A conformationally adaptive macrocycle: conformational complexity and host–guest chemistry of zorb[4]arene

• Liu-Pan Yang,
• Song-Bo Lu,
• Arto Valkonen,
• Fangfang Pan,
• Kari Rissanen and
• Wei Jiang

Beilstein J. Org. Chem. 2018, 14, 1570–1577, doi:10.3762/bjoc.14.134

• explained by invoking a solvent reorganization during the formation of 18+@ZB4 complex, which is common for reactions taking place in aqueous solution [41]. Conclusion In summary, we systematically studied the guest binding scope, electronic substituent effects and thermodynamic origin on the molecular

Two new 2-alkylquinolones, inhibitory to the fish skin ulcer pathogen Tenacibaculum maritimum, produced by a rhizobacterium of the genus Burkholderia sp.

• Dandan Li,
• Naoya Oku,
• Atsumi Hasada,
• Masafumi Shimizu and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2018, 14, 1446–1451, doi:10.3762/bjoc.14.122

• Gram-negative rods of strictly terrestrial origin. Although isolation of Burkholderia from marine sediments has been reported, these bacteria may not originate in the marine environment, as enrichment in low salinity media is a prerequisite for isolation [4][5][6]. Most of them live in close

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• less pronounced in KOH. The less favored formation of highly oxidized C3 species and of carbonate is deduced to be the origin of the lower current densities in the cyclic voltammograms (CVs) for Pd/NCNT in KOH. The enhanced current densities in NaOH are rationalized by the presence of Na+ ions bound to

Three-component coupling of aryl iodides, allenes, and aldehydes catalyzed by a Co/Cr-hybrid catalyst

• Kimihiro Komeyama,
• Shunsuke Sakiyama,
• Kento Iwashita,
• Itaru Osaka and
• Ken Takaki

Beilstein J. Org. Chem. 2018, 14, 1413–1420, doi:10.3762/bjoc.14.118

• 1) and the three-component coupling without CrCl3 catalyst (reaction 2). The origin of the diastereoselectivity in the present three-component coupling. Plausible reaction mechanism of the three-component coupling. Screening of the reaction conditions.a Supporting Information Supporting Information

London dispersion as important factor for the stabilization of (Z)-azobenzenes in the presence of hydrogen bonding

• Andreas H. Heindl,
• Raffael C. Wende and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2018, 14, 1238–1243, doi:10.3762/bjoc.14.106

• density functional theory (DFT) computations, attractive LD forces were identified as the origin of this stability trend. Based on this study, LD interactions represent a valuable tool for the design of novel azobenzene photoswitches [24]. Herein we provide further evidence for the importance of LD as

Are dispersion corrections accurate outside equilibrium? A case study on benzene

• Tim Gould,
• Erin R. Johnson and
• Sherif Abdulkader Tawfik

Beilstein J. Org. Chem. 2018, 14, 1181–1191, doi:10.3762/bjoc.14.99

• ][27] that is often used to semi-empirically optimize dispersion corrections, and is almost always used as a test of such methods. They are thus an excellent test of the quality of dispersion models on a system where failures may have chemical relevance. Results and Discussion The origin of dispersion

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

• the Nagy lab in the context of developing models for the origin of non-racemic amino acid content within meteorites [110][111]. A role for mechanochemistry in understanding the origins of biochirogenesis is suggested by phase separation of co-crystals of the D- and L-enantiomers of malic acid in the

Volatiles from three genome sequenced fungi from the genus Aspergillus

• Jeroen S. Dickschat,
• Ersin Celik and
• Nelson L. Brock

Beilstein J. Org. Chem. 2018, 14, 900–910, doi:10.3762/bjoc.14.77

• quenching of cation J with water (box in Scheme 2), suggesting that this enzyme is responsible for the biosynthesis of 15 in A. fischeri. Therefore, the enzyme XP_001265719 is likely responsible for the biosynthesis of 19 and its byproducts. The biosynthetic origin of the observed traces of monoterpenes is

Synthesis and in vitro biochemical evaluation of oxime bond-linked daunorubicin–GnRH-III conjugates developed for targeted drug delivery

• Sabine Schuster,
• Beáta Biri-Kovács,
• Bálint Szeder,
• Viktor Farkas,
• László Buday,
• Zsuzsanna Szabó,
• Gábor Halmos and
• Gábor Mező

Beilstein J. Org. Chem. 2018, 14, 756–771, doi:10.3762/bjoc.14.64

• nm, respectively. Cytostasis was measured using 4 parallels, each experiment was repeated twice. Cytostatic effect (and IC50 values) were calculated by using nonlinear regression (sigmoidal dose response) with Origin Pro8 (OriginLab Corp., Northampton, MA, USA.). Cellular uptake determination by flow

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

• were used to probe the ability to tune the Wittig reaction under mechanochemical conditions. To determine the origin of benzyl benzoate, we performed a number of control reactions to determine if all reactants are necessary to form the side product (Table 2). Benzyl bromide was absent in each control

• between the steps. LAG solvent effect on the mechanochemical Wittig reaction. Control reactions to determine the origin of the side product benzyl benzoate. Counter-ion partnerships. Counter-ion partnerships in the solvent-free mechanochemical Wittig reaction. How much 4-nitrobenzyl bromide adds to the

Enhanced quantum yields by sterically demanding aryl-substituted β-diketonate ancillary ligands

• Rebecca Pittkowski and
• Thomas Strassner

Beilstein J. Org. Chem. 2018, 14, 664–671, doi:10.3762/bjoc.14.54

• /s. All measurements were internally referenced against the Fc/Fc+ redox couple. For visualization, the EC-Lab software V11.01 and Origin 2017 were used. Synthesis (SP-4-4)-[1-Methyl-3-phenyl-1H-imidazolin-2-yliden-κC2,κC2‘][dimesitoylmethanato-κO,κO’]platinum(II) (2) General procedure: A flame-dried

Enzyme-free genetic copying of DNA and RNA sequences

• Marilyne Sosson and
• Clemens Richert

Beilstein J. Org. Chem. 2018, 14, 603–617, doi:10.3762/bjoc.14.47

• -free primer extension is a fascinating reaction that has been linked to the origin of the first self-replicating systems. The reaction does produce extended primers with nucleotides complementary to the template sequence being appended at the 3'-terminus, but it is slow and low-yielding, particularly

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

• . For each structure, the direction of two of the three lattice vectors (a, b, c) is shown in the figure and the third one points inwards at the origin (o). Absorption intensity (in arbitrary units) as a function of the frequency for the two TNT polymorphs studied in this work. (E) Experimental spectrum

Transition-metal-free [3 + 3] annulation of indol-2-ylmethyl carbanions to nitroarenes. A novel synthesis of indolo[3,2-b]quinolines (quindolines)

• Michał Nowacki and
• Krzysztof Wojciechowski

Beilstein J. Org. Chem. 2018, 14, 194–202, doi:10.3762/bjoc.14.14

• (quindoline) system is present in numerous alkaloids of plant origin representing several biological activities and used in traditional tropical medicine for the treatment of various diseases, particularly malaria [1][2][3][4][5]. Further development revealed the potential of synthetic quindoline derivatives

Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)

• Tao Wang,
• Kathrin I. Mohr,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9

• limits [36]. Their origin by biomethylation of the corresponding phenols is frequently discussed, but the de novo formation of compounds 14 and 15 without administration of the corresponding phenols has not been reported before. Volatiles from Daldinia clavata identified by synthesis Several other

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• starting materials absorbs visible-light, the mixture of all reagents shows absorption in the visible-light region, which indicates the formation of donor–acceptor complexes. The exact origin of the absorption could not be specified until now. The reaction tolerates diverse functional groups. Electron-rich

What contributes to an effective mannose recognition domain?

• Christoph P. Sager,
• Deniz Eriş,
• Martin Smieško,
• Rachel Hevey and
• Beat Ernst

Beilstein J. Org. Chem. 2017, 13, 2584–2595, doi:10.3762/bjoc.13.255

• -mannopyranoside (2) [40][41][42][43][44]. In contrast, the receptors G and H of bacterial origin show affinities in the micromolar range (71 and 2.8 µM, respectively) for methyl α-D-mannose (2) [31][45]. Despite the 71 µM affinity, LecB (G) preferably binds L-fucose (3 µM) and methyl α-L-fucoside (0.4 µM) [45

• carbohydrate binding is extensively reduced. This remarkable form of inactivation is only possible due to loop flexibility. However, it is also the origin of the low affinity (9.4 mM) towards methyl mannoside (2) due to entropic costs associated with the formation of the binding site. Multivalency. Dam and

Herpetopanone, a diterpene from Herpetosiphon aurantiacus discovered by isotope labeling

• Xinli Pan,
• Nicole Domin,
• Sebastian Schieferdecker,
• Hirokazu Kage,
• Martin Roth and
• Markus Nett

Beilstein J. Org. Chem. 2017, 13, 2458–2465, doi:10.3762/bjoc.13.242

• originated from the MEV pathway (Figure 1). The possible number of labeled carbon atoms was compatible, however, with an octaketide origin or with a diterpene from the MEP pathway. We then recorded the high resolution (HR) mass of the unlabeled compound and determined its molecular formula as C20H36O4

• . Although the elemental composition does not necessarily exclude a polyketide origin, it perfectly matches a diterpene comprising four intact isoprene units. To obtain sufficient material for structure elucidation, the fermentation of H. aurantiacus 114-95T was repeated on a 50 L scale in VNY medium

Comparative profiling of well-defined copper reagents and precursors for the trifluoromethylation of aryl iodides

• Peter T. Kaplan,
• Jessica A. Lloyd,
• Mason T. Chin and
• David A. Vicic

Beilstein J. Org. Chem. 2017, 13, 2297–2303, doi:10.3762/bjoc.13.225

• solvent signals. 19F NMR spectra were recorded on the Bruker Ascend NMR spectrometer operating at 376 MHz and referenced to trifluorotoluene set at δ −63.7. All graphical data were treated with a best fit curve generated by the Origin 9.0.0 program. The exponential fit with function ExpGro1 was selected

A mechanochemical approach to access the proline–proline diketopiperazine framework

• Nicolas Pétry,
• Hafid Benakki,
• Eric Clot,
• Pascal Retailleau,
• Farhate Guenoun,
• Fatima Asserar,
• Chakib Sekkat,
• Thomas-Xavier Métro,
• Jean Martinez and
• Frédéric Lamaty

Beilstein J. Org. Chem. 2017, 13, 2169–2178, doi:10.3762/bjoc.13.217

• selective and only one diastereomer was obtained, as supported by analytical data. X-ray analysis of the product confirmed the stereochemistry of the three chiral centres and the structure of 15a. To shed more light on the origin of the selectivity observed in the deprotection–cyclization transformation

• ). The origin of these differences lied in the presence of an H-bond between the methanol molecule and the carbonyl group of the other ester functionality. This interaction stabilized a geometry with a longer C···N distance, and destabilized the transition state structure as it needed to be lost in TS

• be the origin of the stability of the former. Therefore a transition state structure leading to 15b with the methanol molecule in an “exo” position was optimized (TSbis-16b-solv, Figure 4). This transition state was less stable than TS-16b-solv by 2.9 kcal mol−1. Alternatively, a transition state

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• range IAD via dimethylsilane. Allyl-mediated tethering strategy in the IAD. IAD using tethering via the 2-naphthylmethyl group. Origin of selectivity in boronic ester mediated IAD. Arylborinic acid approach to the synthesis of β-mannosides. Possible mechanisms to explain α and β selectivity in palladium

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

• heats of dilution were subtracted from the total heats evolved to give the heats of host–guest complexation from which the complexation constant, K, and the corresponding ΔH, TΔS and N were calculated using the Origin 7.0 MicroCal protocol [53] as described in the Results and Discussion section. UV–vis

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

• organofluorine compounds affects conformational properties, since it can induce stereoelectronic effects, such as σC–H to σ*C–F hyperconjugative interactions in case of an antiparallel oriented C–H bond. This is the origin of the so-called 'gauche effect', because electronegative C–X bonds do not participate in

Theoretical simulation of the infrared signature of mechanically stressed polymer solids

• Matthew S. Sammon,
• Milan Ončák and
• Martin K. Beyer

Beilstein J. Org. Chem. 2017, 13, 1710–1716, doi:10.3762/bjoc.13.165

• property of the applied force, the change of the vibrational modes with increasing force depends on the orientation of the normal mode displacement of each atom relative to the force vector. To illustrate the molecular origin of the changes in the calculated infrared spectrum due to force, the four

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

• David Doran Marc Rodriguez-Garcia Rebecca Turk-MacLeod Geoffrey J. T. Cooper Leroy Cronin WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK 10.3762/bjoc.13.164 Abstract We propose that a chemically agnostic approach to explore the origin of life, using

• the origin of life under very constrained conditions [6]. Many heated debates in the field of prebiotic chemistry have raged over which precise historical environment(s) gave rise to the first lifeforms. However, it is unlikely that this question can ever be answered with reasonable certainty [7

• ]. Therefore, the puzzle most ripe for scientific inquiry is not how did life first arise, but what kind of processes can facilitate the origin of life? Identification of processes that produce complex, autocatalytic chemical networks [8] from simple inputs via gradual, step-wise complexification could go some