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Search for "flow" in Full Text gives 642 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Clustering and curation of electropherograms: an efficient method for analyzing large cohorts of capillary electrophoresis glycomic profiles for bioprocessing operations
Beilstein J. Org. Chem. 2020, 16, 2087–2099, doi:10.3762/bjoc.16.176
- Xevo G2S QToF (Waters Corp). The flow rate was set at 0.4 mL/min and a linear gradient was used: 25–49% of buffer A (50 mM ammonium formate solution, pH 4.4) and buffer B (100% ACN) was run across 40 minutes, followed by a 3 min wash step using buffer A. The column was then equilibrated back to 25
- of m/z 400–2000 was used, with an acquisition speed of 1 Hz, and the mass spectrometry was set at the following conditions: 2.75 kV electrospray ionization capillary voltage, 15 V cone voltage, 120 °C ion source temperature, 300 °C desolvation temperature, 800 L/h desolvation gas flow. A lockspray
pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide
Beilstein J. Org. Chem. 2020, 16, 2017–2025, doi:10.3762/bjoc.16.168
- in 40 min at 25 °C ) on a SymmetryPrepTM C18 preparative column (7 µm, 7.8 × 300 mm) at a flow rate of 2 mL/min. Peaks were detected at 214 nm. The desired peak was collected, and the purity was checked in an analytical Symmetry C18 column (5 µm, 4.6 × 250 mm). The single peak demonstrated the purity
Automated high-content imaging for cellular uptake, from the Schmuck cation to the latest cyclic oligochalcogenides
Beilstein J. Org. Chem. 2020, 16, 2007–2016, doi:10.3762/bjoc.16.167
- employed to generate dose–response curves and to calculate the CP50 value of the transporters, described as the half-maximal cell penetration. In a CAPA, the final fluorescence response is usually recorded by flow cytometry [55][62]. In a HC CAPA, flow cytometry is replaced by HC automated microscopy
- , masking exclusively the mitochondria region, gave a small but significant increase to r2 = 0.983 (Figure 8b). Although optimized toward perfection with stable HGM cells, this increase demonstrated that the HC CAPA adds a precision that is overlooked with flow cytometry. The off-target staining of 26 in
- 0.983 quantified the increase in accuracy achieved moving from a cell-body mask to a mitochondrial mask. This difference revealed that even with fully optimized stable HGM cell lines, whole-cell analyses, such as flow cytometry, of the CAPA contain a small but nonnegligible error that can be removed
A complementary approach to conjugated N-acyliminium formation through photoredox-catalyzed intermolecular radical addition to allenamides and allencarbamates
Beilstein J. Org. Chem. 2020, 16, 1983–1990, doi:10.3762/bjoc.16.165
- findings on the performance of allenamides. Specifically, the electron-withdrawing group on the allenamide and the nucleophile is examined. We provide evidence for the formation of the N-acyliminium intermediate through direct sample loop and flow injection analysis by HRESIMS, and DFT analysis of the N
- -catalyzed photoredox conditions in the presence of 4-bromoaniline was monitored by direct sample loop and flow injection analysis by HRESIMS [56][57]. After 5 minutes we observed a peak at m/z 284.1129 that corresponded satisfactorily to the expected iminium complex 14a (m/z 284.1129: calcd for [C13H18NO6
- conjugated N-acyliminium intermediate; (b) the calculated HOMO [54] for allenamide 15; (c) the identification of intermediate 14a by direct sample loop and flow injection HRESIMS analysis. Supporting Information Supporting Information File 366: Experimental details, analytical (1H NMR, 13C NMR) and ESIMS
Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions
Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159
- , Janssen-Cilag, S.A., C/ Jarama 75A, Toledo, Spain 10.3762/bjoc.16.159 Abstract The combination of supported ionic liquids and immobilized NHC–Pd–RuPhos led to active and more stable systems for the Negishi reaction under continuous flow conditions than those solely based on NHC–Pd–RuPhos. The fine tuning
- complexes enabling a simpler recovery and reuse of the catalysts by filtration [5]. Furthermore, the immobilized NHC-complexes can be easily adapted to flow processes using a fix-bed reactor set-up increasing simultaneously the sustainability and the efficiency of the C–C coupling reactions [6][7]. In the
- under continuous flow conditions. Results and Discussion Scheme 1 summarizes the synthetic approach used for the preparation of the functionalized polymers considered in this work. A commercially available PS-DVB bead-type macroporous chloromethylated polymer 1 (Merrifield resin with 20% DVB and 1.2
Design, synthesis and application of carbazole macrocycles in anion sensors
Beilstein J. Org. Chem. 2020, 16, 1901–1914, doi:10.3762/bjoc.16.157
- was an opening with an adjustable plastic plug, which can be used to empty the outer filling solution compartment, and the greater standard deviations in the results could be explained by slight differences in the flow of chloride between measurements. These variations in flow rate were likely due to
- variations in the position of the plug as a result of handling the reference electrode while setting up the measurements. This flow of chloride resulted in narrower linear ranges, lower slopes, and poorer detection limits due to the mixed responses to acetate and chloride. The degree of deviation from the
- coefficients for fluoride were due to an abnormally large flow rate of chloride from the reference electrode during a single measurement. This affected the responses for sensors that were used. The ISMs showed modest selectivities. However, incorporating any of the three receptors in the membrane as an
When metal-catalyzed C–H functionalization meets visible-light photocatalysis
Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147
- of both substrates bearing various functional groups, thus furnishing more than 30 acylated products in moderate to good yields. As the molecular oxygen was the terminal oxidant, the typical high loading of an external oxidant could be avoided. Flow chemistry is an important technology for
- photochemical reactions due to the inherent lack of scalability issues as a consequence of the Beer–Lambert law of absorption. Consequently, continuous-flow chemistry represents one of the few ways in which pharmaceutically relevant quantities of compounds can be synthesized through photoinduced transformations
- [91]. In this context, great advances were also recently achieved in the field of direct C–H functionalization reactions under flow conditions. Persistent improvements enabled the development of innovative flow techniques, encompassing large-scale photochemical procedures, which were successfully
One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?
Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143
- this reaction under continuous flow using two catalytic beds. Finally, we emphasize that mechanistic insights on the catalytic conversion of biomass-derived platform molecules are required to make this value chain competitive with respect to the traditional synthesis of chemicals from fossil fuels. In
Pauson–Khand reaction of fluorinated compounds
Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138
- described, including the use of metals other than cobalt (such as rhodium, iridium, titanium, ruthenium, nickel, and palladium), or the use of CO surrogates such as aldehydes, alcohols and formates. Recently, its utility in flow chemistry has also been described [42]. Intramolecular Pauson–Khand reactions
Antibacterial scalarane from Doriprismatica stellata nudibranchs (Gastropoda, Nudibranchia), egg ribbons, and their dietary sponge Spongia cf. agaricina (Demospongiae, Dictyoceratida)
Beilstein J. Org. Chem. 2020, 16, 1596–1605, doi:10.3762/bjoc.16.132
- % acetic acid. The gradient began after 0.5 min to 100% acetonitrile (0.1% acetic acid) in 4 min. 2 µL of a 1 mg/mL sample solution was injected to a flow of 0.8 mL/min. HRAPCIMS were recorded on LTQ Orbitrap XL mass spectrometer. HPLC was carried out on a Waters Breeze HPLC system equipped with a 1525µ
- :30 (MeOH/H2O) to 100% MeOH in 25 min, and a flow of 1.5 mL/min was used for separation. The isolated metabolite had a retention time around 13 minutes. 12-Deacetoxy-4-demethyl-11,24-diacetoxy-3,4-methylenedeoxoscalarin C29H42O6, white amorphous solid (12.7 mg); [α]D20 +40.5 (c 0.6, CHCl3); IR (ATR
A dynamic combinatorial library for biomimetic recognition of dipeptides in water
Beilstein J. Org. Chem. 2020, 16, 1588–1595, doi:10.3762/bjoc.16.131
- . The mobile phase was a mixture of water (0.1 % NH4FA, pH 3.2) and acetonitrile. The injection volume was 5 µL. The following gradient was used with a flow rate of 150 µL/min (Table 2). ITC measurements For determination of binding constants ITC was measured in phosphate buffered solutions (pH 7.4, 100
Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle
Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128
- voltage was maintained at 3200 V and the capillary temperature set to 320 °C. Samples were introduced by injection through a 20 µL loop into a 300 µL/min flow of methanol from the LC pump. Electrochemistry: Cyclic voltammetry was carried out in a Metrohm Autolab PGSTAT302N potentiostat using a three
Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers
Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127
- Analyzer from TA Instruments. Parameters for all TG analyses were as the following: nitrogen flow, ramp rate 10 °C/min, rt to 700 °C. IR spectra of dried powders were recorded on a PerkinElmer Spectrum 100 FT-IR Spectrometer with 16 scans. Zeta potential and DLS measurements were performed on Zetasizer
- ) synthesis. Conditions: nitrogen flow, ramp rate 10 °C/min, rt to 700 °C. Thermogravimetric analysis of α, β and γ-CD-based carbonate nanosponges, obtained through ball-mill synthesis. Conditions: nitrogen flow, ramp rate 10 °C/min. Adsorption of organic dyes by ball-mill synthesized β-CD-based carbonate
Heterogeneous photocatalysis in flow chemical reactors
Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125
- Christopher G. Thomson Ai-Lan Lee Filipe Vilela Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS Scotland, United Kingdom 10.3762/bjoc.16.125 Abstract The synergy between photocatalysis and continuous flow chemical reactors
- photocatalysts (HPCats) are an attractive alternative, as the requirement for the separation and purification is largely removed, but typically at the cost of efficiency. Flow chemical reactors can, to a large extent, mitigate the loss in efficiency through reactor designs that enhance mass transport and
- irradiation. Herein, we review some important developments of heterogeneous photocatalytic materials and their application in flow reactors for sustainable organic synthesis. Further, the application of continuous flow heterogeneous photocatalysis in environmental remediation is briefly discussed to present
4-Hydroxy-3-methyl-2(1H)-quinolone, originally discovered from a Brassicaceae plant, produced by a soil bacterium of the genus Burkholderia sp.: determination of a preferred tautomer and antioxidant activity
Beilstein J. Org. Chem. 2020, 16, 1489–1494, doi:10.3762/bjoc.16.124
- MeCN/0.1% HCOOH mixed in ratios of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, and 8:2, respectively. A fraction eluted by 30% MeCN was evaporated to provide 69.4 mg of a solid, which was purified by HPLC on an ODS column (Cosmosil AR-II, 1 × 25 cm) eluted with 16% MeCN containing 0.1% HCO2H at a flow rate of 4 mL
The McKenna reaction – avoiding side reactions in phosphonate deprotection
Beilstein J. Org. Chem. 2020, 16, 1436–1446, doi:10.3762/bjoc.16.119
- spectroscopy; see Figure S13 in Supporting Information File 1). When performing the reaction of 9b with BTMS under a gentle flow of inert gas (in order to remove the volatile ethyl bromide), we observed a slight decrease in the formation of the N-alkylated product 20 (from 7–10% to 5%). However, the flow of
An overview on disulfide-catalyzed and -cocatalyzed photoreactions
Beilstein J. Org. Chem. 2020, 16, 1418–1435, doi:10.3762/bjoc.16.118
- -membered keto ester derivatives did not show any desired reaction. In combination with a continuous-flow strategy, this disulfide-catalyzed aerobic oxidation process can be scaled up to a gram-scale. A plausible mechanism of the reaction is shown in Scheme 11. The hydroxylation starts with the formation of
Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides
Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115
- Mateo Berton Kevin Sheehan Andrea Adamo D. Tyler McQuade Department of Chemical and Life Sciences Engineering, Virginia Commonwealth University, Biotech Eight, 737 N. 5th St., Box 980100, Richmond, VA 23219, USA Zaiput Flow Technologies, 300 2nd Avenue, Waltham, MA 02451, USA 10.3762/bjoc.16.115
- batch-to-batch variability. Tubular reactors of solid reagents combined with solution-phase reagents enable the continuous-flow preparation of organomagnesium reagents. The use of stratified packed-bed columns of magnesium metal and lithium chloride for the synthesis of highly concentrated turbo
- fresh organomagnesium reagents on a discovery scale and will do so independent from the operator’s experience in flow and/or organometallic chemistry. Keywords: Knochel–Hauser base; lithium chloride; magnesium; on-demand; packed-bed reactors; plug and flow reactor; synthesizer; turbo Grignard reagent
Photocatalytic trifluoromethoxylation of arenes and heteroarenes in continuous-flow
Beilstein J. Org. Chem. 2020, 16, 1305–1312, doi:10.3762/bjoc.16.111
- Alexander V. Nyuchev Ting Wan Borja Cendon Carlo Sambiagio Job J. C. Struijs Michelle Ho Moises Gulias Ying Wang Timothy Noel Micro Flow Chemistry and Synthetic Methodology, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Het Kranenveld, Bldg 14 − Helix, 5600
- , Road, North Chicago, Illinois 60064, United States of America 10.3762/bjoc.16.111 Abstract The first example of photocatalytic trifluoromethoxylation of arenes and heteroarenes under continuous-flow conditions is described. Application of continuous-flow microreactor technology allowed to reduce the
- residence time up to 16 times in comparison to the batch procedure, while achieving similar or higher yields. In addition, the use of inorganic bases was demonstrated to increase the reaction yield under batch conditions. Keywords: C–H functionalization; continuous-flow; organic synthesis; photoredox
Oxime radicals: generation, properties and application in organic synthesis
Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107
- strong single-electron oxidant, cerium(IV) ammonium nitrate, in methanol [38]. To record EPR spectra, a flow system was used, which allowed observation of radicals with lifetimes of about 10−2 s [39]. The EPR spectra of iminoxyl radicals are characterized by large values of the hyperfine splitting
Anthelmintic drug discovery: target identification, screening methods and the role of open science
Beilstein J. Org. Chem. 2020, 16, 1203–1224, doi:10.3762/bjoc.16.105
- an open source software package. It uses two algorithms (Lucas–Kanade optical flow estimation, and a pixel change method) to determine the motility of macroparasites in microtitre plates [122]. The Worminator builds on WormAssay for the use with microscopic parasites [123]. This system has been
- available, enabling utilisation and modification by other groups. Stress-Chip is a chip that allows the isolation of a hundred worms in single-worm arenas and monitoring as chemicals flow over the worms [153]. The CAD file for producing the microfluidic device has been made available on Figshare under the
Activated carbon as catalyst support: precursors, preparation, modification and characterization
Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104
- chemical activation process. A few examples for the different preparation conditions are the choice of the activing agent (KOH, NaOH, ZnCl2, H3PO4, MgCl2, AlCl3, K2CO3, etc.), the impregnation technique used or physically mixing processes, the activation reagent to carbon precursor ratio, the flow of inert
Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis
Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103
- visible-light irradiation. The key aryl radical was trapped with heteroarenes, such as 11.2, to give the arylation products 11.3. Recently, similar methodologies for aryl radical generations have been developed exploiting flow techniques [74] and different organophotocatalysts, such as a metal-free
Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules
Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102
- that of the pristine solution, while the other remaining PL bands in the short-wavelength region do not change. Judging from the PL behavior under N2 or O2 flow conditions, the PL bands at the short-wavelength region around 395 nm and long-wavelength region around 560 nm can be safely considered
- I560/I395 values of benzils 2a and 2b under N2 flow conditions increase up to sevenfold compared with those of the corresponding pristine solutions. On the other hand, the increase in the I560/I395 values of fluorinated bisbenzil derivatives 3a and 3b is low (only 1.1 times) under N2 flow conditions
- photophysical behavior of the benzils and bisbenzils through several PL measurements under N2 and O2 flow conditions probed the successful room-temperature phosphorescence of the compounds in toluene solution. A fuller understanding of the excited-state dynamics of these benzil and bisbenzil derivatives will
A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium
Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97
- ) was added and then diluted with MeCN/0.2% HCO2H aqueous solution (100 μL, 50:50). The Marfey’s derivatives of the hydrolysate and standards were analyzed by LC–MS using a Cosmosil 5C18-AR-II column eluted with MeCN/0.1% HCO2H aqueous solution at a flow rate of 1.0 mL/min, monitoring at 340 nm with a
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