Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa

• Tian Cheng,
• Clara Chepkirui,
• Cony Decock,
• Josphat C. Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270

• of secondary metabolites for later comparison with herbarium specimens of other species by HPLC–diode array detection (HPLC–DAD)–MS. Surprisingly, we detected further members of the skeletocutin family that were not present in the cultures. The current paper is dedicated to the description of their

• , solvent A: H2O + 0.1% formic acid, solvent B: acetonitrile + 0.1% formic acid, elution gradient: 5% solvent B for 0.5 min, increasing solvent B to 100% within 19.5 min, 100% solvent B for 5 min, flow rate: 0.6 mL/min, UV–vis detection at λ = 200–600 nm) and ESI–TOF–MS analysis (maXis™ system, Bruker, scan

• ), respectively, were used as mobile phases (elution gradient: 50% solvent B, increasing solvent B to 100% within 60 min, 100% solvent B for 5 min, flow rate: 40 mL/min, UV–vis detection at 210, 254, and 350 nm). Eight fractions (F1–F8) were collected, in accordance with the observed signals. F1 was further

Diversity-oriented synthesis of spirothiazolidinediones and their biological evaluation

• Sambasivarao Kotha,
• Gaddamedi Sreevani,
• Lilya U. Dzhemileva,
• Milyausha M. Yunusbaeva,
• Usein M. Dzhemilev and
• Vladimir A. D’yakonov

Beilstein J. Org. Chem. 2019, 15, 2774–2781, doi:10.3762/bjoc.15.269

• cytometry staining buffer (PBS without Ca2+and Mg2+, 2.5% FBS) and stained with 5 µL of 7-AAD staining solution for 15 minutes at room temperature in the dark. Samples were acquired on a NovoCyteTM 2000 Flow Cytometry System (ACEA) equipped with a 488 nm argon laser. Detection of 7-AAD emission was

• −), early apoptosis (annexin V+/PI−), late apoptosis (annexin V+/PI+), and necrosis (annexin V−/PI+). Apoptosis was quantified by the detection of phosphatidylserine surface exposure on apoptotic cells using an Alexa Fluor® 488 Annexin V/Dead Cell Apoptosis Kit. HEK293 cells were incubated with or without

Unexpected one-pot formation of the 1H-6a,8a-epiminotricyclopenta[a,c,e][8]annulene system from cyclopentanone, ammonia and dimethyl fumarate. Synthesis of highly strained polycyclic nitroxide and EPR study

• Sergey A. Dobrynin,
• Igor A. Kirilyuk,
• Yuri V. Gatilov,
• Andrey A. Kuzhelev,
• Olesya A. Krumkacheva,
• Matvey V. Fedin,
• Michael K. Bowman and
• Elena G. Bagryanskaya

Beilstein J. Org. Chem. 2019, 15, 2664–2670, doi:10.3762/bjoc.15.259

• -recovery technique with a π-pulse for inversion and a two-pulse ESE sequence for detection. The π-pulse lengths were nominally 20 ns. X-ray structure of compound 1 (one of the two enantiomers present in the crystal). A possible mechanism for the trans-position of the methyne hydrogens in the azepine ring

Arylisoquinoline-derived organoboron dyes with a triaryl skeleton show dual fluorescence

• Vânia F. Pais,
• Tristan Neumann,
• Ignacio Vayá,
• M. Consuelo Jiménez,
• Abel Ros and
• Uwe Pischel

Beilstein J. Org. Chem. 2019, 15, 2612–2622, doi:10.3762/bjoc.15.254

• observed. The formation of the fluoroboronate complexes was corroborated by the detection of the corresponding mass peaks (see Supporting Information File 1). In addition, 11B NMR spectra, for the example of dye 17, reveal that the boron changes from sp2 to sp3 hybridization on addition of 1 equiv F−; i.e

α,ß-Didehydrosuberoylanilide hydroxamic acid (DDSAHA) as precursor and possible analogue of the anticancer drug SAHA

• Shital K. Chattopadhyay,
• Subhankar Ghosh,
• Sarita Sarkar and
• Kakali Bhadra

Beilstein J. Org. Chem. 2019, 15, 2524–2533, doi:10.3762/bjoc.15.245

• was added per 100 mL gel solution for a final concentration of 0.5 μg/mL. Comet assays for detection of DNA damage of both control and 11b treated HeLa cells were detected by single cell gel electrophoresis. We isolated DNA of HeLa cells by a standardized salting out method according to Miller et al

Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

• Alessandro Iagatti,
• Baihao Shao,
• Alberto Credi,
• Barbara Ventura,
• Ivan Aprahamian and
• Mariangela Di Donato

Beilstein J. Org. Chem. 2019, 15, 2438–2446, doi:10.3762/bjoc.15.236

• 440–460 nm range (blue dots) and in the 500–520 nm range (red dots) of the same streak camera image. A double exponential fitting of the profile in the blue region results in a main component with a lifetime of 1.3 ps (at the limit of the detection of the system: 1.0 ps) accounting for 97% of the

• small portion of the fundamental laser output radiation on a 2 mm thick calcium fluoride window. Pump-probe delays were introduced by sending the probe beam through a motorized stage. Multichannel detection was achieved by sending the white light continuum after passing through the sample to a flat

Targeted photoswitchable imaging of intracellular glutathione by a photochromic glycosheet sensor

• Xianzhi Chai,
• Hai-Hao Han,
• Yi Zang,
• Jia Li,
• Xiao-Peng He,
• Junji Zhang and
• He Tian

Beilstein J. Org. Chem. 2019, 15, 2380–2389, doi:10.3762/bjoc.15.230

• recognition between β-D-galactoside and asialoglycoprotein receptor (ASGPr) on cell membranes. The dynamic fluorescence signals and excellent selectivity for detection and imaging of GSH ensure the precise determination of cell states, promoting its potential applications in future disease diagnosis and

• fluorescence spectroscopy. As shown in Figure S3A (Supporting Information File 1), GSH showed a distinct selectivity over other analytes, suggesting a specific GSH detection performance of Glyco-DTE@MnO2. A linear response of the normalized fluorescent intensity I/Imax at 535 nm within 0–0.4 mM GSH

• concentration range was determined (Supporting Information File 1, Figure S3B), where Imax represents the emission intensity before the addition of MnO2 and I is the emission intensity after the addition of GSH, through which the limit of detection (LOD) was calculated to be 0.99 μM. These results demonstrate

Synthesis of a dihalogenated pyridinyl silicon rhodamine for mitochondrial imaging by a halogen dance rearrangement

• Jessica Matthias,
• Thines Kanagasundaram,
• Klaus Kopka and
• Carsten S. Kramer

Beilstein J. Org. Chem. 2019, 15, 2333–2343, doi:10.3762/bjoc.15.226

• highly interesting for precise medical imaging of diseases, the fluorescence modality can be utilized for medical interventions, such as fluorescence-guided surgery or sentinel lymph node detection or for histopathological analyses of biopsy material. To date, only two pyridinyl-substituted silicon

Isolation and biosynthesis of an unsaturated fatty acid with unusual methylation pattern from a coral-associated bacterium Microbulbifer sp.

• Amit Raj Sharma,
• Enjuro Harunari,
• Tao Zhou,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2327–2332, doi:10.3762/bjoc.15.225

• EtOAc. The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated to give a semi-pure material (21 mg). Final purification was achieved by preparative HPLC (Cosmosil Cholester 5 µm, 10 × 250 mm, 4 mL/min, UV detection at 254 nm) with an isocratic elution of MeCN/0.1% HCO2H solution

Azologization and repurposing of a hetero-stilbene-based kinase inhibitor: towards the design of photoswitchable sirtuin inhibitors

• Christoph W. Grathwol,
• Nathalie Wössner,
• Sören Swyter,
• Adam C. Smith,
• Enrico Tapavicza,
• Robert K. Hofstetter,
• Anja Bodtke,
• Manfred Jung and
• Andreas Link

Beilstein J. Org. Chem. 2019, 15, 2170–2183, doi:10.3762/bjoc.15.214

• UV irradiation of 365 nm. The photoisomerization could be reversed by exposure to visible light, i.e. 452 nm, albeit the PSS at 452 nm still comprised about 25% of (Z)-11 as determined by HPLC analysis using UV–vis detection at the isosbestic points (Table 2). Light of 500 nm could also reverse

• with a Torus DIOL (Waters) or Phenomenex CSP (Lux Amylose-2, i-Amylose-3, i-Cellulose-5), a degasser (DGU-20A5R), a communications module (CBM-20A), and two back pressure regulators BPR A and B (SFC-30A). UV and MS spectra were recorded via photodiode array detection (SPD-M20A) and electrospray

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

• -triazole units to more electrophilic 1,2,3-triazolium units by influencing both hydrogen bonding-like and anion–π interactions. Moreover, halogen bond (XB) and chalcogen bond (ChB) interactions (see Figure 1) also been applied for the selective detection of anions by exchanging C5–H protons with halogens

• illustrated the way of utilizing different types of noncovalent interactions including hydrogen bonding, halogen and chalcogen bonding for the selective detection of anions by triazolium macrocycles. The selectivity and the ability of detection of anions are highly dependent on the solvent polarity. We have

Synthesis and properties of sulfur-functionalized triarylmethylium, acridinium and triangulenium dyes

• Marco Santella,
• Eduardo Della Pia,
• Jakob Kryger Sørensen and
• Bo W. Laursen

Beilstein J. Org. Chem. 2019, 15, 2133–2141, doi:10.3762/bjoc.15.210

• fluorescence lifetime has been a key point of interest since it enables time-gated detection for suppression of autofluorescence [25][26] and provides attractive advantages in fluorescence polarization assays [13][27][28]. A common characteristic feature of triangulenium dye synthesis is the use of methoxy

• spectrometry. In case of the reactions with tert-butylthiolate, neither detection of the target molecule nor any of the intermediates were observed. This lack of reactivity is likely explained by the tert-butylthiolate nucleophile being too bulky to undergo reaction. In the successful reactions, which had

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

• method for the detection of the novel impurities In order to provide a convenient method for including our new findings into quality control of atorvastatin batches, we worked out an isocratic HPLC protocol, which prettily separates the four artefacts 2, 3, 6 and 7 from atorvastatin (1). This method uses

• an RP18 stationary phase (Eurospher 100–C18), isocratic elution with 0.01 M ammonium acetate buffer (pH 4)-acetonitrile 54:46 (v/v) at a flow rate of 1 mL/min at 40 °C, with UV detection at 246 nm (Figure 3). Discussion In this investigation we first confirmed some pathways of decomposition of

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

• Arnault Heynderickx,
• Sébastien Nénon,
• Olivier Siri,
• Vladimir Lokshin and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2019, 15, 2059–2068, doi:10.3762/bjoc.15.203

• Reagents and starting materials were used as received without further purification from Alfa Aesar and Aldrich. Analytical thin-layer chromatography (TLC) was done on Merck 60F254 silica gel plates from Macherey-Nagel. Detection of TLC components was accomplished using a 254/366 nm UV lamp. Column liquid

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

• efficiently enriched via an abundant FPP supply. Detection and characterisation of Tvi09626 products By semi-preparative high-performance liquid chromatography (HPLC), we purified compound 1 and compound 2 (23.1 mg and 13.2 mg, respectively). The structures of the two new compounds were characterised by 1D

Bipolenins K–N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana

• Chin-Soon Phan,
• Hang Li,
• Simon Kessler,
• Peter S. Solomon,
• Andrew M. Piggott and
• Yit-Heng Chooi

Beilstein J. Org. Chem. 2019, 15, 2020–2028, doi:10.3762/bjoc.15.198

• /MeCN equipped with the C18 column, and DAD detector to yield 1 (1.5 mg), 2 (0.4 mg), 3 (0.4 mg), 4 (0.4 mg), 5 (0.5 mg), 6 (1.0 mg), 7 (4.0 mg), 8 (1.8 mg), 9 (2.8 mg), 10 (3.0 mg), 11 (0.4 mg), and 12 (1.3 mg). The Kinetex C18 on RP-HPLC (Phenomenex, 2.6 µm, 2.1 × 100 mm, 0.75 mL/min, DAD detection

Isolation and characterisation of irinans, androstane-type withanolides from Physalis peruviana L.

• Annika Stein,
• Dave Compera,
• Bianka Karge,
• Mark Brönstrup and
• Jakob Franke

Beilstein J. Org. Chem. 2019, 15, 2003–2012, doi:10.3762/bjoc.15.196

• reactivity of 4ß-hydroxywithanolide E (1) under acidic/basic and oxidative conditions, respectively. (A) LC–MS chromatograms (ELS detection) of 1 incubated at different pH values. (B) LC–MS chromatograms (UV detection at 200–400 nm) of 1 treated with different oxidative reagents. The formation of 2 in the

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

• different selectivity, resulting in optimized resolution. Increased resolution makes coelutions less likely and minimizes chromatographic noise. In addition, modulator-controlled focusing effects favor the detection of analytes in the trace range. Furthermore, GC×GC is used to obtain structured

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

• spectrophotometric detection (450 nm, reference 630 nm) as described in [10]. Briefly, WST-1 assay is based on reduction of a tetrazolium salt on soluble formazan in metabolically active cells. The measured absorbance is directly proportional to the number of metabolically active cells. For this assay, cells were

• , Austria). A nitrite calibration curve was used to convert absorbance to concentration (µM) of nitrite. Cytokine assay Analogous to NO detection, supernatants of all samples were analyzed for cytokine content after 24 h. The concentration of secreted TNF-α was determined by ELISA assay (R&D Systems

Complexation of chiral amines by resorcin[4]arene sulfonic acids in polar media – circular dichroism and diffusion studies of chirality transfer and solvent dependence

• Bartosz Setner and
• Agnieszka Szumna

Beilstein J. Org. Chem. 2019, 15, 1913–1924, doi:10.3762/bjoc.15.187

• sensitive technique for the detection of noncovalent interactions involving chiral molecules, even if only one component of the interaction pair is chiral. Considering strong interactions with amino acids we think that RSAs, in analogy to CSAs, can also act as modulators of protein crystallizations

Tautomerism as primary signaling mechanism in metal sensing: the case of amide group

• Vera Deneva,
• Georgi Dobrikov,
• Aurelien Crochet,
• Daniela Nedeltcheva,
• Katharina M. Fromm and
• Liudmil Antonov

Beilstein J. Org. Chem. 2019, 15, 1898–1906, doi:10.3762/bjoc.15.185

• of the development of coordination chemistry [1]. Particularly chromophore ligands have been successfully utilized for colorimetric detection of the majority of metal ions as complex [2]. Some of them are used as standard tools in chelatometric titrations [3]. The design of specific ligands for

• similar. However, as shown in Figure 5 and Table 1, the difference in the spectral maxima of the complexes allows detection of each of the studied cations. Conclusion In the current study, we modeled theoretically and experimentally the tautomerism and complexation abilities of a new tautomeric ligand

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

• for in vitro detection of G4 structures and their differentiation from other DNA or RNA forms [6][7][8][9][10], topological characterization of G4 structures [11][12][13][14], real-time detection of G4 formation [15], and implementation of G4-based molecular devices [16][17] and biosensors [18][19][20

• detection of double-stranded DNA. Compounds 15a and 16a are homo-dimeric derivatives, featuring two distyryl moieties connected via a C3 (15a) or a C4 (16a) linker. In addition, we included 9 mono-styryl derivatives. Among these, compounds 17a and 18a are long-known [66][67]; however, to the best of our

• 22 nt oligonucleotide. All samples were prepared in a K+-rich buffer solution (K-100, see Table 1 footnote). Thioflavin T (ThT), which is widely used for detection of G4 structures, was included for comparison. The fluorescence intensity was measured using a microplate reader. In order to screen a

Cyclobutane dication, (CH₂)₄²⁺: a model for a two-electron four-center (2e-4c) Woodward–Hoffmann frozen transition state

• G. K. Surya Prakash and
• Golam Rasul

Beilstein J. Org. Chem. 2019, 15, 1475–1479, doi:10.3762/bjoc.15.148

• cation (H3+, i) is the simplest known structure involving a two-electron three-center (2e-3c) bond (Scheme 1). The first spectroscopic detection of the H3+ ion was reported by Oka in 1980 [1]. Similarly, the structure of five coordinated protonated methane (CH5+, ii), a prototype of nonclassical

2,3-Dibutoxynaphthalene-based tetralactam macrocycles for recognizing precious metal chloride complexes

• Li-Li Wang,
• Yi-Kuan Tu,
• Huan Yao and
• Wei Jiang

Beilstein J. Org. Chem. 2019, 15, 1460–1467, doi:10.3762/bjoc.15.146

• macrocycle, which make it conformationally adaptive to maximize the binding affinities. In addition, the macrocycle shows fluorescent quenching when adding the chloride metal complexes in its solution and may be used as a fluorescent sensor for the detection of these coordination complexes. Keywords: host

• ). A linear relationship between fluorescent intensity and the concentrations of TBA[AuCl4] was observed at the concentration range of 20–96 μM, giving a detection limit of 0.61 μM for TBA[AuCl4] according to standard methods [45] (Figure 6b). This is similar for (TBA)2[PtCl4] within a linear

• concentration range of 20–970 μM and a detection limit of 3.9 μM (Figure S23, Supporting Information File 1). For (TBA)2[PdCl4], the fluorescence intensity was enhanced at the beginning (Figure S24, Supporting Information File 1), and then quenched with increasing concentrations of (TBA)2[PdCl4] (Figure S25a

Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions

• László Jicsinszky,
• Federica Calsolaro,
• Katia Martina,
• Fabio Bucciol,
• Maela Manzoli and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145

• in similar DS values within the calculation limits. The lack of sharp signals in both the core- and methyl signal regions allowed us to assume that PGs were present in amounts that were below the detection limits. The mother liquors of the MeOH–acetone crystallisation of the products were hygroscopic