Search results
Search for "control" in Full Text gives 1522 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
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
A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001
Beilstein J. Org. Chem. 2024, 20, 497–503, doi:10.3762/bjoc.20.44
- University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan Graduate School of Infection Control Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan Faculty of Agriculture, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan 10.3762/bjoc.20.44 Abstract
Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination
Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43
- were shown to proceed with anti-selectivity and that was used as support for gold catalysis [15], but mechanism studies of triflic acid catalysis showed a preference for anti-selectivity as well [31]. Despite similarities, control studies indicate meaningful differences in catalytic activity between
- are apparent from others’ HOTf control studies. First, a “simple” Bronsted acid-catalyzed mechanism that is possible with sulfonamides (i.e., with HOTf catalyst) is not operating here. Second, more complex acid-mediated rearrangements observed with ureas (authors propose a hetero-ene mechanism with
Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793
Beilstein J. Org. Chem. 2024, 20, 470–478, doi:10.3762/bjoc.20.42
- , the bacteria were cultivated in the LB broth medium at 37 °C for the human pathogenic bacteria, while the temperature was 28 °C for the aquatic pathogens, and they were prepared at a concentration of 1.5 × 108 CFU/mL. Tested compounds and positive control (chloramphenicol) were dissolved in DMSO to
- give a stock solution with DMSO as a negative control. Then, 95 μL of thus prepared bacteria and 5 μL of the above tested compounds or chloramphenicol (with the final concentration of 0.5, 1, 2, 4, 8, 16, 32, 64 μg/mL) were added into the 96-well plates and cultivated at 37 °C or 28 °C for 24 h
Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles
Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36
- reduction in the concentration of these cytokines, as well as, increased intestinal permeability and improved expression of tight junction proteins that control the polarity of cells when using DIM in Caco-2 human cells [3]. BIMs have also been linked with the therapy of various cancers with one of their
- ]. DIM has also been found to initiate the expression of tumor suppressing proteins (ATM, p21, p27kip), which control cell growth and protect cells against ionizing radiation, which can cause DNA mutations, decreasing the overall risk of breast cancer [1][5][6]. The cytotoxicity of DIM and BIMs in
Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters
Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35
- of parameters with which to control reactivity. In this perspective, we provide an overview of the different mechanisms for radical reactions involving NHPI esters, with an emphasis on recent applications in radical additions, cyclizations and decarboxylative cross-coupling reactions. Within these
Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin
Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31
- measure its ability to agglutinate erythrocytes, compared to other lectins, such as AAL, ConA, RCA1, and SNA-I, as well as a PBS negative control. (b, c) Thermal shift assay. After comparing the melting curves of CMA1 produced in mammalian cells (CHO-S) and bacteria (E. coli), we incubated the bacterially
Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments
Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30
- conversion in situ, triggered by thermal activation, photoirradiation or redox control. Beside well-established reactions involving the elimination of carbon-based small molecules, i.e., retro-Diels–Alder and decarbonylation processes, the late-stage extrusion of chalcogen fragments has emerged as a highly
- sulfide (Na2S). Since the nature of the imide substituents is very important to control the solid state molecular arrangement, the same authors revised their initial synthetic route to allow for a late stage introduction of the imide groups, thus leading to the preparation of a series of variously
- , since previously reported bare and aryl-substituted dinaphthooxepines exhibited reversible reduction [67]. In summary, owing to the heteroatom-dependent behavior of heteropines, it is possible to control the structure of the target compound: on the one hand, thermally stable chalcogen-doped π-CPCs with
Photochromic derivatives of indigo: historical overview of development, challenges and applications
Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23
- appealing due to the possibility of performing the switching within the biooptical transparency window (650–900 nm) [87]. Additionally, significant structural differences (180° flip) between the E- and Z-isomers of the compounds provide a prerequisite of light-controllable geometry control in biomolecular
- thermal half-lives of the photoisomers range from seconds to days. Detailed photophysical and photochemical studies have provided insight into the photoswitching mechanisms of indigo derivatives and enabled control of their photochemical properties through targeted design of the molecular structure. The
Copper-catalyzed multicomponent reaction of β-trifluoromethyl β-diazo esters enabling the synthesis of β-trifluoromethyl N,N-diacyl-β-amino esters
Beilstein J. Org. Chem. 2024, 20, 212–219, doi:10.3762/bjoc.20.21
- reaction, several control experiments were performed. First, the reaction was conducted under the optimized conditions without the addition of CuI. The conversion of the starting substrates to the desired product 4a was decreased and only 14% yield of 4a was obtained (Scheme 3a). However, as shown in entry
- . Control experiments. Proposed reaction mechanism. Scale-up synthesis. Optimization of reaction conditions.a Supporting Information Supporting Information File 8: Experimental details and spectral data. Funding We gratefully acknowledge the financial support from the National Natural Science Foundation
Comparison of glycosyl donors: a supramer approach
Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18
- ), stereoselectivity (α/β) (b), and reaction time (c). See Scheme 1 for the structures of the compounds. The reaction was quenched after complete consumption of glycosyl donors (TLC control). The crude product was treated with MeONa in MeOH in order to remove all O-acyl groups and then with Ac2O in Py to install O
Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides
Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14
- , the amount of alkyl bromide and temperature affected the reaction significantly (Table 1, entries 20 and 21). Finally, control experiments demonstrated that copper promoted the transformation and a base was the indispensable factor for the reaction (Table 1, entries 22–24). Therefore, a facile and
- gram-scale preparation was carried out using 1a, that afforded the desired product in 96% yield (Scheme 4, reaction 4). To gain more insight into the reaction mechanism, several control experiments were carried out (Scheme 5). On one hand, the failure of substrates 10–15 to participate in the reaction
- . Reaction conditions: 1a (0.2 mmol), 2 (0.8 mmol), Cu(OAc)2·H2O (20 mol %), K2CO3 (0.2 mmol), DMSO (1.0 mL), stirred under air at 100 ºC for 12 h. Isolated yield. Further substrate scope investigations and gram-scale application. Control experiments and proposed mechanism. Optimization of the reaction
Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles
Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12
- -reductive quench process (Table 1). The indole substrate 1a was chosen as a model substrate, and the reaction mixture was irradiated under 450 nm visible light for 12 h, resulting in the formation of the desired product 3a, albeit in a relatively low yield (Table 1, entry 1). Control experiments revealed
- short, this reaction tolerates different substituents on the indole ring, including electron-donating and electron-withdrawing groups, providing access to a diverse array of dihydropyrido[1,2-a]indolone derivatives. To gain insight into the reaction process, we performed a series of control experiments
Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions
Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11
- -binder and resembling intercalators can be directly generated upon irradiation of styrylazines under aerobic conditions, even in the presence of DNA, which provides local and temporal control of the DNA-binding event (Scheme 1) [14]. Specifically, the styrylpyridine, which does not bind to DNA, can be
- comparison with control experiments without photosensitizer. In general, a photoinduced DNA damage by the quinolizinium 3f was observed, whose extent increased with increasing irradiation time and with increasing concentration of 3f. Thus, after 2 min of irradiation with fixed concentration (c = 2.5 × 10−5 M
- min of irradiation (Table 2C). To investigate the mechanism of the DNA cleavage, commonly employed control experiments [46][77] were performed exemplarily with ligand 3f (Table 3 and Supporting Information File 1, Figure S16). To assess the influence of oxygen, the DNA–ligand mixture was irradiated
Other Beilstein-Institut Open Science Activities
