An uracil-linked hydroxyflavone probe for the recognition of ATP

• Márton Bojtár,
• Péter Zoltán Janzsó-Berend,
• Dávid Mester,
• Dóra Hessz,
• Mihály Kállay,
• Miklós Kubinyi and
• István Bitter

Beilstein J. Org. Chem. 2018, 14, 747–755, doi:10.3762/bjoc.14.63

• complex were computed. Foremost, a molecular mechanical (MM) conformation analysis was performed for the individual molecules using the MMFF force field [47]. The stable conformers were optimized further at the density functional theory (DFT) level using the PBE functional [48][49] with D3BJ dispersion

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• demonstrated the specific features which make these nanoreactors an advantageous choice for chemical synthesis. In particular, they combine a high active surface area with a good dispersion in solution and therefore are ideal structures for facile diffusion of reactants. Furthermore, the compartments protect

Liquid-assisted grinding and ion pairing regulates percentage conversion and diastereoselectivity of the Wittig reaction under mechanochemical conditions

• Kendra Leahy Denlinger,
• Lianna Ortiz-Trankina,
• Preston Carr,
• Kingsley Benson,
• Daniel C. Waddell and
• James Mack

Beilstein J. Org. Chem. 2018, 14, 688–696, doi:10.3762/bjoc.14.57

• formation of this bond may have a large influence under mechanochemical conditions because there is not a solvent reservoir to accept the dispersion of these ions. Using Pearson’s hard and soft acid and base (HSAB) theory [29] and the Jones–Dole viscosity B coefficient [30] (Table 3), we can predict which

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

• in water of 0.03 wt % (upper), 0.30 wt % (middle) and 1.0 wt % (lower) at different times since preparation. A is the aqueous dispersion of particles, B is after addition of oil but before emulsification. Optical microscopy images of cyclohexane-in-water emulsions of Figure 4 after one month for

• in Figure 4 (note nonlinear scale). Mean particle diameter in aqueous dispersions as a function of Ce0.495Sn0.495Pd0.01O2–δ concentration. Particle size measurements were carried out with a Mastersizer 2000 laser diffraction granulometer with the dispersion unit Hydro2000SM(A). Variation of the zeta

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• water-in-oil (w/o) microemulsion (water/Brij@30/n-heptane). This methodology has been previously used in our laboratory [27][28]. We first explored the morphology, size and dispersion of Pd nanoparticles supported on Vulcan XC72R carbonaceous material (Pd/C electrocatalysts) using TEM micrographs. As

• shown in Figure 1a, a good dispersion of spherical Pd nanoparticles of about 4–5 nm size is obtained. As expected, EDX analysis of Pd nanoparticles displays palladium as the sole metal, as shown in Figure 1b. With respect to the Pd loading in the Pd/C electrocatalyst, TGA results shown in Figure 1c lead

• nanoparticles supported in Vulcan XC72R 30 wt % dispersion in isopropanol containing a Nafion dispersion of 5 wt %. All electrodes have a Pd/C to Nafion ratio of 60:40 in the electrocatalytic layer with Pd loadings of 0.20 and 0.02 mg cm−2. Cathodes were named as Pdx/C/T where x stands for the Pd loading and T

Terahertz spectroscopy of 2,4,6-trinitrotoluene molecular solids from first principles

• Ido Azuri,
• Anna Hirsch,
• Anthony M. Reilly,
• Alexandre Tkatchenko,
• Shai Kendler,
• Oded Hod and
• Leeor Kronik

Beilstein J. Org. Chem. 2018, 14, 381–388, doi:10.3762/bjoc.14.26

• theory that includes Tkatchenko–Scheffler pair-wise dispersion interactions. Furthermore, we show that for these polymorphs the theoretical results are only weakly affected by many-body dispersion contributions. The absence of dispersion interactions, however, causes sizable shifts in vibrational

• yield reliable simulated spectra for complex materials is density functional theory (DFT) [23]. A significant complication, however, is that conventionally used exchange–correlation energy functionals in DFT do not describe the intermolecular dispersion interactions well. Therefore, early calculations

• employing them were not always able to achieve satisfactory agreement with experiment, as cautioned in [24]. Recent years have seen major improvements in DFT augmented by pair-wise dispersion interaction terms, to the point where they can be used regularly to predict properties of molecular solids [21][25

A permutation approach to the assignment of the configuration to diastereomeric tetrads by comparison of experimental and ab initio calculated differences in NMR data

• Przemysław J. Boratyński

Beilstein J. Org. Chem. 2017, 13, 2478–2485, doi:10.3762/bjoc.13.245

• , 132.1, 128.0, 122.25, 122.20, 119.9, 114.9, 100.4, 61.4, 57.4, 56.0, 55.8, 41.5, 39.5, 27.7, 27.2, 25.2 ppm; HRMS–ESI–TOF (m/z): [M + H]+ calcd for C22H26N5O, 376.2132; found, 376.2141. 9R-Phenyl-9-deoxyquinine (2b): Under inert gas (Ar), a sodium hydride dispersion (60% in mineral oil, 195 mg, 4.9 mmol

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• , Figures S11–S14). Computational details. Calculations were carried out using the B3LYP hybrid functional combined with an empirical Grimme’s D3 dispersion correction [55] (B3LYP-D3) implemented in Gaussian 09 [56]. The standard 6-311+G(2d,p) basis set with the ultrafine method was used for C, H, N, F, Cl

An efficient synthesis of a C₁₂-higher sugar aminoalditol

• Łukasz Szyszka,
• Anna Osuch-Kwiatkowska,
• Mykhaylo A. Potopnyk and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2017, 13, 2146–2152, doi:10.3762/bjoc.13.213

• , 6.72; N, 0.88. To a stirred solution of 8 (0.35 g, 0.21 mmol) in DMF (20 mL) containing imidazole (1.5 mg), sodium hydride (60% dispersion in mineral oil, 80.6 mg, 2.1 mmol) was added, and the mixture was stirred at 20 °C for 30 min. Benzyl bromide (0.2 mL, 1.68 mmol) was added dropwise and the mixture

Main group mechanochemistry

• Agota A. Gečiauskaitė and
• Felipe García

Beilstein J. Org. Chem. 2017, 13, 2068–2077, doi:10.3762/bjoc.13.204

• complete eradication of solvents might not be entirely beneficial. Solvents ameliorate reactant interactions, control reaction rates, and aid heat dispersion in exothermic reactions inter alia. Needless to say, solvents are necessary for the extraction, separation, and purification of the final products

Conformational impact of structural modifications in 2-fluorocyclohexanone

• Francisco A. Martins,
• Josué M. Silla and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2017, 13, 1781–1787, doi:10.3762/bjoc.13.172

• ωB97X-D/6-311++g(d,p) [28][29] level (thus including empirical dispersion effects) to obtain the Gibbs free energies (1.00 atm and 298.15 K). Natural orbital bond (NBO) analyses were carried out for the optimized structures at the same level of theory using the NBO 6.0 program [30], in order to obtain

An efficient Pd–NHC catalyst system in situ generated from Na₂PdCl₄ and PEG-functionalized imidazolium salts for Mizoroki–Heck reactions in water

• Nan Sun,
• Meng Chen,
• Liqun Jin,
• Wei Zhao,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 1735–1744, doi:10.3762/bjoc.13.168

• ), 3.04 (s, 3H, SO2CH3); 13C NMR (CDCl3) δ 71.9–68.2 (CPEG), 60.7, 58.2, 36.8. Synthesis of MeO-PEG1900-Im To a solution of imidazole (0.89 g, 13 mmol) in 120 mL of dry THF at room temperature under N2 atmosphere was added NaH (60% dispersion in mineral oil, 0.8 g, 20 mmol). The mixture was then heated to

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• -bromoacetophenone (1a) and styrene (2a). In our previous reports [46][47][48], it was exposed that a PVP-Pd NPs aqueous dispersion exhibited a high stability, and for that reason, the Pd NPs cannot be separated by a physical technique. Any attempt to separate the nanocatalyst from reaction media by centrifugation

• (20 ± 10) nm with high dispersion in size (Figures S1 and S2, Supporting Information File 1). However, these bigger NPs were still active as catalysts, since with this larger NPs several catalytic cycles were performed (Figure 1). The morphology of the NPs like a “blackberry” appeared not to be

• the galvanostatic electrolysis. After completion of the reaction the aqueous dispersion of Pd NPs was placed in a 25 mL volumetric flask to be used as catalyst solution for Mizoroki–Heck coupling reaction without further purification. Average dimensions and shapes of Pd NPs were determined by

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

• − successfully intercalated into the MgAl-LDHs interlayers. As compared with MgAl-LDHs and MgAl-LDHs-PdCl42−, the catalyst of Pd/MgAl-LDHs exhibited a lower intensity pattern except for the diffraction peaks at 38° and 44°, which was due to the random dispersion of the Pd component on the Pd/MgAl-LDHs surface

Chemical systems, chemical contiguity and the emergence of life

• Terrence P. Kee and
• Pierre-Alain Monnard

Beilstein J. Org. Chem. 2017, 13, 1551–1563, doi:10.3762/bjoc.13.155

• , nor preclude the “re”-dispersion of the lipid phases into dispersed aggregates with encapsulated catalysis products [52]. Chemical systems and chemical contiguity in the dispersed state The chemical systems aspect during the emergence of cell-like entities can also be highlighted once the chemical

BODIPY-based fluorescent liposomes with sesquiterpene lactone trilobolide

• Ludmila Škorpilová,
• Silvie Rimpelová,
• Michal Jurášek,
• Miloš Buděšínský,
• Jana Lokajová,
• Roman Effenberg,
• Petr Slepička,
• Tomáš Ruml,
• Eva Kmoníčková,
• Pavel B. Drašar and
• Zdeněk Wimmer

Beilstein J. Org. Chem. 2017, 13, 1316–1324, doi:10.3762/bjoc.13.128

• formulation (ratio 4:4:1:1, respectively). A hydrophobic film prepared by evaporation of a lipid–chloroform solution was hydrated with physiological solution. The desired unilamellar vesicles were obtained by homogenization of the dispersion through a 100 nm pore size polycarbonate filter. Characterization of

Cycloheximide congeners produced by Streptomyces sp. SC0581 and photoinduced interconversion between (E)- and (Z)-2,3-dehydroanhydrocycloheximides

• Li Yang,
• Ping Wu,
• Jinghua Xue,
• Huitong Tan,
• Zheng Zhang and
• Xiaoyi Wei

Beilstein J. Org. Chem. 2017, 13, 1039–1049, doi:10.3762/bjoc.13.103

• functional theory (TDDFT) calculations were performed with the Gaussian 09 program package [24]. For computations of ECD spectra, the conformers generated by a MMFF conformational search in an energy window of 10 kcal/mol were subjected to geometry optimization using the dispersion-corrected DFT-D3 method

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97

The effect of cyclodextrin complexation on the solubility and photostability of nerolidol as pure compound and as main constituent of cabreuva essential oil

• Joyce Azzi,
• Pierre-Edouard Danjou,
• David Landy,
• Steven Ruellan,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2017, 13, 835–844, doi:10.3762/bjoc.13.84

• (randomly methylated β-CD, RAMEB, or a low 2-O-methylated-β-CD, CRYSMEB) and sulfobutylether-β-CD (SBE-β-CD) (Figure 1). Molecular complexation in CDs has been widely proposed for EOs to limit their degradation during processing and storage and to offer a good dispersion of compounds in the aqueous media

Cyclodextrins tethered with oligolactides – green synthesis and structural assessment

• Cristian Peptu,
• Mihaela Balan-Porcarasu,
• Alena Šišková,
• Ľudovít Škultéty and
• Jaroslav Mosnáček

Beilstein J. Org. Chem. 2017, 13, 779–792, doi:10.3762/bjoc.13.77

• DL-LA) are solid in the range of temperature applied during the reaction. Attempts to resolve the reactants mixing problem were made by using δ-valerolactone (VL) as dispersion environment for the lactides. A better overall conversion and increased molecular weights were observed but the authors did

• spectroscopy. Liquid chromatography and tandem MS fragmentation studies [21][22][23] are also important additions in deeper structural characterization of CD-oligoester conjugates. The L-LA was reacted with α-, β- and γ-CD (Scheme 1) in bulk at 110 °C in order to ensure a good dispersion of reactants. The

• molar ratio between L-LA and OH groups of CDs was kept to a value of 5 for all types of CDs (Table 1) and the reaction was stopped after 72 hours. Although the cyclodextrins were only dispersed in the molten monomer the magnetic stirring insured a good dispersion of the reactants. In previous studies

Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes

• Carmen Moreno-Marrodan,
• Francesca Liguori and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2017, 13, 734–754, doi:10.3762/bjoc.13.73

• conditions compared to Pd (373 K, 10 bar H2) [123]. Interestingly, the productivity of these systems could be significantly improved by adopting the same atomic level dispersion approach above described for palladium. Thus, Ag onto tricyanomethanide doped mpg-C3N4 provided comparatively much higher reaction

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

• dispersion of this nucleus. The authors determined the association constant of the complex of NaPF6 with α-cyclodextrin at the picomole level with a detection volume of 50 nL and using non-deuterated solvents [25]. To conclude with the different coil geometries, microslot NMR microprobes and stripline coils

• regard to high field instruments, it is possible to obtain a ratio of up to 10:1 and this is sufficient for many applications. The major problems arise in reactions involving complex structures with small chemical shift dispersion and second-order coupling, which produce complex spectra with several

Self-optimisation and model-based design of experiments for developing a C–H activation flow process

• Alexander Echtermeyer,
• Yehia Amar,
• Jacek Zakrzewski and
• Alexei Lapkin

Beilstein J. Org. Chem. 2017, 13, 150–163, doi:10.3762/bjoc.13.18

• to inaccuracies of generating mixtures with specific concentrations by pumps. Laminar flow through long pipes will necessarily cause dispersion, which dictates the minimum reaction slug length that can be used. This was determined experimentally, which also allowed to develop the method of detection

• , see Figure 2. The reaction mixture segments and the solvent were pumped through a 10 mL polytetrafluoroethylene (PTFE) tubular reactor and quenched in an ice bath at the reactor outlet. A minimum segment volume of 2 mL was found to be necessary to avoid dispersion effects in the centre of the segment

• segment, which was assumed to behave as a batch reactor, as samples were taken in the dispersion-free centre of the segment. For the purpose of calculating the cost associated with heating the system, a steady state energy balance, Equation 9, was established. were ηheat denotes an overall efficiency of

A postsynthetically 2’-“clickable” uridine with arabino configuration and its application for fluorescent labeling and imaging of DNA

• Heidi-Kristin Walter,
• Bettina Olshausen,
• Ute Schepers and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2017, 13, 127–137, doi:10.3762/bjoc.13.16

• ice bath. Then NaH (0.168 g, 4.20 mmol of 60% dispersion in mineral oil) was added and the reaction mixture was stirred for 15 min at 0 °C. The reaction mixture was warmed to room temperature and propargyl bromide (0.94 mL, 1.25 g, 8.40 mmol) was added slowly within 30 minutes. The reaction was

Extrusion – back to the future: Using an established technique to reform automated chemical synthesis

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 65–75, doi:10.3762/bjoc.13.9

• industry, generally for the dispersion of materials (e.g., graphene or quantum dots) into polymers [7]. However, REX is also employed as a technique to synthesise polymers or to carry out post synthetic polymer modification (e.g., functionalisation of polymer chains) via organic transformations, which in