Search results
Search for "monitoring" in Full Text gives 386 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices
Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122
- solution over a period of 2 h, while monitoring the reaction by TLC (CH2Cl2/hexane 1:4). Then, the reaction was quenched with water (100 mL) and the mixture extracted with CH2Cl2 (50 mL × 3). The combined organic layer was washed with water, brine, dried over anhydrous Na2SO4, filtered, and concentrated
Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity
Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121
- PC61BM (VI, Figure 7) and that of the 12 derivatives with 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene, VII, Figure 7), since we have previously found that these dopant class/SC combinations often react on a timescale suitable for monitoring using UV–vis–NIR spectroscopy (1H derivatives do
Lewis acid-promoted direct synthesis of isoxazole derivatives
Beilstein J. Org. Chem. 2023, 19, 1562–1567, doi:10.3762/bjoc.19.113
- TLC monitoring. Upon completion, the solution was cooled to room temperature and the solvent was removed under vacuum directly. The crude residue was purified by column chromatography on silica gel (ethyl acetate/petroleum ether 40:1) to afford product 3a with 87% yield. Natural products and drug
Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction
Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91
- structures of the obtained dispiro compounds 3a–m were fully characterized by IR, HRMS, 1H and 13C NMR spectroscopy. Because of the three chiral carbon atoms in the product, several diastereomers might be formed in the reaction. However, TLC monitoring and 1H NMR spectra of the crude products clearly
Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines
Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80
- NMR reaction monitoring showed that compound 1d under conditions of excess of KOH in methanol undergoes alkaline hydrolysis along with transesterification of the ester group to give the ring-opened form 6d (Scheme 4), the maximum concentration of which was observed approximately 30 minutes after the
The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads
Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79
- methods (the UV–vis absorption and fluorescence emission spectra, etc.), and herein we also demonstrated that transient absorption spectra (femtosecond/nanosecond transient absorption spectra) can be used to study the TADF properties, for instance by monitoring the dark states. In addition, we show that
First synthesis of acylated nitrocyclopropanes
Beilstein J. Org. Chem. 2023, 19, 892–900, doi:10.3762/bjoc.19.67
- (C), 125.6 (C), 127.3 (C), 128.4 (CH), 128.7 (CH), 128.9 (CH), 129.2 (CH), 131.2 (CH), 139.3 (C), 154.9 (C), 162.5 (C), Two signals were lacked presumably due to overlapping. IR (ATR): 1359, 1593, 1730 cm−1; HRESIMS–TOF (m/z): [M + Na]+ calcd for C19H19NO6, 374.0999; found, 374.1000. Monitoring the
Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors
Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65
- diastereoselectivity. The reaction was also carried out using 3.3 equiv of the electrophile added in one portion. The full conversion of the starting acylimidazole 1a was observed after 30 minutes (TLC monitoring), however, the diastereoselectivity remained low (Table 1, entry 6). Neither an increase nor decrease of
Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment
Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58
- the model compound 10a in DMSO-d6 solution using 1H NMR monitoring (Figure 1). Thus, the NMR spectrum recorded after UV irradiation (365 nm) for 24 h contained signals of protons of two products along with signals of the starting pyrimidine 10a (Figure 1B). The complete conversion of the starting
- sigmatropic shift step [23][24][25][30]. However, in all cases we failed to detect these intermediates even in the reaction mixture using NMR monitoring. However, in the present communication, for the first time, we managed to isolate and fully characterize a product of this class. Previously, we have shown
- the preparation of polycyclic benzo[h]pyrano[2,3-f]quinazolines was elaborated. The method comprises the preliminary photoreaction of the starting compounds and the conclusive dehydration under the action of CDI. 1H NMR monitoring of the photoreaction of compound 10a under UV irradiation (365 nm) in
Construction of hexabenzocoronene-based chiral nanographenes
Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54
- this helical aza-NG was achieved by introducing a chiral auxiliary reagent at the nitrogen site [40], and the racemization barrier of one enantiomer was measured as 26.2 kcal/mol by monitoring the changes of CD spectra at 60–80 °C. The synthesis started with the Diels−Alder reaction of 5H-dibenzo[b,f
Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles
Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46
- yields of the corresponding products 3 and the general course of the reaction. However, the structure of the alcohols 2a–c had an effect on the studied reaction. Reactions with isopropyl alcohol 2b required longer reaction times (UPLC–UV–MS monitoring). This phenomenon could be due to the steric factors
- isolated yield of compound 3aa was 50%. However, under such conditions, a longer reaction time was required (about 3 h, UPLC–UV–MS monitoring). Then, to expand the scope of the developed approach to PBTAs, we examined several more groups of nucleophilic reagents. For these purposes, we carried out a test
- corresponding products 12 and the general course of the reaction. However, the reaction with o-aminoacetanilide 11d required shorter reaction times (visual monitoring of the reaction mixture color change and the precipitate formation) and afforded products 12 with higher isolated yields, which could probably be
Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview
Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35
- 30% yield. A careful monitoring of the reaction unveiled the rapid formation of the CF3SeSeCF3 dimer, which could be the active trifluoromethylselenolating reagent in this transformation. In 2022, Magnier, Billard and co-workers applied the previous methodology to the trifluoromethylselenolation of
Recommendations for performing measurements of apparent equilibrium constants of enzyme-catalyzed reactions and for reporting the results of these measurements
Beilstein J. Org. Chem. 2023, 19, 303–316, doi:10.3762/bjoc.19.26
- is convenient to perform (e.g., continuous spectroscopic monitoring), it requires a substantial amount of additional effort by the investigator. We note that it is not necessary to know the mechanism or the kinetic constants or the rate of approach to equilibrium to obtain an accurate value of K
Revisiting the bromination of 3β-hydroxycholest-5-ene with CBr4/PPh3 and the subsequent azidolysis of the resulting bromide, disparity in stereochemical behavior
Beilstein J. Org. Chem. 2023, 19, 91–99, doi:10.3762/bjoc.19.9
- . Flash chromatography was carried out on silica gel (Baker, 30–60 µm) (Type-I silica gel) and LiChroprep Si 60 (Merck; Ø (15–25 µm) (Type-II silica gel). TLC Monitoring tests were carried out using plastic sheets precoated with silica gel 60 F245 (layer thickness 0.2 mm) purchased from Merck. Spots were
Inline purification in continuous flow synthesis – opportunities and challenges
Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182
- optimization as well as a set of pumps and several membranes are required, and scalability is often limited. In this context, Kappe and co-workers achieved the effective synthesis of methyl oximino acetoacetate using a multistage separation platform, including inline monitoring as depicted in Scheme 2 [51
Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface
Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156
- Kendra Drayton-White Siyue Liu Yu-Chia Chang Sakashi Uppal Kevin D. Moeller Washington University in Saint Louis, Saint Louis, Missouri 63130, United States 10.3762/bjoc.18.156 Abstract Microelectrode arrays are powerful tools for monitoring binding interactions between small molecules and
- ; microelectrode array; Introduction Microelectrode arrays composed of collections of electrodes that can each be individually addressed are powerful platforms for monitoring interactions between a protein target and small molecules [1][2][3][4][5][6][7][8]. In these efforts, molecules are either placed or
- functionalized electrode into a solution containing a redox mediator and then monitoring the current associated with a redox mediator. The method is different relevant to the traditional methods lacking the polymer surface in that the current is dependent on changes to the polymer coating; a situation that can
Synthesis of C6-modified mannose 1-phosphates and evaluation of derived sugar nucleotides against GDP-mannose dehydrogenase
Beilstein J. Org. Chem. 2022, 18, 1379–1384, doi:10.3762/bjoc.18.142
- -phosphates 13, 17, and 18 were individually incubated with GDP-Man PP at 37 °C (Scheme 2) and the reactions monitored by TLC (iPrOH/NH4OH/H2O 6:3:1). Monitoring of analytical scale reactions showed an indicative conversion for substrate 17 after 16 h; no conversion was observed after this time for 13 or 18
Ferrocenoyl-adenines: substituent effects on regioselective acylation
Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133
- )B3LYP/6-31+G(d) method.a Supporting Information Supporting Information File 234: Details on experimental procedures, DFT calculated energies and optimized coordinates for transition state structures and reactants, and the results of in situ 1H NMR monitoring. Acknowledgements All calculations were
Polymer and small molecule mechanochemistry: closer than ever
Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128
- backbone, ultimately reaching and activating the mechanophores within it (Figure 1a). The technical simplicity of the method and the compatibility with spectroscopic analytical techniques for monitoring [22] have made sonication of polymer solutions the primary method in the field of polymer
Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor
Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115
- uniformity and activity, while partially homogeneous systems would need downstream separations. We used in-line reaction monitoring to study several process parameters, such as time, temperature and the photon flux, to maximize the throughput and evaluate the long-term stability of this catalytic approach
- enabled straightforward reaction monitoring via 19F NMR. To this end, a 1 T benchtop NMR equipped with a flow cell was connected to the reactor outlet and used to acquire a series of spectra. In particular, a series of 128 repetitions with a 90° pulse width and a relatively long repetition time of 5.2 s
- , because of the low flow rate some delay is also due to dead volume between the reactor and the NMR spectrometer used for reaction monitoring. For example, the NMR flow cell volume, about 1 mL, is alone responsible for 100 minutes of delay. (b) Time conversion plot, almost full conversion is observed after
New azodyrecins identified by a genome mining-directed reactivity-based screening
Beilstein J. Org. Chem. 2022, 18, 1017–1025, doi:10.3762/bjoc.18.102
- N2H4, which could be generated upon the acid hydrolysis of azoxy natural products. In the assay, N2H4 is captured by two equivalents of p-dimethylaminobenzaldehyde (DAB) to generate p-dimethylaminobenzaldazine, which can be sensitively detected by HPLC by monitoring the UV absorption at 485 nm (Scheme
Mechanochemical halogenation of unsymmetrically substituted azobenzenes
Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69
- -bromosuccinimide (NBS) under neat grinding (NG) and liquid-assisted grinding (LAG) conditions in a ball mill [51]. Insight into the dynamics of the formation of reaction intermediates and products was obtained by in situ Raman monitoring that provided information on the nature of the catalytically active PdII
- species, cyclopalladated intermediates, and products (Figure 1). The monitoring results confirmed the crucial role of TsOH and acetonitrile (MeCN) as additives in the catalytic bromination of the C–H bond in L1. The experimental results were supported by quantum-chemical calculations, which showed that
- azobenzene with NXS and Pd(OAc)2 as precatalyst in the presence of TsOH and MeCN as solid and liquid additives, respectively, led to the ortho-halogenated products relative to the azo group of the azobenzenes. In situ Raman monitoring of these reactions confirmed that the most favorable reaction pathway is
A study of the photochemical behavior of terarylenes containing allomaltol and pyrazole fragments
Beilstein J. Org. Chem. 2022, 18, 588–596, doi:10.3762/bjoc.18.61
- ). The phototransformation of compound 12a was studied using NMR monitoring. UV irradiation was carried out at a wavelength of 365 nm in a solution of DMSO-d6 (Figure 1). It should be noted that after UV irradiation for 8 h of the studied sample the NMR spectrum contained signals of protons of the
- synthesized products were confirmed by X-ray diffraction. 1H NMR monitoring of the photoreaction of compound 12a under UV irradiation (365 nm) in DMSO-d6 solution. The X-ray crystal structure of compound 15a. The X-ray crystal structure of compound 15m. The X-ray crystal structure of compound 18
Borylated norbornadiene derivatives: Synthesis and application in Pd-catalyzed Suzuki–Miyaura coupling reactions
Beilstein J. Org. Chem. 2022, 18, 368–373, doi:10.3762/bjoc.18.41
- overlap of its absorption with the one of the norbornadiene. However, upon heating to 60 °C in MeCN solution the norbornadiene was regained after 25 h, as shown by photometric monitoring of the reaction (Scheme 3 and Figure 1, inset). These photochemical properties are comparable to the ones of literature
- synthesis of monoaryl-substituted norbornadiene derivatives is possible in a highly modular approach. Considering the paucity of such derivatives in this field, this synthetic route may pave the way for a new series of promising norbornadiene-based MOST materials. Photometric monitoring of the
A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions
Beilstein J. Org. Chem. 2022, 18, 337–349, doi:10.3762/bjoc.18.38
- subsequent water elimination leading to a stable tertiary, bis-benzyl carbocation that evolves forming the corresponding alkene by proton elimination (Scheme 3). The reaction was carried out at 60 °C with 10 mol % of 16 (Table 2, entry 1), monitoring the formation of the products by 1H NMR and GC–MS (see
Other Beilstein-Institut Open Science Activities
