Copper-promoted/copper-catalyzed trifluoromethylselenolation reactions

• Clément Ghiazza and
• Anis Tlili

Beilstein J. Org. Chem. 2020, 16, 305–316, doi:10.3762/bjoc.16.30

• ]. Noteworthy, depending on the nature of the bidentate ligand used, the corresponding copper complex could be isolated as monomer or dimer, and both were air-stable. Among the new complexes, the reactivity of [(bpy)CuSeCF3]2 in trifluoromethylselenolations was thoroughly investigated using a large panel of

Two antibacterial and PPARα/γ-agonistic unsaturated keto fatty acids from a coral-associated actinomycete of the genus Micrococcus

• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku,
• Nobuyasu Matsuura,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 297–304, doi:10.3762/bjoc.16.29

• the cells at a final density of 5 × 103 cells/well, and 200 µL cultures thus made were incubated for 96 h at 37 °C in an atmosphere of 5% CO2 in air with 100% humidity. The viability of the cells was visualized by the addition of 50 μL of the medium containing XTT (1 mg/mL) and PMS (40 µg/mL) to each

Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation

• Jucleiton J. R. Freitas,
• Queila P. S. B. Freitas,
• Silvia R. C. P. Andrade,
• Juliano C. R. Freitas,
• Roberta A. Oliveira and
• Paulo H. Menezes

Beilstein J. Org. Chem. 2020, 16, 168–174, doi:10.3762/bjoc.16.19

• organometallic species of Cd [16], Ga [17], In [18], Ti [19], Al [20] and Bi [21] were described. However, the majority of these methods involve reagents that are difficult to prepare and to handle due to the sensitivity to air and moisture. The use of less reactive species based on tin [22][23][24], silicon [25

• great care on a case-by-case basis. Even so, the search for safer alternatives to current synthetic methodologies avoiding the use of moisture/air-sensitive organometallics and, more important, the development of solvent-free protocols are in accordance with the concept of environmental impact factor (E

Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo

• Alexander Sailer,
• Franziska Ermer,
• Yvonne Kraus,
• Rebekkah Bingham,
• Ferdinand H. Lutter,
• Julia Ahlfeld and
• Oliver Thorn-Seshold

Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14

• condensation of benzaldehyde onto thioindoxyls. However, the key step is the formation (and where necessary, isolation) of the thioindoxyl species. In our studies, the electron-rich dimethoxy- and trimethoxy-substituted thioindoxyls were noted to be unstable to air, base, and silica gel during chromatography

Halogen-bonding-induced diverse aggregation of 4,5-diiodo-1,2,3-triazolium salts with different anions

• Xingyu Xu,
• Shiqing Huang,
• Zengyu Zhang,
• Lei Cao and
• Xiaoyu Yan

Beilstein J. Org. Chem. 2020, 16, 78–87, doi:10.3762/bjoc.16.10

• mixed in acetonitrile (30 mL) in a round bottom flask, then the mixture was stirred for 24 h under air. Then the acetonitrile was removed under reduced pressure. Dichloromethane (50 mL) was added and the excess potassium chloride was removed by filtration. Then the dichloromethane was removed by

• , 6.96%. A single crystal of 2-Cl was obtained by slow evaporation of a dichloromethane solution. 2-Br: Potassium bromide (1190 mg, 10 mmol) and 2-BF4 (128 mg, 0.2 mmol) were mixed in acetonitrile (30 mL) in a round bottom flask, then the mixture was stirred under air for 24 h. Then the acetonitrile was

A green, economical synthesis of β-ketonitriles and trifunctionalized building blocks from esters and lactones

• Daniel P. Pienaar,
• Kamogelo R. Butsi,
• Amanda L. Rousseau and
• Dean Brady

Beilstein J. Org. Chem. 2019, 15, 2930–2935, doi:10.3762/bjoc.15.287

• Kim et al. [10], we did not obtain increased product yields when carrying out the reaction in air. Furthermore, heating the reaction mixtures above rt when using NaH as a base in refluxing THF was clearly detrimental to product yield according to our previous observations and was not attempted

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

• air-stable and readily available PdCl2(PPh3)2 was selected as a catalyst precursor to facilitate C–C bond couplings involving various iodoaromatic compounds (1a–l) and phenylacetylene (2a) in [TBP][4EtOV] in the absence of any additional ligands and auxiliary base at 55 °C for 3 h. In general, the

• of substrates and several products (3a–n, 5a–c, 7a–c, 9a–c) were isolated in good to excellent yields. The Cu- and base-free reaction can be performed under air and are highly tolerant to moisture. Experimental The sources of chemicals are listed in Supporting Information File 1. The NMR spectra were

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

• NH4PF6 was performed to generate tetraperimidine hexafluorophosphate 3 with a yield of 85%. Compound 3 was stable to heat, moisture, and air, and it had a good solubility in DCM, DMSO, and CH3CN. In turn, it had a poor solubility in benzene and petroleum ether. In the 1H NMR spectrum of 3, the proton

Photoreversible stretching of a BAPTA chelator marshalling Ca²⁺-binding in aqueous media

• Aurélien Ducrot,
• Arnaud Tron,
• Robin Bofinger,
• Ingrid Sanz Beguer,
• Jean-Luc Pozzo and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273

• , 0.26 mmol) in 128 mL pyridine was added CuCl (260 mg, 2.62 mmol), the flask was left open to the air and the resulting mixture was stirred at room temperature for 48 h. Then, the solvent was removed in vacuo and column chromatography (SiO2, EtOAc/petroleum ether 2:8, v/v) yielded the cyclized

An improved, scalable synthesis of Notum inhibitor LP-922056 using 1-chloro-1,2-benziodoxol-3-one as a superior electrophilic chlorinating agent

• Nicky J. Willis,
• Elliott D. Bayle,
• George Papageorgiou,
• David Steadman,
• Benjamin N. Atkinson,
• William Mahy and
• Paul V. Fish

Beilstein J. Org. Chem. 2019, 15, 2790–2797, doi:10.3762/bjoc.15.271

• air- and moisture-stable. The scope of published substrates includes chlorination of 7H-pyrrolo[2,3-d]pyrimidines and we wished to see if we could extend the scope to include sulphur containing heterocycles such as thieno[3,2-d]pyrimidines (e.g., 6). It was also important to explore if 12 would

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

• cathodes in the presence of chiral inductors, including tertiary amines, optically active proteins, and alkaloids [19][20], in 1975, Miller’s group reported the first example of the modification of electrodes via covalent binding [21]. They chemically modified air-oxidized graphite electrodes via treatment

AgNTf₂-catalyzed formal [3 + 2] cycloaddition of ynamides with unprotected isoxazol-5-amines: efficient access to functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives

• Ziping Cao,
• Jiekun Zhu,
• Li Liu,
• Yuanling Pang,
• Laijin Tian,
• Xuejun Sun and
• Xin Meng

Beilstein J. Org. Chem. 2019, 15, 2623–2630, doi:10.3762/bjoc.15.255

• high efficiency. The reaction conditions involve the use of catalytic AgNTf2 with DCE as the solvent at 80 °C, without needing to exclude moisture or air. The presumed reaction mechanism might involve the generation of an unusual α-imino silver carbene species (or a silver-stabilized carbocation) and

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

• does not engage in the formation of an intramolecular Lewis pair, akin to related borylated arylisoquinolines [37][38]. UV–vis absorption and fluorescence properties The absorption and fluorescence properties of the herein investigated dyes 16–19 in air-equilibrated solutions, using three solvents

• (λexc = 308 nm; 17 ns fwhm; 20 mJ/pulse). Alternatively, a Q-switched Nd:YAG laser (Quantel Brilliant, 355 nm, 5 ns fwhm, 15 mJ/pulse) was coupled to a mLFP-111 Luzchem miniaturized equipment. The concentration of 16–19 was kept in the range of 20–30 μM in acetonitrile. The solutions were air

• , 83.4, 24.5, 24.4 ppm, C–B not observed; 11B NMR (160 MHz, C6D6) δ 31.5 ppm (br s); HREIMS m/z: [M]+ calcd. for C39H32BNO2, 557.2526; found, 557.2508. Structures of the dyes 16–19. UV–vis absorption (solid line) and fluorescence (dashed line) spectra of a) 16, b) 17, c) 18, and d) 19 in air-equilibrated

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

• electrochemical experiments. With repetitive conditioning and scanning under argon-deaerated conditions, the initially yellow 1b solution turned to an orange-red color, which we hypothesized to be the LW dianion, 2b2−. Upon exposure to air this solution immediately turned green, the known color of the LW isomer

• (presumably while air oxidation of 2b2− to 2b could keep up with electrochemical reduction). With further electrolysis even these solutions turned to the orange-red color observed for the deaerated solutions. The solutions did become green upon prolonged exposure to air. This behavior seems indicative of

• insufficient transport of air into the cell through the small vents in the cell cap to replace the oxygen being consumed during repeated electrolytic scans. Similar results were observed for solutions of 3b suggesting a similar ECE mechanism to that of 1a is likely also occurring for 3b. Cyclic voltammetric

Effect of ring size on photoisomerization properties of stiff stilbene macrocycles

• Sandra Olsson,
• Óscar Benito Pérez,
• Magnus Blom and
• Adolf Gogoll

Beilstein J. Org. Chem. 2019, 15, 2408–2418, doi:10.3762/bjoc.15.233

• mmol) was dissolved in dry DCM (10 mL) in a flame-dried MW vial and cooled in ice-bath. TfOH (3.7 mL, 41.9 mmol) was added dropwise. The vial was sealed, the air was replaced by argon gas, and the reaction mixture was heated in the MW to 110 °C, 5 bar, for 1 h. The reaction mixture was poured on ice

In water multicomponent synthesis of low-molecular-mass 4,7-dihydrotetrazolo[1,5-a]pyrimidines

• Irina G. Tkachenko,
• Sergey A. Komykhov,
• Vladimir I. Musatov,
• Svitlana V. Shishkina,
• Viktoriya V. Dyakonenko,
• Vladimir N. Shvets,
• Mikhail V. Diachkov,
• Valentyn A. Chebanov and
• Sergey M. Desenko

Beilstein J. Org. Chem. 2019, 15, 2390–2397, doi:10.3762/bjoc.15.231

• spectra were measured on a GC–MS Varian 1200L (ionizing voltage 70 eV, direct input of the sample) instrument. Elemental analysis was realized on a EuroVector EA-3000. Analytical samples of the compounds were obtained by crystallization from water and further drying at room temperature in air. Microwave

• acetoacetic ester derivative 8a–d (1.77 mmol) in water (3.5 mL) was irradiated in a microwave reactor at 100 °C for 25–30 minutes. The crystalline product started to separate either during the course of reaction or just after cooling. The precipitate was filtered off, washed with water and air-dried. Ethyl 5

• ) triflate (Sc(OTf)3·nH2O) in water (3.2 mL) was irradiated in a microwave reactor at 100 °C for 20 min. The crystalline product started to separate after cooling to 5 °C. The resulting precipitate was filtered off, washed with water and air-dried. Colorless solid, yield 78%; mp 165–167 °C; 1H NMR (400 MHz

Excited state dynamics for visible-light sensitization of a photochromic benzil-subsituted phenoxyl-imidazolyl radical complex

• Yoichi Kobayashi,
• Yukie Mamiya,
• Katsuya Mutoh,
• Hikaru Sotome,
• Masafumi Koga,
• Hiroshi Miyasaka and
• Jiro Abe

Beilstein J. Org. Chem. 2019, 15, 2369–2379, doi:10.3762/bjoc.15.229

• and the lifetimes are estimated to be 260 and 820 ns (Figure 2c). On the other hand, while the transient absorption spectra of Benzil-PIC in benzene under air show the same transient absorption spectrum as under argon at 0.5 ns, the transient absorption band at 580 nm is not observed in the time scale

• spectra of Benzil-PIC in benzene under (a) argon and (b) air at room temperature excited with a 355 nm picosecond laser pulse (30 μJ pulse−1). Decay profiles of the transient species of Benzil-PIC in benzene probed at 590 nm under (c) argon and (d) air at the same conditions. Femtosecond-to-nanosecond

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• (Scheme 10). Notably, this reaction used an air and moisture-stable chiral palladium complex as the catalyst, which worked well at low catalyst loading (as low as 0.5 mol %). In 2015, Shi et al. [47] introduced a Pd(II)/Pd(IV)-catalyzed fluorination of β-methylene C(sp3)–H bonds of α-amino acid

• –H fluorination of benzaldehydes. Notably, these transformations were achieved with orthanilic acids as new transient directing groups (TDGs) in DCE in the presence of air (Scheme 23). This approach employed 1-fluoro-2,4,6-trimethylpyridinium salts as a bystanding F+ oxidant or an electrophilic

• -diamine complexes are air and moisture-stable (Scheme 49). In 2011, two nickel-catalyzed protocols for the enantioselective α-fluorination of β-ketoesters were reported separately. In van Leeuwen’s reaction, SPANamine derivatives were synthesized and applied as chiral ligands in the asymmetric α

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

• with autoclaved deionized water to remove sediment and soil and opened under a laminar air flow cabinet. Each agar plug was transferred to a corresponding agar plate for cultivation. The agar plates contained the same minimal nutrient medium as the agar solution into which the central plate was dipped

• cultures, however, are from less examined classes, e.g., Eurotiomycetes and Leotiomycetes. Only Chaetomium globosum aggr. comes into consideration as a common air mould. In a next series of experiments, we set out to shed light on the halotolerance of our isolates from experiments 2 and 3 by testing their

• chamber device experiments inside and outside of the device a minimal nutrient medium – FIND agar medium (FAM: 0.05% casamino acids, 0.025% fish peptone, 1.5% agar in sea water from the given sample) – was compiled to oppress growth of fast-growing fungi like common air moulds. For soil samples fish

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

• ionization single quadrupole MS (LCMS-2020) controlled by Shimadzu LabSolution software (Version 5.91). Chromatographic purification of products was performed by flash chromatography on silica gel (20–45 µm, Carl Roth) applying pressured air up to 0.8 bar. NMR spectra were recorded on a Bruker Avance III

Regioselective Pd-catalyzed direct C1- and C2-arylations of lilolidine for the access to 5,6-dihydropyrrolo[3,2,1-ij]quinoline derivatives

• Hai-Yun Huang,
• Haoran Li,
• Thierry Roisnel,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2019, 15, 2069–2075, doi:10.3762/bjoc.15.204

• so far (Scheme 1c). Herein, we report i) on the simple access to α-arylated 5,6-dihydropyrrolo[3,2,1-ij]quinolines using an air-stable Pd catalyst associated to an inexpensive base, ii) on the sequential access to α,β-diarylated 5,6-dihydropyrrolo[3,2,1-ij]quinolines containing identical or different

• -arylated lilolidines were generally obtained in high regioselectivities and in good yields using aryl bromides as easily available aryl sources, acetates as inexpensive bases and PdCl(C3H5)(dppb) as air-stable catalyst. The reaction tolerated a wide variety of useful functional groups such as nitrile

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

• ]. A strongly fluorescent compound, 3, has been isolated from the reaction of ethylenediamine with noradrenaline, 2-methylnoradrenaline, adrenolone, 3,4-dihydroxymandelic acid or catechol [8]. The reaction with 2,5-dihydroxy-p-benzoquinone (4) under a stream of air affording 3 in 50% yield was proposed

Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via intramolecular 1,3-dipolar cycloaddition

• Yulia V. Khoroshunova,
• Denis A. Morozov,
• Andrey I. Taratayko,
• Polina D. Gladkikh,
• Yuri I. Glazachev and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2019, 15, 2036–2042, doi:10.3762/bjoc.15.200

• -hydroxypyrrolidines 6a–c to corresponding nitrones 7a–c. Therefore, this conversion was finalised via bubbling of air into the solution in the presence of Cu(NH3)42+ (Scheme 2). Samples of resulting 2-(pent-4-enyl)nitrones 7a–c remarkably deteriorate during storage under aerobic conditions with dark tar formation. A

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

• ). Liquid nitrogen was used for cryofocusing of the analytes eluting from the first dimension (1D) column, whereas heated air was used for releasing and reinjecting these compounds onto the second dimension (2D) column. A modulation period of 5 s and a hot jet duration of 0.35 s were used. The column set

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

• noted otherwise, all reactions were carried out under an atmosphere of air. 1H and 13C NMR spectra were recorded at 303 K on Bruker 400 MHz and at 298 K on Varian VNMRS 600 MHz instruments with a residual solvent signal as an internal standard. All 2D NMR spectra were recorded at 298 K on a Varian 600