Perspective isomorphs – a new classification of molecular structures based on artistic and chemical concepts

• Jannis Neumann,
• Ansgar Schnurr and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2019, 15, 2319–2326, doi:10.3762/bjoc.15.224

• substances by transforming their structural information into an explicit character sequence for identification. The information is given in terms of layers around the atoms and their bond connectivity, tautomeric information, isotope information, stereochemistry, and electronic charge information. In

Isolation of fungi using the diffusion chamber device FIND technology

• Benjamin Libor,
• Henrik Harms,
• Stefan Kehraus,
• Ekaterina Egereva,
• Max Crüsemann and
• Gabriele M. König

Beilstein J. Org. Chem. 2019, 15, 2191–2203, doi:10.3762/bjoc.15.216

• . Unfortunately, sequences for only 33 Chrysosporium species are available as reference sequences, and thus no identification on the species level could be achieved. Interestingly, the sequence of our isolated Leucothecium species is 100% identical to the reference sequence of an uncultured fungus isolated from

• attached carbon atoms with an HSQC experiment, analysis of the 1H,1H-COSY data led to the identification of two major 1H–1H spin systems, one corresponding to the H-2–H-1b–H-6 moiety (spin system A) and the second to the H2-8–H3-13 subunit (spin system B; Figure 2). Spin system B was extended by a

• be cultivated for further purposes like taxonomic identification or natural product isolation. Isolation methods like baiting may lead to bait-specific fungi only. A strain of A. umbrinum was isolated by Deshmukh et al. using a hair baiting technique. The majority of those isolates showed

1,2,3-Triazolium macrocycles in supramolecular chemistry

• Mastaneh Safarnejad Shad,
• Pulikkal Veettil Santhini and
• Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

• -derived tris(crown ether) host (eTC) via a dynamic covalent chemistry approach involving triple threading and a Grubbs-catalyzed ring-closing metathesis [68]. 1H NMR titration experiments have been used for the identification of co-conformations of the four related stable states of 19. The authors have

Characterization of two new degradation products of atorvastatin calcium formed upon treatment with strong acids

• Jürgen Krauß,
• Monika Klimt,
• Markus Luber,
• Peter Mayer and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2085–2091, doi:10.3762/bjoc.15.206

• structures of the degradation products. Here we report the identification of two novel degradation products of atorvastatin, which are formed only under drastic acidic conditions. While treatment with conc. sulfuric acid led to a loss of the carboxanilide residue (accompanied by an expectable lactonization

Genome mining in Trichoderma viride J1-030: discovery and identification of novel sesquiterpene synthase and its products

• Xiang Sun,
• You-Sheng Cai,
• Yujie Yuan,
• Guangkai Bian,
• Ziling Ye,
• Zixin Deng and
• Tiangang Liu

Beilstein J. Org. Chem. 2019, 15, 2052–2058, doi:10.3762/bjoc.15.202

• Trichoderma, such as trichodiene synthase homologous gene isolation and characterisation in T. harzianum [32] and functional identification of terpene synthase vir4 in T. virens [33]. However, owing to the general lack of previous studies of terpene synthases in T. viride, Tvi09626 is the first terpene

Multicomponent reactions III

• Thomas J. J. Müller

Beilstein J. Org. Chem. 2019, 15, 1974–1975, doi:10.3762/bjoc.15.192

• environmental concern, the concept of multicomponent reactions (MCRs) [1] has become a particularly powerful principle of synthetic design, combining synthetic efficiency with conceptual efficacy. The importance of rapid lead finding and identification has demanded novel ways of synthetic approaches, ultimately

Analysis of sesquiterpene hydrocarbons in grape berry exocarp (Vitis vinifera L.) using in vivo-labeling and comprehensive two-dimensional gas chromatography–mass spectrometry (GC×GC–MS)

• Philipp P. Könen and
• Matthias Wüst

Beilstein J. Org. Chem. 2019, 15, 1945–1961, doi:10.3762/bjoc.15.190

• ) coupled to a time-of-flight mass spectrometer (TOF–MS) after headspace-solid phase microextraction (HS-SPME). The identification of structurally complex natural compounds, such as sesquiterpenes from fruits and vegetables, is often reported as “tentative”, as authentic standards are not commercially

• chromatograms, i.e., compounds of common structure classes are grouped. The coupling of comprehensive two-dimensional gas chromatography with mass spectrometry as the “third dimension” also provides important information for substance identification. The combination of these advantages makes the GC×GC one of

• , 25 sesquiterpene hydrocarbons were found in the exocarp of ripe grapes (Vitis vinifera L.) of the red wine variety Lemberger. The unequivocal identification of these structurally complex natural compounds was performed by combining multidimensional gas chromatography with in vivo labeling using the

Archangelolide: A sesquiterpene lactone with immunobiological potential from Laserpitium archangelica

• Silvie Rimpelová,
• Michal Jurášek,
• Lucie Peterková,
• Jiří Bejček,
• Vojtěch Spiwok,
• Miloš Majdl,
• Michal Jirásko,
• Miloš Buděšínský,
• Juraj Harmatha,
• Eva Kmoníčková,
• Pavel Drašar and
• Tomáš Ruml

Beilstein J. Org. Chem. 2019, 15, 1933–1944, doi:10.3762/bjoc.15.189

• anti-inflammatory activity of compound 1 using rat macrophages. Results and Discussion L. archangelica metabolite isolation and identification For isolation of the major metabolites of L. archangelica, we used 100 g of fine ground seeds (Supporting Information File 1, Figure S2) and the method of

Identification of optimal fluorescent probes for G-quadruplex nucleic acids through systematic exploration of mono- and distyryl dye libraries

• Xiao Xie,
• Michela Zuffo,
• Marie-Paule Teulade-Fichou and
• Anton Granzhan

Beilstein J. Org. Chem. 2019, 15, 1872–1889, doi:10.3762/bjoc.15.183

• values cf. Supporting Information, Table S1). In addition, group-average data, i.e., average fluorescence response of each dye towards 12 G4 (DNA and RNA) analytes vs average response to non-G4 (ct DNA and cl RNA) controls, are presented in Figure 6. This plot facilitates the identification of the most

• a set of G4-DNA and G4-RNA analytes, as well as the respective non-G4 controls. The data were analyzed aiming at the identification of structural motifs or physical properties (such as aggregation in aqueous medium) of dyes which could govern their fluorimetric response towards one or another group

Synthesis and biological evaluation of truncated derivatives of abyssomicin C as antibacterial agents

• Leticia Monjas,
• Peter Fodran,
• Johanna Kollback,
• Carlo Cassani,
• Thomas Olsson,
• Maja Genheden,
• D. G. Joakim Larsson and
• Carl-Johan Wallentin

Beilstein J. Org. Chem. 2019, 15, 1468–1474, doi:10.3762/bjoc.15.147

• develop new antibiotics, but the reevaluation of known natural products (NP) and the identification of new NPs and derivatives thereof is considered an especially important pathway in the search for more robust antibiotics [1][2]. The main reasons are the inherent high selectivity and appropriate

Fluorine-containing substituents: metabolism of the α,α-difluoroethyl thioether motif

• Andrea Rodil,
• Alexandra M. Z. Slawin,
• Nawaf Al-Maharik,
• Ren Tomita and
• David O’Hagan

Beilstein J. Org. Chem. 2019, 15, 1441–1447, doi:10.3762/bjoc.15.144

• into diethyl ether and dichloromethane (DCM) and then carrying out HPLC analyses. Incubation of thioether 4 with C. elegans led to the identification of three metabolites 6–8 as illustrated in Scheme 1. These were isolated by semi-preparative HPLC. Two of these (6 and 7) displayed an AB system in the

Introduction of an isoxazoline unit to the β-position of porphyrin via regioselective 1,3-dipolar cycloaddition reaction

• Xiujun Liu,
• Xiang Ma and
• Yaqing Feng

Beilstein J. Org. Chem. 2019, 15, 1434–1440, doi:10.3762/bjoc.15.143

• -generated nitrile oxide, which showed inferior selectivity and afforded regio-/stereoisomers [43]. NMR analysis assisted the identification of various isomeric isoxazoline-linked chlorin products. Here, we would like to report an artificial vinylporphyrin 2, which has been designed to control the

Genomics-inspired discovery of massiliachelin, an agrochelin epimer from Massilia sp. NR 4-1

• Jan Diettrich,
• Hirokazu Kage and
• Markus Nett

Beilstein J. Org. Chem. 2019, 15, 1298–1303, doi:10.3762/bjoc.15.128

• production and complexing properties [15]. Therefore, we decided to initially focus our genome mining efforts on the micacocidin-type cluster in Massilia sp. NR 4-1. Here, we report the outcome of this study, which led to the identification of a previously unrecognized agrochelin epimer and, furthermore

Phylogenomic analyses and distribution of terpene synthases among Streptomyces

• Lara Martín-Sánchez,
• Kumar Saurabh Singh,
• Mariana Avalos,
• Gilles P. van Wezel,
• Jeroen S. Dickschat and
• Paolina Garbeva

Beilstein J. Org. Chem. 2019, 15, 1181–1193, doi:10.3762/bjoc.15.115

• ). These exceptions may indicate horizontal gene transfer of the genes encoding for these enzymes. The sesquiterpene 7-epi-α-eudesmol synthase from S. viridochromogenes DSM 40736 has been chemically characterised in vivo by heterologous expression in E. coli BL21 and identification of the product in

Precious metal-free molecular machines for solar thermal energy storage

• Meglena I. Kandinska,
• Snejana M. Kitova,
• Vladimira S. Videva,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• Stanislav B. Baluschev,
• Silvia E. Angelova and
• Aleksey A. Vasilev

Beilstein J. Org. Chem. 2019, 15, 1096–1106, doi:10.3762/bjoc.15.106

• -system [9] with a triplet–triplet annihilation photon energy upconversion system (TTA-UC) [10][11] an effective utilization of sub-bandgap photons is possible [12][13]. Nevertheless, the identification of a precious metal-free MOST system utilizing the visible part of the sun spectrum remains a

• improvements and brings the scientists nearer to the identification of the “perfect” MOST system. In this connection we identified crown ether-containing styryl dyes [14][15] as promising substances due to their ability to undergo trans-to-cis photoisomerization (E/Z) with very high quantum yields. In addition

Stereo- and regioselective hydroboration of 1-exo-methylene pyranoses: discovery of aryltriazolylmethyl C-galactopyranosides as selective galectin-1 inhibitors

• Alexander Dahlqvist,
• Axel Furevi,
• Niklas Warlin,
• Hakon Leffler and
• Ulf J. Nilsson

Beilstein J. Org. Chem. 2019, 15, 1046–1060, doi:10.3762/bjoc.15.102

• excellent diastereoselectivities (1:19 and 1:99 α:β ratio, respectively). Hydroboration of the glucose enol ether 6 afforded a mixture of both diastereomers (1:2.3 α:β ratio) in good yield (43% β and 18% α isolated yields, respectively). Identification of the diastereomers was accomplished by NOESY

Mechanistic investigations on multiproduct β-himachalene synthase from Cryptosporangium arvum

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2019, 15, 1008–1019, doi:10.3762/bjoc.15.99

• (path A) and an hypothetical alternative mechanism via an initial 1,6-cyclisation (path B). Alternative mechanistic and reaction arrows belonging to branching points are shown in red. HcS product identification by retention indices. Supporting Information Experimental details for gene cloning, gene

An anomalous addition of chlorosulfonyl isocyanate to a carbonyl group: the synthesis of ((3aS,7aR,E)-2-ethyl-3-oxo-2,3,3a,4,7,7a-hexahydro-1H-isoindol-1-ylidene)sulfamoyl chloride

• Aytekin Köse,
• Aslı Ünal,
• Ertan Şahin,
• Uğur Bozkaya and
• Yunus Kara

Beilstein J. Org. Chem. 2019, 15, 931–936, doi:10.3762/bjoc.15.89

• exact configuration was determined by X-ray crystal analysis. We explain the mechanism of product formation supported by theoretical calculations. Keywords: addition reaction; chlorosulfonyl isocyanate; sulfamoyl chloride; theoretical calculations; Introduction Since its identification in 1959 [1

Strong hyperconjugative interactions limit solvent and substituent influence on conformational equilibrium: the case of cis-2-halocyclohexylamines

• Camila B. Francisco,
• Cleverton S. Fernandes,
• Ulisses Z. de Melo,
• Roberto Rittner,
• Gisele F. Gauze and
• Ernani A. Basso

Beilstein J. Org. Chem. 2019, 15, 818–829, doi:10.3762/bjoc.15.79

• group and equatorial halogen) and ea (equatorial amine group and axial halogen) conformers (Figure 1) by dynamic NMR (DNMR) and theoretical calculations. Results and Discussion Experimental conformational population Low-temperature NMR experiments allow the identification of the individual conformers

An improved synthesis of adefovir and related analogues

• David J. Jones,
• Eileen M. O’Leary and
• Timothy P. O’Sullivan

Beilstein J. Org. Chem. 2019, 15, 801–810, doi:10.3762/bjoc.15.77

• -butoxide and DMF, to achieve high conversions to the target. A systematic study within our laboratory led to the identification of an iodide reagent which affords higher yields than previous approaches and allows for reactions to be conducted up to 10 g in scale under milder conditions. The use of a novel

• identification of a correlation between the methylene protons adjacent to the purine ring with C-5. A similar analysis by us revealed the same correlation, confirming 29 as the major product (Figure 4). While the amidine is itself an important moiety in medicinal chemistry [57], it can also be readily converted

Homo- and hetero-difunctionalized β-cyclodextrins: Short direct synthesis in gram scale and analysis of regiochemistry

• Gábor Benkovics,
• Mihály Bálint,
• Éva Fenyvesi,
• Erzsébet Varga,
• Szabolcs Béni,
• Konstantina Yannakopoulou and
• Milo Malanga

Beilstein J. Org. Chem. 2019, 15, 710–720, doi:10.3762/bjoc.15.66

• identification, the authentic diazido compounds with known regiochemistry were synthesized using the appropriately spaced disulfonate capping agent, followed by azide opening of the cap and by chromatographic purification of the diazidated fractions [11][12] (reference reactions 1–3, Scheme 1). Direct

• allowed the identification of the spin system of each glucopyranose unit among which the tosylated ones can be identified using the resonance frequencies of H6,6’ as an entry point. Three staggered conformers with respect to the TsO–C(6)–C(5)–H(5) dihedral angle (see Figure 3d for numbering) are possible

• indicating (a) the anomeric proton (H1) region (5.20 to 4.70 ppm) and (b) the H6,6’-OTs proton region (4.30 to 3.90 ppm). (c) 2D TOCSY NMR spectrum of 6A,6D-ditosyl-β-CD: starting from each H1 resonance, identification of the signals that belong to the same spin system (dotted lines) is possible leading to

New sesquiterpenoids from the South China Sea soft corals Clavularia viridis and Lemnalia flava

• Qihao Wu,
• Yuan Gao,
• Meng-Meng Zhang,
• Li Sheng,
• Jia Li,
• Xu-Wen Li,
• Hong Wang and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2019, 15, 695–702, doi:10.3762/bjoc.15.64

• Natural Science Foundation of China (Nos. 21672230, 81603022, 81125023), the SKLDR/SIMM Projects (SIMM 1705ZZ-01). We thank Prof. Xiu-Bao Li from Hainan University for the taxonomic identification of the soft coral material.

Back to the future: Why we need enzymology to build a synthetic metabolism of the future

• Tobias J. Erb

Beilstein J. Org. Chem. 2019, 15, 551–557, doi:10.3762/bjoc.15.49

• misannotated proteins, which is caused by automatized annotation algorithms that are often based on “simple” sequence similarities [43][44]. In selected enzyme (super)families the annotation error can be as high as 90% [45], which masks or even impedes the identification of novel functions within a given

Synthesis and SAR of the antistaphylococcal natural product nematophin from Xenorhabdus nematophila

• Frank Wesche,
• Hélène Adihou,
• Thomas A. Wichelhaus and
• Helge B. Bode

Beilstein J. Org. Chem. 2019, 15, 535–541, doi:10.3762/bjoc.15.47

• . Compounds 11 and 12 were separated during the isolation process and initially constructed to enable target identification. Compounds 11 and 12 might act as Michael acceptor (α,β-unsaturated carbonyl) and attach irreversibly and covalently to a potential target [23]. After purification and characterization

• , the azaindole derivatives are currently under investigation upon their use for fluorescence imaging. Furthermore, derivatives 3 and 6 will be further studied for identification of their actual target in S. aureus. This could be a serine protease that can also be addressed in the future by more stable

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• reactions can be integrated in the toolbox of chemical proteomics. Recently, following a similar strategy, Lu et al. reported on-DNA RCM and CM, an application potentially useful to generate DNA-encoded libraries for hit identification and target validation [90]. Substrates appended to oligonucleotides