzed by DABCO, followed by elimination of SO under the influence of base and subsequent aromatization in an open atmosphere. Read More

View Article
November 2018
3 Reads

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes.

Beilstein J Org Chem 2018 1;14:2745-2770. Epub 2018 Nov 1.

Department of Chemistry, Shiraz University, Shiraz, Iran.

This review article discusses the progress related to the synthesis and catalytic applications of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials for industrial and laboratory products. These catalysts are widely used in acid-catalyzed processes. Most of these acid catalysts are eco-friendly, reusable, and stable. Read More

View Article
November 2018

Synthesis of a tyrosinase inhibitor by consecutive ethenolysis and cross-metathesis of crude cashew nutshell liquid.

Beilstein J Org Chem 2018 31;14:2737-2744. Epub 2018 Oct 31.

Lehrstuhl für Organische Chemie I, Ruhr-Universität Bochum, ZEMOS, Universitätsstraße 150, 44801 Bochum, Germany.

A convenient and sustainable three-step synthesis of the tyrosinase inhibitor 2-hydroxy-6-tridecylbenzoic acid was developed that starts directly from the anacardic acid component of natural cashew nutshell liquid (CNSL). Natural CNSL contains 60-70% of anacardic acid as a mixture of several double bond isomers. The anacardic acid component was converted into a uniform starting material by ethenolysis of the entire mixture and subsequent selective precipitation of 6-(ω-nonenyl)salicylic acid from cold pentane. Read More

View Article
October 2018

Photocatalyic Appel reaction enabled by copper-based complexes in continuous flow.

Beilstein J Org Chem 2018 30;14:2730-2736. Epub 2018 Oct 30.

Department of Chemistry and Centre for Green Chemistry and Catalysis, Université de Montréal, CP 6128 Station Downtown, Montréal, Québec, H3C 3J7, Canada.

A copper-based photocatalyst, Cu(tmp)(BINAP)BF, was found to be active in a photoredox Appel-type conversion of alcohols to bromides. The catalyst was identified from a screening of 50 complexes and promoted the transformation of primary and secondary alcohols to their corresponding bromides and carboxylic acids to their anhydrides. The protocol was also amendable and optimized under continuous flow conditions. Read More

View Article
October 2018

Unprecedented nucleophile-promoted 1,7-S or Se shift reactions under Pummerer reaction conditions of 4-alkenyl-3-sulfinylmethylpyrroles.

Beilstein J Org Chem 2018 29;14:2722-2729. Epub 2018 Oct 29.

Department of Chemistry, Faculty of Education, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan.

A unique 1,7-S- and Se-shift reaction under Pummerer reaction conditions of 4-alkenyl-3-sulfinyl- and seleninylpyrroles was described. The usual Pummerer reaction of 4-(alkenylaminomethyl)-3-phenylsulfinylpyrroles and a successive reaction with tetrabutylammonium hydroxide (TBAH) yielded either pyrrolo[3,2-]azepines or -pyrrol-3-ylmethyl--(4-hydroxy-3-sulfanylpropyl)--toluenesulfonamides (diols). -Pummerer reactions of 3-selanylmethylpyrroles also proceeded via in situ generation of selenoxides, followed by a treatment with TBAH. Read More

View Article
October 2018

Exploring the photoleakage current and photoinduced negative bias instability in amorphous InGaZnO thin-film transistors with various active layer thicknesses.

Beilstein J Nanotechnol 2018 26;9:2573-2580. Epub 2018 Sep 26.

School of Environmental Science and Engineering, Kochi University of Technology, Kami, Kochi 782-8502, Japan.

The photoleakage current and the negative bias and illumination stress (NBIS)-induced instability in amorphous InGaZnO thin-film transistors (a-IGZO TFTs) with various active layer thicknesses () were investigated. The photoleakage current was found to gradually increase in a-IGZO TFTs irrespective of the when the photon energy of visible light irradiation exceeded ≈2.7 eV. Read More

View Article
September 2018

Friction reduction through biologically inspired scale-like laser surface textures.

Beilstein J Nanotechnol 2018 26;9:2561-2572. Epub 2018 Sep 26.

Institute for Applied Materials (IAM), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, 76131 Karlsruhe, Germany.

Reducing friction forces is a major challenge in many engineering applications involving moving parts. For the past 50 years, the morphological texturing of surfaces for improving tribological properties has been investigated. Only recently, the application of biologically inspired surface features, like scales found on lizards and snakes, has come to the attention of tribologists. Read More

View Article
September 2018

Accurate control of the covalent functionalization of single-walled carbon nanotubes for the electro-enzymatically controlled oxidation of biomolecules.

Beilstein J Nanotechnol 2018 26;9:2750-2762. Epub 2018 Oct 26.

SRSMC, UMR CNRS-Université de Lorraine 7565, Campus Victor Grignard, Faculté des Sciences et Technologies, F-54506 Vandoeuvre-lès-Nancy, France.

Single-walled carbon nanotubes (SWCNTs) were functionalized by ferrocene through ethyleneglycol chains of different lengths (FcETGn) and the functionalized SWCNTs (f-SWCNTs) were characterized by different complementary analytical techniques. In particular, high-resolution scanning electron transmission microscopy (HRSTEM) and electron energy loss spectroscopy (EELS) analyses support that the outer tubes of the carbon-nanotube bundles were covalently grafted with FcETGn groups. This result confirms that the electrocatalytic effect observed during the oxidation of the reduced form of nicotinamide adenine dinucleotide (NADH) co-factor by the f-SWCNTs is due to the presence of grafted ferrocene derivatives playing the role of a mediator. Read More

View Article
October 2018

Contactless photomagnetoelectric investigations of 2D semiconductors.

Beilstein J Nanotechnol 2018 25;9:2741-2749. Epub 2018 Oct 25.

Institute of Physics, Center for Science and Education, Silesian University of Technology, Krasińskiego 8, 40-019 Katowice, Poland.

Applications of two-dimensional (2D) materials in electronic devices require the development of appropriate measuring methods for determining their typical semiconductor parameters, i.e., mobility and carrier lifetime. Read More

View Article
October 2018
1 Read

Oriented zinc oxide nanorods: A novel saturable absorber for lasers in the near-infrared.

Beilstein J Nanotechnol 2018 23;9:2730-2740. Epub 2018 Oct 23.

Functional Materials, Applied Physics Department, School of Engineering Sciences, KTH Royal Institute of Technology, Isafjordsgatan 22, SE-164 40 Kista Stockholm, Sweden.

Zinc oxide (ZnO) nanorods (NRs) oriented along the crystallographic [001] axis are grown by the hydrothermal method on glass substrates. The ZnO NRs exhibit a broadband (1-2 µm) near-IR absorption ascribed to the singly charged zinc vacancy V. The saturable absorption of the ZnO NRs is studied at ≈1 µm under picosecond excitation, revealing a low saturation intensity, ≈10 kW/cm, and high fraction of the saturable losses. Read More

View Article
October 2018
3 Reads