Peptide–polymer ligands for a tandem WW-domain, an adaptive multivalent protein–protein interaction: lessons on the thermodynamic fitness of flexible ligands

• Katharina Koschek,
• Vedat Durmaz,
• Oxana Krylova,
• Marek Wieczorek,
• Shilpi Gupta,
• Martin Richter,
• Alexander Bujotzek,
• Christina Fischer,
• Rainer Haag,
• Christian Freund,
• Marcus Weber and
• Jörg Rademann

Beilstein J. Org. Chem. 2015, 11, 837–847, doi:10.3762/bjoc.11.93

• formed peptide-polymer–protein complex. Inspection of the test solution revealed the formation of a colloidal suspension/dispersion both for pHPMA and for hPG-based peptide conjugates indicating the formation of insoluble aggregates possibly generated through crosslinking. Corresponding to the observed

• colloidal suspension/dispersion the stoichiometry of peptide ligands per protein receptor resulting from the ITC experiments was >2 for each of either pHPMA or hPG-based material, most pronounced for pHPMA with n = 2.6–2.8. Dextran-based conjugates displayed a ligand stoichiometry of 1.4 for the most potent

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

• reaction solution was exchanged with fresh reactants via centrifugation, decantation and re-dispersion of the PEG-SCPs before the next irradiation step. Using this approach, we varied the number of replenishing steps as well as irradiation interval between the replenishing step and measured the resulting

• Irgacure 2959 was added at a concentration of (1 mg, 4.5 µmol) to the dispersion and vigorously shaken and photopolymerized with UV light. Water was exchanged by ethanol and benzophenone (250 mg, 1.4 mmol) and an unsaturated carboxylic acid (acrylic acid (1.2 mL, 17.7 mmol), methacrylic acid (1.5 mL, 17.7

• acid in PEG-SCPs The carboxylic acids in the PEG-SCPs were quantified by titration with TBO, zeta potential measurements and IR spectroscopy. The TBO measurement was conducted as follows. 1.5 mL of PEG-SCP dispersion were centrifuged and a solution of 0.5 mM TBO solution (pH 10.3) was added to the

First principle investigation of the linker length effects on the thermodynamics of divalent pseudorotaxanes

• Andreas J. Achazi,
• Doreen Mollenhauer and
• Beate Paulus

Beilstein J. Org. Chem. 2015, 11, 687–692, doi:10.3762/bjoc.11.78

• energies of association (Gibbs free (binding) energies) for divalent crown-8/ammonium pseudorotaxanes are determined by investigating the influence of different linkers onto the binding. Calculations are performed with density functional theory including dispersion corrections. The translational

• linker shows an enhanced binding strength due to electronic effects, namely the dispersion interaction between the linkers from the guest and the host. For the longer linkers this ideal packing is not possible due to steric hindrance. Keywords: density functional theory (DFT); dispersion correction

• (deviation less than 0.3%). This very good agreement is somewhat fortunate, because a basis set extrapolation with DZ and TZ is only accurate to within a few percent. Additionally, the possible errors of the functional and the dispersion correction can also be in the range of 10% for the system under

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

• Tor E. Kristensen

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

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

Bis(vinylenedithio)tetrathiafulvalene analogues of BEDT-TTF

• Erdal Ertas,
• İlknur Demirtas and
• Turan Ozturk

Beilstein J. Org. Chem. 2015, 11, 403–415, doi:10.3762/bjoc.11.46

• thickness of the film was obtained. The film was annealed at 25, 55, 85, 115 and finally at 145 °C for 30 min. Electronic transitions of the complex 54, i.e. n–π* and π–π* transitions, led to the formation of radical ion pairs 55. The refractive index dispersion and optical constant of the annealed film

Novel biphenyl-substituted 1,2,4-oxadiazole ferroelectric liquid crystals: synthesis and characterization

• Mahabaleshwara Subrao,
• Dakshina Murthy Potukuchi,
• Girish Sharada Ramachandra,
• Poornima Bhagavath,
• Sangeetha G. Bhat and
• Srinivasulu Maddasani

Beilstein J. Org. Chem. 2015, 11, 233–241, doi:10.3762/bjoc.11.26

• ., 13a with phenyl end group. The large mesomorphic thermal range in the 13b (C12.Ox.C*Cn) series are due to the higher number of methylene units in the alkyl end chain, which results in the higher surface area and higher London dispersion forces between the molecules. Interestingly, a tilted chiral SmC

A one-pot multistep cyclization yielding thiadiazoloimidazole derivatives

• Debabrata Samanta,
• Anup Rana,
• Jan W. Bats and
• Michael Schmittel

Beilstein J. Org. Chem. 2014, 10, 2989–2996, doi:10.3762/bjoc.10.317

• with a 6-31G(d,p) basis set for hydrogen to include polarization on hydrogen and the 6-31G(d) basis set for the other main group elements using NWChem 6.3 [15]. During optimization, we utilized Grimme’s D3 dispersion [16] for a better description of non-covalent interactions like hydrogen bonding and π

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

• ethidium bromide and its neutral analogue, revealing detailed description of the forces included in the intercalation process, stressing the dispersion energy as a control factor [50]. Moreover, a number of kinetic measurements provided for the binding of ligands to DNA additionally clarify mechanistic

Synthesis of uniform cyclodextrin thioethers to transport hydrophobic drugs

• Lisa F. Becker,
• Dennis H. Schwarz and
• Gerhard Wenz

Beilstein J. Org. Chem. 2014, 10, 2920–2927, doi:10.3762/bjoc.10.310

• -methoxyethoxy)ethoxy)ethyl)]-β-cyclodextrin: 2.60 g (65 mmol) NaH (60 wt % dispersion in mineral oil, Sigma-Aldrich) was washed twice with 25 mL of n-pentane under N2 and stirred at rt for 1 h. After addition of 6.25 g (4.64 mmol) heptakis(6-deoxy-6-methylsulfanyl)-β-cyclodextrin dissolved in 130 mL of DMF

Cyclodextrin–polysaccharide-based, in situ-gelled system for ocular antifungal delivery

• Anxo Fernández-Ferreiro,
• Noelia Fernández Bargiela,
• María Santiago Varela,
• Maria Gil Martínez,
• Maria Pardo,
• Antonio Piñeiro Ces,
• José Blanco Méndez,
• Miguel González Barcia,
• Maria Jesus Lamas and
• Francisco.J. Otero-Espinar

Beilstein J. Org. Chem. 2014, 10, 2903–2911, doi:10.3762/bjoc.10.308

• stirring for 24 hours. Incorporation of drug and CD–drug complexes into ophthalmic gels Fluconazole was incorporate at the gel at a concentration of 2 mg/mL by dispersion of the solid drug into the gel under magnetic stirring. To incorporate the fluconazole–CD complex, cyclodextrin were previously

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

• . Sedimentation and agglomeration of several modified DND appeared to have a substantial influence on the success of the electrochemical immobilization. Silanized DND modified with O-phosphorylethanolamine 6 showed better dispersion in buffer compared to other samples and hence resulted in more homogeneous

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

• and dispersion behaviour due to their protic character and the possibility to protonate the nitrogen. In the case of diamond the direct amination of the surface has rarely been reported. Sotowa et al. used the photochemical reaction of ammonia with chlorinated diamond [3]. However, the termination

• centrifugation (15000 min−1, 10 min). The precipitate was washed eight times with acetone, three times with water, three times with acetone and three times with dichloromethane in consecutive dispersion/centrifugation cycles. 150 mg (60% yield) of a black solid was obtained as the product. Elemental analysis: N

• particles were isolated by centrifugation (15000 min−1, 10 min). The precipitate was washed six times with a mixture of dioxane/water (9:1), three times with acetone and three times with dichloromethane in consecutive dispersion/centrifugation cycles. 49 mg (75% yield) of a black solid was obtained as the

Aspergiloid I, an unprecedented spirolactone norditerpenoid from the plant-derived endophytic fungus Aspergillus sp. YXf3

• Zhi Kai Guo,
• Rong Wang,
• Wei Huang,
• Xiao Nian Li,
• Rong Jiang,
• Ren Xiang Tan and
• Hui Ming Ge

Beilstein J. Org. Chem. 2014, 10, 2677–2682, doi:10.3762/bjoc.10.282

• -temperature (100 K) single-crystal X-ray diffraction experiment, which is shown in Figure 3. As compound 1 has a relatively high percentage of oxygen, it shows enough anomalous dispersion of Cu Kα radiation and allows to determinate the absolute stereochemistry with the Hooft parameter 0.17(15) for 992

Synthesis and characterization of a hyper-branched water-soluble β-cyclodextrin polymer

• Francesco Trotta,
• Fabrizio Caldera,
• Roberta Cavalli,
• Andrea Mele,
• Carlo Punta,
• Lucio Melone,
• Franca Castiglione,
• Barbara Rossi,
• Monica Ferro,
• Vincenza Crupi,
• Domenico Majolino,
• Valentina Venuti and
• Dominique Scalarone

Beilstein J. Org. Chem. 2014, 10, 2586–2593, doi:10.3762/bjoc.10.271

• at 450 nm, consistent with the formation of a SF/polymer complex. The solubilization capacity of the new branched β-CD polymer was also evaluated toward a very poor water soluble anticancer drug, i.e., paclitaxel, showing a great improvement in dispersion in water (data not shown). Conclusion A new

A versatile δ-aminolevulinic acid (ΑLA)-cyclodextrin bimodal conjugate-prodrug for PDT applications with the help of intracellular chemistry

• Chrysie Aggelidou,
• Theodossis A. Theodossiou,
• Antonio Ricardo Gonçalves,
• Mariza Lampropoulou and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 2414–2420, doi:10.3762/bjoc.10.251

• (1 mM solution, with respect to ALA content) in phosphate buffer saline (pH 7.4) was mixed with fluorescein isothiocyanate-labeled 1-adamantylamine (0.2 mM) [21] and the dispersion was stirred for 20–30 min until a clear solution was obtained. This solution was subsequently used for cell incubation

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• and their values of the α parameter and the grain diameter reflect the chemical changes of the conjugated polymer surfaces. Thus, the 4a film surface shows smaller grains with an average diameter of 86 ± 8 nm. Furthermore, the relative uniform grain size dispersion induces the lower value of α (0.229

• ) and 0.0773 g (0.2 mmol) of monomer 1 were added and stirred at room temperature in the dark under nitrogen atmosphere for 72 h to give a dispersion. Then 0.334 g (0.8 mmol) of 2, 0.577 (1 mmol) of 2, 2 mL of 3 M Na2CO3 and 20.8 mg (1.82 × 10−2 mmol) of (Ph3P)4Pd(0), dissolved in 5 mL of degassed

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

• point pressure) is the minimum pressure where a dispersion is a stable single transparent phase. It has been used as a measure of surfactant efficiency in CO2, with a lower Ptrans being equated to a more efficient surfactant. The w value expresses the degree of water uptake or the number of water

Theoretical study of the adsorption of benzene on coinage metals

• Werner Reckien,
• Melanie Eggers and
• Thomas Bredow

Beilstein J. Org. Chem. 2014, 10, 1775–1784, doi:10.3762/bjoc.10.185

• = Cu), silver (M = Ag) and gold (M = Au) is studied on the basis of density functional theory (DFT) calculations with an empirical dispersion correction (D3). Variants of the Perdew–Burke–Ernzerhof functionals (PBE, RPBE and RevPBE) in combination with different versions of the dispersion correction

• ; dispersion correction; template; Introduction The adsorption of organic molecules on metals is of great interest since the formation of thin films and self-assembled monolayers opens the way toward a functionalization of surfaces [1][2][3][4][5][6][7][8]. The adsorbed molecules often contain an aromatic

• framework that can be substituted with functional groups. The bonding between the surface and the adsorbate is an interplay between electrostatic interaction, including charge transfer (CT) to the surface, and covalent contributions [9][10][11]. In addition, it was found that dispersion interaction plays a

Bis(β-lactosyl)-[60]fullerene as novel class of glycolipids useful for the detection and the decontamination of biological toxins of the Ricinus communis family

• Hirofumi Dohi,
• Takeru Kanazawa,
• Akihiro Saito,
• Keita Sato,
• Hirotaka Uzawa,
• Yasuo Seto and
• Yoshihiro Nishida

Beilstein J. Org. Chem. 2014, 10, 1504–1512, doi:10.3762/bjoc.10.155

• using an Amicon Ultra-15 device (molecular weight cut: off 5000, Millipore, Co., USA). The concentrate was transferred into a measuring flask, and the total volume was adjusted with distilled water to give a bis-Lac-C60 dispersion colloidal suspension at the desired concentration. Precipitation assay

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

• GNPs water-dispersion that was also used for the cellular experiments. The GNPs dimension was evaluated by electron microscopy (Supporting Information File 1) showing an average gold diameter of ~3 nm. The GNPs contain around 10% of ABC or 3TC were analysed by HPLC and mass spectrometry (see next

Substitution effect and effect of axle’s flexibility at (pseudo-)rotaxanes

• Friedrich Malberg,
• Jan Gerit Brandenburg,
• Werner Reckien,
• Oldamur Hollóczki,
• Stefan Grimme and
• Barbara Kirchner

Beilstein J. Org. Chem. 2014, 10, 1299–1307, doi:10.3762/bjoc.10.131

• substitution with different functional groups and of molecular flexibility by changing within the axle from a single C–C bond to a double C=C bond. Therefore, we present static quantum chemical calculations at the dispersion-corrected density functional level (DFT-D3) for several Leigh-type rotaxanes. The

• binding is weakened by approximately 10 kcal/mol, and hydrogen bonds are slightly shortened (by up to 0.2 Å). Keywords: dispersion interaction; hydrogen bond; supramolecular chemistry; template; theoretical chemistry; Introduction Rotaxanes are prototypes for molecular machines and molecular switches [1

• =O stretch mode [27]. Different density functionals, including one functional with an empirical correction for dispersion interaction, for the treatment of such rotaxane complexes were studied. We compared these density functional theory (DFT) results with Møller–Plesset second-order perturbation

Unusual polymorphism in new bent-shaped liquid crystals based on biphenyl as a central molecular core

• Anna Kovářová,
• Svatopluk Světlík,
• Václav Kozmík,
• Jiří Svoboda,
• Vladimíra Novotná,
• Damian Pociecha,
• Ewa Gorecka and
• Natalia Podoliak

Beilstein J. Org. Chem. 2014, 10, 794–807, doi:10.3762/bjoc.10.75

• stable during the frequency sweeps in the range of 10 Hz ÷ 10 MHz. The frequency dispersion data were analysed using the Cole–Cole formula for the frequency dependent complex permittivity ε*(f) = ε′ – iε′′ where fr is the relaxation frequency, Δε is the dielectric strength, α is the distribution

Integration of enabling methods for the automated flow preparation of piperazine-2-carboxamide

• Richard J. Ingham,
• Claudio Battilocchio,
• Joel M. Hawkins and
• Steven V. Ley

Beilstein J. Org. Chem. 2014, 10, 641–652, doi:10.3762/bjoc.10.56

• volume, with a small degree of dispersion. It then starts to decrease after the water is used up and the ability of the column to hydrate is exhausted. The fall-off takes place over about one column volume, indicating a low retention of material by the heterogeneous bed. (a) Fluidic setup for the

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

• rates and result in axial dispersion. Consequently, restricting the temperature below 65 °C can avoid the dinitro products, ensuring that the reaction mixture is locally homogeneous. One of the ways to reduce the axial dispersion is a segmented flow, which is implemented by using an inert gas or

Decandrinin, an unprecedented C₉-spiro-fused 7,8-seco-ent-abietane from the Godavari mangrove Ceriops decandra

• Hui Wang,
• Min-Yi Li,
• Félix Zongwe Katele,
• Tirumani Satyanandamurty,
• Jun Wu and
• Gerhard Bringmann

Beilstein J. Org. Chem. 2014, 10, 276–281, doi:10.3762/bjoc.10.23

• , Ceriops decandra, collected in the estuary of Godavari, Andhra Pradesh. The constitution and the relative configuration of 1 were determined by HRMS (ESI) and extensive NMR investigations, and the absolute configuration by circular dichroism (CD) and optical-rotatory dispersion (ORD) spectroscopy in

• NMR investigations, and by circular dichroism (CD) and optical-rotatory dispersion (ORD) spectroscopy in combination with quantum-chemical calculations. Results and Discussion Decandrinin (1) was obtained as a colorless solid. Its molecular formula was established as C20H28O4 by HRMS (ESI) (m/z

• /def2-TZVP [31][32] level and TDB2PLYP/def2-TZVP [33][34][35] calculations in combination with the COSMO solvation model with acetonitrile as a solvent and the chain-of-spheres approximations [35][36][37] were done using ORCA [38]. The optical rotatory dispersion (ORD) was calculated at the PBE0/cc-pVDZ