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Search for "ultrasound" in Full Text gives 86 result(s) in Beilstein Journal of Organic Chemistry.

Encaging palladium(0) in layered double hydroxide: A sustainable catalyst for solvent-free and ligand-free Heck reaction in a ball mill

  • Wei Shi,
  • Jingbo Yu,
  • Zhijiang Jiang,
  • Qiaoling Shao and
  • Weike Su

Beilstein J. Org. Chem. 2017, 13, 1661–1668, doi:10.3762/bjoc.13.160

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  • supported Pd(PPh3)4 catalyst with high activity in a Glaser reaction (Scheme 1). They found that the catalyst could only be recycled twice without the addition of the PPh3 ligand and the Pd component was significantly leached from polymer support after each run. Cravotto et al. [37] used an ultrasound
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Published 14 Aug 2017

1-Imidoalkylphosphonium salts with modulated Cα–P+ bond strength: synthesis and application as new active α-imidoalkylating agents

  • Jakub Adamek,
  • Roman Mazurkiewicz,
  • Anna Węgrzyk and
  • Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

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  • tetrafluoroboric acid to the reaction mixture effectively suppressed this side reaction. The solubility of phosphonium salts in some aromatic hydrocarbons is limited. In such cases, to ensure an effective mass transfer of reactants, sonification of the reaction mixture was examined. The use of ultrasound reduced
  • the product was isolated by column chromatography (toluene/ethyl acetate 10:1, v/v). The crude crystalline compounds 9aa, 9ab, 9bb, 9ia were recrystallized from toluene or toluene/hexane 1:1, v/v. Ultrasound assisted synthesis of N-(1-arylalkyl)imides 9: A suspension of 1-(N-imido
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Published 24 Jul 2017

Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

  • Gabriel P. Costa,
  • Natália Seus,
  • Juliano A. Roehrs,
  • Raquel G. Jacob,
  • Ricardo F. Schumacher,
  • Thiago Barcellos,
  • Rafael Luque and
  • Diego Alves

Beilstein J. Org. Chem. 2017, 13, 694–702, doi:10.3762/bjoc.13.68

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  • DMSO using Et2NH (1 mol %) was also performed under ultrasound irradiation. The reaction performed under ultrasound irradiation with 20% of the amplitude for 20 minutes (followed by TLC until the total consumption of the starting materials) yielded product 3a in 92% (conditions B, Scheme 2). Inspired
  • by results described under conditions B, we performed additional experiments using ultrasound irradiation with Et2NH as organocatalyst (Table 1). Initially, substrates 1a and 2a were reacted in DMSO under ultrasound irradiation for 20 min using different amplitudes (Table 1, entries 1–4). We observed
  • (Scheme 3) after 5 minutes reaction under ultrasound irradiation (40% of amplitude) at room temperature. Comparing these results with already published ones under conventional conditions, our methodology using ultrasound irradiation affords the products in 5 minutes and in comparable yields while the
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Published 11 Apr 2017

A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

  • Arno Verlee,
  • Thomas Heugebaert,
  • Tom van der Meer,
  • Pavel I. Kerchev,
  • Frank Van Breusegem and
  • Christian V. Stevens

Beilstein J. Org. Chem. 2017, 13, 303–312, doi:10.3762/bjoc.13.33

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  • avoided. A general concern is the clogging of the channels. There are numerous reports about handling solids in flow. For example, the use of ultrasound [27][28][29][30][31][32] can reduce the particle size of the precipitates, and preventing the clogging of the small channels. A second example is the
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Published 16 Feb 2017

NMR reaction monitoring in flow synthesis

  • M. Victoria Gomez and
  • Antonio de la Hoz

Beilstein J. Org. Chem. 2017, 13, 285–300, doi:10.3762/bjoc.13.31

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  • (photochemistry, electrochemistry, microwave, ultrasound, etc.) [6][7][8][9]. In this regard, in a recent paper a compact reconfigurable flow system was described for the continuous flow production of pharmaceuticals. The system comprised different types of preparation, reaction and elaboration modules that could
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Published 14 Feb 2017

A new class of organogelators based on triphenylmethyl derivatives of primary alcohols: hydrophobic interactions alone can mediate gelation

  • Wangkhem P. Singh and
  • Rajkumar S. Singh

Beilstein J. Org. Chem. 2017, 13, 138–149, doi:10.3762/bjoc.13.17

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  • interactions, they can be assembled or disassembled in response to appropriate external stimuli. Functional gels have been reported that are sensitive to physical stimuli like UV–vis light [14], ultrasound [15], and mechanical forces [16]. On the other hand, chemical stimuli-sensitive gels respond to stimuli
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Published 23 Jan 2017

Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

  • Andrea Mascitti,
  • Massimiliano Lupacchini,
  • Ruben Guerra,
  • Ilya Taydakov,
  • Lucia Tonucci,
  • Nicola d’Alessandro,
  • Frederic Lamaty,
  • Jean Martinez and
  • Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 19–25, doi:10.3762/bjoc.13.3

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  • other alternative energy inputs is still scarce. Only three examples highlight their peculiar role for metal-catalysed processes in a ball mill (Mirozoki–Heck reaction) [6], by ultrasound (copper-catalysed cyanation reaction) [7], and for co-crystal formation in the polymer-assisted grinding process
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Published 04 Jan 2017

A versatile route to polythiophenes with functional pendant groups using alkyne chemistry

  • Xiao Huang,
  • Li Yang,
  • Rikard Emanuelsson,
  • Jonas Bergquist,
  • Maria Strømme,
  • Martin Sjödin and
  • Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 2682–2688, doi:10.3762/bjoc.12.265

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  • Huisgen 1,3-dipolar cycloaddition between N-(2-azidoethyl)phthalimide and the alkyne terminal of pyEDOT under ultrasound conditions in 73% yield. Detailed synthetic routes are presented in Supporting Information File 1. Figure 1a shows the cyclic voltammograms (CVs) for electrochemical polymerization of
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Published 09 Dec 2016

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

  • Ming Liu,
  • Jan C. Namyslo,
  • Martin Nieger,
  • Mika Polamo and
  • Andreas Schmidt

Beilstein J. Org. Chem. 2016, 12, 2673–2681, doi:10.3762/bjoc.12.264

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  • bis(3-butyl-1-(2-phenolate)-1H-imidazolium-2-yl)gold (10): A solution of 0.066 g (0.10 mmol) of bis(3-butyl-1-(2-hydroxyphenyl)-1H-imidazolium-2-yl)gold chloride (9) and 0.014 g (0.10 mmol) of K2CO3 in 5 mL of methanol was stirred for 30 minutes under ultrasound irradiation. After concentrating the
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Published 08 Dec 2016

Superstructures with cyclodextrins: chemistry and applications III

  • Gerhard Wenz and
  • Eric Monflier

Beilstein J. Org. Chem. 2016, 12, 937–938, doi:10.3762/bjoc.12.91

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  • , ultrasound or ball mills) appeared to be energetically more efficient as compared to classical synthetic tools. Gerhard Wenz and Eric Monflier Saarbrücken, Lens, April 2016
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Published 10 May 2016

Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions

  • Vito Rizzi,
  • Sergio Matera,
  • Paola Semeraro,
  • Paola Fini and
  • Pinalysa Cosma

Beilstein J. Org. Chem. 2016, 12, 549–563, doi:10.3762/bjoc.12.54

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  • tissue. Then, the electrode was treated with alumina slurry, rinsed well with distilled water and sonicated for about 3 min in a shallow amount of distilled water to remove residual abrasive particles. After the ultrasound bath treatment, the electrode was rinsed again with distilled water, again briefly
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Published 21 Mar 2016

Enabling technologies and green processes in cyclodextrin chemistry

  • Giancarlo Cravotto,
  • Marina Caporaso,
  • Laszlo Jicsinszky and
  • Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

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  • green strategies for the selective modification of cyclodextrins (CDs) is still a challenging task. Outstanding results have been achieved in recent years by means of so-called enabling technologies, such as microwaves, ultrasound and ball mills, that have become irreplaceable tools in the synthesis of
  • ; cyclodextrin; microwaves; synthesis; ultrasound; Review The last decade has witnessed the development of highly efficient alternative synthetic methods which make use of new enabling technologies. The need for a more rational approach to the synthesis of cyclodextrin (CD) derivatives has led to several energy
  • sources been tested for their ability to activate C–C and C–X bond formation. In recent years non-conventional energy sources, such as microwaves (MW), ultrasound (US), ball mills (BM) and microreactors have made access to CD derivatives much simpler, as have heterogeneous catalysts and greener solvents
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Published 15 Feb 2016

Smart molecules for imaging, sensing and health (SMITH)

  • Bradley D. Smith

Beilstein J. Org. Chem. 2015, 11, 2540–2548, doi:10.3762/bjoc.11.274

Graphical Abstract
  • . Another use for these dyes is as contrast agents for photoacoustic imaging where short laser pulses are converted into sound waves that are detected using an ultrasound scanner. Synthavidin technology While working with the molecular building blocks to make squaraine and croconaine rotaxanes we discovered
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Published 10 Dec 2015

Interactions between tetrathiafulvalene units in dimeric structures – the influence of cyclic cores

  • Huixin Jiang,
  • Virginia Mazzanti,
  • Christian R. Parker,
  • Søren Lindbæk Broman,
  • Jens Heide Wallberg,
  • Karol Lušpai,
  • Adam Brincko,
  • Henrik G. Kjaergaard,
  • Anders Kadziola,
  • Peter Rapta,
  • Ole Hammerich and
  • Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2015, 11, 930–948, doi:10.3762/bjoc.11.104

Graphical Abstract
  • ). A solution of 11 (37 mg, 0.09 mmol) in (iPr)2NH (8 mL) was degassed with argon on an ultrasound bath for 30 min. Then Pd(PPh3)4 (7 mg, 0.01 mmol), CuI (4 mg, 0.02 mmol), followed by 9 (106 mg, 0.21 mmol) in degassed (iPr)2NH (2 mL) were added, instantly turning the mixture to dark purple. The
  • . A solution of 13 (99 mg, 0.07 mmol) in (iPr)2NH (10 mL) was degassed on an ultrasound bath for 30 min. Thereafter, PdCl2(PPh3)2 (5 mg, 0.01 mmol), CuI (1 mg, 0.01 mmol), and trimethylsilylacetylene (0.15 mL, 1.03 mmol) were subsequently added. After stirring at rt for 1.5 h, the mixture was filtered
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Published 02 Jun 2015

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

  • Igor B. Krylov,
  • Vera A. Vil’ and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

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Published 20 Jan 2015

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

  • Alan M. Jones and
  • Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

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  • -up where the nucleophile is insoluble in an electrolytic medium and is dispersed as sub-micrometre sized droplets by the application of power ultrasound; such an approach results in a high interfacial liquid–liquid area of the sono-emulsion and trapping of the product. Power ultrasound (20 kHz
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Published 18 Dec 2014

The unexpected influence of aryl substituents in N-aryl-3-oxobutanamides on the behavior of their multicomponent reactions with 5-amino-3-methylisoxazole and salicylaldehyde

  • Volodymyr V. Tkachenko,
  • Elena A. Muravyova,
  • Sergey M. Desenko,
  • Oleg V. Shishkin,
  • Svetlana V. Shishkina,
  • Dmytro O. Sysoiev,
  • Thomas J. J. Müller and
  • Valentin A. Chebanov

Beilstein J. Org. Chem. 2014, 10, 3019–3030, doi:10.3762/bjoc.10.320

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  • ]pyridine 5a or through nucleophilic substitution involving the phenolic hydroxy group under ultrasonic activation furnishing the oxygen-bridged compound 6a. Most likely, here the key influence of ultrasound is the transfer of energy to the reaction mixture that is required for intramolecular cyclization
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Published 17 Dec 2014

Recent advances in the electrochemical construction of heterocycles

  • Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

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  • byproduct, higher temperatures lead to preferential formation of the desired cyclization product. In the reported case, the use of ultrasonic radiation leads to significantly better results compared to conventional heating. These results suggest that the effect of ultrasound on the selectivity is
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Published 03 Dec 2014

Synthesis of nanodiamond derivatives carrying amino functions and quantification by a modified Kaiser test

  • Gerald Jarre,
  • Steffen Heyer,
  • Elisabeth Memmel,
  • Thomas Meinhardt and
  • Anke Krueger

Beilstein J. Org. Chem. 2014, 10, 2729–2737, doi:10.3762/bjoc.10.288

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  • ). All other chemicals have been purchased from Aldrich and Fluka and have been used without further purification. Solvents have been dried according to standard procedures. The following apparatus have been used for the experimental work: Sonication: Ultrasound bath: Bandelin Sonorex Digitec Type DT52
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Published 20 Nov 2014

Derivatives of the triaminoguanidinium ion, 3. Multiple N-functionalization of the triaminoguanidinium ion with isocyanates and isothiocyanates

  • Jan Szabo,
  • Kerstin Karger,
  • Nicolas Bucher and
  • Gerhard Maas

Beilstein J. Org. Chem. 2014, 10, 2255–2262, doi:10.3762/bjoc.10.234

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  • %) under sonication of the reaction mixture with ultrasound. Concerning the conversion of salt 4 into a 1,2,3-tris(2-phenylpropylamino)guanidinium salt 5, all attempts to reduce 4 by catalytic hydrogenation failed, and classical reducing agents such as sodium borohydride and lithium aluminum hydride showed
  • , ultrasound, 2 h, 72%; d) 1. dimethylaminoborane, p-toluenesulfonic acid, CH2Cl2, MeOH, rt, 1.5 h; 2. Na2CO3 aq, rt, 1 h, 84%. Carbamoylation of 1,2,3-tris(benzylamino)guanidinium salts 3 and 5-OTs. Deprotonation of 7a to yield the neutral guanidine derivative 8. Sulfonylcarbamoylation of salt 3. Reaction of
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Published 24 Sep 2014

Indium-mediated allylation in carbohydrate synthesis: A short and efficient approach towards higher 2-acetamido-2-deoxy sugars

  • Christopher Albler,
  • Ralph Hollaus,
  • Hanspeter Kählig and
  • Walther Schmid

Beilstein J. Org. Chem. 2014, 10, 2230–2234, doi:10.3762/bjoc.10.231

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  • , biologically active octodioses are now accessible from compounds 7b and 7c, which is subject of ongoing research. Functionalization of carbohydrates; reagents and conditions: (a) In, allyl bromide, EtOH/H2O, ultrasound, 2.5–7 h, then Ac2O/pyridine, DMAP, rt, 16 h, quant.; (b) O3, CH2Cl2, −78 °C then thiourea
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Published 19 Sep 2014

From porphyrin benzylphosphoramidate conjugates to the catalytic hydrogenation of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin

  • Marcos C. de Souza,
  • Leandro F. Pedrosa,
  • Géssica S. Cazagrande,
  • Vitor F. Ferreira,
  • Maria G. P. M. S. Neves and
  • José A. S. Cavaleiro

Beilstein J. Org. Chem. 2014, 10, 628–633, doi:10.3762/bjoc.10.54

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  • case. The use of ultrasound was necessary to improve the solubility of the porphyrin when ethanol was the solvent. The progress of the reaction was monitored by UV–vis and TLC in petroleum ether/CHCl3 (4:1). When finished the catalyst was filtered off, and the solvent was evaporated. In THF, CHCl3 and
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Published 10 Mar 2014

One-pot sequential synthesis of isocyanates and urea derivatives via a microwave-assisted Staudinger–aza-Wittig reaction

  • Diego Carnaroglio,
  • Katia Martina,
  • Giovanni Palmisano,
  • Andrea Penoni,
  • Claudia Domini and
  • Giancarlo Cravotto

Beilstein J. Org. Chem. 2013, 9, 2378–2386, doi:10.3762/bjoc.9.274

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  • high purity products [21]. So called “enabling techniques”, mainly non-conventional energy sources such as microwaves (MW) and ultrasound (US), can dramatically enhance reaction rates in organic synthesis [22][23]. Kinetics and yields of any chemical modification are strongly improved by the optimal
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Published 06 Nov 2013

Self-assembly of 2,3-dihydroxycholestane steroids into supramolecular organogels as a soft template for the in-situ generation of silicate nanomaterials

  • Valeria C. Edelsztein,
  • Andrea S. Mac Cormack,
  • Matías Ciarlantini and
  • Pablo H. Di Chenna

Beilstein J. Org. Chem. 2013, 9, 1826–1836, doi:10.3762/bjoc.9.213

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  • stimuli such as light, ultrasound or chemical stimuli [8][9][10][11][12]. A wide variety of structurally diverse molecules have the ability to form physical gels (e.g., saccharides, peptides, ureas, nucleobases, steroids, dendrimers, etc. [13]). Although a great effort has been made to investigate the
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Published 09 Sep 2013

Camera-enabled techniques for organic synthesis

  • Steven V. Ley,
  • Richard J. Ingham,
  • Matthew O’Brien and
  • Duncan L. Browne

Beilstein J. Org. Chem. 2013, 9, 1051–1072, doi:10.3762/bjoc.9.118

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  • to investigate the methods of aggregate formation. Using this information, they employed acoustic irradiation to eliminate channel bridging, and flow rate control to manage channel constriction. Others have also recognised the benefits of ultrasound techniques, for example, during palladium catalysed
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Published 31 May 2013
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