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Search for "distribution" in Full Text gives 579 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity
Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195
- of compound 3 in DMSO-d6 (400.13 MHz, 297 K). Intensity-weighted mean hydrodynamic diameter (left), and zeta potential distribution (right) of compound 3 (1 mg/mL water), after vortex and sonication. Antiproliferative effects by compound 3 and its chemical precursor 1. A) Results on proliferative
Pentacyclic aromatic heterocycles from Pd-catalyzed annulation of 1,5-diaryl-1,2,3-triazoles
Beilstein J. Org. Chem. 2025, 21, 2524–2534, doi:10.3762/bjoc.21.194
- orientation, the distribution of nitrogen atom centers within the ring system appears essential for eliciting bioactivity. Orientation of isoquinoline and N3-triazole subunit nitrogen atoms is identical between 17 and 35 as well as between 18 and 36. In contrast, 34 showed toxicity towards Gram-positive
The high potential of methyl laurate as a recyclable competitor to conventional toxic solvents in [3 + 2] cycloaddition reactions
Beilstein J. Org. Chem. 2025, 21, 2389–2415, doi:10.3762/bjoc.21.184
- space is shown in Figure 8a. The distribution of these selected solvents with other organic solvents in the 3D Hansen solubility space is determined by three Hansen solubility parameters (HSPs): dispersion (δD), polarity (δP), and hydrogen bonding (δH). As is well established, information about their
- aromatic aldehydes exhibit a Z-configuration [112][113] and it appears that endo-coupling of the Z-configured C,N-diphenylnitrone with maleimide is more favorable. Indeed, the distribution of the cis/trans product is also found to be significantly influenced by the nature of the substituents present in the
- synthetic methods for cycloaddition reactions. In this study, a series of natural organic compounds from diverse classes and an acetonide [129] derivative were selected for investigation, with a focus on their potential catalytic effects in relation to the alteration of cis/trans product distribution under
Pathway economy in cyclization of 1,n-enynes
Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173
- regulatory role in chemical transformations, exerting kinetic modulation through solvation effects on activation barriers and reaction rates, dictating thermodynamic equilibria that govern product distribution, and enabling precise reaction pathway regulation via selective stabilization of critical
A m-quaterphenyl probe for absolute configurational assignments of primary and secondary amines
Beilstein J. Org. Chem. 2025, 21, 2211–2219, doi:10.3762/bjoc.21.168
- a P twist. Based on a Boltzmann distribution analysis (T = 298 K), the relative populations of the P and M conformers in (S)-3a were determined to be 48:52. (Table S3 in Supporting Information File 1). In contrast, the P conformers were found to predominate in (S)-3b (Figure S21 and Table S4 in
- described above, the C6–C1–C1'–C6' dihedral angles in all conformers of (S)-3a–g and (R)-3h were approximately constant (plus or minus ca. 42 degree). The range of distribution of the angles was also small, ranging from +39.8 to +43.9 degrees, or −40.2 to −45.8 degrees (Figure 5). In the solid state of (S
- )-3a–g and (R)-3h using MMFF. All local minimum conformers were then optimized with DFT using the B3LYP/6-31G* model [47]. The lower energy conformers with relative energies ranging from 0.0 to 10.0 kJ/mol were selected. By the Bolzmann distribution based on the energy difference of the conformers at
Solar thermal fuels: azobenzene as a cyclic photon–heat transduction platform
Beilstein J. Org. Chem. 2025, 21, 2036–2047, doi:10.3762/bjoc.21.159
- significant photothermal energy storage capacity of 430 J/g (Figure 5c). This study presents potential implications for energy distribution and utilization in domestic consumer applications, and for photothermal-assisted insulation strategies. Azobenzene small molecule derivative solar thermal fuels
Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics
Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156
- surface hopping (FSSH) [92][93] to investigate the photochemical pathways of compounds 1, 3, and 5 along the potential energy surfaces (PESs) of both ground and three excited states. The initial nuclear positions and velocities were sampled based on the Wigner distribution [108] at 300 K. All quantum
Systematic pore lipophilization to enhance the efficiency of an amine-based MOF catalyst in the solvent-free Knoevenagel reaction
Beilstein J. Org. Chem. 2025, 21, 1854–1863, doi:10.3762/bjoc.21.144
- extent of alkyl grafting, the –CH2– content in the pores of KSU-1n-Hex and KSU-1C14 is still greater than for KSU-1iPr and KSU-1t-Bu, assuming a uniform distribution of alkyl chains. Additionally, although the introduction of large alkyl substituents in a MOF is associated with a reduction in pore
- distribution of intermediate versus product during the reaction. Both these behaviors, increased efficiency and different intermediate:product distributions, call to mind the effect of lipophilic pockets in enzyme catalysis, and they offer a view to the possibilities that can be achieved in enzyme-inspired
Photoswitches beyond azobenzene: a beginner’s guide
Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143
- two isomers do not overlap, only one isomer is excited by the irradiation wavelength, enriching the other isomer until an equilibrium is reached. This equilibrium is called a photostationary state (PSS) [1]. The isomeric distribution at equilibrium can also be called photostationary distribution (PSD
- ). It must be noted, though, that in literature both PSS and PSD are used to indicate the photostationary distribution [2]. We will use the PSS notation throughout the review. Often, the two absorption spectra overlap, and both isomers are excited to different extents at the same time. The extent of
Research progress on calixarene/pillararene-based controlled drug release systems
Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139
- prepared a novel supramolecular ternary polymer DiCh@a-CD-bisSC4A and binary polymers DiCh@bisSC4A Compared to binary DiCh@bisSC4A, ternary DiCh@a-CD-bisSC4A has not only a larger polymer size but also a better size distribution and topological structure due to the integration of quasi rotaxanes with
Continuous-flow-enabled intensification in nitration processes: a review of technological developments and practical applications over the past decade
Beilstein J. Org. Chem. 2025, 21, 1678–1699, doi:10.3762/bjoc.21.132
- tubular, continuous tank, bubbling and injection nitration reactor – directly governs thermodynamic control, product distribution, process scalability, and quality assurance [4][5]. Batch systems remain prevalent for low-throughput fine chemicals due to their operational flexibility, whereas continuous
- compliance or specific product distribution patterns. Nitration solvents: The selection of solvents for nitration reactions significantly influences reaction kinetics, selectivity, and process safety, requiring careful consideration of both chemical compatibility and operational parameters. Traditional batch
- nitration process using continuous-flow, several approaches are listed in the literature, e.g., external numbering up, internal numbering up and sizing up [74]. In the numbering-up approach, ensuring a uniform flow distribution in parallel channels is difficult. The numbering-up approach inherently
Facile synthesis of hydantoin/1,2,4-oxadiazoline spiro-compounds via 1,3-dipolar cycloaddition of nitrile oxides to 5-iminohydantoins
Beilstein J. Org. Chem. 2025, 21, 1552–1560, doi:10.3762/bjoc.21.118
- regioselectivity of the cycloaddition reaction between nitrile oxides and C=N bonds can be rationalized by considering the relative electronegativities of the terminal elements and the distribution of electron density in the frontier orbitals of the reagents [35]. The electrons are preferentially located on the
Microwave-enhanced additive-free C–H amination of benzoxazoles catalysed by supported copper
Beilstein J. Org. Chem. 2025, 21, 1462–1476, doi:10.3762/bjoc.21.108
- -formylpiperidine and aminophenol (2a-o-hydrol) (see Figure 1a). To better understand the influence of the reaction conditions on product distribution, we plotted conversion versus selectivity in Figure 1b. Crudes were analysed by 1H NMR spectroscopy, as shown in Figure S1 (Supporting Information File 1), to
- in the preparation (theoretical loading). This suggests that optimum catalyst distribution and activity is achieved with 5 wt % supported CuCl. The two catalysts were also characterised by FTIR and DR UV–vis spectroscopy, to obtain information about the grafted aminopropyl ligand and inserted copper
Tautomerism and switching in 7-hydroxy-8-(azophenyl)quinoline and similar compounds
Beilstein J. Org. Chem. 2025, 21, 1404–1421, doi:10.3762/bjoc.21.105
- relative Gibbs’ free energies suggest a distribution of 88% E and 12% KE. The theoretical results for acetonitrile show that the tautomer fractions are almost equal, which reflects to the existing experimental ΔG values in acetonitrile, obtained by two different approaches (−0.15 [53] and 0.25 [56] kcal
Selective monoformylation of naphthalene-fused propellanes for methylene-alternating copolymers
Beilstein J. Org. Chem. 2025, 21, 1183–1191, doi:10.3762/bjoc.21.95
- ], [4.3.3]_Br and [4.3.3]_2Br. To gain insight into the different reactivity between [3.3.3] and [4.3.3], theoretical calculations were performed at the ωB97X-D/6-31G(d,p) level of theory (Figures S901–S903 in Supporting Information File 1). Although distribution of the highest occupied molecular orbitals
Enhancing chemical synthesis planning: automated quantum mechanics-based regioselectivity prediction for C–H activation with directing groups
Beilstein J. Org. Chem. 2025, 21, 1171–1182, doi:10.3762/bjoc.21.94
- C–H bond. Example of combinations of C–H bonds and DGs that are considered identical because of symmetry of the DG. Example of combinations of C–H bonds and DGs that are considered identical because of resonance structures of the DG. A: Distribution of correct (green) and wrong (red) predictions for
- black cross. B: Distribution of correct (green), semi-correct (yellow), and wrong (red) predictions for the same molecules, evaluated with an energy threshold of 1.0 kcal·mol−1. Molecules with five potential reaction sites that are predicted wrong by the QM workflow. The experimentally observed and
A multicomponent reaction-initiated synthesis of imidazopyridine-fused isoquinolinones
Beilstein J. Org. Chem. 2025, 21, 1161–1169, doi:10.3762/bjoc.21.92
- . A comprehensive DFT investigation of reactant 6 was carried out to analyze the transition state of the IMDA reaction for a Br-substituted diene and its charge distribution (Figure 2). The diene has a notable positive charge (+0.318, +0.098, 6a), (+0.334, +0.082, 6h) and (+0.316, +0.074, 6r) whereas
Investigations of amination reactions on an antimalarial 1,2,4-triazolo[4,3-a]pyrazine scaffold
Beilstein J. Org. Chem. 2025, 21, 1126–1134, doi:10.3762/bjoc.21.90
- good yield with this straightforward methodology (and without the need for toluene reflux), and to determine the distribution of products obtained for this synthetic approach, by exhaustive analysis of reaction mixtures by HPLC, MS and NMR. Ultimately, 14 aminated derivatives of 5-chloro-3-(4
Supramolecular assembly of hypervalent iodine macrocycles and alkali metals
Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87
- macrocycle’s cavity, we considered the charge distribution on three iodine atoms, three carbonyl carbon atoms and six oxygen atoms that constitute a small cavity within the macrocycle. The Mulliken charge distribution diagram of HIM 1 (Figure 3, middle) shows that the summation of the overall charge on three
- curcumscribe the small cyclic core represented by blue color. Three carbonyl amides project outward. B) DFT image of 1 displaying the distribution of Mulliken charges on iodine (purple), oxygen (red), and carbon (grey); benzyl groups are ommited for clarity. C) Calculated electrostatic potential map showing
On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals
Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80
- change from the D3 symmetry as observed in TTM to a C2 symmetry in the orbital distribution in the ground state. In spite of this break in symmetry to C2 – where all relevant transitions will be allowed – an enhancement of the respective absorption bands or an improvement in the ϕ has not been observed
- . However, one can observe a loss of the vibronic features in the fluorescence signal, indicating that the emission occurs from a CT state, in agreement with the DFT orbital distribution in the ground state geometry (see Figure 2e for different orbital location in HDMO and SOMO). Interestingly, successive
- -shaped distribution for ϕ. The bathochromic shift in λem has previously been described to result from the better stabilization of the CT excited state for stronger donors, and therefore a stabilization of the highest occupied molecular orbital (HOMO) when only considering the acceptor moiety (see also
Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts
Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76
- density distribution in the charge transfer (CT) excited state is facilitated by the presence of an electron-rich moiety and an electron-poor part in the same molecule, increasing the lifetime in the excited state. One of the representative classes of molecules demonstrating dual use in materials
- 5a (3.9 eV) as a consequence of the extended π conjugation compared with 4a and 6a (4.4 and 4.4 eV, respectively). Interestingly, compound 6a, which possesses the weakest sulfur-based acceptor, showed an inversion in the LUMO distribution, localizing it in the TBA core – this behavior of the named
Substituent effects in N-acetylated phenylazopyrazole photoswitches
Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66
- photostationary distribution (PSD) of the initial dark state could not be fully regenerated by photochemical means for all 33 PAPs (vide infra, ex-situ NMR measurements and thermal half-lifes). The recyclability of NH-PAPs was previously studied by Rustler et al. by altered irradiation with 365 and 420 or 455 nm
- 1H NMR spectrum. We compared these results to simply estimating the isomer distribution at the PSS (cf. Supporting Information File 1, section 3.1) from the UV–vis spectra and observed good agreement, meaning the results from UV–vis spectroscopy can be used for rough PSD estimation, due to good
- distribution of 98% Z by UV–vis and 96% Z by 1H NMR. EWGs, such as NAc-PAP-CF3, on the other hand, showed a lower PSD for the Z isomer of 83% by both UV–vis and 1H NMR spectroscopy. For NMe- and NAc-PAPs, we observed increased Z content to almost quantitative photoisomerization after 365 nm illumination for
4-(1-Methylamino)ethylidene-1,5-disubstituted pyrrolidine-2,3-diones: synthesis, anti-inflammatory effect and in silico approaches
Beilstein J. Org. Chem. 2025, 21, 817–829, doi:10.3762/bjoc.21.65
- interactions of these derivatives with the enzyme inducible nitric oxide synthase (iNOS), compared to dexamethasone used as a reference. Furthermore, ADMET (absorption, distribution, metabolism, excretion, and toxicity) predictions were performed to assess their drug-likeness and pharmacokinetic properties
- prediction of drug-like properties, in silico evaluations of ADMET (absorption, distribution, metabolism, excretion, and toxicity) characteristics of all potential drug candidates were conducted using the pkCSM online tool [28]. The resulting data are presented in Table 3. The absorption capability of the
- excellent when it falls within the range of 70% to 100% [29]. The data in Table 3 indicate that all studied compounds exhibit substantial absorption within the human intestines. In terms of distribution, key factors influencing the distribution of the compounds comprise the volume of distribution at steady
Photocatalyzed elaboration of antibody-based bioconjugates
Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49
- stability, and/or a shorter ADC half-life [14]. Optimization of the drug/antibody ratio (DAR) and payload distribution/location thus becomes significant for ideal ADC design. Given the complexity of biological macromolecules, there are inherent limitations in terms of the types of reactions that can be used
Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages
Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30
- transform the ligands can result in changes in cage topology distribution [204]. Self-assembly can also prescribe limitations on the symmetry of cages [36]. Notably, Clever has recently reported the first Pd2(ABCD) MOC [205], which may signal the possibility of using low-symmetry cavities [206][207][208
- ]. In this approach, symmetric topologies undergo a natural symmetry-lowering process when the restricted angles possible in a polymacrocycle environment lead to non-symmetric conformations in the pursuit of equal strain distribution. In the case of cage 3e, the mixed pyridyl/aryl system results in a
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