NMR Spectroscopy of supramolecular chemistry on protein surfaces

• Peter Bayer,
• Anja Matena and
• Christine Beuck

Beilstein J. Org. Chem. 2020, 16, 2505–2522, doi:10.3762/bjoc.16.203

• increase in particle size. Interestingly, a >2-fold excess of calix[8]arene over Cyt c results in a breaking up of the ligand-induced tetramers, which also results in a resharpening of the NMR signals at higher ligand concentrations [24]. This tendency to bridge protein molecules and assemble them into

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

• Emine Kayahan,
• Mathias Jacobs,
• Leen Braeken,
• Leen C.J. Thomassen,
• Simon Kuhn,
• Tom van Gerven and
• M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

• reaction medium is usually transparent to light. Solid photocatalysts, on the other hand, are absorbing and scattering light. The scattering of light by a particle depends on the refractive index of the medium and the particle, the particle size, and the wavelength of light. The ratio of the diameter of

Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

• Poulami Jana,
• Filip Šupljika,
• Carsten Schmuck and
• Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

• higher r values (r = 1.25, excess of dye over DNA) more compact condensed DNA structures were observed with a diameter of 500 nm and a height of 10 nm (Figure 6c, see Supporting Information File 1, Figure S26 for height profile), so called polyplexes. For the estimation of the condensed particle size at

• and 115 nm at ratios of r = 0.1 and 0.5, respectively. Higher ratios resulted in even larger particle size, which eventually ended in precipitation. Conclusion We designed and synthesized a novel naphtalene diimide analogue equipped at imide positions with two guanidinio-carbonyl-pyrrole (GCP) pendant

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• ), calf thymus (ct)-DNA, and poly(dG-dC)2 were obtained from Sigma–Aldrich. The starting compound 1 was prepared according to the literature [31]. Column chromatography was performed on silica gel (MerckSilica 60, particle size 0.04–0.063 mm). Semipreparative HPLC was performed on a Jai system (LC-9105

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• 750 mg of 9a SILLP low loading. Yield calculated by GC and confirmed by 1H NMR. TEM images of the polymer after the Negishi reaction between 5 and 6 under flow conditions. a) 8a + 9c, bar scale 20 nm, PdNPs particle size distribution 4.72 ± 1.44 nm. b) 8a + 9a bar scale 20 nm, PdNPs particle size

Regiodivergent synthesis of functionalized pyrimidines and imidazoles through phenacyl azides in deep eutectic solvents

• Paola Vitale,
• Luciana Cicco,
• Ilaria Cellamare,
• Filippo M. Perna,
• Antonio Salomone and
• Vito Capriati

Beilstein J. Org. Chem. 2020, 16, 1915–1923, doi:10.3762/bjoc.16.158

• heating to 473 K until blue spots appeared. Column chromatography was conducted by using silica gel 60 with a particle size distribution of 40–63 μm and 230–400 ASTM, using hexane/EtOAc mixtures as the eluent. High-resolution mass spectrometry (HRMS) analyses were performed using a Bruker microTOF QII

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• )cellulose such as the acidity, the crystallinity and the particle size of cellulose as well as the nature of the feedstocks. This review highlights all these parameters and all the strategies employed to produce isosorbide from (ligno)cellulose in a one-pot process. Keywords: catalysis; cellulose

• wheat straw pulp led to 63% of isosorbide, corresponding to a productivity of 40 g·L−1·h−1 with 72% of purity. This high yield can be ascribed to several parameters such as small particle diameter, large surface area/porosity and lower crystallinity. For the particle size, cellulose fiber diameters are

• 2 µm and 50 µm of respectively pre-treated wheat straw and microcrystalline Avicel PH-101, that can explain the higher yield of isosorbide from CIMV-delignified wheat straw pulp. The crystallinity and the particle size effects were confirmed by starting from a ball-milled Avicel PH-101 cellulose. A

A dynamic combinatorial library for biomimetic recognition of dipeptides in water

• Florian Klepel and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2020, 16, 1588–1595, doi:10.3762/bjoc.16.131

• analyzed using Compass DataAnalysis version 5.0 R1 (Bruker). The column oven was set to 40 °C. A SeQunant ZIC-HILIC (Merk KGaA, 150 × 2.1 mm, particle size 3.5 µM, pore size 200 Å) with a SeQunant ZIC-HILIC (Merk KGaA, 20 × 2.1 mm, particle size 5 µM, pore size 200 Å) precolumn was used as stationary phase

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• at around 345 °C for both the βNS-CDI 1:4 from DMF and for the βNS-CDI 1:4 from ball mill. The initial mass loss present in both βNS-CDI 1:4 was due to adsorbed environmental water, always present when dealing with hygroscopic cyclodextrin-based nanoparticles. In addition to this, the particle size

• βNS-CDI obtained through ball milling, were less than a micron (800–900 nm) immediately after the synthesis. Moreover, stable suspensions (also in time) with a particle size of around 200 nm for all βNS-CDI were obtained after a short cycle of ball milling with smaller spheres (for details, see

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• packed bed is not new, many features must be considered and solved for success, including: (1) the column packing–making sure the particle size range and how the column is packed provides a system with minimal channeling; (2) selecting a column with the right properties, such as the materials of

• construction, pressure tolerance, heat conduction, and diameter/particle size matching; (3) the column orientation and setup–filters, etc.; (4) activation of the solid phase. The activation issue is one of the most important factors when considering the metal packing. Although our team had success with zinc

• new Knochel-type alkoxides using a stratified bicomponent packed-bed column of magnesium and lithium chloride is presented. Critical insights, such as column packing, particle size, metal excess, reagent scope, order of addition, column stability, reproducibility, and consideration of solid/liquid

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

Synthesis and characterization of bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives

• David Martínez-López,
• Amirhossein Babalhavaeji,
• Diego Sampedro and
• G. Andrew Woolley

Beilstein J. Org. Chem. 2019, 15, 3000–3008, doi:10.3762/bjoc.15.296

• thermal relaxation (τ1/2 ca. 10 min). Experimental General All commercial materials (solvents, reagents, and substrates) were used as received. SilicaFlash silica gel, P60, 40–63 µm particle size (SiliCycle) was used for column chromatography. High-performance liquid chromatography was performed on a

Friedel–Crafts approach to the one-pot synthesis of methoxy-substituted thioxanthylium salts

• Kenta Tanaka,
• Yuta Tanaka,
• Mami Kishimoto,
• Yujiro Hoshino and
• Kiyoshi Honda

Beilstein J. Org. Chem. 2019, 15, 2105–2112, doi:10.3762/bjoc.15.208

• sulfur were performed with a CHNOS Elemental Analyzer Vario ELIII Elemental (Elementar Co.). Column chromatography was carried out with Cicareagent silica gel 60 N (spherical, particle size 63–210 mm). Thin-layer chromatography (TLC) was carried out with Merck TLC plates with silica gel 60 F254. Unless

A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• subjected to various studies like SEM, TEM and DLS experiments. The DLS data revealed that the dispersed particles size in the aqueous phase varied from ≈60 nm to ≈105 nm (Figure 2a). Interestingly, when the same dispersion was used for the analysis of the particle size distribution on a solid surface, i.e

• using 60–120 mesh silica gel and petroleum ether/ethyl acetate mixture as eluent. We got pure products at 3–4% ethyl acetate in petroleum ether and the pure catalyst using 5% methanol in dichloromethane. Bis-amido-tris-amine macrocycle BATA-MC. (a) Number distribution plot with particle size in DLS, (b

Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions

• László Jicsinszky,
• Federica Calsolaro,
• Katia Martina,
• Fabio Bucciol,
• Maela Manzoli and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145

• more effective synthesis of highly substituted γ-CD. Epichlorohydrin-crosslinked CD-polymers (CDPs) have also been effectively prepared in the ball mill. The unoptimised preparations of soluble and insoluble CDPs displayed very small particle size distributions, while the prepared polymers currently

• challenging. Achieving a uniform insoluble CDP particle size is difficult and usually requires special, poorly transferable techniques [13][14][16][20]. The drawbacks of classical derivatisation methods include their problematic scale-up, which explains the limited number of sources of insoluble CDPs and also

• the formed polymers are in progress. Under an electron microscope, the bead polymer showed a smooth surface and a non-Gaussian particle-size distribution that was centred around 65–70 µm, while the ball-milled CDPs were completely bumpy and considerably smaller than the bead polymer, as seen in Figure

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• dried by standard methods prior to use. All synthetic steps were carried out under an argon atmosphere and all glassware used for reactions was dried prior to use. Column chromatography was performed on glass columns packed with silica gel, Merck Silica 60, particle size 40–63 µm (Macherey-Nagel). Thin

Understanding the unexpected effect of frequency on the kinetics of a covalent reaction under ball-milling conditions

• Ana M. Belenguer,
• Adam A. L. Michalchuk,
• Giulio I. Lampronti and
• Jeremy K. M. Sanders

Beilstein J. Org. Chem. 2019, 15, 1226–1235, doi:10.3762/bjoc.15.120

• distance was measured at 4 cm. Supporting Information Supporting Information File 165: Experimental methodology for ball mill grinding experiments, analysis by HPLC and PXRD; quantitation by Rietveld refinement and particle size analysis by Scherrer equation. Supporting Information File 166: Kinetic model

Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

• Alexander F. de la Torre,
• Gabriel S. Scatena,
• Oscar Valdés,
• Daniel G. Rivera and
• Márcio W. Paixão

Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118

• system by charging an HPLC column with PFA-supported catalyst 3. Thus, polymer 3 was packed into a stainless-steel column (Ø = 0.21 cm (diameter), l = 15 cm (length), particle size = 45 µm). The main features of the resulting packed microreactor were determined by pycnometry methodology [20][21], as

• sheets. HPLC chromatograms were obtained on a Shimadzu apparatus, LC-10AT Pump, SPD-10A UV–vis detector, SCL-10A system controller, using a Chiralpak AD-H (4.6 mm Ø × 250 mm length, particle size 5 μm). Optical rotations were measured at the indicated temperature using a Perkin-Elmer Polarimeter, Mod

• , suspended in 25 mL of ethanol) was packed into a stainless-steel HPLC column (Ø = 2.1 mm, l = 150 mm, particle size ≤ 45 µm). The packing was performed under constant pressure (2500 psi) using ethanol (250 mL) as the solvent by using an air-driven liquid pump. Analysis of the continuous-flow catalytic

Extending mechanochemical porphyrin synthesis to bulkier aromatics: tetramesitylporphyrin

• Qiwen Su and
• Tamara D. Hamilton

Beilstein J. Org. Chem. 2019, 15, 1149–1153, doi:10.3762/bjoc.15.111

• particle size), ethyl acetate (anhydrous, 99.8%), hexane (mixture of isomers, 98.5%), deuterated chloroform (99.8 atom % D) were used. 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ, 97.0%) was purchased from TCI America and used without further purification. Pyrrole (98%) was purchased from Sigma-Aldrich

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

• Yo Hiranoi and
• Koji Nakano

Beilstein J. Org. Chem. 2018, 14, 2779–2788, doi:10.3762/bjoc.14.255

• chromatography was performed on glass plates coated with 0.25 mm 230–400 mesh silica gel containing a fluorescence indicator. Column chromatography was performed on silica gel (spherical neutral, particle size: 63–210 μm). Most of the reagents were purchased from commercial suppliers, such as Sigma-Aldrich Co

Dynamic light scattering studies of the effects of salts on the diffusivity of cationic and anionic cavitands

• Anthony Wishard and
• Bruce C. Gibb

Beilstein J. Org. Chem. 2018, 14, 2212–2219, doi:10.3762/bjoc.14.195

• software (Mestrelab Research, S.L.). All dynamic light scattering measurements were performed on a Nicomp ZLS Z3000 particle size analyzer (Particle Sizing Systems – Port Richey, FL), with a 50 mW laser diode (660 nm wavelength) and an avalanche photodiode (APD) detector. Measurements of scattered light

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• treatment was done using t-Student coefficient and the particle size determination error was <2%. The prepared samples were ultrasonicated for 30 min at 25 °C before measurements. Fluorescence spectroscopy Fluorescence experiments were performed in 1.0 cm quartz cuvettes and recorded on a Fluorolog FL-221

Diazirine-functionalized mannosides for photoaffinity labeling: trouble with FimH

• Femke Beiroth,
• Tomas Koudelka,
• Thorsten Overath,
• Stefan D. Knight,
• Andreas Tholey and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1890–1900, doi:10.3762/bjoc.14.163

• silica gel 60 (230–400 mesh, particle size 40–63 µm, Merck). All used solvents were distilled. NMR spectra were recorded on Bruker DRX 500 or Bruker Avance 600 instruments at 300 K. Chemical shifts are relative to the solvent peak of MeOD (3.35 ppm and 4.78 ppm for 1H, 49.3 for 13C). Assignments of the

An amine protecting group deprotectable under nearly neutral oxidative conditions

• Shahien Shahsavari,
• Chase McNamara,
• Mark Sylvester,
• Emily Bromley,
• Savannah Joslin,
• Bao-Yuan Lu and
• Shiyue Fang

Beilstein J. Org. Chem. 2018, 14, 1750–1757, doi:10.3762/bjoc.14.149

• , silica gel 60F-254 over glass support, 0.25 μm thickness. Flash column chromatography was performed using SiliCycle silica gel, particle size 40–63 μm. 1H and 13C spectra were measured on Varian UNITY INOVA spectrometer at 400 and 100 MHz, respectively; chemical shifts (δ) were reported in reference to

Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry

• Katharina Hiebler,
• Georg J. Lichtenegger,
• Manuel C. Maier,
• Eun Sung Park,
• Renie Gonzales-Groom,
• Bernard P. Binks and
• Heidrun Gruber-Woelfler

Beilstein J. Org. Chem. 2018, 14, 648–658, doi:10.3762/bjoc.14.52

• connected to their catalytic activity. Nevertheless, there are indications that the surface area and the particle size distribution play a role in the catalytic performance of the palladium substituted metal oxides. In view of the aimed application of the Pd metal oxides for targeted API synthesis, the

• reduction of catalyst particles As mentioned before, the as synthesised catalyst particles have particle diameters in the range of 10–100 µm. Since the stabilisation of micron-sized Pickering emulsion droplets requires particle sizes <1 μm, a decrease of particle size was necessary. For that purpose, a

• particle concentrations may be due to particle aggregation in water prior to emulsification. Such large particle aggregates of high density would be weakly retained at the oil–water interfaces offering little protection to the coalescence between drops. However, a more detailed look at the particle size in