Synthesis, biophysical properties, and RNase H activity of 6’-difluoro[4.3.0]bicyclo-DNA

• Sibylle Frei,
• Adam K. Katolik and
• Christian J. Leumann

Beilstein J. Org. Chem. 2019, 15, 79–88, doi:10.3762/bjoc.15.9

• calculated using quantum mechanical methods. For the calculations we used the Gaussian 09 software package [47] at the second order Møller–Plesset (MP2) level of theory, the 6-311G* basis set, and the same methodology as for the 6’F-bc4,3- T [37]. The obtained energy profile of nucleoside 7 (Figure 3a

Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand

• Anne Schnell,
• J. Alexander Willms,
• S. Nozinovic and
• Marianne Engeser

Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3

• -proline and the carbonyl substrate acetone [40]. Houk and co-worker [41] verified the mechanism with quantum mechanical calculations, thus giving rise to the “List–Houk” mechanism. A discussion about the role of oxazolidinones as isomeric species to enamines has been raised in the scientific community [42

6’-Fluoro[4.3.0]bicyclo nucleic acid: synthesis, biophysical properties and molecular dynamics simulations

• Sibylle Frei,
• Andrei Istrate and
• Christian J. Leumann

Beilstein J. Org. Chem. 2018, 14, 3088–3097, doi:10.3762/bjoc.14.288

• of nucleoside 8 using quantum mechanical methods. The calculations were performed in vacuum with the Gaussian 09 software package [65] utilizing the second order Møller–Plesset perturbation theory (MP2) and the 6-311G* basis set. The energy profile of nucleoside 8 was obtained through a stepwise

Dispersion interactions

• Peter R. Schreiner

Beilstein J. Org. Chem. 2018, 14, 3076–3077, doi:10.3762/bjoc.14.286

• : they sum up to zero. The neglect of the attractive part of the vdW potential probably derives from the fact that there is no classic analogue as in the case of repulsion for which the hard sphere atom model works well. LD is a purely quantum mechanical effect due to electron correlation. It is present

Repurposing the anticancer drug cisplatin with the aim of developing novel Pseudomonas aeruginosa infection control agents

• Mingjun Yuan,
• Song Lin Chua,
• Yang Liu,
• Daniela I. Drautz-Moses,
• Joey Kuok Hoong Yam,
• Thet Tun Aung,
• Roger W. Beuerman,
• May Margarette Santillan Salido,
• Stephan C. Schuster,
• Choon-Hong Tan,
• Michael Givskov,
• Liang Yang and
• Thomas E. Nielsen

Beilstein J. Org. Chem. 2018, 14, 3059–3069, doi:10.3762/bjoc.14.284

• anesthetized by topical administration of xylocaine 1%. A corneal wound was made by using a 5 mm trephine and mechanical removal of epithelial cells was carried out by sterile mini blade (BD-Beaver) leaving the basal lamina intact [22][23]. All the groups were treated by topical administration of the

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

• precipitated out after about 30 minutes at 70 °C. The heterogeneous reaction mixture was aged for 12 hours then cooled to room temperature (25 °C). The slurry was poured into a 600 mL beaker equipped with overhead mechanical stirrer (PTFE 75 mm paddle) containing 250 mL of deionized water. With vigorous

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

• gradients control repetitive motions of these biological nanomachines, researchers have been seeking for synthetic analogues, i.e., artificial molecular machines (AMMs), with the ultimate goal to convert energy into directional mechanical motion on the nanoscale [4][5][6]. The field of AMMs beautifully

• molecules, the mechanical bond provides cohesive supramolecular assemblies with unique properties and a high flexibility and mobility of the subcomponents in a small molecular space. To control molecular motion, one of the most important construction principles to transform a simple MIM into an AMM is to

• -electron-poor molecule. The electrochemical switching of a TTF unit and the change of electronic or conformational properties not necessarily results in a mechanical motion of a MIM. A prerequisite is that at least one of the above-mentioned properties of TTF is interacting with other parts of the MIM. If

A switchable [2]rotaxane with two active alkenyl groups

• Xiu-Li Zheng,
• Rong-Rong Tao,
• Rui-Rui Gu,
• Wen-Zhi Wang and
• Da-Hui Qu

Beilstein J. Org. Chem. 2018, 14, 2074–2081, doi:10.3762/bjoc.14.181

• polymers. Keywords: alkenyl bond; functional crown ether; stimuli-responsiveness; switchable rotaxane; Introduction Along with the development of supramolecular chemistry, much attention has been paid to the design and synthesis of novel and complicated mechanical interlocked molecules (MIMs) [1][2][3][4

A hemicryptophane with a triple-stranded helical structure

• Augustin Long,
• Olivier Perraud,
• Erwann Jeanneau,
• Christophe Aronica,
• Jean-Pierre Dutasta and
• Alexandre Martinez

Beilstein J. Org. Chem. 2018, 14, 1885–1889, doi:10.3762/bjoc.14.162

• parallel peptide chains coil about each other in a triple stranded left-handed helical structure. Its high thermal and mechanical stability results mainly from the numerous hydrogen bonds found in the triple helix framework [2]. Bioinspired structures, based on peptide backbones, have been built, allowing

Efficient catenane synthesis by cucurbit[6]uril-mediated azide–alkyne cycloaddition

• Antony Wing Hung Ng,
• Chi-Chung Yee,
• Kai Wang and
• Ho Yu Au-Yeung

Beilstein J. Org. Chem. 2018, 14, 1846–1853, doi:10.3762/bjoc.14.158

• simultaneously mediate the mechanical and covalent bond formations. By coupling the mechanical interlocking with covalent macrocyclization, formation of topological isomers is eliminated and the [3]catenanes are formed exclusively in good yields. The efficient access to these [3]catenanes and the presence of

• other recognition units render them promising building blocks for the construction of other high-order interlocked structures. Keywords: azide–alkyne cycloaddition; catenane; click chemistry; cucurbit[6]uril; mechanical bond; Introduction Catenanes are topologically non-trivial molecules possessing

• mechanically interlocked macrocycles. The flexible but strong mechanical bond between the interlocked macrocycles offers a unique opportunity for exploiting catenanes as molecular machines or new materials with unusual mechanical properties [1][2][3][4][5][6][7][8][9]. Over the years, different templates and

Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

• Alberto Spinella,
• Marco Russo,
• Antonella Di Vincenzo,
• Delia Chillura Martino and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

• [21][22][23][24][25][26][27]. The properties of CyNSs, in terms of physical and mechanical features, porosity, thermal stability and adsorption or release abilities, may be modulated up to a certain extent by a sensible choice of the linker unit, depending on its length and possible functionalization

• very similar apparent features, irrespective of particular linker used. Considering that all products are preliminarily subjected to mechanical grounding and then are passed through a 150 μm sieve, powders show averagely a much finer granulometry. Grains appear quite compact, with a fairly rough

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

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

• Olga Eguaogie Joseph S. Vyle Patrick F. Conlon Manuela A. Gilea Yipei Liang School of Chemistry and Chemical Engineering, Queen’s University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, UK 10.3762/bjoc.14.81 Abstract The application of mechanical force to induce the formation

• materials: "[a mechano-chemical reaction is one] induced by the direct absorption of mechanical energy" [2]. The etymology and early history of this field have been reviewed comprehensively by Takacs [1]. Several recent reviews discuss both general aspects of mechanochemistry [3][4] as well as more focussed

• reaction [17]. In this review we have also adopted Hanusa’s formalism which distinguishes ball milling from other forms of mechanochemistry [18]. Perhaps most critical to the recent interest in this field has been the ability to deliver consistent and reproducible levels of mechanical energy using

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

• case with DNA that is cleaved by an attack of an external nucleophile. Recent hybrid quantum mechanical/effective fragment potential (QM/EEP) calculations on the hydroxide-ion-catalyzed hydrolysis of diethyl phosphate monoanion, however, suggest that the acyclic phosphorane obtained still is an

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

• mechanical parameters, a series of non-activated 3-bromoindazoles and a broad scope of olefins worked well to give the corresponding coupling products in good to excellent yields. A further application of this protocol was performed in a two-step mechanochemical Heck/Migita cross coupling, which provided a

• reaction pathway for this Heck reaction under mechanical ball milling conditions was proposed. As shown in path a, (Scheme 4). The reaction proceeded through Heck cross coupling, where a catalytic amount of TBAB was enough to stabilize the Pd(0). However, the oxidative addition intermediate I was unstable

• ]. Adjusting of mechanical parameters Having identified the optimal chemical conditions for the reaction selectivity on the basis of the reaction pathway, we then focussed on the milling parameters such as rotation speed (νrot), ball milling time (t), milling ball filling degree (ФMB), and milling ball

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

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor

• Morten M. C. H. van Schie,
• Tiago Pedroso de Almeida,
• Gabriele Laudadio,
• Florian Tieves,
• Elena Fernández-Fueyo,
• Timothy Noël,
• Isabel W. C. E. Arends and
• Frank Hollmann

Beilstein J. Org. Chem. 2018, 14, 697–703, doi:10.3762/bjoc.14.58

• areas can be achieved via heterogeneous intake, by bubbling, stirring, etc. Soluble enzymes, however, are often rather unstable under these conditions, possibly owing to the mechanical stress leading to irreversible inactivation of the biocatalyst [7][8]. Methods of bubble-free aeration have been

High-yielding continuous-flow synthesis of antimalarial drug hydroxychloroquine

• Eric Yu,
• Hari P. R. Mangunuru,
• Nakul S. Telang,
• Caleb J. Kong,
• Jenson Verghese,
• Stanley E. Gilliland III,
• Saeed Ahmad,
• Raymond N. Dominey and
• B. Frank Gupton

Beilstein J. Org. Chem. 2018, 14, 583–592, doi:10.3762/bjoc.14.45

• reacted under hydrogen pressure with mechanical stirring. The dip tube in the CSTR was outfitted with a fritted metal filter, allowing for retention of the heterogeneous catalyst within the CSTR vessel. Optimization of this CSTR-based flow process (Table 3) showed near quantitative yields of 12 over a

• bar of hydrogen supplied by hydrogen gas (ultrahigh purity) at a flow rate of 0.5 mL min−1. The reaction temperature was set to 80 °C which was controlled by a thermocouple positioned in the reaction mixture. The reaction was stirred with mechanical stirring (750 rpm) to provide proper mixing. Two

Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review

• Fabio Tonin and
• Isabel W. C. E. Arends

Beilstein J. Org. Chem. 2018, 14, 470–483, doi:10.3762/bjoc.14.33

• the half-life (23 h) is lower and the biocatalyst can be reused for only five cycles of conversions. In order to reduce the mechanical stress that might inactivate the immobilized enzymes, the flow-system represents a valid technology. The packed-bed reactor set up by Zheng et al. partially solved

Palladium-catalyzed ortho-halogenations of acetanilides with N-halosuccinimides via direct sp² C–H bond activation in ball mills

• Zi Liu,
• Hui Xu and
• Guan-Wu Wang

Beilstein J. Org. Chem. 2018, 14, 430–435, doi:10.3762/bjoc.14.31

• products 3a and 4a were obtained in 73% and 77% yields, respectively (Scheme 4). Conclusion In summary, we have developed a solvent-free and efficient protocol to synthesize ortho-iodinated acetanilide derivatives with Pd(OAc)2 as the catalyst and N-iodosuccinimide as the halogen source under mechanical

Polarization spectroscopy methods in the determination of interactions of small molecules with nucleic acids – tutorial

• Tamara Šmidlehner,
• Ivo Piantanida and
• Gennaro Pescitelli

Beilstein J. Org. Chem. 2018, 14, 84–105, doi:10.3762/bjoc.14.5

Synthesis, effect of substituents on the regiochemistry and equilibrium studies of tetrazolo[1,5-a]pyrimidine/2-azidopyrimidines

• Elisandra Scapin,
• Paulo R. S. Salbego,
• Caroline R. Bender,
• Alexandre R. Meyer,
• Anderson B. Pagliari,
• Tainára Orlando,
• Geórgia C. Zimmer,
• Clarissa P. Frizzo,
• Helio G. Bonacorso,
• Nilo Zanatta and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 2396–2407, doi:10.3762/bjoc.13.237

• , since the dipole moment of the DMSO-d6 is greater than the dipole moment of CDCl3, in addition to being able to stabilize the tetrazole form more effectively. Moreover, the results from quantum mechanical calculation confirmed that the tetrazole 3a form is 2.98 kcal mol−1 more stable in DMSO-d6 when

• predominant in the tetrazolo[1,5-a]pyrimidine2-azidopyrimidine equilibrium [1][21][22][23][24][26][27]. Additionally, from quantum mechanical calculations, it was possible to note that compound 3a (tetrazole form) is 1.54 kcal mol−1 more stable than 4a (azide form) in the solid state. To corroborate this

• corroborating the SCXRD results (see Figures S11–S13 in Supporting Information File 1). Despite the considerable amount of experimental data reported in the literature regarding the azido–tetrazole equilibrium, quantum mechanical studies in this context have yet to be thoroughly explored. This approach provides

Mechanochemistry

• José G. Hernández

Beilstein J. Org. Chem. 2017, 13, 2372–2373, doi:10.3762/bjoc.13.234

• Jose G. Hernandez Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany 10.3762/bjoc.13.234 Keywords: green chemistry; mechanochemistry; organic chemistry; solvent-free; The scientific community’s general interest in using mechanical energy to trigger or

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

• for CuAAC. In a broader sense, mechanochemistry, i.e., chemical transformations induced by mechanical force [14], has been rapidly advancing in various fields of synthesis and materials sciences, including inorganic [15], organic [16][17] and supramolecular materials [18][19], intermetallic compounds

Superstructures with cyclodextrins: Chemistry and applications IV

• Gerhard Wenz

Beilstein J. Org. Chem. 2017, 13, 2157–2159, doi:10.3762/bjoc.13.215

• , belong to this category and have been known since the pioneering work of Friedrich Cramer in 1951 [4][5]. Superstructures can also be held together by repulsive forces, so-called mechanical bonds [6], as exemplified in catenanes, rotaxanes, and knots [7]. Because of their restricted mobility, rotaxanes