New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

• Daily Rodríguez-Padrón,
• Alina M. Balu,
• Antonio A. Romero and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

• basic probe molecules applying a pulse chromatographic titration methodology. The catalyst used (≈0.025 g) was fixed inside a tubular stainless steel microreactor (4 mm internal diameter) by Pyrex glass wool. A cyclohexane solution of titrant (0.989 M in PY and 0.686 M in DMPY, respectively) was

Influence of the milling parameters on the nucleophilic substitution reaction of activated β-cyclodextrins

• László Jicsinszky,
• Kata Tuza,
• Giancarlo Cravotto,
• Andrea Porcheddu,
• Francesco Delogu and
• Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 1893–1899, doi:10.3762/bjoc.13.184

• the reactor, the nucleophilic substitution with NaN3 was performed using glass reactors 2 and 25 mL in volume and the same number of balls of equal size (30 balls of 1 mm in diameter). The experimental findings are summarized in Figure 1 and Supporting Information File 1, Table S1 entries 18 and 19

• zirconia balls of 12 mm in diameter (ø) for comparison). Values given on the graph bars indicate, respectively, the yield and the reaction time to achieve full conversion of the starting Ts-β-CD. Reaction time as a function of ball materials at 550 min−1 in glass vials of 25 mL: a) equal weight: 60 steel

β-Cyclodextrin- and adamantyl-substituted poly(acrylate) self-assembling aqueous networks designed for controlled complexation and release of small molecules

• Liang Yan,
• Duc-Truc Pham,
• Philip Clements,
• Stephen F. Lincoln,
• Jie Wang,
• Xuhong Guo and
• Christopher J. Easton

Beilstein J. Org. Chem. 2017, 13, 1879–1892, doi:10.3762/bjoc.13.183

• two cases. All sample solutions were prepared in D2O Na2HPO4/KH2PO4 buffer solutions at pD 7.0 and I = 0.10 mol dm−3 and were equilibrated at the thermostated probe temperature of 298.2 ± 0.1 K for 30 min in 5 mm diameter NMR tubes prior to their spectra being recorded. Chemical shifts (δ, ppm) were

Selective enzymatic esterification of lignin model compounds in the ball mill

• Ulla Weißbach,
• Saumya Dabral,
• Laure Konnert,
• Carsten Bolm and
• José G. Hernández

Beilstein J. Org. Chem. 2017, 13, 1788–1795, doi:10.3762/bjoc.13.173

• diameter) [9], demonstrated to efficiently mediate the enzymatic kinetic resolution of secondary alcohols under solvent-free conditions in both mixer and planetary ball mills (Scheme 1b) [10]. Interestingly, this latter lipase (a commercial preparation known as Novozyme 345, hereinafter referred as CALB

• -1a with CALB in the ball mill A mixture of erythro-1a (50 mg, 0.15 mmol), acyl donor 2 (0.60 mmol) and CALB (30 mg of the immobilized enzyme) was milled for 2 h to 6 h at 30 Hz in a 10 mL ZrO2 milling jar loaded with 6 ZrO2 milling balls (5 mm in diameter). After the milling was stopped, the reaction

• erythro-1a with isopropenyl acetate (2a) in the ball mill. Reaction conditions: erythro-1a (50 mg, 0.15 mmol), 2a (0.60 mmol), CALB (30 mg of immobilized enzyme) or NaOH (12 mg, 0.30 mmol), 10 mL ZrO2 milling jar, 6 ZrO2 milling balls (5 mm in diameter). CALB-catalyzed esterification of lignin model

Mechanochemical enzymatic resolution of N-benzylated-β³-amino esters

• Mario Pérez-Venegas,
• Gloria Reyes-Rangel,
• Adrián Neri,
• Jaime Escalante and
• Eusebio Juaristi

Beilstein J. Org. Chem. 2017, 13, 1728–1734, doi:10.3762/bjoc.13.167

• CALB enzyme under high-speed ball-milling (HSBM) conditions as a method to obtain enantiopure N-benzylated-β3-amino acids (Scheme 1). Results and Discussion A racemic mixture of substrate rac-1a (82 mg, 1 equiv) was milled in an Agate jar (12 mm of diameter, 4.6 mL) with an Agate ball (6 mm of diameter

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

• -Pd NPs of a mean diameter of 10 nm were obtained using a platinum electrode, characterized as previously reported, and used without additional purification [46][47]. In a previous work the PVP-Pd NPs synthesized using a vitreous carbon electrode were tested on the Mizoroki–Heck reaction with 4-iodo

• cycle was performed. The physical separation of NPs was carried out by centrifugation as previously reported [48]. The comparison of both TEM micrographs disclosed that the original PVP-Pd NPs [(9 ± 2) nm] clump to larger aggregates after the first catalytic cycle, providing NPs with a mean diameter of

A recursive microfluidic platform to explore the emergence of chemical evolution

• David Doran,
• Marc Rodriguez-Garcia,
• Rebecca Turk-MacLeod,
• Geoffrey J. T. Cooper and
• Leroy Cronin

Beilstein J. Org. Chem. 2017, 13, 1702–1709, doi:10.3762/bjoc.13.164

• neighbouring droplets. Size sorting is then used to select for droplets with a diameter (D) above a size threshold for droplets to be used in the next generation (f). Those droplets are recirculated into the next generation, replenished with fresh feedstock, and the process is repeated in an iterative fashion

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

• Sadaf Hanif,
• Bernd Oschmann,
• Dmitri Spetter,
• Muhammad Nawaz Tahir,
• Wolfgang Tremel and
• Rudolf Zentel

Beilstein J. Org. Chem. 2017, 13, 1693–1701, doi:10.3762/bjoc.13.163

• 10% for the carbon coated particles (Figure 4a). The resulting particles were also characterized by transmission electron microscopy (TEM), and corresponding images are shown in Figure 6a and 6b. The average particle diameter is ≈8 nm. Figure 6b shows nanoparticles sheathed and connected through

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

• of the milling-ball diameter is, the tendency of the product yield is similar under different filling degrees. A maximum yield (84%) was obtained by using 5 mm milling balls at 0.25 filling degree. In addition, the 14 mm milling balls exhibited the higher yields than 5 mm, 8 mm and 10 mm milling

Photocatalyzed synthesis of isochromanones and isobenzofuranones under batch and flow conditions

• Manuel Anselmo,
• Lisa Moni,
• Hossny Ismail,
• Davide Comoretto,
• Renata Riva and
• Andrea Basso

Beilstein J. Org. Chem. 2017, 13, 1456–1462, doi:10.3762/bjoc.13.143

• atmosphere was not essential, we therefore decided to test our synthetic methodology with an in house-made flow apparatus. The reaction coil was formed with 1 m of FEP tubing (internal diameter 0.8 mm) wrapped around a glass cylinder. Irradiation was obtained with strips of blue LEDs attached inside a hollow

Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

• Ana Franco,
• Sudipta De,
• Alina M. Balu,
• Araceli Garcia and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1439–1445, doi:10.3762/bjoc.13.141

• with a pore diameter of 39 nm and pore volume of 0.74 cm3 g−1 (Table 1). After the ball milling with metal precursors, the mesoporous structure of RGO was found to be partially collapsed as observed from BET isotherms in Figure 1b and c. BET surface areas of metal supported RGO materials consequently

• decreased, with increased pore diameter and pore volume as a consequence of the structure deterioration observed after milling. Additional macroporosity (interparticular) was created upon milling, which increased both pore diameter and volume. SEM results also support the observation from BET analysis. The

• for 24 h at 30 °C under vacuum (P0 < 10−2 Pa) and subsequently analyzed. Surface areas were calculated according to the BET (Brunauer–Emmet–Teller) equation. Mean pore size diameter and pore volumes were measured from porosimetry data by using the BJH (Barret–Joyner–Halenda) method. Wide-angle X-ray

A new member of the fusaricidin family – structure elucidation and synthesis of fusaricidin E

• Marcel Reimann,
• Louis P. Sandjo,
• Luis Antelo,
• Eckhard Thines,
• Isabella Siepe and
• Till Opatz

Beilstein J. Org. Chem. 2017, 13, 1430–1438, doi:10.3762/bjoc.13.140

• phase was concentrated in vacuo again. This step was repeated until no further salt precipitates were visible. A portion of the extract (30 g) was dissolved in methanol and adsorbed to silica gel (Merck, K60, 70–230 mesh, 50 g), dried at 40 °C and applied onto silica gel (1 kg, column 10 cm diameter, 30

Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

• Desirée Leistenschneider,
• Nicolas Jäckel,
• Felix Hippauf,
• Volker Presser and
• Lars Borchardt

Beilstein J. Org. Chem. 2017, 13, 1332–1341, doi:10.3762/bjoc.13.130

• average diameter of 8 nm (due to the removal of TiO2 nanodomains) (Figure 6, Equation 1). The mesopore diameter (Table 1 and Figure 6) aligns very well with the calculated domain size of TiO2 nanocrystals derived from the Scherrer equation. A more precisely evaluation of the hierarchical pore structure is

• pores. This process finally leads to a higher mesopore volume at the expense of a narrower pore-size distribution (Figure 6). The EG ratio does not impact the particle size of the TiO2 nanostructures and thus the pore-size distributions are similar for all investigated materials (average diameter of 8

• ZrO2 with a diameter of 15 mm were used. Afterwards, different amounts of EG are added and the mixture was ball-milled for another 5 min with 700 rpm. The molar ratio of CA and EG was varied from 1:3 to 1:1. For the liquid-assisted synthesis, 5 mL EtOH were added to the first grinding step. The

Kinetic analysis of mechanoradical formation during the mechanolysis of dextran and glycogen

• Naoki Doi,
• Yasushi Sasai,
• Yukinori Yamauchi,
• Tetsuo Adachi,
• Masayuki Kuzuya and
• Shin-ichi Kondo

Beilstein J. Org. Chem. 2017, 13, 1174–1183, doi:10.3762/bjoc.13.116

• samples mechanically fractured at room temperature were multicomponent. The radical concentration of Dx and Gly mechanoradicals gradually decreased during vibratory milling after reaching the maximum value. Although the molecular weight of Dx or the particle diameter of Gly steeply diminished until

• reaching the each maximum value of radical concentration, after that the molecular weight or the particle diameter slowly decreased. These results suggested that Dx and Gly mechanoradicals might be more unstable than amylose radicals possessing an intramolecular helical structure due to the branched

• difference of bonding type. The present paper focused on the polymer structure, such as helical (amylose), branched (Dx) and hyper-branched structure (Gly), to clarify the stability of component radicals depending on the polymer structure. Progressive changes in Dx molecular weight and Gly particle diameter

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• diameter range can be obtained [4]. Moreover, this synthetic procedure allows to introduce different types of carbohydrates and other ligands (i.e., polyethylene chains, lipids, peptides, DNA, RNA or fluorescent dyes) in controlled ratios [4]. A modification of this technique consists in the application of

• ligand exchange protocol to introduce the thiolated saccharide molecules [20][21][22]. In this frame, the Turkevich method [23] is the most common protocol to produce citrate-capped spherical nanoparticles, with diameter size between 10 and 50 nm. Noteworthy, by employing surfactant or templating agents

• the gold Fermi wavelength, the nanoparticles acquire photoluminescence properties [31]. These small clusters typically present a diameter between 0.5 and 2 nm. When clusters are bigger, they do not present fluorescent emission but they show a localized surface plasmon resonance (LSPR) around 520 nm

Aggregation behaviour of a single-chain, phenylene-modified bolalipid and its miscibility with classical phospholipids

• Simon Drescher,
• Vasil M. Garamus,
• Christopher J. Garvey,
• Annette Meister and
• Alfred Blume

Beilstein J. Org. Chem. 2017, 13, 995–1007, doi:10.3762/bjoc.13.99

• function, pCS(r), has been obtained (Supporting Information File 1, Figure S1). This distribution function gives values of the diameter of cross section of ≈ 50–55 Å and an aggregation number Nagg of about 9 ± 1 bolalipid molecules per 1 nm length of cylinder at T = 4 °C. At 32 °C – a temperature between

• scale above 100 Å. It can be concluded that an increase of temperature from 4 °C to 32 °C shifts system from long and rigid fibres to flexible chains. Additionally, also the cross-sectional parameters of flexible chain changes, i.e., the diameter increases up to 70 Å (Supporting Information File 1

• , Figure S1) and Nagg slightly increases to 10 ± 1 bolalipid molecules per 1 nm length of flexible chain. At 60 °C, the scattering intensities at lowest q-range are typical for scattering from small globular objects such as micelles. Mean diameter D of these objects (q << 1/D) and p(r) has been obtained in

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

Interactions between shape-persistent macromolecules as probed by AFM

• Johanna Blass,
• Jessica Brunke,
• Franziska Emmerich,
• Cédric Przybylski,
• Vasil M. Garamus,
• Artem Feoktystov,
• Roland Bennewitz,
• Gerhard Wenz and
• Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

• unit of Lmon = 9.2 Å and the chemical composition C54H75NO35 (molecular weight 1298.17 g/mol). Rg,CS has been used to calculate the cross-section diameter of the homogeneous cylinder to be 30 Å. Scattering intensities do not change significantly with concentration indicating that the value of S(0) is

Expression, purification and structural analysis of functional GABA transporter 1 using the baculovirus expression system

• Jing Hu,
• Chris Weise,
• Christoph Böttcher,
• Hua Fan and
• Jian Yin

Beilstein J. Org. Chem. 2017, 13, 874–882, doi:10.3762/bjoc.13.88

• hydrated state. After a BCA control, the fraction of peak 2 containing the larger amount of protein was characterized by cryo-TEM and showed a very monodisperse distribution of particles (Figure 5B) with a diameter in the 5–6 nm range, which might correspond to protein monomers. The peak 1 fraction

• : SE-FPLC fractions from 8.8 to 10.8 mL. Characterization of the GAT1/GFP fusion protein after SE-FPLC. (A) Elution profile of GAT1/GFP protein after SE-FPLC on a Superdex 200TM column. (B) Cryo-TEM image of fraction peak 2. Assumed monomeric GAT1/GFP fusion proteins (M, diameter = 5–6 nm) are

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

• hydrogenations are conveniently achieved under flow using fixed bed devices, wherein the size of the inner diameter of reactor channels distinguishes between micro (10–500 μm) or mesofluidic (500 μm up to several mm) reactors [79][80]. This size range may allow for the production of mg to tens of tons of target

• and will not be discussed. Capillary reactors (10–1000 μm internal diameter, 0.1–30 m length) are routinely used in the lab-scale synthesis due to the ease of operations, negligible heat effects and fast reactants mixing [84][85]. Issues may arise from miniaturization of the catalysts, where the most

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• carbon-based nanomaterials which are typically discrete, quasi-spherical nanoparticles, with sizes usually less than 10 nm in diameter (although bigger sizes have recently been reported). These relatively new nanomaterials have found many applications in the fields of photo- and electrocatalysis

• -dopant/surface passivation agent (Scheme 5) [33]. The resultant CDs had a QY of up to 12% (34-times higher than that of the undoped CDs). Interestingly, the N-doped CDs in this report had a 20 nm diameter, as determined by TEM, which is contrary to the generally held belief that CDs’ particular

• properties are only observed below a diameter of 10 nm, which is not the case here and has since been observed in one other carbohydrate-derived CD synthesis [34]. The team demonstrated the utility of the glucose/tryptophan-derived CDs as a sensor of peroxynitrite anions (NO3−) in solution. The peroxynitrite

Fast and efficient synthesis of microporous polymer nanomembranes via light-induced click reaction

• Qi An,
• Youssef Hassan,
• Xiaotong Yan,
• Peter Krolla-Sidenstein,
• Tawheed Mohammed,
• Mathias Lang,
• Stefan Bräse and
• Manuel Tsotsalas

Beilstein J. Org. Chem. 2017, 13, 558–563, doi:10.3762/bjoc.13.54

• investigations. The thin films show high mechanical stability as evidenced by the possibility to create feestanding membranes across holes of about 3–5 µm diameter. The rapid and scalable synthetic method for CMP nanomembranes described in this article, along with the possibility to transfer the nanomembranes to

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

• have a larger inner diameter at the centre than at the ends (Figure 1). The larger central portion of the flow cell is the sample chamber, i.e., the detection zone. The smaller segments at the ends correspond to the inlet and the outlet stems. When designing a flow cell, the total volume of the sample

• breakage of glass sample tubes. Microcoil probes An interesting way to increase the sensitivity of NMR is the use of microcoil probes [15][16]. Based on the reciprocity principle [15], it has been shown that for a constant length-to-diameter ratio, the NMR detector (i.e., coil) sensitivity is inversely

• proportional to its diameter. For a volume-limited sample, the signal is maximized when the coil is scale-down to enclose this volume sample. Although these probes show several advantages, as for instance are the coupling into continuous flow systems and its integration in compact magnets due to their lower

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

• Andrew J. Capel,
• Andrew Wright,
• Matthew J. Harding,
• George W. Weaver,
• Yuqi Li,
• Russell A. Harris,
• Steve Edmondson,
• Ruth D. Goodridge and
• Steven D. R. Christie

Beilstein J. Org. Chem. 2017, 13, 111–119, doi:10.3762/bjoc.13.14

• of 123 × 67 × 42 mm (volume ≈68 cm3), and a continuous cylindrical channel running throughout the part (channel diameter = 1.5 mm, channel length = 1600 mm, reaction volume = 2.8 mL). The external dimensions of the flow cell would match the internal dimensions of the DAD compartment, allowing the

• use of an Ocean optics DH2000 light source (400 micron diameter illumination fibre, 600 micron collection fibre) and an Ocean Optics S2000 variable wavelength detector [27]. It was possible to determine the amount of stray light (predominantly from fluorescent strip lighting within the laboratory

• continuous cylindrical channel running throughout (channel diameter = 2 mm, channel length = 3200 mm, theoretical reaction volume = 10 mL). The titanium alloy used to manufacture the part is thermally stable across a substantial temperature range, and chemically compatible with a wide range of organic

Nucleophilic displacement reactions of 5′-derivatised nucleosides in a vibration ball mill

• Olga Eguaogie,
• Patrick F. Conlon,
• Francesco Ravalico,
• Jamie S. T. Sweet,
• Thomas B. Elder,
• Louis P. Conway,
• Marc E. Lennon,
• David R. W. Hodgson and
• Joseph S. Vyle

Beilstein J. Org. Chem. 2017, 13, 87–92, doi:10.3762/bjoc.13.11

• a single (patent) report of CldA substitution using the Mob-thiolate anion (requiring 12 hours at up to 55 °C to achieve 68% yield) [25]. Optimisation of VBM conditions was performed over several phases using 25 mL vessels and 15 mm diameter balls (both with either steel or zirconia components in