Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• numbers (100–400) on bacterial surfaces, have a diameter of 5–7 nm and can extend hundreds of nanometers in length. Pili, on the other hand, are thicker, longer, and less abundant. Most bacteria encode multiple lectins, each with different carbohydrate specificities [63]. The most intensely studied

• and with aggregative properties. These cell surface structures are produced by several members of the Enterobacteriaceae family [112]. The Mtb curli-like pili (MTP) encoded by Rv3312A, although currently disputed [113], are 2–3 nm in diameter, have a similar ultrastructure to curli pili of E. coli or

MoO₃ on zeolites MCM-22, MCM-56 and 2D-MFI as catalysts for 1-octene metathesis

• Hynek Balcar,
• Martin Kubů,
• Naděžda Žilková and
• Mariya Shamzhy

Beilstein J. Org. Chem. 2018, 14, 2931–2939, doi:10.3762/bjoc.14.272

• . 6MoO3/SBA-15 was prepared from all-siliceous SBA-15 (SBET = 877m2/g, V = 1.07cm3/g, pore diameter D = 6.4 nm) and it is known as a very active and selective catalyst [9][10]. Under reaction conditions applied the selectivity to tetradecene was about 98% during the whole experiment, and therefore only

• Agilent 6890 with a DB-5 column (length: 50 m, inner diameter: 320 μm, stationary phase thickness: 1 μm), equipped with a 7683 Automatic Liquid Sampler and a FID detector and GC/MS (ThermoFinnigan, FOCUS DSQ II single Quadrupole) were used. Conversions were calculated from the mass balance. A,B,C,D: XRD

Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis

• Daniel F. Sauer,
• Johannes Schiffels,
• Takashi Hayashi,
• Ulrich Schwaneberg and
• Jun Okuda

Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265

• ]. Common anchoring strategies for metal-complex or metal ion incorporation into protein scaffolds. Top: NB4 (PDB 3WJB); bottom: NB4exp. Highlighted in blue are the additional two β-sheets. Highlighted in red is the diameter of the cavity. Left: Mechanism of the olefin metathesis reaction postulated by

Quinolines from the cyclocondensation of isatoic anhydride with ethyl acetoacetate: preparation of ethyl 4-hydroxy-2-methylquinoline-3-carboxylate and derivatives

• Nicholas G. Jentsch,
• Jared D. Hume,
• Emily B. Crull,
• Samer M. Beauti,
• Amy H. Pham,
• Julie A. Pigza,
• Jacques J. Kessl and
• Matthew G. Donahue

Beilstein J. Org. Chem. 2018, 14, 2529–2536, doi:10.3762/bjoc.14.229

• stirring, the mixture became homogenous followed by precipitation of a pale white solid. The solid was collected by vacuum filtration on a Büchner funnel (7.6 cm diameter) with Whatman #1 filter paper (70 mm) and air pulled through for 5 minutes. The material was transferred to a 250 mL Erlenmeyer flask

• . The reaction solution was cooled to room temperature (25 °C) and poured into a 500 mL beaker equipped with cylindrical PTFE stir bar (16 mm × 37 mm) containing 250 mL of deionized water causing a beige solid to precipitate out of solution. The solid was collected on a Büchner funnel (7.6 cm diameter

The mechanochemical synthesis of quinazolin-4(3H)-ones by controlling the reactivity of IBX

• Md Toufique Alam,
• Saikat Maiti and
• Prasenjit Mal

Beilstein J. Org. Chem. 2018, 14, 2396–2403, doi:10.3762/bjoc.14.216

• preparation of 3a: One third of the 25 mL stainless steel milling jar was filled with 2-aminobenzamide (550 mg, 4.04 mmol), 4-ethylbenzaldehyde (541.5 µL, 4.04 mmol), 550 mg silica gel and one ball (15 mm diameter). After 1 h of milling, IBX (1.24 g, 4.44 mmol) was added and milling continued for 1.5 h. Then

Bioinspired cobalt cubanes with tunable redox potentials for photocatalytic water oxidation and CO₂ reduction

• Zhishan Luo,
• Yidong Hou,
• Jinshui Zhang,
• Sibo Wang and
• Xinchen Wang

Beilstein J. Org. Chem. 2018, 14, 2331–2339, doi:10.3762/bjoc.14.208

• /s scan rate in 0.2 M Na2SO4, (b) at a 50 mV/s scan rate in MeCN (0.1 M TBAPF6) under CO2-saturated conditions. The working electrode used was 3 mm diameter glassy carbon electrode, the counter electrode was a platinum foil and the reference electrode was a Ag/AgCl. The activity of 1-R for (a) water

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

• hydrodynamic diameter of the host to a more realistic ≈ 2 nm. In all cases, however, the nature of the cation had no perceivable effect; each metal ion resulted in a hydrodynamic diameter for 1 of 2.1 ± 0.2 nm (Table 1). The invariance in these results reveals the power of the carboxylate as a water

• titration point of 80 mM salt the curvature of the autocorrelation function greatly increased, and the observed hydrodynamic diameter approached the expected ≈2.0 nm. Hence although for all of the studies here the starting point for each titration was 20 mM salt, the first data point for each titration was

• ignored. An obvious trend in the data for host 2 (Figure 3) is how the nature of the halide affects aggregation. Over all concentrations of F− salts the hydrodynamic diameter of the host was anomalously small, with maximum diameters measured in the presence of NaF, KF, and CsF being 1.6, 1.9, and 1.8 nm

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• crossbar architecture in which a monolayer of amphiphilic rotaxanes is sandwiched by a bottom Si nanowire electrode and a top Ti nanowire electrode. Both layers of nanowires are orthogonal to each other. This produces several crossing points or “junctions” whose areas are defined by the diameter of the

• nanowires. In the present example, a very small diameter gives a junction area of only 16 nm2 which corresponds to approximately 100 rotaxanes per junction. When a high pulse voltage is applied (±1.5 V), the junctions can be switched back and forward between the two switching states of the rotaxane. The

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• formed by numerous fibrillar and globular structures of ca. 2–4 μm in diameter (Figure 4C, D). Although the recorded images correspond to the bulk material, it should be stressed that the formation of artifacts during the drying process can not be completely ruled out [42]. Hence, the interpretation of

• , 1466, 1377, 1147, 839, 720. HRMS (ESI+) m/z: [M + Na]+ calcd for C27H46N2O6Na, 517.3248; found, 517.3217. Preparation and characterization of gel materials Gels were prepared in screw-capped glass vials (4.5 cm length × 1 cm diameter) having a specific amount of the desired gelator and solvent (p.a

A self-assembled photoresponsive gel consisting of chiral nanofibers

• Lei Zou,
• Dan Han,
• Zhiyi Yuan,
• Dongdong Chang and
• Xiang Ma

Beilstein J. Org. Chem. 2018, 14, 1994–2001, doi:10.3762/bjoc.14.174

• form nanotwists of wider diameter. Finally, the gel system was irradiated with ultraviolet light or visible light to test its stimuli response. Under 365 nm light exposure, the gel melted into a turbid liquid within 20 min. However, the system could not easily be reversed due to the poor reversibility

Synthesis and characterization of π–extended “earring” subporphyrins

• Haiyan Guan,
• Mingbo Zhou,
• Bangshao Yin,
• Ling Xu and
• Jianxin Song

Beilstein J. Org. Chem. 2018, 14, 1956–1960, doi:10.3762/bjoc.14.170

• . Furthermore, we speculate that this strain should be the origin of the much lower yield of 3 comparing to the corresponding “earring” porphyrins. Concerning the diameter of the cavity and the strain of the skeleton, we assumed that some metal ions may insert into the hole surrounded by the tripyrrin moiety

Assessing the possibilities of designing a unified multistep continuous flow synthesis platform

• Mrityunjay K. Sharma,
• Roopashri B. Acharya,
• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2018, 14, 1917–1936, doi:10.3762/bjoc.14.166

• a flow reactor tube of required length and diameter or a microchannel reactor having various geometries or a static mixer) or a continuous stirred tank reactor or a fixed bed reactor or other intensified process equipment viz. spinning disc reactor, impinging jet reactor etc.) and a thermostat which

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

• Cristina Morar,
• Pedro Lameiras,
• Attila Bende,
• Gabriel Katona,
• Emese Gál and
• Mircea Darabantu

Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145

• propensity for self-assembly as nano-aggregates. Indeed, covalent dendrimers 5–7a generated nanospheres with much smaller average diameter (259–732 nm, Figure 9) than the ionic 7b–9 (992–1454 nm, Figure 10). Moreover, according to the literature [71], the last ones appeared to be among the greatest

• case of G-1 amino-dendron D-N

  NH and of covalent G-2 dendrimers 5–7a. D is the average diameter of nanospheres; the red arrow shows the nano-particles that aggregate. TEM images of homogeneously packed spherical nano-aggregates (a) and their agglomerations (b) in the case of G-2 ionic dendrimers 7b

• , 8 and 9; the red arrow indicates the nano-particles that aggregate. D is the average diameter of nanospheres. Proposed π-stacking interactions in compounds D-N

  NH and 5–7a. Convergent versus divergent three steps (a–c) synthesis of central building blocks C1 and C3. Synthesis of G-1 dendrons D-Cl

The phenyl vinyl ether–methanol complex: a model system for quantum chemistry benchmarking

• Dominic Bernhard,
• Fabian Dietrich,
• Mariyam Fatima,
• Cristóbal Pérez,
• Hannes C. Gottschalk,
• Axel Wuttke,
• Ricardo A. Mata,
• Martin A. Suhm,
• Melanie Schnell and
• Markus Gerhards

Beilstein J. Org. Chem. 2018, 14, 1642–1654, doi:10.3762/bjoc.14.140

• -FTMW) spectrometer COMPACT covering the 2–8 GHz frequency range, which has been described in detail in [52]. The molecules were seeded into a supersonic expansion with neon as the carrier gas by using a pulse nozzle (Parker General Valve, Series 9, 0.9 mm diameter orifice) equipped with a heatable

Mechanochemistry of nucleosides, nucleotides and related materials

• Olga Eguaogie,
• Joseph S. Vyle,
• Patrick F. Conlon,
• Manuela A. Gîlea and
• Yipei Liang

Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81

• copper salts was found. In an attempt to expedite the LAG reaction, millimol-scale reactions between the p-azobenzene-appended alkyne and 5′-azido-5′-deoxythymidine were attempted in a more capacious copper vessel with a 15 mm diameter zirconia ball (Figure 3). Clean and complete click reactions were

• grinding stones (15–20 mm in diameter), 100 g of dried tissue powder and petroleum ether (200–450 mL) [73][74][75]. As early as 1903, low temperature grinding was applied to disrupting refractory mycobacteria (using zirconia components under cooling in liquid air) [76] and subsequently mechanised using a

Bromide-assisted chemoselective Heck reaction of 3-bromoindazoles under high-speed ball-milling conditions: synthesis of axitinib

• Jingbo Yu,
• Zikun Hong,
• Xinjie Yang,
• Yu Jiang,
• Zhijiang Jiang and
• Weike Su

Beilstein J. Org. Chem. 2018, 14, 786–795, doi:10.3762/bjoc.14.66

• diameter (dMB), which usually play important roles in mechanochemistry processes [57][58][59][60]. First, the combined effect between ball-milling time and rotation speed was screened systematically (Figure 2). The results show a sharp increase of the product yield when elevating the rotation speed from

• around 0.3–0.35 for all types of the milling balls, and then decreased gradually due to milling vessel space limitations [24][61][62]. A maximum product yield (93%) was obtained by using 6 mm diameter milling balls (ФMB = 0.293), indicating small-size milling balls more beneficial for the reaction, which

• acrylate (2a). (173 stainless-steel balls (dMB = 6 mm, ФMB = 0.245) were used. dMB = milling ball diameter. ФMB = milling ball filling degree.) The control experiments. aTEA (1.8 mmol), silica gel (5.0 g), bPd(OAc)2 (5 mol %), PPh3 (10 mol %), TEA (1.8 mmol), silica gel (5.0 g), cPd(OAc)2 (5 mol %), PPh3

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

• fractions are <5 µm (= x90) in diameter. The overall yield for this particle fraction was 20%, but future work will concentrate on the optimisation of this step. Microscopic pictures indicate spherical particle shape. The density of the particles, also important for the usage of the particles as stabilisers

• Chemicals, >99%, density 0.865 g/cm3). Emulsions were prepared using a rotor-stator homogeniser (IKA T25 digital Ultra-Turrax) with a stator diameter of 8 mm for 1 min at 10,000 rpm at room temperature. Emulsion type was established using the drop test (addition of a drop of emulsion to either water or oil

• which are of a size smaller than the resolution limit of the microscope. By contrast, the larger sized particles appear aggregated at droplet interfaces. The variation in the average oil droplet diameter with particle concentration is given in Figure 6 (top). Relatively small drops (between 70 and 150

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

• Marco Russo,
• Daniele La Corte,
• Annalisa Pisciotta,
• Serena Riela,
• Rosa Alduina and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2751–2763, doi:10.3762/bjoc.13.271

• . Unfortunately, very poor results were obtained. At pH 6.5, the clear supernatant liquor of the prepared samples after 24 h standing, showed the presence of no object larger than 2 nm (which corresponds, more or less, to the hydrodynamic diameter of a single AmCD unit). The same attempt made at pH 8.4 revealed

• the presence of a very small population of objects having an average diameter of 450 ± 150 nm. However, their concentration was so low that the relevant diffusion signal was very poor in quality. Therefore, the result found must be considered only merely indicative. However, this apparent failure is

Synthesis and supramolecular properties of regioisomers of mononaphthylallyl derivatives of γ-cyclodextrin

• Markéta Bláhová,
• Sergey K. Filippov,
• Lubomír Kováčik,
• Jiří Horský,
• Simona Hybelbauerová,
• Zdenka Syrová,
• Tomáš Křížek and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2017, 13, 2509–2520, doi:10.3762/bjoc.13.248

• aggregates: large aggregates (around 600 nm in diameter) and smaller aggregates (around 140 nm in diameter, Figure 1). Aggregates formed by 2-O-isomer 2a were similar to those of the 3-O-sample. On the other hand, the 6-Ο-isomer 2c produced different results. Since the measurement of this isomer was

• only in solutions of the 2-O- and 3-O-regioisomers after filtration through a filter with 0.22 μm pores. Indeed, larger particles with diameter in the range of tens and hundreds nm dominate the scattering, and such large objects of various morphologies were also detected by cryo-TEM. In this respect

Structure–property relationships and third-order nonlinearities in diketopyrrolopyrrole based D–π–A–π–D molecules

• Jan Podlesný,
• Lenka Dokládalová,
• Oldřich Pytela,
• Adam Urbanec,
• Milan Klikar,
• Numan Almonasy,
• Tomáš Mikysek,
• Jaroslav Jedryka,
• Iwan V. Kityk and
• Filip Bureš

Beilstein J. Org. Chem. 2017, 13, 2374–2384, doi:10.3762/bjoc.13.235

• ). Electrochemistry Electrochemical measurements of all target compounds were carried out in N,N-dimethylformamide containing 0.1 M Bu4NPF6 in a three electrode cell by cyclic voltammetry (CV) and rotating disk voltammetry (RDV). The working electrode was a platinum disk (2 mm in diameter) for CV and RDV experiments

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

• derivatives 5–8 Method 2a: Compound 4 (80 mg, 0.24 mmol) and the corresponding aryl azide (0.49 mL, 0.24 mmol) were weighed in one half of the reaction vessel and the other half was filled with Cu(OAc)2 (2.24 mg, 0.05 equiv) and two 7 mm diameter stainless steel balls. The aryl azide solution was evaporated

• mmol), DIPEA (4.3 µL, 0.1 equiv) and acetic acid (1.5 µL, 0.1 equiv); the other half was filled with compound 4 (80 mg, 0.24 mmol) and CuI (1 mg, 4.9 mmol, 0.02 equiv), and two 7 mm diameter stainless steel balls (ball weight 1.3 g). The aryl azide solution was evaporated to dryness under vacuo, and

Structural diversity in the host–guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies

• Magdalena Ceborska,
• Magdalena Zimnicka,
• Aneta Aniela Kowalska,
• Kajetan Dąbrowa and
• Barbara Repeć

Beilstein J. Org. Chem. 2017, 13, 2252–2263, doi:10.3762/bjoc.13.222

• the guest (a: from left to right): pemetrexed (PTX) and folic acid (FA), and host molecules with increasing diameter of macrocyclic cavity (b: from left to right: α-, β- and γ-CDs). Dissociation efficiency curves of three CDs/PTX complexes. The ions were collided with nitrogen (pressure ca. 2 × 10−5

The effect of milling frequency on a mechanochemical organic reaction monitored by in situ Raman spectroscopy

• Patrick A. Julien,
• Ivani Malvestiti and
• Tomislav Friščić

Beilstein J. Org. Chem. 2017, 13, 2160–2168, doi:10.3762/bjoc.13.216

• mmol) with benzil (210 mg, 1.0 mmol) using a Retsch MM400 mixer mill operating at 30 Hz. The reaction mixture was placed in a 15 mL volume optically transparent poly(methyl metacrylate) (PMMA) jar, along with one zirconia ball of 10 mm diameter (ca. 3 grams weight). After 30 minutes milling, the

• from Alfa Aesar. Both were used without further purification. Milling reactions and characterization The double condensation was conducted by milling 210 mg of benzil (1.0 mmol) and 108 mg of o-phenylenediamine (1.0 mmol) with a single zirconia ball of 10 mm diameter (ca. 3 grams weight) in a 15 mL

Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound

• Joana M. Pais,
• Maria João Barroca,
• Maria Paula M. Marques,
• Filipe A. Almeida Paz and
• Susana S. Braga

Beilstein J. Org. Chem. 2017, 13, 2138–2145, doi:10.3762/bjoc.13.212

• continuous mode in the 3.5° ≤ 2θ ≤ 50° interval. TG studies were performed on a Shimadzu TGA-50 thermogravimetric analyzer, using a heating rate of 5 °C min−1, under air atmosphere, with a flow rate of 20 mL min−1. The sample holder was a 5 mm in diameter platinum plate and the sample mass was about 5 mg

Mechanochemical Knoevenagel condensation investigated in situ

• Sebastian Haferkamp,
• Franziska Fischer,
• Werner Kraus and
• Franziska Emmerling

Beilstein J. Org. Chem. 2017, 13, 2010–2014, doi:10.3762/bjoc.13.197

• quantities of the reactants p-nitrobenzaldehyde (800 mg, 5.29 mmol) and malononitrile 349.67 mg, 5.29 mmol) were weighed in milling jars (10 mL, stainless steel or Perspex). Two milling balls (stainless steel, 4 g, 10 mm diameter) were added to the reaction mixture. The reaction was performed in two