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Beilstein Journal of Organic Chemistry

Yajun Liu, Shasha Liu, Yan Xiao
Phenols and aryl thiols are fundamental building blocks in organic synthesis and final products with interesting biological activities. Over the past decades, substantial progress has been made in transition-metal-catalyzed coupling reactions, which resulted in the emergence of new methods for the synthesis of phenols and aryl thiols. Aryl halides have been extensively studied as substrates for the synthesis of phenols and aryl thiols. In very recent years, C-H activation represents a powerful strategy for the construction of functionalized phenols directly from various arenes...
2017: Beilstein Journal of Organic Chemistry
Jan Szabo, Julian Greiner, Gerhard Maas
Depending on the reaction conditions, N,N',N''-tris(benzylamino)guanidinium salts can react with carboxylic acid chlorides to form either symmetrical N,N',N''-tris(N-acyl-N-benzylamido)guanidines 6 or mesoionic 4-amino-1,2,4-triazolium-3-hydrazinides 7. The latter were converted into 1,2,4-triazolium salts by protonation or methylation at the hydrazinide nitrogen atom. Neutral 1,2,4-triazoles 10 were obtained by catalytic hydrogenation of an N-benzyl derivative. Crystal structure analyses of a 4-benzylamino-1,2,4-triazolium-3-hydrazinide and of two derived 1,2,4-triazolium salts are presented...
2017: Beilstein Journal of Organic Chemistry
Runjun Devi, Sajal Kumar Das
While the exploitation of the Sharpless asymmetric dihydroxylation as the source of chirality in the synthesis of acyclic molecules and saturated heterocycles has been tremendous, its synthetic utility toward chiral benzo-annulated heterocycles is relatively limited. Thus, in the search for wider applications of Sharpless asymmetric dihydroxylation-derived diols for the synthesis of benzo-annulated heterocycles, we report herein our studies in the asymmetric synthesis of (R)-1-((R)-6-fluorochroman-2-yl)ethane-1,2-diol, (R)-1-((S)-6-fluorochroman-2-yl)ethane-1,2-diol and (S)-6-fluoro-2-((R)-oxiran-2-yl)chroman, which have been used as late-stage intermediates for the asymmetric synthesis of the antihypertensive drug (S,R,R,R)-nebivolol...
2017: Beilstein Journal of Organic Chemistry
Nikolay V Lukashev, Gennadii A Grabovyi, Dmitry A Erzunov, Alexey V Kazantsev, Gennadij V Latyshev, Alexei D Averin, Irina P Beletskaya
Cu- and Pd-catalyzed arylation of aminocholanes has been described for the first time. While this Cu-catalyzed protocol provides high yields in reactions of aminocholanes with iodoarenes, Pd catalysis was found to be preferable for the reactions of aminocholanes with dichloroanthraquinones. UV-vis titration of bis(cholanylamino)anthraquinones with a series of cations demonstrated their high binding affinity to Cu(2+), Al(3+), and Cr(3+).
2017: Beilstein Journal of Organic Chemistry
Qi An, Youssef Hassan, Xiaotong Yan, Peter Krolla-Sidenstein, Tawheed Mohammed, Mathias Lang, Stefan Bräse, Manuel Tsotsalas
Conjugated microporous polymers (CMPs) are materials of low density and high intrinsic porosity. This is due to the use of rigid building blocks consisting only of lightweight elements. These materials are usually stable up to temperatures of 400 °C and are chemically inert, since the networks are highly crosslinked via strong covalent bonds, making them ideal candidates for demanding applications in hostile environments. However, the high stability and chemical inertness pose problems in the processing of the CMP materials and their integration in functional devices...
2017: Beilstein Journal of Organic Chemistry
Sujit Ghosh, Kinkar Biswas, Suchandra Bhattacharya, Pranab Ghosh, Basudeb Basu
The synthesis of propargylamines via A(3) coupling mostly under metal-catalyzed procedures is well known. This work invented an unprecedented effect of salicylaldehyde, one of the A(3) coupling partners, which could lead to the formation of propargylamine, an important pharmaceutical building block, in the absence of any metal catalyst and under mild conditions. The role of the hydroxy group in ortho position of salicylaldehyde has been explored, which presumably activates the Csp-H bond of the terminal alkyne leading to the formation of propargylamines in good to excellent yields, thus negating the function of the metal catalyst...
2017: Beilstein Journal of Organic Chemistry
Gábor Benkovics, Damien Afonso, András Darcsi, Szabolcs Béni, Sabrina Conoci, Éva Fenyvesi, Lajos Szente, Milo Malanga, Salvatore Sortino
Eosin B (EoB) and eosin Y (EoY), two xanthene dye derivatives with photosensitizing ability were prepared in high purity through an improved synthetic route. The dyes were grafted to a 6-monoamino-β-cyclodextrin scaffold under mild reaction conditions through a stable amide linkage using the coupling agent 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride. The molecular conjugates, well soluble in aqueous medium, were extensively characterized by 1D and 2D NMR spectroscopy and mass spectrometry...
2017: Beilstein Journal of Organic Chemistry
Flavio Fanelli, Giovanna Parisi, Leonardo Degennaro, Renzo Luisi
Microreactor technology and flow chemistry could play an important role in the development of green and sustainable synthetic processes. In this review, some recent relevant examples in the field of flash chemistry, catalysis, hazardous chemistry and continuous flow processing are described. Selected examples highlight the role that flow chemistry could play in the near future for a sustainable development.
2017: Beilstein Journal of Organic Chemistry
Alexander Bogdanov, Cora Hertzer, Stefan Kehraus, Samuel Nietzer, Sven Rohde, Peter J Schupp, Heike Wägele, Gabriele M König
Phyllodesmium longicirrum is the largest aeolidoidean species known to date, and extremely rich in terpenoid chemistry. Herein we report the isolation of a total of 19 secondary metabolites from a single specimen of this species, i.e., steroids 1-4, cembranoid diterpenes 5-13, complex biscembranoids 14 and 15, and the chatancin-type diterpenes 16-19. These compounds resemble those from soft corals of the genus Sarcophyton, of which to date, however, only S. trocheliophorum is described as a food source for P...
2017: Beilstein Journal of Organic Chemistry
Sarah Wallrodt, Edward L Simpson, Andreas Marx
ADP-ribosyl transferases with diphtheria toxin homology (ARTDs) catalyse the covalent addition of ADP-ribose onto different acceptors forming mono- or poly(ADP-ribos)ylated proteins. Out of the 18 members identified, only four are known to synthesise the complex poly(ADP-ribose) biopolymer. The investigation of this posttranslational modification is important due to its involvement in cancer and other diseases. Lately, metabolic labelling approaches comprising different reporter-modified NAD(+) building blocks have stimulated and enriched proteomic studies and imaging applications of ADP-ribosylation processes...
2017: Beilstein Journal of Organic Chemistry
Marika Turek, Dorota Szczęsna, Marek Koprowski, Piotr Bałczewski
This comprehensive review describes methods for the preparation of 1-indanones published in original and patent literature from 1926 to 2017. More than 100 synthetic methods utilizing carboxylic acids, esters, diesters, acid chlorides, ketones, alkynes, alcohols etc. as starting materials, have been performed. This review also covers the most important studies on the biological activity of 1-indanones and their derivatives which are potent antiviral, anti-inflammatory, analgesic, antimalarial, antibacterial and anticancer compounds...
2017: Beilstein Journal of Organic Chemistry
Enjuro Harunari, Hisayuki Komaki, Yasuhiro Igarashi
Butyrolactol A is an antifungal polyketide of Streptomyces bearing an uncommon tert-butyl starter unit and a polyol system in which eight hydroxy/acyloxy carbons are contiguously connected. Except for its congener butyrolactol B, there exist no structurally related natural products to date. In this study, inspired by our previous genomic analysis, incorporation of (13)C- and (2)H-labeled precursors into butyrolactol A was investigated. Based on the labeling pattern and sequencing analytical data, we confirmed that the tert-butyl group is derived from valine and its C-methylation with methionine and the polyol carbons are derived from a glycolysis intermediate, possibly hydroxymalonyl-ACP...
2017: Beilstein Journal of Organic Chemistry
Ramana Sreenivasa Rao, Chinnasamy Ramaraj Ramanathan
An efficient and alternative synthetic approach has been developed to prepare various N-(arylethyl)piperazine-2,6-diones from 4-benzenesulfonyliminodiacetic acid and primary amines using carbonyldiimidazole in the presence of a catalytic amount of DMAP at ambient temperature. Piperazine-2,6-diones are successfully transformed to pharmaceutically useful pyridopyrazines or pyrazinoisoquinolines and ene-diamides via an imide carbonyl group activation strategy using a Brønsted acid. Subsequent dehydrosulfonylation reactions of the ene-diamides, in a one pot manner, smoothly transformed them to substituted pyrazinones...
2017: Beilstein Journal of Organic Chemistry
Sophie Letort, Michaël Bosco, Benedetta Cornelio, Frédérique Brégier, Sébastien Daulon, Géraldine Gouhier, François Estour
New derivatives of cyclodextrins were prepared in order to determine the relative importance of the structural key elements involved in the degradation of organophosphorus nerve agents. To avoid a competitive inclusion between the organophosphorus substrate and the iodosobenzoate group, responsible for its degradation, the latter group had to be covalently bound to the cyclodextrin scaffold. Although the presence of the α nucleophile iodosobenzoate was a determinant in the hydrolysis process, an imidazole group was added to get a synergistic effect towards the degradation of the agents...
2017: Beilstein Journal of Organic Chemistry
Michael L McKee, Grzegorz Mlostoń, Katarzyna Urbaniak, Heinz Heimgartner
An intriguing stepwise diradical mechanism of the dimerization of the reactive intermediate (thiocarbonyl S-methanide) appearing in the reaction of phenyl selenophen-2-yl thioketone with diazomethane was studied by means of computational methods. The preferred formation of the unusual macroheterocycle, competitive with the 1,3-ring closure leading to a thiirane and the head-to-head dimerization yielding a 1,4-dithiane derivative, respectively, was explained based on the analysis of the structure of the favored conformer of the intermediate, delocalized diradical species...
2017: Beilstein Journal of Organic Chemistry
Frank Wesche, Yue He, Helge B Bode
In search for new natural products, which may lead to the development of new drugs for all kind of applications, novel methods are needed. Here we describe the identification of electrophilic natural products in crude extracts via their reactivity against azide as a nucleophile followed by their subsequent enrichment using a cleavable azide-reactive resin (CARR). Using this approach, natural products carrying epoxides and α,β-unsaturated enones as well as several unknown compounds were identified in crude extracts from entomopathogenic Photorhabdus bacteria...
2017: Beilstein Journal of Organic Chemistry
Elisa Biondi, Yoshihiro Furukawa, Jun Kawai, Steven A Benner
The prebiotic significance of laboratory experiments that study the interactions between oligomeric RNA and mineral species is difficult to know. Natural exemplars of specific minerals can differ widely depending on their provenance. While laboratory-generated samples of synthetic minerals can have controlled compositions, they are often viewed as "unnatural". Here, we show how trends in the interaction of RNA with natural mineral specimens, synthetic mineral specimens, and co-precipitated pairs of synthetic minerals, can make a persuasive case that the observed interactions reflect the composition of the minerals themselves, rather than their being simply examples of large molecules associating nonspecifically with large surfaces...
2017: Beilstein Journal of Organic Chemistry
Ghina'a I Abu Deiab, Mohammed H Al-Huniti, I F Dempsey Hyatt, Emma E Nagy, Kristen E Gettys, Sommayah S Sayed, Christine M Joliat, Paige E Daniel, Rupa M Vummalaneni, Andrew T Morehead, Andrew L Sargent, Mitchell P Croatt
Dienoic acids and pentadienyl alcohols are coupled in a decarboxylative and dehydrative manner at ambient temperature using Pd(0) catalysis to generate 1,3,6,8-tetraenes. Contrary to related decarboxylative coupling reactions, an anion-stabilizing group is not required adjacent to the carboxyl group. Of mechanistic importance, it appears that both the diene of the acid and the diene of the alcohol are required for this reaction. To further understand this reaction, substitutions at every unique position of both coupling partners was examined and two potential mechanisms are presented...
2017: Beilstein Journal of Organic Chemistry
Maximilian Maier, Magnus S Schmidt, Markus Ringwald, Christoph P Fik
Six polymerizable N,N'-diacylamides containing spatially arranged N-acryl, N-allyl and/or N-alkyl groups were prepared via two-step syntheses and characterized by (1)H/(13)C NMR-spectra, refractive index (RI) and viscosity measurements. Photo DSC measurements on activated samples provided reactivity parameters ∆Hp, Rp,max and tmax, while FTIR spectra before and after curing elucidated the underlying polymerization mechanism. Mechanical testing of the obtained polymers exhibited gradual differences in network densities, depending on the intramolecular arrangement and number of functional groups...
2017: Beilstein Journal of Organic Chemistry
Kira J Weissman
The biosynthesis of reduced polyketides in bacteria by modular polyketide synthases (PKSs) proceeds with exquisite stereocontrol. As the stereochemistry is intimately linked to the strong bioactivity of these molecules, the origins of stereochemical control are of significant interest in attempts to create derivatives of these compounds by genetic engineering. In this review, we discuss the current state of knowledge regarding this key aspect of the biosynthetic pathways. Given that much of this information has been obtained using chemical biology tools, work in this area serves as a showcase for the power of this approach to provide answers to fundamental biological questions...
2017: Beilstein Journal of Organic Chemistry
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