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Search for "control" in Full Text gives 1585 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets
Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113
- ; separation; Introduction Single-walled carbon nanotubes (SWNTs) have been attracting considerable interest due to their unique physical and chemical properties. For their further applications, structural control of SWNTs is of great importance, since the electronic and optical properties significantly
The Ugi4CR as effective tool to access promising anticancer isatin-based α-acetamide carboxamide oxindole hybrids
Beilstein J. Org. Chem. 2024, 20, 1213–1220, doi:10.3762/bjoc.20.104
- adducts, with stereochemistry control [4][5]. Unquestionable potential of application in the pharmaceutical industry is recognizable by the number of APIs obtained by this reaction approach [6][7]. The oxindole framework is a privileged unit, recognized massively by its extensive biological applications
- . The half-maximal growth inhibitory concentration (GI50) values after 48 hours of exposure were calculated for each compound (Table S1, Supporting Information File 1). The standard anticancer drug cisplatin (CDDP) was used as positive control. The results are viewed as GI50 range plot (Figure 3). The
Introduction of peripheral nitrogen atoms to cyclo-meta-phenylenes
Beilstein J. Org. Chem. 2024, 20, 1207–1212, doi:10.3762/bjoc.20.103
- , including pyridinic, pyrrolic and graphitic nitrogen, play important roles in determining the properties and functions (Figure 1a), top-down, physical production does not enable control of the doped structures with atomic precision. The bottom-up chemical syntheses of molecular nanocarbons have thus become
Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis
Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102
- , compounds 4 and 5 were detected, and notably, a small amount of 10 was also observed (Figure 1, trace e). As expected, in the negative control reactions, 8 was spontaneously oxidized to 1 without any enzyme added, and no 4, 5, or 10 was observed; 1 remained unchanged in the reaction mixture with Fre, NADH
Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction
Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99
- best of our knowledge, this study is unique in the sense that there are no previous reports on the use of bismuth triflate as catalyst for a classic Nazarov reaction. There is also no reported precedent for the preparation of indanones with different substitution patterns through simple control of the
Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer
Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98
- condensation with ketones, yielding an α,β-unsaturated compound, which was hydrogenated by the manganese hydride species, resulting in the final alkylated product (Scheme 25). A set of deuterium labelling tests and additional control studies determined that the alcohol dehydrogenation was aided by an
- control studies with Hg and TEMPO indicated that the reactions were homogeneous and did not proceed through a radical pathway. Synthesis of heterocycles via C–C and C–N bond formation In 2016, Beller and co-workers reported an intramolecular cyclization using 2-(2-aminophenyl)ethanol for the synthesis of
Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A
Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96
- observed that the β-anomer of charge-neutral nucleoside Vb exhibited similar inhibition of hCDA as the control dZ (IIc). Presence of a negative charge in nucleoside Va led to lack of inhibition at pH 7.4. We assumed that protonation of Va might result in some inhibition of hCDA. However, the pKa of Va was
- instead of the target dC in the preferred DNA motif TCA of A3A and A3B on linear DNA. The previously described A3 inhibitor 5'-TTTTFdZAT was used as a control [54][56][57]. The engineered A3A mimic was used in our initial experiments. This is a well-characterised and active derivative of the CTD of A3B
- measured using the NMR-based assay (Figure 2). The results revealed that both anomers of Va do not inhibit engineered A3A mimic even at elevated concentration in comparison to a control ODN containing FdZ (IId) at pH 6.0. It is very likely that a negative charge in nucleobase Va prevents binding to the
Light on the sustainable preparation of aryl-cored dibromides
Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95
- halogenation. Of the two alternatives, the latter is more advantageous, due to three favourable features [65][66]: (i) Optimal control as each ring halogenation inhibits further ring halogenations, (ii) ring halogenation do not negatively affect benzylic bromination, and (iii) aryl bromides often display
Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries
Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93
- propensity of the Id and IId couples towards the undesired thermal degradation product. This clearly indicates that the unit used for elongation of the unsaturated bridge is crucial to control the reversibility of the photoswitching cycle or the stability of the photoproduct against undesired thermal
Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives
Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92
- building blocks 1,2-aceanthrylenedione and 12, as detailed in Table S1 (Supporting Information File 1). However, an inseparable unknown impurity was observed along with the desired product 3a in all cases when analyzed by 1H NMR. Under strict temperature and time control (80 °C for 72 hours) using 2.5
Novel analogues of a nonnucleoside SARS-CoV-2 RdRp inhibitor as potential antivirotics
Beilstein J. Org. Chem. 2024, 20, 1029–1036, doi:10.3762/bjoc.20.91
- ) Graphical representation of the inhibitory activity of selected compounds evaluated from the gels obtained in the primer extension assay. The percentage of inhibition (against control) was plotted against the logarithm of the concentration of compounds. The results were fitted to sigmoidal dose–response
A Diels–Alder probe for discovery of natural products containing furan moieties
Beilstein J. Org. Chem. 2024, 20, 1001–1010, doi:10.3762/bjoc.20.88
- . coelicolor W75, a strain known to produce the MMF molecules was examined, and S. coelicolor M145, a control that does not contain the biosynthetic machinery necessary to produce MMFs but is otherwise genetically identical to S. coelicolor W75. Controls containing just the cell supernatant, as well as
- reactions of the cell supernatant with the maleimide probe, were run on the UPLC-MS after reacting for 18 h. As expected, samples from S. coelicolor M145 did not show any MMFs present in either the control sample or the probe-treated sample, even after concentrating the sample 25-fold. Compound 5 and its
- present. C. Representative UV trace of the reaction products; probe 6, MMF5 (5), and MMF5 cycloadduct 24. All reactions were performed a minimum of three times with similar results being observed in all three replicates. A. The UV trace (254 nm) for M145 control, M145 + probe 6, W75 control, and W75
Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles
Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84
- elimination of methanol favored by the evaporation process. The instability of hemiaminal ethers was previously described in literature [19] during work-up. We then found that careful control of the drying conditions, thus avoiding complete drying of the crude mixture prevents degradation of the Heck products
Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins
Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76
- -positions to the ester group were all well-tolerated (Table 3). To gain further insights into the reaction mechanism, we conducted control experiments. Given the utility of diaryliodonium salts in radical chemistry, we introduced 2 equivalents of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) or 2 equivalents
Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria
Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75
- further characterization. The H73A Vs NnlA variant, previously shown to lack NNG degradation activity, was used as a negative control [21]. E. coli transformants containing the expression vectors were incubated at 37 °C overnight in diluted lysogeny broth (LB) containing NNG and IPTG, the latter component
Discovery and biosynthesis of bacterial drimane-type sesquiterpenoids from Streptomyces clavuligerus
Beilstein J. Org. Chem. 2024, 20, 815–822, doi:10.3762/bjoc.20.73
- DL10092 displayed a new peak in its HPLC profile compared to the control of wild-type E. coli BL21 (DE3) (see Figure S9 in Supporting Information File 1). The fermented product appeared as an alcohol, likely due to the activity of the endogenous hydrolase in E. coli. The retention time of the new peak was
- Streptomyces strains, with S. avermitilis SUKA22 harboring the empty pSET152 vector as the control. (d) HPLC analysis of metabolites co-expressed with drimenyl diphosphate synthases (CavC), Nudix hydrolase (CavB), and one of the P450s, either CavA (DL10089), CavE (DL10090), or CavG (DL10091). Substrate scope
Advancements in hydrochlorination of alkenes
Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72
- dependence (higher temperature results in higher rates). In 1966, Brown and co-worker reported a specialized apparatus enabling the monitoring and control of HCl gas consumption during the reaction [40]. They observed full conversion of α-methylstyrene (11) within minutes and suggested that the
- hydrochlorination is operating within the rate of diffusion control (Figure 4). They also noted that the reaction was significantly slower at room temperature when compared to reactions carried out at 0 °C. However, reaction rates were exclusively reported at 0 and −45 °C, indicating an inverse temperature
- ). Stereoselective hydrochlorination of hexahydro-1H-indene (33). Hydrochlorination of cycloheptene (61). Hydrochlorination of 1-octene (63). Influence of the HCl gas pressure on the reaction yield. Control reactions for the hydrochlorination reaction of alkene 106. Optimization reactions for the hydrochlorination
Methodology for awakening the potential secondary metabolic capacity in actinomycetes
Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69
- components are also present in actinomycetes, and a regulatory system for secondary metabolism has been reported [57]. For example, Świątek et al. proposed that Rok7B7, a transcriptional regulator, acts as the central control protein for carbon control in Streptomyces [58][59]. Rok7B7 also controls the
Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis
Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67
- glutamate decarboxylase, and incubated with BaeJ-KS2. Substrate binding was demonstrated through 13C NMR analysis of the products against the background of various control experiments. Keywords: bacillaene; biosynthesis; enzyme mechanisms; isotopes; trans-AT polyketide synthases; Introduction Polyketides
SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes
Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64
- the reasons why no reaction occurred. Next, we turned our attention to the temperature of the reaction, a factor rarely explored in photocatalyzed reaction due to the lack of available set-ups allowing an efficient light irradiation in addition to a proper temperature control. In our case, since the
- was used with alkyl-substituted alkynyl-BF3K, probably due to the poor solubilization of the catalyst. Finally, control experiments in the absence of photocatalyst or light only afforded traces of product (Table 8, entry 7). The successful scope of the reaction was already described in our previous
Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines
Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59
- temperature (rt), the desired unsaturated ε-AA derivative 4a was obtained in 75% isolated yield (Table 1, entry 1). Isolation and NMR analysis demonstrated that this model reaction provided amino acid 4a with good E-selectivity and excellent regioselectivity (E/Z = 91:9, 1,4-/1,2-addition >20:1). Control
- next turned to evaluate the scope of 1,3-dienes. Although the regioselectivity control of allylic substitution can be attributed to many factors, it is agreed that steric hindrance generally is the primary factor affecting the regioselectivity of nucleophilic attack [54][55][56][57]. Monoalkyl
- ) Radical trapping experiments with TEMPO. b) Exclusion of possible intermediate. c) Subjecting the product Z-6i to the standard conditions. d) The control reaction with HPd(PPh3)2Cl. e) UV–visible absorption analysis. Proposed mechanisms for the carboamination of 1,3-dienes or allenes with diazo esters and
Chemical and biosynthetic potential of Penicillium shentong XL-F41
Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52
- -well plates were incubated at 37 °C for 18 hours, with 1% DMSO serving as the negative control. After incubation, the OD600 of the bacterial cultures was measured using a Microplate Reader. HPLC analysis of small-scale fermentation with different media. More details of media, XISR I and XISR III can be
Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides
Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48
- ], drospirenone (exhibits high affinity to progesterone receptors and is used as a birth control medication) [26][27], griseofulvin (an antifungal agent used to treat fungal infections of the fingernails and toes) [28], as well as oliceridine (a selective G protein-biased μ-opioid receptor agonist used for
Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors
Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46
- Jens Frackenpohl David M. Barber Guido Bojack Birgit Bollenbach-Wahl Ralf Braun Rahel Getachew Sabine Hohmann Kwang-Yoon Ko Karoline Kurowski Bernd Laber Rebecca L. Mattison Thomas Muller Anna M. Reingruber Dirk Schmutzler Andrea Svejda Research & Development, Weed Control, Crop Science Division
- (pentafluorophenyl)borane as a strong Lewis acid. Remarkably, greenhouse trials showed that some of the target compounds outlined herein display promising control of grass weed species in preemergence application, combined with a dose response window that enables partial selectivity in certain crops. Keywords: 2,3
- herbicides remain the most effective solution for weed control due to the associated efficiency and simplicity, they face multiple challenges, such as the emergence and growth of resistant weed populations. It is therefore essential that crop protection research acts rapidly to provide farmers with new
Switchable molecular tweezers: design and applications
Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45
- because of the simple design and high potential for many applications. The drastic conformational change induced by the opening and closing of the tweezers attracted us as a straightforward method to control various properties. This change creates a cavity for guest binding, but tweezers have even greater
- proximity, either by direct interaction or via a small intercalating molecule. Therefore, switchable molecular tweezers can be considered a prototype of a mechanical molecular device capable of allosteric regulation and dual control through switching and guest binding. While the primary application of
- et al. exploited the same scaffold to control the physical properties of materials. They incorporated planar terpyridine-alkyne Pt complexes as functional units and studied the intercalation of a Pt-complex guest in order to obtain Pt–Pt interactions in solution [23]. In the native state of 3, both
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