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Search for "parallel" in Full Text gives 464 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Host–guest complexes of conformationally flexible C-hexyl-2-bromoresorcinarene and aromatic N-oxides: solid-state, solution and computational studies
Beilstein J. Org. Chem. 2018, 14, 1723–1733, doi:10.3762/bjoc.14.146
- cavity is represented as ‘h’, defined as the measured distance from the centroid of the lower-rim host carbon atoms to the nearest endo guest non-hydrogen atom. In the X-ray structure of 3@BrC6 (Figure 2a), guest 3, oriented parallel to the host aromatic rings (h = 3.43 Å) is positioned in one corner of
- the cavity with only the proton meta- to the N–O group interacting with a host aromatic ring. This short contact C–H···π(host) interaction is about 2.65–2.85 Å long. In 4@BrC6 (Figure 2b), once again guest 4 is oriented parallel to the host aromatic rings (h = 3.38 Å) and the H–G recognition occurs by
- example, in 6@BrC6 (Figure 2d) and 7@BrC6 (Figure 2e), guests 6 and 7 have h = 3.23 Å and 3.50 Å, due to their steric demands. However, in complex 8@BrC6 (Figure 2f) the unhindered para-methoxy group facilitates 8 to sit deep inside the cavity at h = 2.82 Å. The guest’s parallel orientation to the host
Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit
Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145
- previously reported nanosystems as polymeric nanoparticles. In covalent series, G-1 dendron D-N
NH itself (as unexpected reference) self-assembled into nanospheres with a high D value (694 nm). We ascribed this packing ability to three basic π stacking interactions [72] associating stratified parallel
- solution, the reaction conditions were found mandatory to the high solvation of the G-0 and G-1 dendrons exhibiting a major (anti–anti) (parallel) rotamerism of the peripheral 4-(n-octyloxy)phenyl units about the C(s-triazine)–N(exocyclic) partial double bonds. The final iterative synthetic step was
- investigations revealed (i) the regular shape in solution of the terminal 4-(n-octyloxy)phenyl units (“parallel”, anti–anti), (ii) the propeller arrangement, in the case of the angular connections of G-1 dendrons around the m-trivalent core, (iii) the vaulted shapes of G-2 dendrimers and (iv) in one case, the
Drug targeting to decrease cardiotoxicity – determination of the cytotoxic effect of GnRH-based conjugates containing doxorubicin, daunorubicin and methotrexate on human cardiomyocytes and endothelial cells
Beilstein J. Org. Chem. 2018, 14, 1583–1594, doi:10.3762/bjoc.14.136
- helps to compare cytotoxic efficacy (IC50) of the 15 GnRH-based antitumor conjugates in 3 reference tumor cell lines representing the most frequent malignancies (breast cancer – MCF-7, colorectal adenocarcinoma – HT-29 and acute monocytic leukemia – MonoMac6). In parallel, the cardiotoxic effects of the
Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis
Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128
- iodoarenes, which are released in stoichiometric amounts in any reaction mediated by λ3- or λ5-iodanes. In parallel to the development of solid-supported reagents or reactions catalytic in iodine, a third strategy has emerged to address this issue in terms of sustainability. The atom-economy of
- investigated and significant achievements have been reported making iodine compounds now useful organocatalysts in asymmetric synthesis (reaction 2 in Scheme 1a) [15][16][17][18][19][20][21][22][23][24]. In parallel to these investigations, a third strategy has been envisaged with the development of tandem
- complex. The group of Sodeoka, in parallel, has described the same 1,2-difunctionalization reaction of alkenes and alkynes with 5 in the presence of [Cu(MeCN)4]PF6 as the catalyst (Scheme 5a) [37]. It should be pointed out that this copper(I) complex was previously described by Szabó as a poor catalyst in
Recent advances in phosphorescent platinum complexes for organic light-emitting diodes
Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124
- crucial for the PLQY attained. In the remarkable case of the crystalline film of complex Pt(fppz)2, the molecular plane of the square-planar compound was mostly perpendicular respect to the substrate and hence, the 3MMLCT photoluminescence dipole lies almost parallel to it. The architecture of the
- value as high as 38.8%, which approaches the maximum EQE estimated value of ca. 45%. This latter could be achieved in the case of a phosphor with 100% of PLQY with a fully parallel emitting dipole. The beneficial effect of the emitting dipole orientation on the light outcoupling efficiency was further
Cobalt–metalloid alloys for electrochemical oxidation of 5-hydroxymethylfurfural as an alternative anode reaction in lieu of oxygen evolution during water splitting
Beilstein J. Org. Chem. 2018, 14, 1436–1445, doi:10.3762/bjoc.14.121
- window between 1.2 V to 1.5 V vs RHE, where HMF oxidation is facilitated by all investigated catalyst materials. However, parallel O2 evolution at slow rates cannot be fully excluded. For a comparison of the HMF oxidation activity of the investigated catalysts, two performance criteria were taken into
A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds
Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115
- -triazine unit and the planes of the two caps are parallel. The central triazine rings in 2 are close to each other, the distance between the heterocycles being 3.63 Å. This value is smaller compared to the distance (3.72 Å) measured between the benzene molecules in their sandwich configuration [40], but it
Are dispersion corrections accurate outside equilibrium? A case study on benzene
Beilstein J. Org. Chem. 2018, 14, 1181–1191, doi:10.3762/bjoc.14.99
- superpositions or pseudopotentials. Firstly, we use the electronic structure codes to calculate energies E(R) directly. We then fit E(R) = E∞ – C6/R6 to the last five points of the parallel configuration data to find E∞, the extrapolated energy of two monomers, which lets us determine interaction energies U(R
- energy for the parallel configuration of the benzene dimer (labelled P – with D6h symmetry). Despite having a minimum as a function of distance between the two centres, this arrangement is unstable as the dimers wish to slide apart sideways (see later discussion on Figure 3) to reduce electrostatic
- energetically very close to it. Here the balance of energetic contributions is more strongly skewed to dispersion, and it is expected that vdW dispersion corrections should work better than for the parallel configuration shown in Figure 1. Indeed, the successful methods for the parallel geometry (XDM, MBD, FI
An overview of recent advances in duplex DNA recognition by small molecules
Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93
- eight Hoogsteen-paired hydrogen bonds to form a tetrad (Figure 1) has further enhanced our understanding of the diversity of DNA shapes and structures. In a parallel tetramolecular quadruplex d(TG4T), the features of nucleotides at each base resemble that of the B-DNA (C2’-endo sugar pucker, anti
- 10. Minor groove complex formation between DNA duplex and Hoechst 33258 is shown in Figure 7b [82]. X-ray crystallographic and NMR studies confirmed that Hoechst 33258 binds to the A·T-rich sequences in minor groove with the planar benzimidazole groups are oriented parallel to the direction of the
Correlation effects and many-body interactions in water clusters
Beilstein J. Org. Chem. 2018, 14, 979–991, doi:10.3762/bjoc.14.83
- -bonded structure to the second one that is characterised by parallel dipoles of the two water molecules. Compared to this, the dispersion interaction hardly changes upon a disordering of the hydrogen atoms. While it has a minimum, too, at the equilibrium structure, for the other two structures it lies
Mechanochemistry of nucleosides, nucleotides and related materials
Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81
- ]. This culminated in Schwander and Signer isolating eight grams of pure material [63] from which high quality X-ray diffraction images (including "Photograph 51") [66] were obtained and its double-helical structure evinced [67]. Parallel to Miescher’s work on salmon sperm, Kossel reported the isolation
Anodic oxidation of bisamides from diaminoalkanes by constant current electrolysis
Beilstein J. Org. Chem. 2018, 14, 861–868, doi:10.3762/bjoc.14.72
- a mixture of MeOH/MeCN (1:1) was used, and in parallel, the C rod anode was replaced with a C felt (that has a considerable larger surface area) in attempts to improve both efficiency and selectivity. The results are described in Table 5 and they show a pronounced difference compared to the ones in
Phosphodiester models for cleavage of nucleic acids
Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68
- original mechanistic suggestion is in principle valid, but has to be supplemented with a general base-catalyzed reaction through a dianionic phosphorane transition state (Scheme 5) that takes place in parallel with the stepwise reaction through a phosphorane monoanion (Scheme 4). The group of Kirby has
Recent advances in synthetic approaches for medicinal chemistry of C-nucleosides
Beilstein J. Org. Chem. 2018, 14, 772–785, doi:10.3762/bjoc.14.65
- ' pseudoaxial methoxy groups further stabilize the intermediate in E3 conformer, thereby favoring the E3 confomer over the 3E. In the case of an anomeric phenyl group (Ph, Figure 6C), stabilization of the positive charge (C=O+) through conjugation, via parallel alignment, helps to overcome the unfavorable
Syn-selective silicon Mukaiyama-type aldol reactions of (pentafluoro-λ6-sulfanyl)acetic acid esters with aldehydes
Beilstein J. Org. Chem. 2018, 14, 373–380, doi:10.3762/bjoc.14.25
- highly selective reaction conditions could be developed in parallel with the progress in understanding the mechanism of these transformations [6][7][8][9]. Also, aldol reactions with fluorinated substrates, particularly with trifluoromethyl-containing ones, were investigated [10][11][12][13]. In recent
Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)
Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18
- diphenylamine unit of D1 by a tert-butyl-substituted carbazole unit in D3, the 3ππ* state was considerably destabilized, raising its energy level and decreasing ΔEST. Parallel to this, a greater separation of the HOMO and LUMO orbitals was evidenced by theoretical calculations for D3, as a result of a larger
- )benzene). Parallel to this, the fluorescence and TADF lifetime were almost the same for both the doped and undoped film, making D6 a candidate applicable for the design of undoped OLEDs. Trilayered undoped OLEDs fabricated with D6 displayed a sky-blue emission peaking at 480 nm, with an EQE of 19.5% at a
- with a photo-oxidation was determined as playing a critical role in the degradation of blue TADF emitters. In fact, a parallel can be easily done with the treatment of wastewater, where pollutants are removed from water by combining a photochemical and an electrochemical process [50]. During this study
Progress in copper-catalyzed trifluoromethylation
Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11
- trifluoromethanes. Conclusion In the past few years, the field of copper-mediated trifluoromethylation of aromatic and aliphatic compounds including heterocycles have experienced significant advances. In parallel with this field, the trifluoromethylation catalyzed by other transition metals like Pd, Ag, Fe and
Polarization spectroscopy methods in the determination of interactions of small molecules with nucleic acids – tutorial
Beilstein J. Org. Chem. 2018, 14, 84–105, doi:10.3762/bjoc.14.5
- (LD) is another type of polarization spectroscopy which does not require a chiral sample but rather an oriented one. It is based on the differential absorption of light polarized either parallel or perpendicular to a certain axis of orientation. This is also applicable to biomacromolecules such as
- ) competition experiments between two ligands aiming for the same binding site would require a specific design; and so on. 3.1. Practical information Cuvettes: quartz, preferably high-quality manufactured with precisely parallel walls (e.g., fluorimetric cuvettes) and minimal residual strain. Cylindrical cells
- conditions). End: maximum absorption of sample + 50 nm (the additional wavelength range is required to monitor if the baseline beyond the absorption region of the sample is flat after spectrum subtraction). It is compulsory to monitor in parallel the two channels corresponding to ECD and HT (related to
The use of 4,4,4-trifluorothreonine to stabilize extended peptide structures and mimic β-strands
Beilstein J. Org. Chem. 2017, 13, 2842–2853, doi:10.3762/bjoc.13.276
- drugs contain fluorine atoms or fluoroalkyl groups, representing 150 fluorinated molecules, and this trend is expected to increase to about 30% in the early future as a new generation of fluorinated compounds is currently in Phase II−III clinical trials [1]. In parallel, pharmaceutical peptides are
The photodecarboxylative addition of carboxylates to phthalimides as a key-step in the synthesis of biologically active 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones
Beilstein J. Org. Chem. 2017, 13, 2833–2841, doi:10.3762/bjoc.13.275
- . Sulfuric acid-catalyzed dehydrations of the benzylated hydroxyphthalimidines 3a–q in dichloromethane at room temperature resulted in the corresponding olefins 7a–q in good to excellent yields of 66–95% (Scheme 5 and Table 3). The simple reaction protocol enabled parallel operations in a Radleys Carousel 6
Metal-mediated base pairs in parallel-stranded DNA
Beilstein J. Org. Chem. 2017, 13, 2671–2681, doi:10.3762/bjoc.13.265
- applying it to parallel-stranded DNA duplexes. The antiparallel-stranded orientation of the complementary strands as found in natural B-DNA double helices enforces a cisoid orientation of the glycosidic bonds. To enable the formation of metal-mediated base pairs preferring a transoid orientation of the
- glycosidic bonds, parallel-stranded duplexes have been investigated. In many cases, such as the well-established cytosine–Ag(I)–cytosine base pair, metal complex formation is more stabilizing in parallel-stranded DNA than in antiparallel-stranded DNA. This review presents an overview of all metal-mediated
- base pairs reported as yet in parallel-stranded DNA, compares them with their counterparts in regular DNA (where available), and explains the experimental conditions used to stabilize the respective parallel-stranded duplexes. Keywords: DNA; metal-mediated base pairs; nucleic acids; Introduction
A concise flow synthesis of indole-3-carboxylic ester and its derivatisation to an auxin mimic
Beilstein J. Org. Chem. 2017, 13, 2549–2560, doi:10.3762/bjoc.13.251
- off from the first separator into a second equivalent unit or by simply splitting the original quenched flow over two parallel separators. Although functional these approaches were not the optimum in design or utilisation of the separator components. We therefore also investigated the replacement of
Syntheses, structures, and stabilities of aliphatic and aromatic fluorous iodine(I) and iodine(III) compounds: the role of iodine Lewis basicity
Beilstein J. Org. Chem. 2017, 13, 2486–2501, doi:10.3762/bjoc.13.246
- "spacers" that electronically insulate the arene ring from the perfluoroalkyl groups, have been previously isolated [17]. As described below, the pursuit of the preceding objectives has met with both success and some unanticipated speed bumps, for which parallel computational studies have provided valuable
- fluorophilicity (extraction of a CH3CN solution with perfluorohexane). An analogous procedure with Rf10I gave the higher homolog 1,3-Rf10C6H4I in 50% yield [9], and a lesser amount of what was presumed to be the dialkylation product. The analogous para diiodide 1,4-C6H4I2 gave parallel chemistry, as illustrated
Sulfation and amidinohydrolysis in the biosynthesis of giant linear polyenes
Beilstein J. Org. Chem. 2017, 13, 2408–2415, doi:10.3762/bjoc.13.238
- (SMALA_2697) was added to the reaction mixture together with PAPS. As shown in Figure 3D, 1d was efficiently converted into 1c under these conditions. Therefore parallel pathways do exist (Scheme 3) for the formation of mediomycin A (1c) from desulfoclethramycin (1b), which is the full-length initial product
- biosynthetic gene clusters for mediomycin (med) from Streptomyces mediocidicus and clethramycin (cle) from S. malaysiensis DSM4137. The numbers refer to the position of each orf in the genome sequence. The parallel pathways for the biosynthesis of mediomycin A. Supporting Information Supporting Information
Homologated amino acids with three vicinal fluorines positioned along the backbone: development of a stereoselective synthesis
Beilstein J. Org. Chem. 2017, 13, 2316–2325, doi:10.3762/bjoc.13.228
- being investigated in parallel [5][6]. At this stage, it was clear that O’Hagan’s method [34] (Scheme 3) was the most promising strategy that had been examined so far. But four major obstacles remained: first, the starting material 27 was volatile and difficult to stockpile; second, the purification of
- unfavourable parallel alignment of the Cα–F and Cγ–F bonds. The extended conformer of 6b may be a minor contributor only. Conclusion Full details have been presented of the efforts that were required to identify and optimise a synthetic route towards the δ-amino acids 6a and 6b, molecules which contain three
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