Binding mode and free energy prediction of fisetin/β-cyclodextrin inclusion complexes

• Bodee Nutho,
• Wasinee Khuntawee,
• Chompoonut Rungnim,
• Piamsook Pongsawasdi,
• Peter Wolschann,
• Alfred Karpfen,
• Nawee Kungwan and
• Thanyada Rungrotmongkol

Beilstein J. Org. Chem. 2014, 10, 2789–2799, doi:10.3762/bjoc.10.296

• calculation for estimating the binding free energies or calculating the free energies of molecules in solution. This method combines the molecular mechanical energies with the calculations of solvation. In order to calculate the electrostatic distribution to the free energy of solvation with a numerical

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

• of their excellent corrosion properties, good mechanical strength and osteointegration, due to naturally occurring oxide layer at their surface [16]. Based on the surface oxide properties, various methods of surface modification of titanium and its alloys have been realized in the past decades to

Removal of volatile organic compounds using amphiphilic cyclodextrin-coated polypropylene

• Ludmilla Lumholdt,
• Sophie Fourmentin,
• Thorbjørn T. Nielsen and
• Kim L. Larsen

Beilstein J. Org. Chem. 2014, 10, 2743–2750, doi:10.3762/bjoc.10.290

• future focus. The challenge with most of these problematic compounds lies in the fact that they cannot be removed using traditional methods, for example, mechanical filtration, due to their extremely small dimensions and extremely low concentration in the wastewater. However, even low concentrations are

Synthesis of a resin monomer-soluble polyrotaxane crosslinker containing cleavable end groups

• Ji-Hun Seo,
• Shino Nakagawa,
• Koichiro Hirata and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2014, 10, 2623–2629, doi:10.3762/bjoc.10.274

• mechanical strength in various applied polymer materials used in industrial or biomedical fields [16][17]. For example, composite resins containing 2-hydroxyethyl methacrylate (HEMA) or methyl methacrylate (MMA) have been widely used to increase the mechanical strength of restorative or adhesive materials in

• significant extent due to the cleaved disulfide end groups of PRX. This is thought to be the reason of the drastic decrease in the hardness of the photosetting plastic. Photosetting plastic is widely used in the field of dental treatment as a form of a composite resin. The mechanical strength of the

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

• the modified ones reached the same level after 240 min because of the formation of inclusion complexes. However, the presence of β-CD and biocide increased the disorder of cellulose microstructure and modified its mechanical properties. The bacterial activity against E. coli and S. aureus exhibited

Oligomerization of optically active N-(4-hydroxyphenyl)mandelamide in the presence of β-cyclodextrin and the minor role of chirality

• Helmut Ritter,
• Antonia Stöhr and
• Philippe Favresse

Beilstein J. Org. Chem. 2014, 10, 2361–2366, doi:10.3762/bjoc.10.246

• ; enzyme; oxidative coupling; phenol oligomer; Introduction Lignin consists of mechanical stabilizing polyphenols and thus plays an important role in many plants [1][2]. For the in vitro synthesis of polyphenols via oxidative coupling reactions, laccases and peroxidases are suitable enzymes to catalyze

Visible light photoredox-catalyzed deoxygenation of alcohols

• Daniel Rackl,
• Viktor Kais,
• Peter Kreitmeier and
• Oliver Reiser

Beilstein J. Org. Chem. 2014, 10, 2157–2165, doi:10.3762/bjoc.10.223

• reductively quenched photocatalyst followed by mesolysis and subsequent hydrogen abstraction (Scheme 4). Quantum mechanical calculations (B3LYP/6-31G*) for benzhydryl 3,5-bis(trifluoromethyl)benzoate (3) revealed that the electron density of the presumed transient radical anion is mainly located at the phenyl

Investigations of thiol-modified phenol derivatives for the use in thiol–ene photopolymerizations

• Sebastian Reinelt,
• Monir Tabatabai,
• Urs Karl Fischer,
• Norbert Moszner,
• Andreas Utterodt and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1733–1740, doi:10.3762/bjoc.10.180

• ], adaptable thiol–ene networks [29], thiol–yne photopolymerizations [30][31][32], and thiol–norbornene materials [33] only to mention a few of them. However, the design of new monomers – both ene and thiol monomers – for thiol–ene polymerization is a sustained necessity in order to improve the mechanical

• properties of the resulting networks [34]. So far most studies focused on the optimization of the ene monomer while PETMP (pentaerythritol tetra(3-mercaptopropionate)) was constantly utilized as the thiol component. The influence of water sorption of cured dental composites on the mechanical properties have

• ][36][37][38]. For studies focusing on thiol–ene photopolymerizations for dental restoratives, the mechanical properties of the cured composites are always determined under ambient conditions. However, the mainly investigated PETMP monomer has a partial hydrophilic character due to its four ester

Synthesis of new, highly luminescent bis(2,2’-bithiophen-5-yl) substituted 1,3,4-oxadiazole, 1,3,4-thiadiazole and 1,2,4-triazole

• Anastasia S. Kostyuchenko,
• Vyacheslav L.Yurpalov,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2014, 10, 1596–1602, doi:10.3762/bjoc.10.165

• , yielding strictly controlled supramolecular organisation, provided that appropriate deposition techniques are applied, such as zone casting [6][7][8], mechanical rubbing or directional epitaxial crystallisation [9]. For many applications, however, the HOMO and LUMO levels of oligo- and polythiophenes and

An economical and safe procedure to synthesize 2-hydroxy-4-pentynoic acid: A precursor towards ‘clickable’ biodegradable polylactide

• Quanxuan Zhang,
• Hong Ren and
• Gregory L. Baker

Beilstein J. Org. Chem. 2014, 10, 1365–1371, doi:10.3762/bjoc.10.139

• Aliphatic polyesters, in particular polylactide (PLA), are now widely used for biomedical applications, such as surgery sutures [1], implants for bone fixation [2], drug delivery vehicles [3][4] and tissue engineering scaffolds [5] because of their excellent biocompatibility, biodegradability and mechanical

• mechanical stirrer, which resulted in a messy mixture of product observed from the 1H NMR spectrum of the crude reaction mixture. The C-alkylation of 4 in a more common solvent, THF, was found to be not suitable due to the low conversion with even a much longer reaction time (entry 3, Table 1) [31]. Under

• a mechanical stirrer was charged with 58 mL (1.0 mol) of propargyl alcohol, 250 g (1.30 mol) of tosyl chloride and 1000 mL of diethyl ether under nitrogen. The resulting reaction mixture was cooled in an ice bath, and NaOH pellets (200 g, 5.00 mol) were added to the solution in 6 portions at 0 °C

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

• (2.5 Å) than other long N–H···O bonds. This also shows the importance of such stopper groups for the interactions within the rotaxanes, as they have notable electronic influence. Thus, their role is not necessarily restricted to the mere mechanical prevention of a dethreading of the axle, which was

Stereocontrolled synthesis of 5-azaspiro[2.3]hexane derivatives as conformationally “frozen” analogues of L-glutamic acid

• Beatrice Bechi,
• David Amantini,
• Cristina Tintori,
• Maurizio Botta and
• Romano di Fabio

Beilstein J. Org. Chem. 2014, 10, 1114–1120, doi:10.3762/bjoc.10.110

• Å, while an energy cutoff of 5 kcal/mol was applied to discard unreasonable conformations. Default values were used for all the remaining parameters. The lowest energy conformation of the four diastereoisomers 20a–d (Figure 3) was saved to perform the following quantum-mechanical calculations, which

cis–trans Isomerization of silybins A and B

• Michaela Novotná,
• Radek Gažák,
• David Biedermann,
• Florent Di Meo,
• Petr Marhol,
• Marek Kuzma,
• Lucie Bednárová,
• Kateřina Fuksová,
• Patrick Trouillas and
• Vladimír Křen

Beilstein J. Org. Chem. 2014, 10, 1047–1063, doi:10.3762/bjoc.10.105

• optically pure compounds was determined by using NMR and comparing their electronic circular dichroism data with model compounds of known absolute configurations. Mechanisms for cis–trans-isomerization of silybin are proposed and supported by quantum mechanical calculations. Keywords: 2,3-cis-silybin

• study the impact of the solvent polarity on the HSAB principle. The hardness of BF3 and silybin A is not significantly modified when the solvent polarity is increased (Table 2). New methods to rationalize chemical reactivity have been developed in the field of quantum mechanical methods over the past

The Ugi four-component reaction as a concise modular synthetic tool for photo-induced electron transfer donor-anthraquinone dyads

• Sarah Bay,
• Gamall Makhloufi,
• Christoph Janiak and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 1006–1016, doi:10.3762/bjoc.10.100

• pairs resulting in four stacked (hetero)aromatic units (Figure 2), so that the anthraquinone moieties of two molecules display an average distance of ~3.8 Å. Based upon the X-ray data quantum mechanical computations on this conformer were envisioned (vide infra). Electronic properties and electronic

Site-selective covalent functionalization at interior carbon atoms and on the rim of circumtrindene, a C₃₆H₁₂ open geodesic polyarene

• Hee Yeon Cho,
• Ronald B. M. Ansems and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2014, 10, 956–968, doi:10.3762/bjoc.10.94

• , optical, magnetic, mechanical, and chemical properties of the material. For such functionalization reactions, site selectivity often becomes an issue when there is more than one site where the reaction could occur. Herein, we report methods for the site-selective covalent functionalization of

N-Alkylated dinitrones from isosorbide as cross-linkers for unsaturated bio-based polyesters

• Oliver Goerz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 902–909, doi:10.3762/bjoc.10.88

• unsaturated polyester was cross-linked by a 1,3-dipolar cycloaddition with the received dinitrones 10a/b. The 1,3-dipolar cycloaddition led to a strong change of the mechanical properties which were investigated by rheological measurements. Nitrones derived from methyl acrylate (3a) and methyl crotonate (3b

Staudinger ligation towards cyclodextrin dimers in aqueous/organic media. Synthesis, conformations and guest-encapsulation ability

• Malamatenia D. Manouilidou,
• Yannis G. Lazarou,
• Irene M. Mavridis and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 774–783, doi:10.3762/bjoc.10.73

• over the cavity indicates that intermediate conformations, between extended and self-included may exist in water as well. Computational results Quantum mechanical calculations were carried out for monomer 4 and dimer 6 at the PM3 level of theory for isolated molecules, as well as in the presence of

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

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

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

• and the solid iodine for the large scale preparation of piperidinol 11a (14 g, Table 2, entry 2) mechanical stirring was preferred. For saponification, saturated KOH solution in MeOH (ca. 4 N) was chosen, because aqueous KOH or NaOH solution would result in biphasic mixtures. A quantitative hydrolysis

Plakilactones G and H from a marine sponge. Stereochemical determination of highly flexible systems by quantitative NMR-derived interproton distances combined with quantum mechanical calculations of ¹³C chemical shifts

• Simone Di Micco,
• Angela Zampella,
• Maria Valeria D’Auria,
• Carmen Festa,
• Simona De Marino,
• Raffaele Riccio,
• Craig P. Butts and
• Giuseppe Bifulco

Beilstein J. Org. Chem. 2013, 9, 2940–2949, doi:10.3762/bjoc.9.331

• sponge Plakinastrella mamillaris collected at Fiji Islands, is reported. The stereostructural studies began on plakilactone H by applying an integrated approach of the NOE-based protocol and quantum mechanical calculations of 13C chemical shifts. In particular, plakilactone H was used as a template to

• extend the application of NMR-derived interproton distances to a highly flexible molecular system with simultaneous assignment of four non-contiguous stereocenters. Chemical derivatization and quantum mechanical calculations of 13C on plakilactone G along with a plausible biogenetic interconversion

• mechanical (QM) calculation of NMR parameters [1][2][3][4][5][6] has been demonstrated to be a valid tool for the stereostructural determination of organic compounds [7][8][9][10][11][12][13][14][15][16][17], especially for high flexible systems. Recently, an additional method has been proposed for the

Cyclopamine analogs bearing exocyclic methylenes are highly potent and acid-stable inhibitors of hedgehog signaling

• Johann Moschner,
• Anna Chentsova,
• Nicole Eilert,
• Irene Rovardi,
• Philipp Heretsch and
• Athanassios Giannis

Beilstein J. Org. Chem. 2013, 9, 2328–2335, doi:10.3762/bjoc.9.267

• [32][33]. Furthermore, quantum mechanical calculations guided our design and synthesis of exo-cyclopamine (2, see Figure 1), a ten-fold more potent and acid-stable analog with an exo-methylene unit at C13–C18 [34]. Herein, we describe a comprehensive study of cyclopamine analogs bearing exo-methylene

Cyclization of substitued 2-(2-fluorophenylazo)azines to azino[1,2-c]benzo[d][1,2,4]triazinium derivatives

• Aleksandra Jankowiak,
• Emilia Obijalska and
• Piotr Kaszynski

Beilstein J. Org. Chem. 2013, 9, 1873–1880, doi:10.3762/bjoc.9.219

• structures. Computational Details The quantum-mechanical calculations were carried out at B3LYP/6-311G(2d,p) level of theory using the Gaussian 09 suite of programs [16]. The geometry optimizations were undertaken using tight convergence limits and with no symmetry constraints. Vibrational frequencies were

Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2013, 9, 1858–1866, doi:10.3762/bjoc.9.217

• with heavy atoms attached, e.g., 6-deoxy-iodo-CDs, are known to even enable room temperature phosphorescence of an excited guest [36]. (b) Moreover, according to the results of the quantum mechanical calculations [25][34] the preferential anti-parallel alignment of the ACE dimer within the CD cavity

• mechanical calculations of the structures and interaction energies ΔE of the four COU dimers were performed using the Gaussian 03 software package to investigate the favored packing [47]. The aromatic dimers were fully optimized at the MP2/6-31G* level without any symmetry restriction during the computation

• , photoproducts are predictable by quantum mechanical optimization of the corresponding dimeric aggregates in vacuo. This work also showed that the addition of salt can further improve supramolecular control by suppression of the free photoactive species. Experimental General: Guests (ANT, ACE, and COU) and

Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization

• Guillaume Moreira,
• Laurence Charles,
• Mohamed Major,
• Florence Vacandio,
• Yohann Guillaneuf,
• Catherine Lefay and
• Didier Gigmes

Beilstein J. Org. Chem. 2013, 9, 1589–1600, doi:10.3762/bjoc.9.181

• of applications of cellulose, a glucose-based polysaccharide, is limited by its inherently poor mechanical properties. The grafting of synthetic polymer chains by, for example, a “grafting from” process may provide the means to broaden the range of applications. The nitroxide-mediated polymerization

• costs and prospective shortage of fossil fuels, an increasing interest is dedicated to the elaboration of materials derived from renewable resources and in particular from natural polysaccharides [1][2]. However, one of the main drawbacks of polysaccharides is their inherently poor mechanical properties

Electron self-exchange activation parameters of diethyl sulfide and tetrahydrothiophene

• Martin Goez and
• Martin Vogtherr

Beilstein J. Org. Chem. 2013, 9, 1448–1454, doi:10.3762/bjoc.9.164

• was done with a Lambda Physik EMG 101 excimer laser (medium, XeCl; wavelength, 308 nm; pulse width, 15 ns) triggered by the computer of the spectrometer. The probe was thermostated to ±0.3 K. Quantum mechanical calculations were carried out with the Gaussian 09 package [53] using the AM1 Hamiltonian