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

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• origin and its chemical structure, this compound was named mycolactone. It is worth noting that mycolactone represented the first polyketide macrolide isolated from a mycobacterial species and was also the first example of a polyketide acting as the virulence factor of a human pathogen [34]. The purified

• [47]. Finally, Asian strains seem to be less virulent than their African complements [48][49][50]. These observations led the Small group to analyze partially purified mycolactones from M. ulcerans isolates of different geographical origin by TLC, (LC–)MS and in a cytopathogenicity assay [47][51

Molecular recognition of N-acetyltryptophan enantiomers by β-cyclodextrin

• Spyros D. Chatziefthimiou,
• Mario Inclán,
• Petros Giastas,
• Athanasios Papakyriakou,
• Konstantina Yannakopoulou and
• Irene M. Mavridis

Beilstein J. Org. Chem. 2017, 13, 1572–1582, doi:10.3762/bjoc.13.157

• (after the appropriate transformation of coordinates due to different origin and axes; Supporting Information File 1, Figures S4 and S5) that the hydrated β-CD macrocycle does not superpose exactly in the lattice of “β-CD–D-NAcTrp”, which may render the two structures not quite isomorphous. It is worth

• noting that many of the hydrated β-CD structures [29][33][34][35], as well as several monomeric β-CD complexes [32][36][37] are determined in lattices with different origin or interchanged crystallographic axes or even inverse coordinates (Supporting Information File 1, Figure S4). Further, by

• -CD dimer; NMR data (Job plots and 2D maps of the observed dipolar interactions); packing, origin selection and comparison of monomeric β-CD complexes; modeling results of D-NAcTrp/β-CD. Acknowledgements The financial support of the following programs is kindly acknowledged: European Program FP7

Chemical systems, chemical contiguity and the emergence of life

• Terrence P. Kee and
• Pierre-Alain Monnard

Beilstein J. Org. Chem. 2017, 13, 1551–1563, doi:10.3762/bjoc.13.155

• towards a simpler origin, is used, the fact that contemporary biomolecules and biochemical molecular assemblies, and their precursors themselves are likely optimized products of a long evolutionary process [4] renders this endeavor quite difficult. Hence, researchers in the field have tended to pursue

• these experiments. This short, necessarily selective, overview clearly underscores the necessity of new approaches, a fact that has led many researchers to propose the concept of chemical systems [22][23]. That is, the origin(s) of life, which is(are) hallmarked by the appearances of emergent properties

• reports on chemical systems, we will highlight the potential of the “chemical system” approach for the investigation of the origin of pre-cellular systems and protocells. What are chemical systems? Chemical systems are defined here as chemical mixtures comprising a network or set of interacting molecules

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

• -diphenylethanol was isolated, although the origin of water was not clear (possibly trapped by the diazonium salts during crystallization since, due to their potential explosivity in the dry state, they were not dried under vacuum). At this stage we postulated that A could be more favourably attacked in an

Framing major prebiotic transitions as stages of protocell development: three challenges for origins-of-life research

• Ben Shirt-Ediss,
• Sara Murillo-Sánchez and
• Kepa Ruiz-Mirazo

Beilstein J. Org. Chem. 2017, 13, 1388–1395, doi:10.3762/bjoc.13.135

• success of molecular biology led a whole generation of origin-of-life researchers to believe that the initial steps towards life could be performed by molecules of a single kind (not embedded in a wider chemical organisation). Then, for years, a strong debate was established in the field about, precisely

• coupling chemistry with the constrained spatial diffusion of the molecules involved [10][11]. Therefore, given the cellular nature of all life known on our planet, and given the importance of compartmentalized chemistries for understanding many biological phenomena, it may be productive to try origin-of

Biomimetic molecular design tools that learn, evolve, and adapt

• David A Winkler

Beilstein J. Org. Chem. 2017, 13, 1288–1302, doi:10.3762/bjoc.13.125

• for the design and discovery of novel technologies, materials, and molecules has its origin in two seemingly unrelated historical figures. Charles Darwin and Josiah Wedgwood Many are not aware that, arguably, one of the first ‘combinatorial’ materials scientists was Josiah Wedgwood. His ultimate

Towards open-ended evolution in self-replicating molecular systems

• Herman Duim and
• Sijbren Otto

Beilstein J. Org. Chem. 2017, 13, 1189–1203, doi:10.3762/bjoc.13.118

• discuss systems of self-replicating molecules in the context of the origin of life and the synthesis of de novo life. One of the important aspects of life is the ability to reproduce and evolve continuously. In this review we consider some of the prerequisites for obtaining unbounded evolution of self

• understanding of how life could have emerged from molecular building blocks and what is needed to create a minimal form of life in the laboratory. Keywords: autocatalysis; open-ended evolution; origin of life; self-replication; synthetic life; Introduction Mankind has always pondered upon its own existence

• and has sought to understand the origin of life. This led us to trace back our roots, from the great apes to a last universal common ancestor, a simple cellular lifeform from which all other present-day organisms have descended. Ultimately this leads us to one of the great questions in science; how