Amphiphilic dendritic peptides: Synthesis and behavior as an organogelator and liquid crystal

• Baoxiang Gao,
• Hongxia Li,
• Defang Xia,
• Sufang Sun and
• Xinwu Ba

Beilstein J. Org. Chem. 2011, 7, 198–203, doi:10.3762/bjoc.7.26

• phase through assignment of the reflections. In the wide angle region, the diffused halo at around 4.5 Å is due to the disorder of the terminal alkyl chains. In the small-angle region, the XRD profile of G3 shows two reflection peaks corresponding to d spacing of 24.8 and 12.5 corresponding to (100) and

Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

• Carolin Fischer and
• Burkhard Koenig

Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10

• synthesis of an atropisomeric N-(2-tert-butylphenyl)lactam as an intermediate for norepinephrine transporter (NET) inhibitor 16. NET inhibitors were developed to treat a variety of mental disorders such as depression and attention deficit hyperactivity disorder (ADHD). Screening different ligands, SERGPHOS

Expanding the gelation properties of valine-based 3,5-diaminobenzoate organogelators with N-alkylurea functionalities

• Hak-Fun Chow and
• Chin-Ho Cheng

Beilstein J. Org. Chem. 2010, 6, 1015–1021, doi:10.3762/bjoc.6.114

• also prevented the organogelators from crystallizing by imposing a higher degree of local disorder. Fourier transform infrared spectroscopy (FT-IR) was employed to elucidate the extent of intermolecular hydrogen bonding in the different macroscopic phases of organogelator 2 (n = 20) in o-xylene (Table

Redox-active tetrathiafulvalene and dithiolene compounds derived from allylic 1,4-diol rearrangement products of disubstituted 1,3-dithiole derivatives

• Filipe Vilela,
• Peter J. Skabara,
• Christopher R. Mason,
• Thomas D. J. Westgate,
• Asun Luquin,
• Simon J. Coles and
• Michael B. Hursthouse

Beilstein J. Org. Chem. 2010, 6, 1002–1014, doi:10.3762/bjoc.6.113

• 133.97(24)° and 81.79(60)°, respectively. There is a slight distortion in the Ni-dithiolene core, which is commonly planar, with an angle of 6.45(2)° between the two planes of the component rings. There is some disorder in one of the peripheral thiophene rings, with atoms S4 and C10 occupying common

• solution was obtained via direct methods and refined [34] by full-matrix least-squares on F2, with hydrogens included in idealised positions. There is rotational disorder of a thiophene moiety in 28, where C10 and S4 occupy the same position in the ring with a site occupancy of 50%. Supplementary data for

Symmetry breaking and structure of a mixture of nematic liquid crystals and anisotropic nanoparticles

• Marjan Krasna,
• Matej Cvetko and
• Milan Ambrožič

Beilstein J. Org. Chem. 2010, 6, No. 74, doi:10.3762/bjoc.6.74

• impact of NPs on orientational ordering of LCs for appropriate concentrations of NPs is reminiscent to the influence of quenched random fields which locally enforce a biaxial ordering. Keywords: liquid crystals; nanoparticles; orientational order; quenched disorder; symmetry breaking; Introduction The

• finite value of s. However, with increasing x the value of s decreases monotonously. Our numerical simulations suggest, that above a threshold value x = xc long range ordering is replaced by short range ordering. Therefore, for a sufficiently large concentration the degree of disorder introduced by

Synthesis, electronic properties and self-assembly on Au{111} of thiolated (oligo)phenothiazines

• Adam W. Franz,
• Svetlana Stoycheva,
• Michael Himmelhaus and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2010, 6, No. 72, doi:10.3762/bjoc.6.72

• corroboration of such disorder effects, coverage seems to decrease with increasing molecule length for even-numbered molecules (cf. Table 2). The highest coverage was obtained with 4, which is not surprising, because the thiol bifunctionality allows chemisorption of the molecule at either side, which reduces

Synthesis and crystallographic analysis of meso-2,3-difluoro-1,4-butanediol and meso-1,4-dibenzyloxy-2,3-difluorobutane

• Bruno Linclau,
• Leo Leung,
• Jean Nonnenmacher and
• Graham Tizzard

Beilstein J. Org. Chem. 2010, 6, No. 62, doi:10.3762/bjoc.6.62

• than the corresponding anti conformation [7][8][9]. O’Hagan has demonstrated that vicinal difluoride substitution along a hydrocarbon chain of a fatty acid leads to conformational rigidity or disorder depending on the relative stereochemistry of the fluorine atoms, which originates from the enforcing

• disparity in the amounts of each conformer present gives rise to the disorder observed in the crystal structure. The vicinal difluoro group adopts an anti conformation with the F–C–C–F dihedral angle exactly 180°, which manifests itself in the crystallographic inversion centre. Nevertheless, each benzyloxy

Preparation, structures and preliminary host–guest studies of fluorinated syn-bis-quinoxaline molecular tweezers

• Markus Etzkorn,
• Jacob C. Timmerman,
• Matthew D. Brooker,
• Xin Yu and
• Michael Gerken

Beilstein J. Org. Chem. 2010, 6, No. 39, doi:10.3762/bjoc.6.39

• molecule, in the monoclinic system (space group: P21/n) and displays bond lengths and angles in the expected ranges. The ethyl acetate displays a small degree of orientation disorder (11.8%). Figure 1a shows a thermal ellipsoid image of 16c and Figure 1b depicts the packing within a unit cell setting. The

The C–F bond as a conformational tool in organic and biological chemistry

• Luke Hunter

Beilstein J. Org. Chem. 2010, 6, No. 38, doi:10.3762/bjoc.6.38

• 19 the gauche effect competes against the zigzag conformation resulting in conformational disorder. Cholesteryl ester transfer protein inhibitors 20 and 21. In the fluorinated analogue 21, nO→σ*CF hyperconjugation leads to an out-of-plane orientation of the fluoroalkyl sidechain, resulting in

Novel loop-like aromatic compounds: a further step on the road to nanobelts and nanotubes

• Venkataramana Rajuri,
• Dariush Ajami,
• Gaston R. Schaller,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2010, 6, No. 30, doi:10.3762/bjoc.6.30

• perspective representations see Supporting Information File 1. a) ORTEP drawing of the crystal structure of 4. Ag+ and Ag+, describe the two disordered positions of Ag+. For further perspective views see Supporting Information File 1. b) Simplified structural scheme for the coordination and disorder of the Ag

Synthesis of lipophilic 1-deoxygalactonojirimycin derivatives as D-galactosidase inhibitors

• Georg Schitter,
• Elisabeth Scheucher,
• Andreas J. Steiner,
• Arnold E. Stütz,
• Martin Thonhofer,
• Chris A. Tarling,
• Stephen G. Withers,
• Jacqueline Wicki,
• Katrin Fantur,
• Eduard Paschke,
• Don J. Mahuran,
• Brigitte A. Rigat,
• Michael Tropak and
• Tanja M. Wrodnigg

Beilstein J. Org. Chem. 2010, 6, No. 21, doi:10.3762/bjoc.6.21

• disease, an X-linked inherited lysosomal storage disorder caused by the deficiency of α-galactosidase A activity resulting in the accumulation of globotriaosylceramide, thereby affecting the lysosomes of vascular endothelial cells. Iminosugar 4 can increase α-galactosidase A levels 1.5 to 28 fold in

Competition between local disordering and global ordering fields in nematic liquid crystals

• Matej Cvetko,
• Milan Ambrožič and
• Samo Kralj

Beilstein J. Org. Chem. 2010, 6, No. 2, doi:10.3762/bjoc.6.2

• anisotropy field type of disorder. The Lebwohl–Lasher lattice type of semi-microscopic approach is used at zero temperature. Therefore, results are valid well below the transition into the isotropic phase. We calculate the correlation function of systems as a function of B, concentration p of impurities

• imposing random anisotropy field disorder, the disorder strength W and system dimensionality (2D and 3D systems). In order to probe memory effects we calculate correlation length ξ for random and homogeneous initial configurations. We determine the crossover fields Bc(p) separating roughly the ordered and

• disordered regime. Memory effects are apparent only in the latter case, i.e. for B < Bc. PACS numbers: 47.51.+a, 47.54.-r, 07.05.Tp, 61.30.-v Keywords: disorder; Imry-Ma theorem; liquid crystals; memory effect; orientational order; Introduction For years there has been a strong interest in the phase and

Versatile supramolecular reactivity of zinc-tetra(4-pyridyl)porphyrin in crystalline solids: Polymeric grids with zinc dichloride and hydrogen-bonded networks with mellitic acid

• Sophia Lipstman and
• Israel Goldberg

Beilstein J. Org. Chem. 2009, 5, No. 77, doi:10.3762/bjoc.5.77

• = C6H4Cl2·3CH3OH, excluded due to disorder), M = 1070.28, triclinic, space group P, a = 11.8660(3) Å, b = 13.8803(4) Å, c = 20.4843(5) Å, α = 78.237(2)°, β = 78.185(2)°, γ = 84.288(1)°, V = 3227.1(2) Å3, Z = 2, Dc = 1.101 g cm−3 and μ(Mo Kα) = 0.44 mm−1 (X excluded), 35843 reflections measured, 15151 unique

• diffractometer, using graphite monochromated Mo Kα radiation (λ = 0.7107 Å). The crystalline samples of the analyzed compounds were covered with a thin layer of light oil and freeze-cooled to ca. 110 K in order to minimize solvent escape, structural disorder, and thermal motion effects, and increase the

Novel banana-discotic hybrid architectures

• Hari Krishna Bisoyi,
• H. T. Srinivasa and
• Sandeep Kumar

Beilstein J. Org. Chem. 2009, 5, No. 52, doi:10.3762/bjoc.5.52

• . Results and Discussion The bend in the rigid cores of the banana liquid crystal compounds leads to a reduction of the rotational disorder of the molecules around their long axes. If segregation of aromatic cores and aliphatic chains is sufficiently strong, the molecular structure facilitates an

Chiral amplification in a cyanobiphenyl nematic liquid crystal doped with helicene-like derivatives

• Alberta Ferrarini,
• Silvia Pieraccini,
• Stefano Masiero and
• Gian Piero Spada

Beilstein J. Org. Chem. 2009, 5, No. 50, doi:10.3762/bjoc.5.50

• relationship between molecular structure, intermolecular interactions, and mesoscale organization. It is known that axially chiral or helical-shaped molecules with reduced conformational disorder are good candidates for high helical twisting power derivatives. In particular, biaryl derivatives are known to be

• standard Quantum Mechanical (QM) tools. It is known that axially chiral or helical-shaped molecules with reduced conformational disorder are good candidates for high HTP derivatives [2][4][6]. In particular, biaryl derivatives have been described as efficient chiral inducers in biaryl nematic mesophases

Studies on polynuclear furoquinones. Part 1: Synthesis of tri- and tetra- cyclic furoquinones simulating BCD/ABCD ring system of furoquinone diterpenoids

• Faruk H. Shaik and
• Gandhi K. Kar

Beilstein J. Org. Chem. 2009, 5, No. 47, doi:10.3762/bjoc.5.47

• viral hepatitis, cardiac and vascular disorder, hypertension, miscarriage and menstrual disorder [3][9] etc. It has been reported to show potential anticancer activity [10] (against human breast cancer), cytotoxic and antiplatelet aggregation activities [1][11]. It also acts as an antibacterial [1

Acid- mediated reactions under microfluidic conditions: A new strategy for practical synthesis of biofunctional natural products

• Katsunori Tanaka and
• Koichi Fukase

Beilstein J. Org. Chem. 2009, 5, No. 40, doi:10.3762/bjoc.5.40

• the reaction is scaled-up. Thus, the disorder of the reaction factors in the scaled-up batch reaction, i.e., (i) precise temperature control, (ii) mixing efficiency between acceptor, donor, and Lewis acid, and (iii) reaction time, might lead to the glycal production. In order to circumvent these

Inversion symmetry and local vs. dispersive interactions in the nucleation of hydrogen bonded cyclic n-mer and tape of imidazolecarboxamidines

• Sihui Long,
• Venkatraj Muthusamy,
• Peter G. Willis,
• Sean Parkin and
• Arthur Cammers

Beilstein J. Org. Chem. 2008, 4, No. 23, doi:10.3762/bjoc.4.23

• the dimers. One molecule in the trimer asymmetric unit was disordered. The two ordered molecules were analogous to an open Ci dimer with θ angles numerically close but of opposite sign. The best solution of the disorder modeled two molecules with large θ of opposite signs with unequal levels of

• . In each case, the lacuna in the lattices occupied by solvent allows for much disorder on the part of the solvent. These three points really do not at all contradict the hypothesis that bringing Ci symmetric dimers of 2 from solution into the solid state results in low-energy packing and high-energy

Crystal engineering of analogous and homologous organic compounds: hydrogen bonding patterns in trimethoprim hydrogen phthalate and trimethoprim hydrogen adipate

• Packianathan Thomas Muthiah,
• Savarimuthu Francis,
• Urszula Rychlewska and
• Beata Warżajtis

Beilstein J. Org. Chem. 2006, 2, No. 8, doi:10.1186/1860-5397-2-8

• the acid adopts the gtt form [34][35]. The adoption of the bent carbon chain conformation by adipic acid seems necessary in order to place the two terminal carboxyl functions in mutual syn orientation so that they can fasten the 2- and 4-amino groups of the TMP molecule. The disorder, on the other

Molecular recognition. 1. Crystal structures of hexaazamacrocyclic amines containing p-xylylene spacers and their adducts with acids

• Teresa Borowiak,
• Grzegorz Dutkiewicz,
• Maciej Kubicki,
• Marek Pietraszkiewicz,
• Agnieszka Gil and
• Rainer Mattes

Beilstein J. Org. Chem. 2005, 1, No. 16, doi:10.1186/1860-5397-1-16

• nitrogens were found in the ΔF maps. The fumaric anion in general position is not planar whereas the anion in the special position displays a statistically averaged planarity with high displacement parameters, as a result of dynamic disorder. The supramolecular structure of 1-FUM is unique and different

• second carboxylic group are hydrogen bonded by bifurcated bonds to another N+- H group and a water molecule (Figure 2). Water molecules located in channels form also infinite tapes by intermolecular hydrogen bonding. Their hydrogen atoms were not found in the ΔF maps probably due to the disorder. The