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

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

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

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

• to their renewable, environmentally benign, naturally abundant, biodegradable and biocompatible nature, as well as their excellent mechanical properties and anticipated low cost [24][25][26]. CNCs are obtained from semicrystalline cellulose derived from wood fibers and plants. Potential applications

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

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

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

• square of the laser power shown in the inset (Figure 5) clearly demonstrates the two-photon excitation nature. Quantum mechanical calculations Quantum mechanical calculations were performed for derivative 4 to gain deeper insight into the nature of the longest wavelength transition and to estimate the

Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

• Josué M. Silla,
• Rodrigo A. Cormanich,
• Roberto Rittner and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2013, 9, 1127–1134, doi:10.3762/bjoc.9.125

• a way that the molecular interactions are characterized by quantum-mechanical delocalization from filled donor to formally unoccupied acceptor NBOs [19]. In addition to the NBO method, the quantum theory of atoms in molecules (QTAIM) [20] has been widely used to examine the electronic densities

Polymerization of novel methacrylated anthraquinone dyes

• Christian Dollendorf,
• Susanne Katharina Kreth,
• Soo Whan Choi and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 453–459, doi:10.3762/bjoc.9.48

• [14][15][16]. Coloration of polymers is usually achieved by mixing dyes or pigments with (other) polymeric ingredients. In many cases, the colors rapidly fade or change as well as lose their mechanical properties when exposed to sunlight. More stable polymers can be prepared by the reaction of

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

Towards a biocompatible artificial lung: Covalent functionalization of poly(4-methylpent-1-ene) (TPX) with cRGD pentapeptide

• Lena Möller,
• Christian Hess,
• Jiří Paleček,
• Yi Su,
• Axel Haverich,
• Andreas Kirschning and
• Gerald Dräger

Beilstein J. Org. Chem. 2013, 9, 270–277, doi:10.3762/bjoc.9.33

• ); surface modification; Introduction Respiratory failures are a significant health-care problem with several hundred thousand adult patients each year [1]. Besides medical treatment, the use of mechanical ventilators that provide breathing support while the lungs recover, is often indispensable. This

• treatment is conducted when patients respond inadequately to medical therapy. However, invasive mechanical ventilation can damage the lungs physically by overpressurizing lung tissue or due to inflammation. This may lead to exacerbation of lung dysfunction or even to multiple-organ failure [2][3]. The

The β-cyclodextrin/benzene complex and its hydrogen bonds – a theoretical study using molecular dynamics, quantum mechanics and COSMO-RS

• Jutta Erika Helga Köhler and
• Nicole Grczelschak-Mick

Beilstein J. Org. Chem. 2013, 9, 118–134, doi:10.3762/bjoc.9.15

• shows multiple topologies/configurations (guest up/down) in MD with λ-dynamics [14]. The association constant Ka for α- and β-CD inclusion complexes with several benzene derivatives was investigated by a genetic algorithm [15] and neuronal networks [16]. An overview of quantum mechanical methods to

• the IR lines of the β-CD most at its frame frequencies and at highly ordered concerted movements of its hydrogen bonds. The IR frequencies of benzene were influenced only marginally upon inclusion. COSMO-RS calculations with Turbomole Quantum mechanical geometry/energy optimisations For the four empty

• β-CD models, for benzene in D6h geometry, and for all eight BCD/benzene complexes, quantum mechanical geometry/energy optimisations with Turbomole and the implemented COSMO-RS method were performed at 0 K. For all starting structures the AM1 optimised geometries were used, and the results are given

A new family of four-ring bent-core nematic liquid crystals with highly polar transverse and end groups

• Kalpana Upadhyaya,
• Venkatesh Gude,
• Golam Mohiuddin and
• Rao V. S. Nandiraju

Beilstein J. Org. Chem. 2013, 9, 26–35, doi:10.3762/bjoc.9.4

• to possibly weakened lateral interactions and increased intermolecular spacing between molecules. Density functional theory calculations The quantum mechanical calculations of molecular properties in the gas phase were performed by using density functional theory (DFT) [58] employing the combination

Theoretical study on β-cyclodextrin inclusion complexes with propiconazole and protonated propiconazole

• Adrian Fifere,
• Narcisa Marangoci,
• Stelian Maier,
• Adina Coroaba,
• Dan Maftei and
• Mariana Pinteala

Beilstein J. Org. Chem. 2012, 8, 2191–2201, doi:10.3762/bjoc.8.247

• theoretically investigates the interaction between PP, PPH+ and β-CD molecules by means of AM1 and PM3 semi-empirical quantum-mechanical calculations, to examine in detail the insertion pathways and to determine the intimate configurations of the β-CD/propiconazole (β-CD/PP and β-CD/PPH+) inclusion complexes

• parameter and the complex stability by means of quantum-mechanical calculations has been previously reported [19][20]. The PP molecule has a permanent electric dipole, and the dipole–dipole interaction can make the difference between the A and B configurations. The decrease of the global dipole moment

Mechanochemistry assisted asymmetric organocatalysis: A sustainable approach

• Pankaj Chauhan and
• Swapandeep Singh Chimni

Beilstein J. Org. Chem. 2012, 8, 2132–2141, doi:10.3762/bjoc.8.240

• . To address many of these issues mechanochemical methods such as ball-milling and grinding with pestle and mortar have emerged as powerful techniques [5][6][7][8][9][10][11][12]. The mechanical energy generated by grinding two solids or one solid and one liquid substance results in the formation of

• mixing of the catalyst and substrates and also provides additional mechanical pressure. The proposed transition state (TS 5) involves a hydrogen-bonded ternary complex of substrates and catalyst, in which the aromatic hydroxy group activates the nitro group of nitroalkene while the tertiary amine of the

Cyclodextrin-based nanosponges as drug carriers

• Francesco Trotta,
• Marco Zanetti and
• Roberta Cavalli

Beilstein J. Org. Chem. 2012, 8, 2091–2099, doi:10.3762/bjoc.8.235

• mechanical strength than activated carbon and are not affected by dust formation during application. Finally, they can be reused indefinitely after simple washing with an environmentally friendly solvent, such as ethanol. Nanosponges can be used as supports for catalysis applications. One important result

Synthesis and ring openings of cinnamate-derived N-unfunctionalised aziridines

• Alan Armstrong and
• Alexandra Ferguson

Beilstein J. Org. Chem. 2012, 8, 1747–1752, doi:10.3762/bjoc.8.199

• ). Problems with mechanical stirring were observed at concentrations above 0.24 M, due to the heterogeneous nature of the reaction mixture. The isolated yield of this reaction (51%) was slightly lower than the conversion, but was reproducible on a 12 mmol scale (Table 1, entry 9). Use of an increased number

Influence of cyclodextrin on the solubility of a classically prepared 2-vinylcyclopropane macromonomer in aqueous solution

• Helmut Ritter,
• Jia Cheng and
• Monir Tabatabai

Beilstein J. Org. Chem. 2012, 8, 1528–1535, doi:10.3762/bjoc.8.173

• with a partially unsaturated backbone [29][30][31], which is suitable for further modifications. As mentioned above, polymerization reactions and mechanical and chemical modifications of vinylcyclopropane derivates have been carefully investigated in recent years. However, up to now, nothing is known

The crystal structure of the Dess–Martin periodinane

• Albert Schröckeneder,
• Desiree Stichnoth,
• Peter Mayer and
• Dirk Trauner

Beilstein J. Org. Chem. 2012, 8, 1523–1527, doi:10.3762/bjoc.8.172

• respect to the mechanism of the Dess–Martin oxidation. Our X-ray structure will serve as a starting point for detailed quantum mechanical calculations to address this topic. Experimental Crystallographic data for 1: Data collected by means of an Oxford Diffraction Xcalibur 3 diffractometer, Mo Kα

Synthesis and characterization of low-molecular-weight π-conjugated polymers covered by persilylated β-cyclodextrin

• Aurica Farcas,
• Ana-Maria Resmerita,
• Andreea Stefanache,
• Mihaela Balan and
• Valeria Harabagiu

Beilstein J. Org. Chem. 2012, 8, 1505–1514, doi:10.3762/bjoc.8.170

• reduced interchain interactions, which allow the polyrotaxane chains to pack densely. A better quality of the film, with higher uniformity, flatness, and better mechanical properties, is always desirable for optoelectronic applications. The optical properties of the PDOF-BT and PDOF-BTc compounds (not