Cobalt–metalloid alloys for electrochemical oxidation of 5-hydroxymethylfurfural as an alternative anode reaction in lieu of oxygen evolution during water splitting

• Jonas Weidner,
• Stefan Barwe,
• Kirill Sliozberg,
• Stefan Piontek,
• Justus Masa,
• Ulf-Peter Apfel and
• Wolfgang Schuhmann

Beilstein J. Org. Chem. 2018, 14, 1436–1445, doi:10.3762/bjoc.14.121

• , Universitätsstraße 150, D-44780 Bochum, Germany Fraunhofer UMSICHT, Osterfelder Straße 3, D-46047 Oberhausen, Germany 10.3762/bjoc.14.121 Abstract The electrochemical water splitting commonly involves the cathodic hydrogen and anodic oxygen evolution reactions (OER). The oxygen evolution reaction is more

• storable energy carrier. We report on the anodic oxidation of 5-hydroxymethylfurfural (HMF) to afford the more valuable product 2,5-furandicarboxylic acid (FDCA) as a suitable alternative to the oxygen evolution reaction. Notably, HMF oxidation is thermodynamically more favorable than water oxidation and

• with the same electrode. Electrolysis of HMF using a CoB modified nickel foam electrode at 1.45 V vs RHE achieved close to 100% selective conversion of HMF to FDCA at 100% faradaic efficiency. Keywords: alternative anode reaction; electrocatalysis; electrosynthesis; HMF oxidation; hydrogen evolution

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• turned the attention of the scientific community towards the evolution of new chiral hypervalent iodine reagents. In recent years, many complex synthetic challenges have been successfully addressed by applying these reagents [21][22]. The superior advantage of these reagents lies in their strong

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

Crystal structure of the inclusion complex of cholesterol in β-cyclodextrin and molecular dynamics studies

• Elias Christoforides,
• Andreas Papaioannou and
• Kostas Bethanis

Beilstein J. Org. Chem. 2018, 14, 838–848, doi:10.3762/bjoc.14.69

• coordinates was based on the asymmetric unit of the determined structure and the dynamic behavior of the inclusion complex was monitored at two different temperatures (300 and 340 K) to gain some insight on the evolution of the host–guest interactions and to estimate the host–guest binding affinity in aqueous

• protrudes from the primary rim of the host B to the solvent in both cases. Figure 3 shows the time evolution of the root mean square deviation (RMSD) from the initial structure, calculated for all CHL (green) and β-CD (blue) atoms in their complex at 300 K (a) and 340 K (b). RMSD for CHL and β-CD are higher

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

• random sequences in one step. Simple forms may have taken advantage of the high ionic strength of the eutectic phase [6], but their evolution must have been preceded by something simples. In a very simple version of RNA-based replication, genetic copying may have occurred in the absence of both protein

• observed in our assays. But, while reactions that take weeks or months are not problematic for prebiotic evolution, which probably occurred over many millions of years, they are difficult to study in detail in an academic setting that requires results on the time scale of Ph.D. theses. Conclusion Enzyme

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• transferred as building blocks into several natural or biologically active compounds. Thanks to the immense number of possibilities for Mannich reaction through the use of various amines, aldehydes and electron-rich aromatic compounds, the continued evolution of the literature on these reactions appears to be

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• , however, Pd accessible surface area per weight unit turns out to be enhanced for the lowest electrocatalytic loading, indicating a benzophenone accessibility to the Pd nanoparticulate electrocatalysts. Hydrogen gas evolution reaction in the cathode compartment can be reused to feed a gas diffusion

Preparation of trinucleotide phosphoramidites as synthons for the synthesis of gene libraries

• Ruth Suchsland,
• Bettina Appel and
• Sabine Müller

Beilstein J. Org. Chem. 2018, 14, 397–406, doi:10.3762/bjoc.14.28

• , adaptation and optimization of proteins can proceed by two major strategies: (i) rational design or (ii) directed evolution. The rational design is based on the introduction of point mutations, insertions or deletions at a defined position of the protein sequence, and requires detailed knowledge of the

• protein structure and the mechanism of action. On the opposite, directed evolution relies on the selection of a mutant with predefined properties from a random protein library. This strategy is advantageous over the rational design; whenever molecular properties of proteins are investigated that are not

• selection and identification of mutants with improved properties is a favoured method in the field of white biotechnology and biocatalysis, to improve the fitness of enzymes for industrial application [5]. In general, directed evolution may be summarized as an iterative two-step process which involves the

Gram-scale preparation of negative-type liquid crystals with a CF₂CF₂-carbocycle unit via an improved short-step synthetic protocol

• Tatsuya Kumon,
• Shohei Hashishita,
• Takumi Kida,
• Shigeyuki Yamada,
• Takashi Ishihara and
• Tsutomu Konno

Beilstein J. Org. Chem. 2018, 14, 148–154, doi:10.3762/bjoc.14.10

• achieved. The present synthetic protocol is promising for the development of a wide range of negative-type LC molecules containing CF2CF2 carbocycles by the selection of the starting Grignard reagent and should contribute to further evolution of VA-type LC display molecules. Typical examples of previously

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

• background spectrum should be subtracted. It takes about 10–20 min to collect one spectrum by multiple accumulations. During that time, the previously recorded spectra can be processed and compared to follow in real time the evolution of spectra. Any deviation from the baseline in the range where the studied

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

• generate a carbon-centred radical intermediate. The cobalt-catalyst is involved in two ways: oxidation and deprotonation of the radical species yielding the desired product and oxidation of the Eosin Y radical anion to close the photocatalytic cycle. The H2 evolution was not quantitative, which was

• explained by the decomposition of the organic photocatalyst during the H2 evolution process. Increasing amounts of the photocatalyst increased the yield of product and H2. Very recently, the same group reported a regioselective photoredox-catalyzed preparation of vinyl sulfones in Markovnikov orientation

Halogen-containing thiazole orange analogues – new fluorogenic DNA stains

• Aleksey A. Vasilev,
• Meglena I. Kandinska,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• David Sucunza,
• Juan J. Vaquero,
• Obis D. Castaño,
• Stanislav Baluschev and
• Silvia E. Angelova

Beilstein J. Org. Chem. 2017, 13, 2902–2914, doi:10.3762/bjoc.13.283

• interchange of the alkyl groups at the thioalkyl unit and nitrogen atom in the quaternized 2-alkylthio starting materials, which leads to unexpected reaction products [45][46]. The other major disadvantage is the evolution of methylmercaptan – a toxic pollutant with a very unpleasant odor. Results and

¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution

• Sergey L. Deev,
• Alexander S. Paramonov,
• Tatyana S. Shestakova,
• Igor A. Khalymbadzha,
• Oleg N. Chupakhin,
• Julia O. Subbotina,
• Oleg S. Eltsov,
• Pavel A. Slepukhin,
• Vladimir L. Rusinov,
• Alexander S. Arseniev and
• Zakhar O. Shenkarev

Beilstein J. Org. Chem. 2017, 13, 2535–2548, doi:10.3762/bjoc.13.250

• ). (A) Fragment of the 1D 1H amplitude-modulated spin-echo spectrum measured without (black trace) or with selective inversion of the 15N2 (blue trace) or 15N3 (red trace) nuclei. The spectrum was measured using a spin-echo delay (delay for the evolution of JHN) of 1 s. The measured JHN values are

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

• significantly more light than the same mass of small particles. Thus, a fairly small amount of large aggregates might dominate the scattering making the contribution of small particles negligible. The long-time evolution of all the isomers after filtration was evaluated according to the approach of Bonini [22

• size continuously fluctuate (Supporting Information File 1, Figure S5), which could be easily monitored by scattering intensities behavior. The evolution of the 2-O-isomer in time has also been investigated, but no trend was observed in this case (Supporting Information File 1, Figure S6). The long

• -time evolution of the 6-O-filtered sample revealed that the size of particles continuously increased with time (Supporting Information File 1, Figure S6), starting from 2 nm particles appearing immediately after the filtration and reaching larger particles that grew in the sample standing overnight

Syntheses, structures, and stabilities of aliphatic and aromatic fluorous iodine(I) and iodine(III) compounds: the role of iodine Lewis basicity

• Tathagata Mukherjee,
• Soumik Biswas,
• Andreas Ehnbom,
• Subrata K. Ghosh,
• Ibrahim El-Zoghbi,
• Nattamai Bhuvanesh,
• Hassan S. Bazzi and
• John A. Gladysz

Beilstein J. Org. Chem. 2017, 13, 2486–2501, doi:10.3762/bjoc.13.246

• structure of which is determined, reacts with Cl2 to give a 75:25 ArICl2/ArI mixture, but partial Cl2 evolution occurs upon work-up. The latter gives the easily isolated dichloride 1,2,4-(Rf8CH2CH2)2C6H3ICl2 (89%). The relative thermodynamic ease of dichlorination of these and other iodine(I) compounds is

• in 80–89% yields. Although these were clean by NMR, only one gave a correct microanalysis. As illustrated in Figure S1 (Supporting Information File 1), CDCl3/C6F6 solutions of 1,3-Rf6C6H4ICl2 and 1,4-Rf6C6H4ICl2 containing an internal standard were monitored by 1H NMR. Slow partial evolution of Cl2

• )2C6H3ICl2 were unsuccessful. It was concluded that 1,3,5-(Rf6)2C6H3ICl2 was much more labile with respect to Cl2 evolution than the fluorous aryliodine(III) dichlorides shown in Scheme 5, and that the 75–80% conversions reflected a thermodynamic limit. Next, analogs of 1,3,5-(Rf6)2C6H3ICl2 with less

Synthesis of naturally-derived macromolecules through simplified electrochemically mediated ATRP

• Paweł Chmielarz,
• Tomasz Pacześniak,
• Katarzyna Rydel-Ciszek,
• Izabela Zaborniak,
• Paulina Biedka and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2017, 13, 2466–2472, doi:10.3762/bjoc.13.243

• purification (in CDCl3). Synthesis of PtBA homopolymers grafted from quercetin-based macroinitiator via seATRP under constant potential conditions; (a) Mn and Mw/Mn vs monomer conversion, and (b) GPC traces of tBA polymerization and their evolution over time. Reaction conditions: [tBA]/[QC-Br5 (per 5

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

• even after 15 minutes milling. Surprisingly, monitoring the mechanochemical formation of 5 by milling with brass balls (method 2c) enabled a clear insight into the evolution of the reaction mixture (Figure 3a). The luminescent peak remained weak throughout the experiment, leaving the Raman signals of

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

• -CD, and γ-CDs were recorded in phosphate buffered saline (PBS) at pH 7.4 using an Evolution 220 UV–vis spectrometer (Thermo Scientific) in the range of 200–450 nm. Evaluation of association constants (Kas) of native CDs with PTX. UV–vis titrations: The change in absorption was measured as a function

Are boat transition states likely to occur in Cope rearrangements? A DFT study of the biogenesis of germacranes

• José Enrique Barquera-Lozada and
• Gabriel Cuevas

Beilstein J. Org. Chem. 2017, 13, 1969–1976, doi:10.3762/bjoc.13.192

• energetic evolution of germacranolides’ Cope transformations. Computational methods DFT has been proved to be a good method for the study of reaction mechanisms of natural products' biogenesis and it has been used in many studies [44][45][46][47][48][49][50][51][52][53][54][55] and it is the method of

A novel application of 2-silylated 1,3-dithiolanes for the synthesis of aryl/hetaryl-substituted ethenes and dibenzofulvenes

• Grzegorz Mlostoń,
• Paulina Pipiak,
• Róża Hamera-Fałdyga and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 1900–1906, doi:10.3762/bjoc.13.185

• some dihetaryl thioketones, e.g., 1d and 1e, were reported [22]. In contrast to CH2N2, TMS-CHN2 reacted with thiobenzophenone (1a) with evolution of N2 even at −75 °C and led to a mixture of 4,4,5,5-tetraphenyl-1,3-dithiolane 6a and 2,2,3,3-tetraphenyl-1,4-dithiane 7 (Scheme 2). This result

Enzymatic synthesis of glycosides: from natural O- and N-glycosides to rare C- and S-glycosides

• Jihen Ati,
• Pierre Lafite and
• Richard Daniellou

Beilstein J. Org. Chem. 2017, 13, 1857–1865, doi:10.3762/bjoc.13.180

• . Rational mutagenesis, directed evolution, or even de novo design have dramatically broaden the applicability of enzymes in biocatalysis [7]. In the glycochemistry field, a vast array of carbohydrate-metabolizing enzymes [8] has been used to synthesize glycosides, even using multiple enzymes systems

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• inorganic chemical into an organic product, at that time only available from living organisms, was in contradiction with the prevailing doctrine of vitalism, which was in the years to come abandoned enabling a rapid evolution of organic chemistry in the 19th century. During the 20th century, synthetic

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

• an automated recursive platform based on droplet microfluidics, could be used to induce artificial chemical evolution by iterations of growth, speciation, selection, and propagation. To explore this, we set about designing an open source prototype of a fully automated evolution machine, comprising

• : artificial life; autocatalysis; automated platforms; chemical evolution; evolution before genes; evolution first; microfluidics; Introduction The transition from an inanimate inorganic world, principally consisting of minerals, gases and small organic compounds, to the living world with the first life forms

• external environment. ii) Metabolism: chemical reaction networks that extract energy from the environment in a useable form. iii) Heritance: reliable transmission of functional information from one generation to the next. iv) Evolution: a means of undergoing an evolutionary selection process, driven by

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• cyclisation and oxidative dehydrogenation in the presence of barium manganate to produce benzimidazoles, benzoxazoles and benzothiazoles 54, respectively in appropriate solvent at ambient or lower temperature (Scheme 16). Catalytic approaches As a normal evolution of any synthetic approaches, oxidative

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

• characteristics of various biomolecules, e.g., the catalytic activity of RNAs and their evolution potential [9][10][11], as well as processes that were essential for their syntheses, such as Fischer–Tropsch-like reactions [12], non-enzymatic RNA [13] or peptide polymerization [14]. Moreover, it has also allowed

• for the determination of environmental conditions conducive to the self-assembly of several cellular-like components, such as bilayer membranes [15] and simple energy systems [16], or dynamic processes, such as growth and division [17][18] and potential evolution [19]. However, the experimental set

• membrane components. Furthermore, experimental conditions are sometimes implausible from the geochemical perspective. Finally, the evolutionary continuity of the systems, which should be paramount to explain the emergence of protocellular systems and evolution towards true cells, is often neglected in