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Search for "flow" in Full Text gives 681 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions
Beilstein J. Org. Chem. 2023, 19, 752–763, doi:10.3762/bjoc.19.55
- 10.3762/bjoc.19.55 Abstract We report on the high potential of a honeycomb reactor for the use in aerobic oxidation under continuous-flow conditions. The honeycomb reactor is made of porous material with narrow channels separated by porous walls allowing for high density accumulation in the reactor. This
- structure raised the mixing efficiency of a gas–liquid reaction system, and it effectively accelerated the aerobic oxidation of benzyl alcohols to benzaldehydes under continuous-flow conditions. This reactor is a promising device for streamlining aerobic oxidation with high process safety because it is a
- from operators or the equipment can have disastrous consequences. Because the large headspace of batch reactor aggravates these safety risks, the use of O2 in batch manufacturing is very limited [14]. Recently, continuous flow synthesis has recently been studied as a way to mitigate the safety risks
Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles
Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44
C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis
Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43
- develop a continuous flow process specifically for the C3-alkylation of furfural (Murai reaction). The transposition of a batch process to a continuous flow process is often costly in terms of time and reagents. Therefore, we chose to proceed in two steps: the reaction conditions were first optimized
- using a laboratory-built pulsed-flow system to save reagents. The optimized conditions in this pulsed-flow mode were then successfully transferred to a continuous flow reactor. In addition, the versatility of this continuous flow device allowed both steps of the reaction to be carried out, namely the
- formation of the imine directing group and the C3-functionalization with some vinylsilanes and norbonene. Keywords: biomass; C–H activation; flow; furfural; homogeneous catalysis; Introduction The conversion of biomass derivatives into value-added products is one of the key branches of green chemistry and
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
- . Note that in 2018, Besset and Lebel developed a more efficient process for the palladium-catalyzed trifluoromethylthiolation by C–H bond activation under continuous flow conditions [127]. I.4) Difluoromethylthiolation of aromatic and vinylic C(sp2)–H bonds (C–SCF2H and C–SCF2CO2Et bonds) More recently
Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis
Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30
- a Netzsch 204 F1 Phoenix apparatus (both from Netzsch Group, Selb, Germany). The TG–DTG and DSC conditions were similar: temperature program of 25–500 °C, with a heating rate of 10 °C/min, nitrogen purge and protection flow of 40 mL/min, the data acquisition and handling by Netzsch Proteus-Thermal
Continuous flow synthesis of 6-monoamino-6-monodeoxy-β-cyclodextrin
Beilstein J. Org. Chem. 2023, 19, 294–302, doi:10.3762/bjoc.19.25
- of Science, Charles University, 128 43 Prague 2, Czech Republic 10.3762/bjoc.19.25 Abstract The first continuous flow method was developed for the synthesis of 6-monoamino-6-monodeoxy-β-cyclodextrin starting from native β-cyclodextrin through three reaction steps, such as monotosylation, azidation
- and reduction. All reaction steps were studied separately and optimized under continuous flow conditions. After the optimization, the reaction steps were coupled in a semi-continuous flow system, since a solvent exchange had to be performed after the tosylation. However, the azidation and the
- reduction steps were compatible to be coupled in one flow system obtaining 6-monoamino-6-monodeoxy-β-cyclodextrin in a high yield. Our flow method developed is safer and faster than the batch approaches. Keywords: azidation; continuous flow; β-cyclodextrin; H-cube; 6-monoamino-6-monodeoxy-β-cyclodextrin
Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone
Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21
- K. HFIP was supplemented with 3 g/L potassium triflate, and the flow rate was adjusted to 0.50 mL/min. Calibration was performed using PEG standards with molar masses ranging from 0.1–1,000 kg/mol. Before every measurement, samples were filtered through 0.2 µm PTFE filters, Roth (Karlsruhe, Germany
Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors
Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14
Synthesis and characterisation of new antimalarial fluorinated triazolopyrazine compounds
Beilstein J. Org. Chem. 2023, 19, 107–114, doi:10.3762/bjoc.19.11
- (0.1% TFA) were held for the first 1 min, followed by a linear gradient to 100% MeOH (0.1% TFA) over 59 min, all at a flow rate of 9 mL/min. Sixty fractions (60 × 1 min) were collected from the start of the HPLC run. Fractions containing UV-active material were analysed by 1H NMR spectroscopy and LCMS
- first 1 min, followed by a linear gradient to 80% MeOH/20% H2O (0.1% TFA) over 59 min, all at a flow rate of 9 mL/min. 3-(4-(Difluoromethoxy)phenyl)-5-phenethoxy-8-(trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyrazine (10). White amorphous solid (6 mg, 12%); UV (MeOH) λmax (log ε): 243 (3.94), 324 (3.50) nm
Modern flow chemistry – prospect and advantage
Beilstein J. Org. Chem. 2023, 19, 33–35, doi:10.3762/bjoc.19.3
- Philipp Heretsch Institute of Organic Chemistry, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany 10.3762/bjoc.19.3 Keywords: flow chemistry; method development; reactor design; Organic chemistry has shaped modern society by fulfilling the basic needs for pharmaceuticals
- , agrochemicals, fragrances, and many more. Implementation of new and innovative technologies has played a vital role in this mission and has contributed to the opening of new research areas and to pushing the frontiers of existing ones. Among these new technologies, continuous flow chemistry has stepped on the
- chemicals. This has again led to improved scalability, higher purity of products, and eventually decreased manufacturing costs. From the undisputed role of continuous flow chemistry for process chemists, the advent of this technology in academic research laboratories, especially for method development and
Two-step continuous-flow synthesis of 6-membered cyclic iodonium salts via anodic oxidation
Beilstein J. Org. Chem. 2023, 19, 27–32, doi:10.3762/bjoc.19.2
- continuous-flow procedure for the generation of six-membered diaryliodonium salts. The accompanying scalability and atom economy are significant improvements to existing batch methods. Benzyl acetates are submitted to this two-step procedure as highly available and cheap starting materials. An acid-catalyzed
- Friedel–Crafts alkylation followed by an anodic oxidative cyclization yielded a defined set of cyclic iodonium salts in a highly substrate-dependent yield. Keywords: electrochemistry; flow chemistry; hypervalent compounds; iodine; oxidation; Introduction Hypervalent iodine compounds (HVI) are well
- anodic oxidation [37][38][39][40]. Due to the apparent advantages of electrochemical processes, their implementation in flow is simple and straightforward since further dilution or additives are unnecessary [41][42]. One early example of this combination in the field of HVI chemistry is the anodic
Combining the best of both worlds: radical-based divergent total synthesis
Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1
- , bipolamine I (176) was obtained from 169 via a samarium diiodide reduction of the mesylate, followed by sodium borohydride reduction of the ketone, hydroboration, and base-mediated cyclization. Flow-controlled divergent synthesis of aporphine and morphinandienone natural products (Felpin 2022) [92
- reported the flow-controlled divergent synthesis of aporphine and morphinandienone alkaloids based on biomimetic common scaffolds (e.g., 180) using hypervalent iodine(III) reagents. Capitalizing on previously reported mechanistic investigations, they assumed that 180 can rearrange to glaucine (183) through
- produce aporphine natural products, while the use of PIDA or PIFA in the presence of BF3·OEt or TMSOTf in wet CH3CN allows to diverge the synthesis to morphinandienone natural products (e.g., 181, Scheme 15). The flow reaction was performed in a reaction coil at room temperature. Two reaction loops were
Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements
Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184
- under dry nitrogen gas with a constant flow rate of 60 cm3·min−1 and the samples were heated to a maximum temperature of 400 °C at a constant rate of 10 K·min−1. Differential scanning calorimetry (DSC): DSC analyses were performed on a DSC XP-10 instrument (Surface Solutions GmbH), and the data analysed
Inline purification in continuous flow synthesis – opportunities and challenges
Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182
- Jorge Garcia-Lacuna Marcus Baumann School of Chemistry, University College Dublin, Science Centre South, Belfield, Dublin 4, Dublin, Ireland 10.3762/bjoc.18.182 Abstract Continuous flow technology has become the method of choice for many academic and industrial researchers when developing new
- exploited to achieve effective and reliable flow processes. This perspective article summarizes recent applications of different inline purification techniques such as chromatography, extractions, and crystallization from academic and industrial laboratories. A discussion of the advantages and drawbacks of
- these tools is provided as a guide to aid researchers in selecting the most appropriate approach for future applications. It is hoped that this perspective contributes to new developments in this field in the context of process and cost efficiency, sustainability and industrial uptake of new flow
Formal total synthesis of macarpine via a Au(I)-catalyzed 6-endo-dig cycloisomerization strategy
Beilstein J. Org. Chem. 2022, 18, 1589–1595, doi:10.3762/bjoc.18.169
- -inflammatory [4][5][6][7][8], insecticidal, fungicidal, etc [9]. In addition to the above-mentioned activities, macarpine was also used as a DNA probe for flow cytometry and fluorescence microscopy due to its fluorescent properties [10]. Despite some research on the activities of macarpine had been performed
Using UHPLC–MS profiling for the discovery of new sponge-derived metabolites and anthelmintic screening of the NatureBank bromotyrosine library
Beilstein J. Org. Chem. 2022, 18, 1544–1552, doi:10.3762/bjoc.18.164
- % formic acid) were employed for the first minute, followed by a linear gradient to 100% MeOH (0.1% formic acid) over 8 min followed by a 1.5 min isocratic elution of 100% MeOH (0.1% formic acid) all at a flow rate of 0.3 mL/min. UHPLC–MS data was analysed using Thermo Scientific Dionex Chromeleon 7
- a further 10 min, all at a flow rate of 9 mL/min. Sixty 1 min fractions were collected from time 0 to 60 min to afford 5-debromopurealidin H (1, 11.1 mg, tR 32–34 min, 0.111% dry wt), and the known alkaloid ianthesine E (2, 161.2 mg, tR 40–41 min, 1.612% dry wt). 5-Debromopurealidin H (1): Yellow
An alternative C–P cross-coupling route for the synthesis of novel V-shaped aryldiphosphonic acids
Beilstein J. Org. Chem. 2022, 18, 1518–1523, doi:10.3762/bjoc.18.160
- note here that the system is kept under a constant flow of either argon or nitrogen, mainly to avoid side reactions with components in the air (humidity, oxygen), but also to prevent the solid in the addition funnel from contacting any vapour and turning soggy before it is added to the round-bottomed
- flask. As can be seen in Figure 1, this is achieved by flowing the gas through the powder addition funnel via a gas inlet. This also allows for the quick removal (usually complete in less than 30 minutes) of residual triisopropyl phosphite at the end of the reaction by simply increasing the gas flow
Molecular and macromolecular electrochemistry: synthesis, mechanism, and redox properties
Beilstein J. Org. Chem. 2022, 18, 1505–1506, doi:10.3762/bjoc.18.158
- of organic electrochemistry for energy material applications. Organic semiconductor design for electron or hole transport is important for transistor and solar cell applications, and redox-active (but stable) organic and polymeric materials are promising for secondary batteries and redox flow
Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence
Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149
- with the measured values. The CT character of the 1CT and 3CT states is visible in the electronic density difference (EDDs) plots shown in Scheme 2, which clearly indicates the flow of electron density from the PTZ to the NI moieties. Conversely, the LE states are fully localized within the acceptor
On drug discovery against infectious diseases and academic medicinal chemistry contributions
Beilstein J. Org. Chem. 2022, 18, 1355–1378, doi:10.3762/bjoc.18.141
- effect on an animal model of the disease. Then, past these two hurdles, the task of selecting a clinical candidate and produce up to tons of it is also a major endeavor that has been often overlooked by the academia. However, a noteworthy exception would be the recent flow chemistry developments in the
Polymer and small molecule mechanochemistry: closer than ever
Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128
- into new modes to activate matter by force (e.g., twin-screw extrusion [71], resonant acoustic mixing [72], vortex fluidic mixing [73], laminar flow [74], etc.) will continue to unveil similarities and complementarities, rather than disparities, between the ways polymer and small molecule
- mechanochemical reactions occur. As a result, the field of mechanochemistry as a whole will ultimately be strengthened. Representation of (a) cavitation and elongational flow caused by pulsed ultrasonication, (b) mixer mill, (c) planetary ball mill, and (d) ring-and-puck mill (vibrating disc mill). Structure of
Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide
Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125
- powder was then allowed to age under an argon atmosphere for 24 hours, prior to washing via centrifugation in a 3:1 by volume mixture of ethanol and deionized (DI) water. This afforded a material referred to below as g-h-PCN. Alternatively, the sample was annealed for 1 hour at 300 °C under a flow of
- =O character from 21% to 18% compared to g-h-PCN and an increase in C–OH character from 35% to 43% suggests mild hydrolysis, likely of terminal trichloroheptazine, during the annealing step at 300 °C, even under a flow of argon gas (Figure 2d). The nitrogen 1s scans show a similar trend, with the
Electro-conversion of cumene into acetophenone using boron-doped diamond electrodes
Beilstein J. Org. Chem. 2022, 18, 1154–1158, doi:10.3762/bjoc.18.119
- starting material, while propylbenzene was not. Moreover, the electrolysis under a flow of oxygen did not improve the yields, which indicates that the BDD cathode can utilize the electrogenerated oxygen species efficiently, as we have reported previously [19]. Conclusion We have demonstrated a
Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor
Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115
- and scalable reaction conditions. Here, we report a continuous-flow approach to metallaphotoredox catalysis using a heterogeneous catalyst that combines the function of a photo- and a nickel catalyst in a single material. The catalyst is embedded in a packed-bed reactor to combine reaction and
- (catalyst) separation in one step. The use of a packed bed simplifies the translation of optimized batch reaction conditions to continuous flow, as the only components present in the reaction mixture are the substrate and a base. The metallaphotoredox cross-coupling of sulfinates with aryl halides was used
- as a model system. The catalyst was shown to be stable, with a very low decrease of the yield (≈1% per day) during a continuous experiment over seven days, and to be effective for C–O arylations when carboxylic acids are used as nucleophile instead of sulfinates. Keywords: flow chemistry
A Streptomyces P450 enzyme dimerizes isoflavones from plants
Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113
- experiments was conducted with a YMC-Triart C18 ExRS column (150 mm × 3.0 mm, 3 μm, 12 nm, YMC) with a gradient of 5% B (0 min) to 95% B (12 min) at a flow rate of 0.5 mL/min (analytical method A). The HPLC–UV analysis of isoflavones was conducted with a Poroshell 120 SB-C18 column (100 mm × 3.0 mm, 2.7 μm
- , Agilent) with a gradient of 30% B (0 min) to 45% B (10 min) at a flow rate of 0.5 mL/min (analytical method B). The UHPLC–HRMS analysis of isoflavones was conducted with a HSS T3 column (100 mm × 2.1 mm, 1.8 μm, Waters) with a gradient of 30% B (0 min) to 45% B (4.5 min) at a flow rate of 0.4 mL/min
- (analytical method C). The UHPLC–HRMS analysis of the substrate scope was conducted with a HSS T3 column (100 mm × 2.1 mm, 1.8 μm, Waters) with a gradient of 0% B (0 min) to 100% B (5.0 min) at a flow rate of 0.4 mL/min (analytical method D). All HRMS analyses were performed in positive model with a scan
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