Fabclavine diversity in Xenorhabdus bacteria

• Sebastian L. Wenski,
• Harun Cimen,
• Natalie Berghaus,
• Sebastian W. Fuchs,
• Selcuk Hazir and
• Helge B. Bode

Beilstein J. Org. Chem. 2020, 16, 956–965, doi:10.3762/bjoc.16.84

• for bioactive compounds are required, such as the bacterial genera Xenorhabdus or Photorhabdus. In these strains, fabclavines are widely distributed SMs with a broad-spectrum bioactivity. Fabclavines are hybrid SMs derived from nonribosomal peptide synthetases (NRPS), polyunsaturated fatty acid (PUFA

• of fabclavines as major antibiotics in several entomopathogenic strains, our work lays the foundation for the rapid fabclavine identification and dereplication as the basis for future work of this widespread and bioactive SM class. Keywords: antibiotic; fabclavine; NRPS-PKS hybrid; secondary

• originally also contained the NRPS-PKS-hybrid genes (Figure 2) [22]. In contrast, the BGC of P. temperata is reduced to only harbor the homologous genes of fclC, fclD and fclE (Figure 2) [22]. X. innexi also harbors a fcl-like BGC, with protein identities of 68–90% compared to X. stockiae (Figure S1

Diversity-oriented synthesis of 17-spirosteroids

• Benjamin Laroche,
• Thomas Bouvarel,
• Martin Louis-Sylvestre and
• Bastien Nay

Beilstein J. Org. Chem. 2020, 16, 880–887, doi:10.3762/bjoc.16.79

• transcription, or directly bind nuclear receptors [59][60][61]. In principle, steroids could thus be used as cargo molecules to deliver new chemical entities inside the nucleus, highlighting the potential of hybrid steroid molecules [62]. For example, De Riccardis designed steroid scaffolds directly fused to a

Copper catalysis with redox-active ligands

• Agnideep Das,
• Yufeng Ren,
• Cheriehan Hessin and
• Marine Desage-El Murr

Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77

• another family of galactose oxidase mimics based on copper(II) complex 4 bearing a non-innocent iminophenol-iminopyridine hybrid ligand 3 that performed two-electron oxidations of primary alcohols to aldehydes (Scheme 2) [15]. Catalyst 4 was fully characterized by combined EPR, cyclic voltammetry and

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• . Subsequently, a range of hybrid molecules, including triazole–benzimidazoles 50–53, triazole–benzothiazole 54, and triazole–benzoxazole 55, was prepared under the above-mentioned conditions (Scheme 8). The benefits of this catalytic system were mild reaction conditions, low catalyst loadings, a diverse set of

Synthesis of triphenylene-fused phosphole oxides via C–H functionalizations

• Md. Shafiqur Rahman and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2020, 16, 524–529, doi:10.3762/bjoc.16.48

• phosphole oxides, which are distinct from Saito’s compounds [15] as well as from other reported examples [26][27][28] in terms of the mode of fusion of the phosphole and triphenylene units. The present phosphole/triphenylene hybrid molecules displayed absorption and emission profiles that reflected the

Six-fold C–H borylation of hexa-peri-hexabenzocoronene

• Mai Nagase,
• Kenta Kato,
• Akiko Yagi,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2020, 16, 391–397, doi:10.3762/bjoc.16.37

• rotating anode (Graphite-monochromated Mo Kα radiation (λ = 0.71073 Å)) and PILATUS200K hybrid photon-counting detector. Cell parameters were determined and refined, and raw frame data were integrated using CrysAlisPro (Agilent Technologies, 2010). The structures were solved by direct methods with (SHELXT

Room-temperature Pd/Ag direct arylation enabled by a radical pathway

• Amy L. Mayhugh and
• Christine K. Luscombe

Beilstein J. Org. Chem. 2020, 16, 384–390, doi:10.3762/bjoc.16.36

• mechanism has been recently supported by 13C and 2H KIE experiments for the arylation of benzo[b]thiophene, although at C3 [13]. In contrast to these pathways, the radical trap and dark experiments reported above indicate a hybrid Pd(I) radical species induced by visible light is involved in the catalytic

• to form hybrid palladium-radical intermediate 5. This carbon-centered radical can then add to the indole. From here, three different pathways to rearomatize 7 are possible, eventually affording the arylated product 10. Pd(0) can be regenerated by a base; in this case, the silver carboxylate. This

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• steps, the lithiation and the introduction of the phosphine were performed at low temperature (−70 °C), compound 81 was obtained in 63% yield [80]. In both instances, the other isomer was present in minute quantities and could be separated by recrystallization. Hybrid phosphine N-heterocyclic carbenes

• , which can present possibilities for other interesting applications not only limited to organometallic catalysis. The combination of different heterocycles to make hybrid ligands can stimulate studies on their applicability in medicinal and OLEDs among other applications. In short, this review article

Allylic cross-coupling using aromatic aldehydes as α-alkoxyalkyl anions

• Akihiro Yuasa,
• Kazunori Nagao and
• Hirohisa Ohmiya

Beilstein J. Org. Chem. 2020, 16, 185–189, doi:10.3762/bjoc.16.21

• JP17H06449 (Hybrid Catalysis), and Kanazawa University SAKIGAKE project 2018 (to H.O.).

The use of isoxazoline and isoxazole scaffolding in the design of novel thiourea and amide liquid-crystalline compounds

• Itamar L. Gonçalves,
• Rafaela R. da Rosa,
• Vera L. Eifler-Lima and
• Aloir A. Merlo

Beilstein J. Org. Chem. 2020, 16, 175–184, doi:10.3762/bjoc.16.20

• previously published [19][21][22][23][24]. The synthetic route used for the synthesis of the hybrid compounds, N-acyl-N'-isoxazolinylthioureas 17a–c and N-acyl-N'- isoxazolylthioureas 18a–c is outlined in Scheme 2. The synthesis of thioureas 17a–c and 18a–c involved the activation of 4-heptyloxybenzoic acid

Understanding the role of active site residues in CotB2 catalysis using a cluster model

• Keren Raz,
• Ronja Driller,
• Thomas Brück,
• Bernhard Loll and
• Dan T. Major

Beilstein J. Org. Chem. 2020, 16, 50–59, doi:10.3762/bjoc.16.7

• provide important information to derive a synthetic strategy for cyclooctatin and related terpene manufacturing. Future studies using hybrid quantum mechanics and molecular mechanics techniques to model the enzyme reaction in a complete enzyme environment will allow careful evaluation of the usefulness of

Why do thioureas and squaramides slow down the Ireland–Claisen rearrangement?

• Dominika Krištofíková,
• Juraj Filo,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2019, 15, 2948–2957, doi:10.3762/bjoc.15.290

• quantum-chemical calculations employing long-range corrected hybrid density ωB97X-D functional [42]. This dispersion-corrected functional displays very balanced overall performances and has demonstrated excellent treatment of noncovalent interactions [43], which are very important in our studied system

• corrected hybrid density ωB97X-D functional showed that thioureas and squaramides stabilize the starting ground state more than the corresponding transitions states. This fact leads to a higher activation barrier and slower reactions in the presence of hydrogen-bond donating organocatalysts. On the other

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

• László Orha,
• József M. Tukacs,
• László Kollár and
• László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

• File 1. Exact mass measurements were performed on a high-resolution Q-Exactive Focus hybrid quadrupole-orbitrap mass spectrometer (Thermo Fisher Scientific, Bremen, Germany) equipped with a heated electrospray ionization (ESI) source. Samples were dissolved in acetonitrile/water 1:1 (v/v) solvent

Preparation of anthracene-based tetraperimidine hexafluorophosphate and selective recognition of chromium(III) ions

• Qing-Xiang Liu,
• Feng Yang,
• Zhi-Xiang Zhao,
• Shao-Cong Yu and
• Yue Ding

Beilstein J. Org. Chem. 2019, 15, 2847–2855, doi:10.3762/bjoc.15.278

• Qing-Xiang Liu Feng Yang Zhi-Xiang Zhao Shao-Cong Yu Yue Ding Tianjin Key Laboratory of Structure and Performance for Functional Molecules, MOE Key Laboratory of Inorganic-Organic Hybrid Functional Material Chemistry, College of Chemistry, Tianjin Normal University, Tianjin 300387, P. R. China

A combinatorial approach to improving the performance of azoarene photoswitches

• Joaquin Calbo,
• Aditya R. Thawani,
• Rosina S. L. Gibson,
• Andrew J. P. White and
• Matthew J. Fuchter

Beilstein J. Org. Chem. 2019, 15, 2753–2764, doi:10.3762/bjoc.15.266

• the possible conformers both in the Z- and E-forms were fully optimized by using the hybrid exchange-correlation PBE0 functional [37] including the Grimme’s dispersion correction in its latest version (D3) [38]. The split-valence Pople’s basis set 6-31G** was used throughout [39]. Transition states

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• following publication [36]. The same group, in 2014, published two concomitant reports on the synthesis of metallo-organic hybrid materials by means of entrapment of alkaloids within silver particles [37][38]. They further used this organically doped metal as cathode for the enantioselective

Plasma membrane imaging with a fluorescent benzothiadiazole derivative

• Pedro H. P. R. Carvalho,
• Jose R. Correa,
• Karen L. R. Paiva,
• Daniel F. S. Machado,
• Jackson D. Scholten and
• Brenno A. D. Neto

Beilstein J. Org. Chem. 2019, 15, 2644–2654, doi:10.3762/bjoc.15.257

• position associated with the π–π* transitions, as expected for this type of 4,7-disubstituted BTDs [46][47][48][49][50]. In Figure 3 the mean absolute error (MAE) between the theoretical and experimental absorption maxima (λmax) in different solvents is shown. The results showed the hybrid XCF, PBE1PBE

• (GGA level) and ωB97XD (long range-corrected hybrid level) XCFs were employed. Both B97D3 and ωB97XD were strongly recommended by a thoroughly benchmarking of DFT methods for thermochemistry by Goerik and Grimme [55]. The new dye was then submitted to an MTT assay to investigate possible cytotoxicity

Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

• Heather J. Lacey,
• Cameron L. M. Gilchrist,
• Andrew Crombie,
• John A. Kalaitzis,
• Daniel Vuong,
• Peter J. Rutledge,
• Peter Turner,
• John I. Pitt,
• Ernest Lacey,
• Yit-Heng Chooi and
• Andrew M. Piggott

Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256

• an Apollo II ESI/MALDI Dual source or a Q Exactive Plus hybrid quadrupole-Orbitrap mass spectrometer (Thermo Fisher Scientific, Bremen, Germany) by direct infusion. NMR data were recorded in DMSO-d6 on either a Bruker Avance III 500 or a Bruker Avance II DRX-600K spectrometer. All NMR spectra were

Anion-driven encapsulation of cationic guests inside pyridine[4]arene dimers

• Anniina Kiesilä,
• Jani O. Moilanen,
• Anneli Kruve,
• Christoph A. Schalley,
• Perdita Barran and
• Elina Kalenius

Beilstein J. Org. Chem. 2019, 15, 2486–2492, doi:10.3762/bjoc.15.241

• dispersion correction (hydrogen bond lengths are listed in Table S2, Supporting Information File 1). This is expected, because the standard hybrid functionals are able to describe strong hydrogen bonds such as NH···O and OH···O in a reasonable manner [31][32]. Due to the encapsulated guest molecule, the [12

Experimental and computational electrochemistry of quinazolinespirohexadienone molecular switches – differential electrochromic vs photochromic behavior

• Eric W. Webb,
• Jonathan P. Moerdyk,
• Kyndra B. Sluiter,
• Benjamin J. Pollock,
• Amy L. Speelman,
• Eugene J. Lynch,
• William F. Polik and
• Jason G. Gillmore

Beilstein J. Org. Chem. 2019, 15, 2473–2485, doi:10.3762/bjoc.15.240

• node (dual Intel X5650 CPU, with 6 cores running at 2.66 GHz) using the Gaussian 09 [30] software package implemented through the WebMO [26] graphical user interface. Restricted open-shell Hartree-Fock (ROHF) theory [31] with the Becke 3, Lee, Yang, and Parr (B3LYP) hybrid functional [32][33][34] was

Combining the Ugi-azide multicomponent reaction and rhodium(III)-catalyzed annulation for the synthesis of tetrazole-isoquinolone/pyridone hybrids

• Gerardo M. Ojeda,
• Prabhat Ranjan,
• Pavel Fedoseev,
• Lisandra Amable,
• Upendra K. Sharma,
• Daniel G. Rivera and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 2447–2457, doi:10.3762/bjoc.15.237

• rhodium(III)-catalyzed intermolecular annulation has been established for the preparation of tetrazole-isoquinolone/pyridone hybrids. Several N-acylaminomethyltetrazoles were reacted with arylacetylenes to form the hybrid products in moderate to very good yields. The method relies on the capacity of the

• , which has been considered of interest for medicinal chemistry applications [7][8]. In recent years, the preparation of hybrid heterocyclic scaffolds including the tetrazole ring (either fused or linked to other heterocycles) has rendered potent bioactive compounds [9][10][11][12][13], which confirms the

• incorporation of three different diversity-generating sites (Scheme 1A), a feature that has been exploited for the construction of libraries of tetrazole-based compounds with potential bioactivity [9][10][11][12][19]. A powerful approach for obtaining hybrid heterocyclic compounds including the tetrazole ring

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

• integrate these functions into one molecule. By taking advantages of both redox-active/high loading features of two-dimensional (2D) manganese dioxide (MnO2) and dynamic fluorescence photoswitching of photochromic sensors, we here design a hybrid photochromic MnO2 glycosheet (Glyco-DTE@MnO2) to achieve the

• design and further broaden the availability of photoswitchable biosensing, herein we report a glycosheet hybrid sensor (Glyco-DTE@MnO2) fabricated by 2D MnO2 nanosheets and dithienylethene fluorescence reporter (Glyco-DTE) to achieve cell-targeted photoswitchable imaging of intracellular GSH. As shown in

• as biosensing/imaging, bioactivity modulation, drug delivery, etc [23][24]. In our system, the Glyco-DTE@MnO2 hybrid sensor undergoes decomposition when encountering the overexpressed intracellular GSH in HepG2 cell lines, following the recovery of the photoswitchable fluorescence signal regulated by

Small anion-assisted electrochemical potential splitting in a new series of bistriarylamine derivatives: organic mixed valency across a urea bridge and zwitterionization

• Keishiro Tahara,
• Tetsufumi Nakakita,
• Alyona A. Starikova,
• Takashi Ikeda,
• Masaaki Abe and
• Jun-ichi Kikuchi

Beilstein J. Org. Chem. 2019, 15, 2277–2286, doi:10.3762/bjoc.15.220

• performed using the Gaussian09 software [63]. The three-parameterized Becke–Lee–Yang–Parr (B3LYP) hybrid exchange-correlation functional [64] was selected using the 6-31G(d) basis set for 1a and 1b with a restricted method and using the 6-311++G(d,p) basis set for the MV species with an unrestricted method

Aggregation-induced emission effect on turn-off fluorescent switching of a photochromic diarylethene

• Luna Kono,
• Yuma Nakagawa,
• Ayako Fujimoto,
• Ryo Nishimura,
• Yohei Hattori,
• Toshiki Mutai,
• Nobuhiro Yasuda,
• Kenichi Koizumi,
• Satoshi Yokojima,
• Shinichiro Nakamura and
• Kingo Uchida

Beilstein J. Org. Chem. 2019, 15, 2204–2212, doi:10.3762/bjoc.15.217

• subsequent TDDFT calculations. For the calculation of the fluorescence, the geometry optimizations were performed for the first excited state obtained by TDDFT. The hybrid B3LYP functional [33][34][35] was adopted to exchange-correlation term of DFT. The gaussian 6-31G(d,p) basis set was adopted to all

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

• SV(P) basis set [68][69]. The 10 lowest excitation energies and their oscillator strengths were computed using the SV(P) basis and the larger def2-TZVP basis set [69]. This was done using TDDFT with the hybrid approximation to the XC functional PBE0, CC2, and ADC(2) [51][52][53][70][71][72]. ADC(2