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Search for "control" in Full Text gives 1615 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Site-specific labelling of native peptides and proteins: chemical and enzymatic strategies
Beilstein J. Org. Chem. 2026, 22, 857–881, doi:10.3762/bjoc.22.67
- (19) was later adapted for modification of an asparagine (Asn) residue in the Fc domain of trastuzumab [61]. Rhodium has also been used in visible-light-triggered single-electron transfer (SET) reactions, enabling labelling under mild conditions with spatiotemporal control. Another strategy employs a
- these options are unsuitable, other solvent-exposed nucleophilic residues (e.g., methionine, histidine, tryptophan, tyrosine or arginine) can be targeted, although such reagents are often prepared in-house and may lack positional control. When high-affinity ligands or binders are available, affinity
The trans-influence in gold chemistry from a catalytic perspective
Beilstein J. Org. Chem. 2026, 22, 838–856, doi:10.3762/bjoc.22.66
- and reactivity in catalytic reactions [11][12][13][14][15][16][17][18][19]. There is however one important aspect of gold chemistry that is often under-appreciated: the strong control of reactions by the influence of a given ligand on another ligand in trans position, known as the trans-influence
- ]. However, there is apparently yet more versatility in the mechanisms of alkyne hydroauration and may operate for the [(P^N^C)AuH]+ cation 11. Nevado et al. found recently that 11 inserts both DMAD as well as terminal alkynes, to give Au(III) Z-vinyl complexes. Control experiments ruled out the involvement
Unsymmetrical sulfoxides with sterically hindered catechol fragment: synthesis, structure, electrochemical properties, and antiradical activity
Beilstein J. Org. Chem. 2026, 22, 828–837, doi:10.3762/bjoc.22.65
- states provides a powerful way to control organic molecules. Through the controlled conversion of thioethers to sulfoxides and sulfones [21], it is possible to tune their reactivity and biological properties. Indeed, compounds of this type possess pronounced neuroprotective properties [12][13][14
- establish a coherent framework for understanding the behavior of S-functionalized catechols. The ability to control the hydrogen-bonding propensity, redox potentials, and antioxidant activity by varying the substituent at sulfur and its oxidation level opens promising avenues for the design of biomimetic
Total synthesis of the capsular polysaccharide repeating unit towards the development of a glycoconjugate vaccine against Klebsiella pneumoniae ST512
Beilstein J. Org. Chem. 2026, 22, 821–827, doi:10.3762/bjoc.22.64
- . Keywords: glycoconjugate vaccines; glycosylation; oligosaccharides; selectivity control; total synthesis; Introduction The emergence and rapid spread of multidrug-resistant bacteria represent a critical threat to global health [1][2][3][4]. Among these pathogens, Klebsiella pneumoniae has surfaced as a
Synthesis and structural elucidation of a novel bis-spirooxindole from isatin and ethylenediamine
Beilstein J. Org. Chem. 2026, 22, 813–820, doi:10.3762/bjoc.22.63
- , these results show that the reaction of isatin with ethylenediamine can be directed toward different structural outcomes depending on stoichiometry. Simple control of stoichiometry governs whether the system evolves through a conventional diimine pathway or diverges toward the assembly of a highly
Synthetic study of vic-bromination of diarylacetylenes, easy purification and separation
Beilstein J. Org. Chem. 2026, 22, 795–802, doi:10.3762/bjoc.22.61
- , and solvent were examined (Table 1, entries 3–12). Because there was a possibility that a bromine radical was involved, TEMPO was used for the purpose of the ratio-control of E and Z isomers. TEMPO was found to have a tendency to suppress the generation of Z-2a in CH2Cl2 (Table 1, entries 6 and 8) [20
- make scale-up very easy. The E-selectivity was dropped in gram-scale synthesis, although the reason is unclear at present. For the understanding of the reaction mechanism, some control experiments were carried out. The reaction of 1a with NBS and n-Bu4NBr without FeBr3 gave trace amount of E-2a (Scheme
- . In addition, heptane played an important and critical role for purification and separation of the crude product. Scope and limitations for bromination of various diarylacetylenes together with the gram-scale synthesis and control experiments were also investigated. These results and findings can
Halogenated azobenzene acrylates: from efficient solution photoswitching to stable solid-state photochromic materials
Beilstein J. Org. Chem. 2026, 22, 782–794, doi:10.3762/bjoc.22.60
- liquid crystalline copolymeric pendants in macromolecules capable to change their reflectance with the temperature. This feature potentially enables their usage in temperature sensing labels [22]. These representative applications clearly demonstrate a wide interest in a light-driven control over the
Design, synthesis, and biological evaluation of FXR/ASK1 dual-target modulators
Beilstein J. Org. Chem. 2026, 22, 771–781, doi:10.3762/bjoc.22.59
- accumulation. The presence of lipid droplets was confirmed through direct visualization using Oil Red O staining (Figure 3A). The combined treatment with GW4064 and GS4997 exerted a stronger lipolytic effect than either positive control alone, and its activity was comparable to that of Z8. As anticipated, both
- -luciferase reporter assay in CHO cells cultured for 24 hours following addition of GW4064 and test compounds. Compared to the control group, **p < 0.01 and ns indicate no significant difference, with control; DMSO serving as the control group. ASK1 inhibition of all compounds. Results of the ADP-Glo™ kinase
- assay after treating ASK1 kinase with selonsertib and test compounds for 1 hour. Compared to the control group: **p < 0.01 and ns indicates no significant difference; control: DMSO control group. Effects of Z8 and Z30 on OA-induced lipid accumulation in HepG2 cells. Cells were treated with GW4064
Synthesis and biological evaluation of new brassinosteroid analogs with C-22 benzoate function
Beilstein J. Org. Chem. 2026, 22, 753–762, doi:10.3762/bjoc.22.57
- -carbonyl or 3β-hydroxy function in this ring. Additionally, the accumulation of the dephosphorylated form of the BES1 protein, which is part of the BRs signaling pathway and control their activity, has been evaluated as well. The results are analyzed in terms of BR analog’s structure and compared with
- –22 have been measured at different concentrations (Table S1, Supporting Information File 1). The activities, calculated as the difference of bending angles obtained for the analogs and the negative control, and normalized respect to the latter, are shown in Table 1. The data show that the plant
- response to exogenous application of brassinolide (1) (positive control) or synthetic BR analogs strongly depends on the chemical structure of the BRs. For example, the activity increases with increasing concentration of 1, and analogs 18, 20 and 22, whereas the opposite effect is obtained by applying
Rongalite addition to dienones: diastereoselectivity in cyclic sulfone synthesis; stereochemical rationalization and prospects as a general conjugate nucleophile
Beilstein J. Org. Chem. 2026, 22, 742–752, doi:10.3762/bjoc.22.56
- sulfide oxidation. In that early work, the stereochemical analysis was dependent on conformational analysis and comparison of coupling constants in the 1H NMR spectra. Experiments discussed in our inital report confirmed that the reaction proceeded under kinetic control [21]. Closer examination of the
- 20, in contrast to the successful reaction with phorone (21) to give 22 [43] (Scheme 4). As a control reaction, we conducted the addition of commercially available sodium p-toluenesulfinate to mesityl oxide under analogous conditions, which produced known sulfone 23 [44] in high yield. This
- selectivity for formation of 26 at room temperature suggests a profile that is more reflective of kinetic control, such that we can argue that 26 forms between 1 and 2 orders of magnitude more rapidly than cyclic products 1a and 1b, such that they are not detectable in the 1H NMR spectra. Further anecdotal
Synthesis of heterocycles based on azomethine ylides from α-amino acids (or amines) and carbonyl compounds
Beilstein J. Org. Chem. 2026, 22, 705–741, doi:10.3762/bjoc.22.55
- chiral metal complexes of Ag(I), Cu(I/II), Zn(II), Ni(II) with ligands of the Segphos, Fesulfos, or Biphamphos type [12][13][14][15]. Such catalytic systems control the enantioselectivity of cycloaddition and allow the preparation of enantioenriched pyrrolidines containing several stereocenters in high
- reactions is due to charge and orbital control [1]. Continuing the study of 1,3-dipolar cycloaddition reactions of ninhydrin-based azomethine ylides with cyclopropene dipolarophiles, our research group examined the interaction of cyclopropenes with azomethine ylides from ninhydrin and acyclic amino acids
- of regio- and endo-stereoselective spiro- and dispiro-derivatives of azabicyclo[3.2.0]heptane 151 and 152 is due to orbital control along with second orbital interactions [101]. In 2015, Wu and co-workers described a multicomponent synthesis of various spiro[indole-pyrrolizine], spiro[indole
Anti-invasive and cytotoxic evaluation of a (+)-pinoresinol-based semisynthetic library against glioblastoma
Beilstein J. Org. Chem. 2026, 22, 691–704, doi:10.3762/bjoc.22.54
- ranging from 1.56−25 µM with a reduction of up to 65% invasion in comparison to the control [22]. Owing to the interesting biological activity of 2 and its moderate abundance in the seeds of E. maculata, we decided to generate five semisynthetic analogues 3−7 (Figure 2) and evaluate these compounds for in
- concentration of 1 µM with a treatment time of 5 h, and only (+)-4,4'-di(3,3-dimethylbutanoyl)pinoresinol (6) reduced the invasion of the cells (by ≈50%) when compared to the vehicle control. None of the other compounds tested reduced the invasive capability of the cells (Figure 7A). Based on the results of the
- to achieve a cell number of 15,000 cells per mL. Cells were seeded in a 96-well plate (Costar #3596) in triplicates at 100 µL/well (i.e., 1,500 cells/well) and incubated for 24 h at 37 °C and 5% CO2. Vehicle control (positive control) was the solvent DMSO, in which all compounds were dissolved, plus
Harnessing light energy with molecules
Beilstein J. Org. Chem. 2026, 22, 680–682, doi:10.3762/bjoc.22.52
- larger systems or smart materials [9]. Photoswitches are, for example, relevant functional units for information storage or molecular electronic devices. They can serve to control ion transport, molecular assembly/disassembly, or the relative movement of units within molecular machines. In a Review
Photoorganocatalytic trifluoromethylation of (het)arenes in green conditions
Beilstein J. Org. Chem. 2026, 22, 662–671, doi:10.3762/bjoc.22.50
- protocol [16]. Finally, a series of control experiments was carried out. No product formation was observed in the absence of catalyst (Table 1, entry 11), in the dark (entry 12), in the presence of TEMPO (entry 13), or under an air atmosphere (entry 14). Based on the optimization studies, the standard
Advantages of PROTACs in achieving selective degradation of homologous protein families
Beilstein J. Org. Chem. 2026, 22, 628–661, doi:10.3762/bjoc.22.49
- nanomolar range, the DC50 values for BRD2/3 were both well above 100 nM. Due to the conformational constraint imposed by the macrocyclic linker, compound 37 did not exhibit a "hook effect" even at concentrations as high as 60 μM, whereas the linear control molecule 35 showed a decline in activity at 30 μM
- life to control the disease's further deterioration. Based on these circumstances, if the PROTAC technology can be used to target the degradation of the BCR-ABL protein, it may maintain a good therapeutic effect for CML and reduce the time for CML patients to take medicine. Therefore, to achieve good
Regioselective approach to 5-arylsulfonylisoxazoles and their antimicrobial activity
Beilstein J. Org. Chem. 2026, 22, 592–602, doi:10.3762/bjoc.22.45
- nitrile oxides in cycloaddition reactions, complete control of regioselectivity without metal catalysis is not always achievable. Another problem with this method is the tendency of nitrile oxides to form dimers (furoxanes), which entails a decrease in the yield of isoxazoles. Due to dimerization, nitrile
- stalled replication forks and impaired DNA synthesis. This disruption triggers cell cycle arrest, which can ultimately result in apoptosis and cell death. However, all tested samples 3h, 3g and 4b exhibited no significant difference compared to the control lane (Figure 3B), indicating that they did not
- passage of the strands through the break and subsequent ligation, leading to DNA relaxation. DNA gyrase performs a similar function but without the requirement for ATP hydrolysis. The antibiotic ciprofloxacin (Cip), which inhibits DNA gyrase, was used as the positive control. In this test, all tested
Continuous-flow carbonyl hydrogenation under subatmospheric to atmospheric hydrogen pressure enabled by robust heterogeneous Pt–Fe catalysts
Beilstein J. Org. Chem. 2026, 22, 575–582, doi:10.3762/bjoc.22.43
- ][10][11][12]. In this context, advanced technologies represented by the precise control of the bimetallic structure of a heterogeneous catalyst, mechanochemical hydrogenation, and continuous-flow methods using packed-bed reactors greatly contributed to advancing this transformation [9][11][12][13
- column with Celite, with the molar amount of Pt adjusted to 0.006 mmol within the column. Both the solution of acetophenone (1a) in ethyl acetate (EtOAc) and hydrogen gas were simultaneously passed through the catalyst-packed column without backpressure control at room temperature (Scheme 1). The powder
Kinetic resolution of racemic planar-chiral vinylcymantrenes by molybdenum-catalyzed asymmetric metathesis dimerization
Beilstein J. Org. Chem. 2026, 22, 568–574, doi:10.3762/bjoc.22.42
- ], reveals that the molybdenum-catalyzed asymmetric metathesis reactions are powerful tools to control planar chirality in various transition-metal complexes. ORTEP drawing of the X-ray structure of (S,S)-(–)-2b with atom numbering (thermal ellipsoids set at the 30% probability level). Selected bond lengths
Molecular tweezer–peptide conjugates disrupt the protein–protein interaction between survivin and histone H3 essential in mitosis
Beilstein J. Org. Chem. 2026, 22, 557–567, doi:10.3762/bjoc.22.41
- centromere protein), and the kinase Aurora B. During mitosis, Aurora B phosphorylates important components of the kinetochore and thus exerts control over key events of the whole process. The other three proteins localize the CPC during the different mitotic phases [4]. Survivin, borealin and INCENP are
Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B
Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39
- mixture of melifolione A (1) and B (2) (181 mg, 0.6 mmol, ratio ca. 10:1) was dissolved in 16 mL acetonitrile. After addition of water (4 mL), the solution was cooled on ice and iodosobenzene diacetate (212 mg, 0.66 mmol) was added under stirring. The solution turned yellow and later orange. TLC control
Recent advances in the stereoselective synthesis of distal biaxially chiral molecules
Beilstein J. Org. Chem. 2026, 22, 461–479, doi:10.3762/bjoc.22.34
- often difficult to control [37], particularly for remote biaxial systems (1,3-biaxial and beyond), where diastereoselectivity and enantioselectivity are challenging to regulate. Various multiaxial chiral natural products with high biological activity exist in nature [28], and in artificial synthesis
- construction of remote biaxial chiral molecules. These strategies enable precise control over the stereochemistry of multiple axes in a single reaction, allowing efficient formation of distal biaxial chiral scaffolds while maintaining excellent enantio- and diastereoselectivity. Recent studies have
- exceeding 60%. Sequential construction of distal biaxial chirality via stepwise axis formation Although one-step catalytic methods enable the efficient and direct construction of remote biaxially chiral molecules, the spatial interactions between multiple chiral axes can make it challenging to fully control
Synthesis and anti-cancer activity of naphthalimide–organylselanyl conjugates
Beilstein J. Org. Chem. 2026, 22, 416–435, doi:10.3762/bjoc.22.29
- viability, one-way ANOVA was performed using GraphPad Prism software [64], as shown in Figure 8, comparing the control group to each test concentration of the compound 7 (Figure 8a) and compound 8 (Figure 8b). The results showed no significant differences between the control and 6.12 µM concentrations
- dissolved in DMSO and administered at concentrations of 6.27, 12.5, 25, 50, 100, and 200 μM, along with a control group. All treatments were performed in triplicate to minimise analytical and experimental errors. Cells were cultured for a further 24 hours under the same conditions following chemical
- concentration (µM) vs cell viability (%) of compounds of a) 7 and b) 8. Significant difference of control vs concentration: a) compound 7, b) compound 8. 2D and 3D binding interaction of active (1M17) EGFR tyrosine kinase and synthesised compounds: a) 7 and b) 8, c) 2D interaction of crystal structure 1M17 and
Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities
Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28
- atoms and/or in the aromatic p-positions to them, which form respectively the narrow (lower) and wide (upper) rims of the calixarene macrocycle when it possesses a cone shape. Both the core functionalization and shape control strategies are most developed for calix[4]arene cores, and that is exactly why
Design, synthesis and biological evaluation of 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines as selective cytotoxic agents against HeLa cells
Beilstein J. Org. Chem. 2026, 22, 390–398, doi:10.3762/bjoc.22.27
- and 1% penicillin/streptomycin mixture, for obtaining concentrations ranging from 0.1 to 1000 µM. All experiments were carried out in triplicate, and the data are presented as mean ± standard deviation. Paclitaxel (PTX) was used as positive control. Compounds-treated and untreated cells were incubated
Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)
Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25
- is often hindered by chemoselectivity and regioselective control. Here, we exploit the differential redox potentials of two coupling partners as a key player to achieve a chemo- and regioselective electrosynthetic access to a new family of unsymmetrical oxaza[8]helicenes. A controlled anodic sequence
- electrochemical arenol activations reported by Waldvogel and co-workers [46]. Subsequent intramolecular dehydrative cyclization furnishes the desired oxaza[8]helicenes 5. The oxidation-potential gap between 3 and 4 and the reactivity of Int-I thus provides a handle to control chemo- and regioselectivity
- designed coupling partners to control both chemo- and regioselectivity. A finely tuned anodic sequence enables selective oxidative hetero-coupling followed by dehydrative cyclization, delivering extended [8]helical scaffolds efficiently under mild, oxidant-free conditions. Combined experimental and DFT
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