Solution-phase automated synthesis of an α-amino aldehyde as a versatile intermediate

• Hisashi Masui,
• Sae Yosugi,
• Shinichiro Fuse and
• Takashi Takahashi

Beilstein J. Org. Chem. 2017, 13, 106–110, doi:10.3762/bjoc.13.13

• photosensor that detects the difference in reflective index between gas and liquid. All the gas/liquid flows are controlled by solenoid valves and/or rotary valves. This transfer system avoids direct contacts of pumps with compounds that frequently cause mechanical troubles of pumps. Formation of emulsions

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

• , whereas TSE, which is more frequently employed, involves the movement of material by two, i.e., the material is conveyed from one screw to the other as it makes its way along the extruder barrel [4]. Both techniques process materials by mixing, heating and also by applying mechanical energy. The main

• just mixing, but also the grinding of the material, which resultantly leads to changes in the material properties, most commonly its rheology [3]. Furthermore, the mechanical energy applied to the system can be controlled by the screw profile, as well as the residence time which is not only dependent

• greater mechanical energy may result in a greater amount of frictional heat being produced, particularly in comparison to those segments which provide less vigorous kneading. Both single and twin screw extruders range from 10–443 mm in screw diameter [6] and extrusion processes are scalable to produce

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

• (POLAG) [8]. However, to the best of our knowledge, the systematic investigation of the influence of PEG polymers has not been reported yet for organic syntheses promoted by mechanical energy. We firstly reported the positive influence of PEG solvents as grinding agents for the mechanochemical

• to the solubility of reactants, reaction intermediates and final products in PEG polymers, although the existence of specific interactions with PEG polymers cannot be excluded. Indeed, especially under mechanical stress, PEGs are known to induce changes in the physical state of the system [8]. These

Computational methods in drug discovery

• Sumudu P. Leelananda and
• Steffen Lindert

Beilstein J. Org. Chem. 2016, 12, 2694–2718, doi:10.3762/bjoc.12.267

• mechanics. Electrostatic (coulombic) interactions and van der Waals interactions (Lennard-Jones potential) contribute to the interaction energy between a target–ligand complex. Two of the most widely used molecular mechanical force-fields are CHARMM [119] (Chemistry at HARvard Macromolecular Mechanics) and

Towards the development of continuous, organocatalytic, and stereoselective reactions in deep eutectic solvents

• Davide Brenna,
• Elisabetta Massolo,
• Alessandra Puglisi,
• Sergio Rossi,
• Giuseppe Celentano,
• Maurizio Benaglia and
• Vito Capriati

Beilstein J. Org. Chem. 2016, 12, 2620–2626, doi:10.3762/bjoc.12.258

• possible interaction between the aldol product and the DES network (Figure 1). Due to its favourable physical and mechanical properties, DES A was selected for the initial screening of the different experimental conditions in continuo. The first experimental set-up that was studied (Figure 1, I) was built

Inhibition of peptide aggregation by means of enzymatic phosphorylation

• Kristin Folmert,
• Malgorzata Broncel,
• Hans v. Berlepsch,
• Christopher H. Ullrich,
• Mary-Ann Siegert and
• Beate Koksch

Beilstein J. Org. Chem. 2016, 12, 2462–2470, doi:10.3762/bjoc.12.240

• with biological function with desirable mechanical properties. Many such peptide aggregates display exceptional stability, mechanical strength, stability at high temperatures and they are resistant towards enzymatic degradation [2]. Several studies have demonstrated the utilization of amyloids as

A direct method for the N-tetraalkylation of azamacrocycles

• Andrew J. Counsell,
• Angus T. Jones,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2016, 12, 2457–2461, doi:10.3762/bjoc.12.239

• be optimised alongside mixing performance [46], and in nanotechnology, where shaking can be used to modulate aggregation so as to favour particular nanostructures [47][48]. Otto and co-workers have investigated the influence of mechanical forces on reactivity in the context of self-replication by

• peptide-based disulfide macrocycles in a dynamic combinatorial library [49]. They observed different product distributions when reaction mixtures were shaken than when stirred, concluding that “mechanical forces can ... determine the outcome of a covalent synthesis” and that the ‘mechanosensitivity’ of

• their system is controlled by the influence of mechanical motion on nanostructure formation (the assembly of β-sheet-based fibres from the peptide building blocks in this example). Given the rapid precipitation of 3 at the phase interface observed in our N-tetrapropargylation reaction, it seems

Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

• Martin Obst and
• Burkhard König

Beilstein J. Org. Chem. 2016, 12, 2358–2363, doi:10.3762/bjoc.12.229

• solvent-free conversion of solid reactants. The reaction is driven by mechanical energy, which is for instance realized by grinding in ball mills or pestle and mortar. Obviously, this method possesses several advantages compared to reactions, which are performed in solution: toxic solvents and wastes are

• substrates would be grinded under visible light irradiation. In contrast to mechanochemistry, the process would be driven by light energy and not by mechanical energy, but profit from the absence of toxic solvents, high concentrations of the substrate, and easy work-up. Furthermore, undesired effects of the

• mechanical but by electromagnetic energy input, realized by blue light irradiation. Furthermore, the heat input is not the primary cause for the reaction, but its prerequisite. Subsequently, the scope of the benzylic alcohol oxidation was investigated, applying 5% of RFTA. Four solid alcohols were oxidized

Experimental and theoretical investigations into the stability of cyclic aminals

• Edgar Sawatzky,
• Antonios Drakopoulos,
• Martin Rölz,
• Christoph Sotriffer,
• Bernd Engels and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 2280–2292, doi:10.3762/bjoc.12.221

• reversed-phase HPLC. Based on these data, quantum mechanical calculations revealed that the hydrolysis of the test compounds is a thermodynamically driven process. Interestingly, we could show that this equilibrium is strongly dependent on the applied reaction conditions and that a change from an acidic to

• form is 1.61 kcal/mol, which is still a moderate value and places it well below compound 9b. Obviously, an exact correlation of this simple measure with the hydrolytic instability is not to be expected, given the limitations of the molecular mechanical approach and the fact that the hydrolysis rate of

Determination of the absolute stereostructure of a cyclic azobenzene from the crystal structure of the precursor containing a heavy element

• Reji Thomas and
• Nobuyuki Tamaoki

Beilstein J. Org. Chem. 2016, 12, 2211–2215, doi:10.3762/bjoc.12.212

• chirality methods [28][29], NMR spectroscopy [30][31][32], X-ray diffraction [33][34][35], etc. In addition to these methods, many researchers explored a combination of vibrational circular dichroism and quantum mechanical calculations to determine the absolute stereostructures [36][37][38]. Among various

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

• Maurizio Selva,
• Alvise Perosa,
• Sandro Guidi and
• Lisa Cattelan

Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181

• -mechanical calculations indicated that the catalyst synergistically activated both BuOH and DMC. A wide variety of acyclic non-symmetrical organic carbonates of general formula ROC(O)OCH3 were prepared by Kumar et al. through the transesterification of DMC using the ionic liquid 1-(trimethoxysilyl)propyl-3

3,6-Carbazole vs 2,7-carbazole: A comparative study of hole-transporting polymeric materials for inorganic–organic hybrid perovskite solar cells

• Wei Li,
• Munechika Otsuka,
• Takehito Kato,
• Yang Wang,
• Takehiko Mori and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2016, 12, 1401–1409, doi:10.3762/bjoc.12.134

• Wei Li Munechika Otsuka Takehito Kato Yang Wang Takehiko Mori Tsuyoshi Michinobu Department of Materials Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan and Department of Mechanical Engineering, National Institute of Technology, Oyama

Effective in silico prediction of new oxazolidinone antibiotics: force field simulations of the antibiotic–ribosome complex supervised by experiment and electronic structure methods

• Jörg Grunenberg and
• Giuseppe Licari

Beilstein J. Org. Chem. 2016, 12, 415–428, doi:10.3762/bjoc.12.45

• , followed by an evaluation of their enthalpic penalties or rewards and the mechanical strengths of the relevant hydrogen bonds (relaxed force constants; compliance constants). The protocol was able to reproduce the experimentally known enantioselectivity favoring the S-enantiomer. In a second step, the

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

• Eric V. Anslyn

Beilstein J. Org. Chem. 2016, 12, 362–376, doi:10.3762/bjoc.12.40

• draw for me to the fields of supramolecular chemistry and molecular orbital theory, because I grew up in a household filled with art. In addition to art, my childhood was filled with repairing and constructing mechanical entities, such as internal combustion motors, where many components work together

• . Keywords: art; assembly; complexity; function; mechanical; supramolecular; Review Introduction The field of supramolecular chemistry abounds with beautiful and aesthetically pleasing molecules. From Stoddart’s rotaxanes [1][2], Sauvage’s knots [3][4], Rebek’s capsules [5], Fujita’s 3-D MOFs [6][7], to

• Abstract Art? Maybe one can, but the similarly is striking (Figure 1). Besides having an aspect of beauty, supramolecular structures are created to achieve a chemical function or task. These functions range from imparting mechanical changes [11][12][13], to altering material properties [14][15], to

Natural products from microbes associated with insects

• Christine Beemelmanns,
• Huijuan Guo,
• Maja Rischer and
• Michael Poulsen

Beilstein J. Org. Chem. 2016, 12, 314–327, doi:10.3762/bjoc.12.34

• species [12][13][14][15][16][17]. As a response to these threats, many insects have evolved defensive strategies, including mechanical and behavioral defense, complex immune systems, and the use of bioactive secondary metabolites produced by residing mutualists [12][13][14][15][16][17][24][25][26]. The

• challenged by invading fungal species such as Escovopsis, Fusarium, and Trichoderma (Ascomycota). To clean the garden, ants apply mechanical grooming [71] and secrete antimicrobial compounds, such as 3-hydroxydecanoic acid, from their metapleural glands [72]. As a second line of defense, the ants are

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

• process control. However microreactors do not tolerate mechanical inhomogeneities. To resolve the problem of microparticles, which often cause clogging, a second generation of microreactors has been developed and called microjetreactor [99]. A typical microreactor is made up of a 'sandwich' of thin metal

Recent advances in metathesis-derived polymers containing transition metals in the side chain

• Ileana Dragutan,
• Valerian Dragutan,
• Bogdan C. Simionescu,
• Albert Demonceau and
• Helmut Fischer

Beilstein J. Org. Chem. 2015, 11, 2747–2762, doi:10.3762/bjoc.11.296

• metallopolymers so as to reach the desired physical and chemical properties suitable for progressive applications [5][6][7]. These functional hybrid materials are highly appreciated for their superior behaviour in catalysis, optics as well as for their magnetic, mechanical and thermal attributes. Structurally

• membranes provided with single cation–anion pairs. Cross-linking with dicyclopentadiene ensured a high mechanical stability of the copolymer. The film cast from 28 displayed an anion conductivity and mechanical properties similar to those of the traditional quaternary ammonium-based anion exchange membranes

Synthesis, structure, and mechanical properties of silica nanocomposite polyrotaxane gels

• Kazuaki Kato,
• Daisuke Matsui,
• Koichi Mayumi and
• Kohzo Ito

Beilstein J. Org. Chem. 2015, 11, 2194–2201, doi:10.3762/bjoc.11.238

• . These toughness and softness properties are attributable to both the characteristic sliding of polymer chains through the immobilized cyclodextrins on the silica nanoparticle and the entropic contribution of the cyclic components to the elasticity of the gels. Keywords: cyclodextrin; gel; mechanical

• modified to react with the surface of silica. The inner structure and the mechanical properties of the silica nanocomposite polyrotaxane gels were studied by small-angle X-ray scattering and viscoelastic measurements, respectively. Results and Discussion To achieve a covalent bond between the cyclic

• the diffraction pattern of chicken tendon collagen. The obtained SAXS patterns were converted into 1D profiles, scattering intensity I vs scattering vector q, by circular averaging. The scattering vector is defined as: Mechanical measurements Obtained silica nanocomposite polyrotaxane gels were cut

Synthesis, antimicrobial and cytotoxicity evaluation of new cholesterol congeners

• Mohamed Ramadan El Sayed Aly,
• Hosam Ali Saad and
• Shams Hashim Abdel-Hafez

Beilstein J. Org. Chem. 2015, 11, 1922–1932, doi:10.3762/bjoc.11.208

• cholesterol (oxysterol) metabolites contributes to the prognosis of major chronic diseases. Cholesterol is completely absent in prokaryotic organisms [1][2][3]. Cholesterol gives eukaryotic membranes sufficient mechanical stiffness against cationic selective antimicrobials (CSAs) such as antimicrobial

Asymmetric 1,4-bis(ethynyl)bicyclo[2.2.2]octane rotators via monocarbinol functionalization. Ready access to polyrotors

• Cyprien Lemouchi and
• Patrick Batail

Beilstein J. Org. Chem. 2015, 11, 1881–1885, doi:10.3762/bjoc.11.202

• potential in the development of molecular machines that can perform mechanical functions can now be systematically studied. Synthesis of the asymmetric rotor 1. Synthesis of dirotors 6 and 10. Synthesis of the tertiary amide 12. Synthesis of the extended alkaloid ligand 14. Supporting Information

Mechanism, kinetics and selectivity of selenocyclization of 5-alkenylhydantoins: an experimental and computational study

• Biljana M. Šmit,
• Radoslav Z. Pavlović,
• Dejan A. Milenković and
• Zoran S. Marković

Beilstein J. Org. Chem. 2015, 11, 1865–1875, doi:10.3762/bjoc.11.200

• used. Full geometry optimizations, without any symmetry constraints, and frequency calculations were performed for all species in acetonitrile as solvent (dielectric constant = 35.688) using the SMD solvation model [44]. SMD is a continuum solvation model based on the quantum mechanical charge density

Thermal properties of ruthenium alkylidene-polymerized dicyclopentadiene

• Yuval Vidavsky,
• Yotam Navon,
• Yakov Ginzburg,
• Moshe Gottlieb and
• N. Gabriel Lemcoff

Beilstein J. Org. Chem. 2015, 11, 1469–1474, doi:10.3762/bjoc.11.159

• initiators where only cross-linked polymers are obtained. This polyolefinic cross-linked thermoset material exhibits outstanding thermal stability [22], mechanical strength [23], fracture toughness [24] and dielectric characteristics [25]. Thanks to these properties PDCPD has become a very attractive polymer

Multivalency as a chemical organization and action principle

• Rainer Haag

Beilstein J. Org. Chem. 2015, 11, 848–849, doi:10.3762/bjoc.11.94

• supramolecular designer systems [4][5]. The influence of spacer length and flexibility on the binding affinity of ligands [6] will be examined as well as the mechanical stability of complexes [7]. Furthermore, the Thematic Series covers the synthesis of various new glycoarchitectures for multivalent interactions

Mechanical stability of bivalent transition metal complexes analyzed by single-molecule force spectroscopy

• Manuel Gensler,
• Christian Eidamshaus,
• Maurice Taszarek,
• Hans-Ulrich Reissig and
• Jürgen P. Rabe

Beilstein J. Org. Chem. 2015, 11, 817–827, doi:10.3762/bjoc.11.91

• 10.3762/bjoc.11.91 Abstract Multivalent biomolecular interactions allow for a balanced interplay of mechanical stability and malleability, and nature makes widely use of it. For instance, systems of similar thermal stability may have very different rupture forces. Thus it is of paramount interest to study

• and understand the mechanical properties of multivalent systems through well-characterized model systems. We analyzed the rupture behavior of three different bivalent pyridine coordination complexes with Cu2+ in aqueous environment by single-molecule force spectroscopy. Those complexes share the same

• be used to study selected parameters [4][5]. The mechanical stability of a molecular system is characterized by its rupture forces under a given loading rate. Malleability describes the ability of a protein complex or bond to deform without being disrupted and is characterized by the rupture length

Regulation of integrin and growth factor signaling in biomaterials for osteodifferentiation

• Qiang Wei,
• Theresa L. M. Pohl,
• Anja Seckinger,
• Joachim P. Spatz and
• Elisabetta A. Cavalcanti-Adam

Beilstein J. Org. Chem. 2015, 11, 773–783, doi:10.3762/bjoc.11.87

• virtually all cells in the body are exposed to and stem cells reside in, is an essential component in the stem cell niche [3]. The ECM is not an inert scaffold; instead, it is a dynamic network of molecules secreted by cells. Moreover, its biochemical, biophysical, and mechanical properties have emerged as

• -bound cells and their cytoskeleton. Second, the signals resulting from these interactions enable cells to sense the chemical and mechanical properties of the microenvironment (niche) and to respond by activating signaling systems for regulating the cell fate [19]. Conversely, the contraction of the

• mechanical unit rather than biochemical unit in the theory of mechanotransduction. In this theory, integrin–ligand interactions cause cytoskeleton reorganization, which further affects the nuclear morphology, since the nucleus connects to the other side of the cytoskeleton. The change of the nuclear