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Search for "distribution" in Full Text gives 566 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines
Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162
- product 4a. As well, the phenyl ortho-substituent in the aryl ring for 4f was twisted out of the plane and was not involved in the electronic orbital distribution (Figure 8). As shown in Figure 9, the HOMO and LUMO frontier orbitals of products 4a–d are extended over the π-conjugated part of the molecules
- outside the carbon cores. It was observed for compound 4c that the two trifluoromethoxy groups were twisted out of the plane and consequently did not participate in the orbital distribution. The HOMO electronic distributions of 4b and 4d were spread over the two non-twisted methoxy groups. The calculated
- adopted a distorted molecular geometry. In contrast to methoxy groups, the trifluoromethoxy groups are twisted out of plane and, therefore, are not involved in the electronic orbital distribution. Experimental energy band gaps of the prepared tetrahydroacridines were found to be an average of 3 eV which
Isolation and characterization of new phenolic siderophores with antimicrobial properties from Pseudomonas sp. UIAU-6B
Beilstein J. Org. Chem. 2021, 17, 2390–2398, doi:10.3762/bjoc.17.156
- ]. One way out of this is an extensive search for novel bioactive natural products from microbial sources [2][3]. There is focus on the genus Pseudomonas for scientific research due to its widespread distribution in water, soil, and extreme habitats, including the exceptional ability to colonize the
Post-functionalization of drug-loaded nanoparticles prepared by polymerization-induced self-assembly (PISA) with mitochondria targeting ligands
Beilstein J. Org. Chem. 2021, 17, 2302–2314, doi:10.3762/bjoc.17.148
- subject to CC BY 4.0. Summary of the pPEGMA and pMPC block copolymers prepared by PISA at 70 °C including the hydrodynamic diameter Dh and particle size distribution PdI obtained by DLS and the drug loading content (DLC) calculated using DLC = m(PENAO)/[m(PENAO) + m(polymer)]. The table here contains the
Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura
Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141
- canonical structures of 4 (4a–d in Figure 5). The calculated ECD spectra of 4a–d and the one of 4, which includes all contributions from each tautomer according to the energy distribution, are shown in Figure 5 and Figure 4, respectively. The experimental ECD spectrum of 4, with positive and negative Cotton
- the above-obtained spectra (half-width: 0.29 eV) according to the Boltzmann distribution, corrected by a red-shift of 15 nm, and scaled to adjust the strength of the vertical axis. The spectra of structures 4b, 4c, and 4d were similarly simulated using 122, 126, and 475 OPLS3e-minimized structures and
- 26, 22, and 31 DFT-optimized structures, respectively. The spectrum of 4 was created using the weighted average of the spectra of all low-lying conformers of 4a–d according to the respective Boltzmann distribution. The Cartesian coordinates and the energies of the most stable conformers for each
Chemical syntheses and salient features of azulene-containing homo- and copolymers
Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139
- ). The striking feature of azulene is its permanent dipole moment (1.08 D) and blue color unlike its colorless isomer naphthalene [4]. Azulene possesses an unequal distribution of electron density between its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO
Constrained thermoresponsive polymers – new insights into fundamentals and applications
Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138
- for any real polymer solution. Every polymer always exhibits a molar mass distribution. Therefore, a quasi-binary mixture is usually considered. It is possible to measure the cloud-points, but the obtained cloud-point (Tcp) curve differs from a simple bimodal. Thus, the critical point (LCST or UCST
- state is characterized by the change of the segment distribution from a parabolic to a step profile and a rearrangement of the chain ends [126]. This collapse can be described by the classical Flory–Huggins model. It follows that this vertical collapse above the LCST or below the UCST is merely a
An initiator- and catalyst-free hydrogel coating process for 3D printed medical-grade poly(ε-caprolactone)
Beilstein J. Org. Chem. 2021, 17, 2095–2101, doi:10.3762/bjoc.17.136
- coating and corroborates the inhomogeneous distribution of PHEMA inside the boxes (Figure 3). Compared to the pristine scaffold (Figure 3A and Figure 3B), the PHEMA coat can be clearly distinguished both as a thin coat on the fibers as well as in form of films between fibers and spanning boxes (Figure 3C
A study on selective transformation of norbornadiene into fluorinated cyclopentane-fused isoxazolines
Beilstein J. Org. Chem. 2021, 17, 2051–2066, doi:10.3762/bjoc.17.132
- enhance the pharmacokinetic properties of lead candidates in drug research through the improvement in lipophilicity, absorption, distribution, hydrophobicity and metabolism. Considering the high importance of organofluorine chemistry and that of fluoroalkyl groups in pharmaceutical chemistry, a wide range
Progress and challenges in the synthesis of sequence controlled polysaccharides
Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129
- and enzymatic methods have been optimized to obtain samples with well-defined substitution patterns and narrow molecular weight distribution. Chemical synthesis has granted access to polysaccharides with full control over the length. Here, we review the progress towards the synthesis of well-defined
- amylose with narrow MW distribution, amylose hybrids, and amylose-functionalized materials [186]. Linear and branched oligosaccharides with mixed α(1–3) and α(1–4) linkages were synthesized using a glucansucrase from Lactobacillus reuteri [187][188]. Even though several chemical methods are available for
Regioselective N-alkylation of the 1H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution
Beilstein J. Org. Chem. 2021, 17, 1939–1951, doi:10.3762/bjoc.17.127
- distribution. For example, employing C-7 NO2 or CO2Me substituted indazoles conferred excellent N-2 regioselectivity (≥ 96%). Importantly, we show that this optimized N-alkylation procedure tolerates a wide structural variety of alkylating reagents, including primary alkyl halide and secondary alkyl tosylate
- , respectively). Substituting potassium carbonate (K2CO3) for Cs2CO3 did not show any improvement in the regioisomeric distribution of 10 and 11 (ratio N-1 (10)/N-2 (11) = 1.4:1) (Table 1, entry 4). Similarly, the use of sodium carbonate under identical conditions gave a notably lower combined yield of 10 and 11
- equivalents of 15-crown-5 from one to five equivalents (with respect to NaH) gave a similar regioisomeric distribution of N-substituted indazoles 10 and 11 (Table 5, entry 2). These control experiments show that 15-crown-5 disrupts tight ion pair formation, providing further support for our mechanistic
Cationic oligonucleotide derivatives and conjugates: A favorable approach for enhanced DNA and RNA targeting oligonucleotides
Beilstein J. Org. Chem. 2021, 17, 1828–1848, doi:10.3762/bjoc.17.125
- endogenous nucleic acid targets, thereby inhibiting the gene expression. Although ASOs have great potential in the treatment of many diseases, the search for favorable toxicity profiles and distribution has been challenging and consequently impeded the widespread use of ASOs as conventional medicine. One
Sustainable manganese catalysis for late-stage C–H functionalization of bioactive structural motifs
Beilstein J. Org. Chem. 2021, 17, 1733–1751, doi:10.3762/bjoc.17.122
- electron-rich benzylic position, rationalizing the involvement of electrophilic metallonitrene intermediate 18A. Manganese-catalyzed late-stage C–H methylation The incorporation of methyl groups has the potential to manipulate absorption, distribution, metabolism, and excretion (ADME), solubility, and
A systems-based framework to computationally describe putative transcription factors and signaling pathways regulating glycan biosynthesis
Beilstein J. Org. Chem. 2021, 17, 1712–1724, doi:10.3762/bjoc.17.119
- cancer type must be greater than the median RPKM expression of the TF across all 29 different cancer types; ii) the RNA expression of the TF and target gene should be correlated. To determine this, Cistrome first compares the selected TF–gene correlation with a null distribution computed by randomly
Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications
Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116
Chemical synthesis of C6-tetrazole ᴅ-mannose building blocks and access to a bioisostere of mannuronic acid 1-phosphate
Beilstein J. Org. Chem. 2021, 17, 1527–1532, doi:10.3762/bjoc.17.110
- instance we were able to modify the nucleophile component to O-benzylhydroxylamine and supress unwanted elimination. Unable to do this here, we instead reduced the reaction temperature to 0 °C, maintaining this for 40 minutes. Pleasingly, the yield and product distribution were improved, affording
Synthesis of 1-indolyl-3,5,8-substituted γ-carbolines: one-pot solvent-free protocol and biological evaluation
Beilstein J. Org. Chem. 2021, 17, 1453–1463, doi:10.3762/bjoc.17.101
- derivative 3ac (10 nM, 100 nM, 1 μM, 10 μM, and 100 μM), the cellular uptake and distribution was monitored by using confocal microscopy (λex = 405 nm; λem range = 420–470 nm). Selected examples of compounds containing the γ-carboline core. Single-crystal XRD structure of 3ac (CCDC: 1897787). UV–vis
- of carboline derivative 3ac in HeLa cells. a) Confocal fluorescent image of HeLa cells after 3 h incubation with 10 μM concentration of 3ac (20-fold magnification, 2-fold zoom); b) DIC image of HeLa cells; c) overlay of (a) and (b) indicating the distribution of 3ac in the cytoplasm with distinct
Antiviral therapy in shrimp through plant virus VLP containing VP28 dsRNA against WSSV
Beilstein J. Org. Chem. 2021, 17, 1360–1373, doi:10.3762/bjoc.17.95
- (pigment red, McCormick4, USA) was administered through the oral cavity using an insulin syringe (BD Micro-FineTM) of 0.5 mL (31G × 6 mm). The distribution of the red-stained solution was observed with a stereoscopic microscope (Labomed, Model CZM6 Trinocular, Stereo Microscope) to determine the time and
- distribution of the product in the digestive tract of the shrimp. After that, two sets of groups in four replicates with five shrimp each. In one of them, 6.0 µg (50 µL) of free dsRNAvp28 was administered, whereas in the second, 50 µL of VLP-dsRNAvp28 (6.0 µg of dsRNAvp28) was applied. After 18 hours both
- . The morphology of the VLPs is maintained after this last step of the assembly process. The VLPs synthesized had two types of morphologies: icosahedral capsids and large rods (Figure 2A, c to f). Also, aggregations of spherical capsid can be observed at the last VLP assembly step. The distribution of
Photoinduced post-modification of graphitic carbon nitride-embedded hydrogels: synthesis of 'hydrophobic hydrogels' and pore substructuring
Beilstein J. Org. Chem. 2021, 17, 1323–1334, doi:10.3762/bjoc.17.92
- results of HGCM-vTA are exhibiting a sulfur content allocation in accordance with the nitrogen atom distribution in a fair amount of abundance (Figure 2b). Determination of the sulfur content is a facile approval for the surface modification as neither monomers nor g-CN from HGCM are possessing a sulfur
A new glance at the chemosphere of macroalgal–bacterial interactions: In situ profiling of metabolites in symbiosis by mass spectrometry
Beilstein J. Org. Chem. 2021, 17, 1313–1322, doi:10.3762/bjoc.17.91
- macroalgae establish close mutualistic relationships, in which both gain reciprocal benefits forming an ecological unit (holobiont) [1][2][3]. Chemical exchange and physical proximity are the basis of this algae–bacterial mutualism [4], but little is known about the spatial distribution of the bacteria on
- reveal any information on the metabolically active bacteria and the spatial distribution of substances exchanged. While the study of bacterial symbiosis is often limited to either chemistry or microscopy work, recent functional and metabolomics methods are available to enable chemical imaging of
- Information File 1). Even though most of the seawater media was removed from the Ulva samples during sample preparation, crystallisation of seawater salts on the sample surface occurred. The size of the crystals and their distribution within an imaged area were examined using a digital microscope and found to
A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries
Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90
- companies further down the supply chain for formulation, packaging and distribution. International fragrance companies are mainly responsible for the discovery, creation, process development and manufacturing of synthetic fragrance ingredients with all of these representing active areas of current research
- offer the advantage of high surface-to-volume ratio and scalability. These systems consist of nanoparticles embedded into a porous polymer matrix. In heterogeneous catalysis, a higher particle stability and good distribution of the catalyst leads to a reduction in pressure drop alongside a stronger
Synthesis of 10-O-aryl-substituted berberine derivatives by Chan–Evans–Lam coupling and investigation of their DNA-binding properties
Beilstein J. Org. Chem. 2021, 17, 991–1000, doi:10.3762/bjoc.17.81
- the Cu2+-catalyzed coupling reaction with the boronic acid (Scheme 2). The regioselectivity of the latter reaction step is most likely determined by a stronger nucleophilicity of the oxyanion in the 10-position of 6 that is caused by the particular electron distribution in the intermediate 6
Enhanced target cell specificity and uptake of lipid nanoparticles using RNA aptamers and peptides
Beilstein J. Org. Chem. 2021, 17, 891–907, doi:10.3762/bjoc.17.75
- lipid, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), cholesterol, and PEG-lipid, each with an essential role in the design (Figure 1). These lipids promote the effective distribution of the LNP in vivo as well as aid in effective cargo release from the endosome [1][37]. To this end, we herein
- , USA). Briefly, the scale was set to the scale bar on the image, and the diameter for entire nanoparticles was measured in each image. At least 3 images per LNP formulation were used to determine the size distribution of the LNPs. Data are represented as a box and whisker plot, with min and max values
Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects
Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71
- , multimode microwave reactors for parallel synthesis and multimode microwave reactors for single-batch scale-up. The reactors vary in capacity and the distribution mode of the electromagnetic wave in the reactor vessel. The introduction of the Si–C (silicon–carbon) vials enables high temperature resistance
Valorisation of plastic waste via metal-catalysed depolymerisation
Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53
- these processes are promoted by heterogeneous acid catalysts (e.g., zeolites, alumina, silica) and are usually unselective, resulting in a broad distribution of gas (C3 and C4 hydrocarbons), liquids (cycloparaffins, oligomers, aromatics) and solid products (char, coke) as a consequence of the random
- in >97% yield into liquid hydrocarbon (alkane) products having a narrow distribution of the molecular weight (960–1130 g⋅mol−1) under 11.7 bar H2 at 300 °C and solvent-free conditions [146]. The pyrolysis oils produced may be used as lubricants, waxes or further processed into detergents and
Designed whole-cell-catalysis-assisted synthesis of 9,11-secosterols
Beilstein J. Org. Chem. 2021, 17, 581–588, doi:10.3762/bjoc.17.52
- the low solubility of corticosteroids in aqueous solution. The expression of KshA5 and KshB was verified from the cell lysate by polyacrylamide gel electrophoresis and western blotting (see Supporting Information File 1, Figure S1). The product distribution between the cellular pellet and supernatant
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