Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• Orbitrap XL equipped with nitrogen UV laser (337 nm, 60 Hz, 8–20 μJ) in positive ion mode. For the CID experiment using the linear trap quadrupole (LTQ) helium was used as the collision gas and 2,5-dihydroxybenzoic acid (DHB) or (2-methylprop-2-en-1-yliden)malononitrile (DCTB) as the MALDI matrix

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• were characterized by TEM and dynamic laser scattering (DLS). TBTQ-C6/CS-TPE containing either of the different TPE-loadings all formed uniform spherical nanoparticles with average diameters of 152 nm, 158 nm and 199 nm, respectively, as determined by TEM measurements (Figure 6a and Figures S5a and S6a

• under an infrared lamp to prepare a sample for TEM measurement. The morphology of nanoparticles was observed at an accelerating voltage of 200 kV, and high-resolution TEM images were obtained. DLS and Zeta potential measurements. The measured samples were examined by a laser particle size analyzer

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• . Size exclusion chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry were performed to determine the molar mass of the resulting polymers. Our work shows clearly that the solvent is not inert under the conditions typically used for the cationic ring-opening

• polymerization process. Further work will be necessary to establish whether a living polymerization can be achieved by additional adjustments. Keywords: 2-alkyl-2-oxazolines; matrix-assisted laser desorption/ionization mass spectrometry; nuclear magnetic resonance; polymerization kinetics; Introduction

• ). Obtained data were processed with Win-GPC software. Matrix-assisted laser desorption/ionization time-of-flight mass spectra (MALDI-TOF MS) were recorded on an Autoflex II (Bruker Daltonics, Bremen, Germany) using an N2 laser (λ = 337 nm). All spectra were recorded in positive reflector mode. Detection was

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• S33a, Supporting Information File 1), sharp excited state absorption (ESA) bands centered at 360 and 470 nm were observed in HEX, and a 63 μs lifetime was determined. For NI-PTZ, positive absorption bands centered at 360, 470, 390, and 520 nm were observed upon pulsed laser in HEX (Figure 8a). This

• recorded on a LP920 laser flash photolysis spectrometer (Edinburgh Instruments, Ltd., U.K.). The data (kinetic decay traces and the transient difference absorption spectra) were analyzed with the L900 software. All samples were deaerated with N2 for ca. 15 min in collinear configuration of the pump and

• probe beams measurements before measurement, and excited with a nanosecond pulsed laser (Quantel Nd: YAG nanosecond pulsed laser). The typical laser power is 65 mJ per pulse. Computational study The ground state (S0) geometries of compounds NI-N-PTZ, NI-PTZ, NI-PTZ-O, NI-PTZ2, NI-Ph-PTZ, and NI-PhMe2

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• Giambastiani et al. developed homogeneously sized Ni nanoparticles (4 ± 1 nm) decorated on an oxidized carbon felt (OCF) matrix [40]. A laser pyrometer was used to measure the temperature of the catalyst bed in the quartz reactor. The inductor was controlled by a proportional-integral-derivative (PID

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• and ΦDF values were estimated according to [50]. Time-integrated fluorescence, phosphorescence spectra as well as fluorescence decay kinetics were recorded with a time-gated intensified iCCD camera iStar DH340T (Andor) with a spectrograph SR-303i (Shamrock) coupled with nanosecond YAG:Nd3+ laser NT

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

• Inaiá O. Rocha,
• Yuri G. Kappenberg,
• Wilian C. Rosa,
• Clarissa P. Frizzo,
• Nilo Zanatta,
• Marcos A. P. Martins,
• Isadora Tisoco,
• Bernardo A. Iglesias and
• Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

• ; Figure 7). In this way, Schiff bases presented moderate singlet oxygen species generator character (ΦΔ between 0.07–0.51) after 600 s of irradiation with a red-light diode laser source (λ = 660 nm, 100 mW). The moderate generation of singlet oxygen species may be attributed to the formation of other

• 660 nm red light diode laser positioned 2.0 cm from the sample (TheraLase DMC, São Carlos, SP, Brazil) with an average power of 100 mW, during 10 min (irradiation intervals every 30 s). All spectra are provided in Supporting Information File 1 (Figures S8–S17). Synthetic procedures General procedure

• solution after irradiation with white-light LED array system (400–800 nm) at a fluence rate of 25 mW/cm2 for different periods (0 to 60 min; total light dosage = 90 J/cm2). DPBF photooxidation assays by red-light irradiation with diode laser (λ = 660 nm) in the presence of quinoline 3bb (R = Ph, R1 = 5

Adjusting the length of supramolecular polymer bottlebrushes by top-down approaches

• Tobias Klein,
• Franka V. Gruschwitz,
• Maren T. Kuchenbrod,
• Ivo Nischang,
• Stephanie Hoeppener and
• Johannes C. Brendel

Beilstein J. Org. Chem. 2021, 17, 2621–2628, doi:10.3762/bjoc.17.175

• coupled to a UV detector and a multiangle laser light scattering detector (AF4–MALLS technique) to estimate the apparent structure length and the length distribution of the SPBs. Results and Discussion The general structure of the tested BTP and BTU is depicted in Figure 1 [19][20]. While the hydrogen

Post-functionalization of drug-loaded nanoparticles prepared by polymerization-induced self-assembly (PISA) with mitochondria targeting ligands

• Janina-Miriam Noy,
• Fan Chen and
• Martina Stenzel

Beilstein J. Org. Chem. 2021, 17, 2302–2314, doi:10.3762/bjoc.17.148

• mitochondria target containing nanoparticles PPM-NP4-TPP and MPM-NP2-TPP were further analysed using 3D spheroid tumour models [47]. The samples were incubated with 143B and SW982 cells and the penetration profiles of the micelles were investigated using laser scanning confocal microscopy. After 3 hours of

• zwitterionic drug particles similar anticancer efficiency than that of the non-conjugated PPM-NP4 micelles. The co-localization of the TPP-variants into the mitochondria, lysosomes and nuclei were analysed using laser scanning confocal microscopy. Surprisingly, there was no improvement in mitochondria

Transition-metal-free intramolecular Friedel–Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives

• Tülay Yıldız,
• İrem Baştaş and
• Hatice Başpınar Küçük

Beilstein J. Org. Chem. 2021, 17, 2203–2208, doi:10.3762/bjoc.17.142

• used in pH-sensitive fluorescent materials [10] and laser technologies [11][12][13][14]. Moreover, xanthenes are present in some natural sources, such as santalin pigments found in many varieties of plants [15][16]. There have been many studies on the synthesis of xanthene derivatives to date because

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

An initiator- and catalyst-free hydrogel coating process for 3D printed medical-grade poly(ε-caprolactone)

• Jochen Löblein,
• Thomas Lorson,
• Miriam Komma,
• Tobias Kielholz,
• Maike Windbergs,
• Paul D. Dalton and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2021, 17, 2095–2101, doi:10.3762/bjoc.17.136

• ], micro-extrusion [7] and selective laser sintering have all been used to fabricate clinical implants [6][7]. Other emerging 3D printing technologies can also fit the prerequisites described above, including melt electrowriting (MEW) [8]. This technology is based on the direct-writing of ultra-fine (800

Towards new NIR dyes for free radical photopolymerization processes

• Haifaa Mokbel,
• Guillaume Noirbent,
• Didier Gigmes,
• Frédéric Dumur and
• Jacques Lalevée

Beilstein J. Org. Chem. 2021, 17, 2067–2076, doi:10.3762/bjoc.17.133

• in Figure 1. They are characterized by a sharp and intense absorption band in the NIR range. Remarkably, absorption of most of the dyes is excellent in the 700–850 nm spectral range, ensuring fairly good overlap with the emission spectrum of the laser diode used in this work (i.e., LD@785 nm

• polymerization upon exposure to the laser diode at 785 nm was successfully initiated using new synthesized dyes. This can be used to obtain tack-free polymers after only a few seconds of NIR irradiation. Markedly, IPNs can also be prepared with NIR light. Potential applications and investigations of the

• ) IR 813. B) NIR dyes with I− as counter anion: (1) CI3, (2) CI4, (3) CI5, (4) CI8, (5) CI9, and (6) IR 813; upon exposure to a 785 nm laser diode (0.9 W/cm2), thickness = 1.4 mm. The irradiation starts at t = 10 s. Photopolymerization profiles of PETIA monomer under air (acrylate functions conversion

Asymmetric organocatalyzed synthesis of coumarin derivatives

• Natália M. Moreira,
• Lorena S. R. Martelli and
• Arlene G. Corrêa

Beilstein J. Org. Chem. 2021, 17, 1952–1980, doi:10.3762/bjoc.17.128

• acetylcholinesterase inhibitors [11][12][13], being LSPN223 the most potent compound (Figure 2). Furthermore, coumarin derivatives have been used as fluorescent probes, laser dyes, fluorescent chemosensors, light absorbers for solar cells, optical brighteners, and organic light emitting diodes (OLEDs) [14][15]. From a

2,4-Bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridines: synthesis and photophysical properties

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli,
• Noureddine Chaaben,
• Kamel Alimi,
• Stefan Jopp and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 1629–1640, doi:10.3762/bjoc.17.115

• optical band gaps. However, the optical band gaps of 4b and 4g are lower (3.05 eV and 2.98 eV, respectively). Emission spectra of synthesized tetrahydroacridine derivatives were measured in dichloromethane solutions under UV-laser excitation of 325 nm. The emission spectrum of compound 4a presents a

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• conditions, under laser irradiation, and the biocompatibility make it possible to conclude that the design of these compounds is promising for mass spectrometry, for catalysts for hydrogen production, and for photothermal cancer therapy. Representatives of isomeric bisoxindoles. Isoindigo-based OSCs with the

Synthesis of 1-indolyl-3,5,8-substituted γ-carbolines: one-pot solvent-free protocol and biological evaluation

• Premansh Dudhe,
• Mena Asha Krishnan,
• Kratika Yadav,
• Diptendu Roy,
• Krishnan Venkatasubbaiah,
• Biswarup Pathak and
• Venkatesh Chelvam

Beilstein J. Org. Chem. 2021, 17, 1453–1463, doi:10.3762/bjoc.17.101

• , 3ca, 3ga in the breast cancer cell line, MCF7 and (B) doxorubicin against the panel of tested cancer cell lines. Dose–response curve of γ-carbolines 3ac, 3bc, 3ca, 3ga in macrophage cell line, RAW264.7. Laser scanning confocal microscopy studies (λex = 405 nm; collection range = 420–470 nm) for uptake

A new glance at the chemosphere of macroalgal–bacterial interactions: In situ profiling of metabolites in symbiosis by mass spectrometry

• Marine Vallet,
• Filip Kaftan,
• Veit Grabe,
• Fatemeh Ghaderiardakani,
• Simona Fenizia,
• Aleš Svatoš,
• Georg Pohnert and
• Thomas Wichard

Beilstein J. Org. Chem. 2021, 17, 1313–1322, doi:10.3762/bjoc.17.91

• used mass spectrometry profiling and imaging techniques with high spatial resolution and sensitivity to gain a new perspective on the mutualistic interactions between bacteria and macroalgae. Using atmospheric pressure scanning microprobe matrix-assisted laser desorption/ionisation high-resolution mass

• -pyrimidinecarboxylic acid) was found in bacterial presence. Ectoine was used as a metabolic marker for localisation studies of Roseovarius sp. within the tripartite community because it was produced exclusively by these bacteria. By combining confocal laser scanning microscopy (cLSM) and AP-SMALDI-HRMS, we proved that

• specialised metabolites involved in host–bacteria interactions. In our study, comparative metabolomics using atmospheric pressure scanning microprobe matrix-assisted laser desorption/ionisation high-resolution mass spectrometry (AP-SMALDI-HRMS) enables the identification of specialised metabolites of the

Structural effects of meso-halogenation on porphyrins

• Keith J. Flanagan,
• Maximilian Paradiz Dominguez,
• Zoi Melissari,
• Hans-Georg Eckhardt,
• René M. Williams,
• Dáire Gibbons,
• Caroline Prior,
• Gemma M. Locke,
• Alina Meindl,
• Aoife A. Ryan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

• quadrupole time-of-flight (Q-TOF) mass spectrometer equipped with Z-spray electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) sources either in a positive or negative mode with DCTB (trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile) as the matrix. UV

Enhanced target cell specificity and uptake of lipid nanoparticles using RNA aptamers and peptides

• Roslyn M. Ray,
• Anders Højgaard Hansen,
• Maria Taskova,
• Bernhard Jandl,
• Jonas Hansen,
• Citra Soemardy,
• Kevin V. Morris and
• Kira Astakhova

Beilstein J. Org. Chem. 2021, 17, 891–907, doi:10.3762/bjoc.17.75

• Nano ZS (Malvern Instruments, UK), having He–Ne 633 nm laser at an angle of detection of 90°, with an incubation time of 60 s. Samples were diluted 50-fold in Milli-Q water and placed into the disposable plastic cuvettes for measurement performed in triplicates (n ≥ 3) to obtain a mean value. NTA

• Concentration and size of LNPs with and without peptides were additionally confirmed using the NanoSight NS300 device (Malvern Panalytical, UK) with the NTA software (Version 3.44, Malvern Panalytical, UK). Samples were run at a 1:1000 dilution, with three technical replicates per sample. A blue 488 nm laser

Synthesis of (Z)-3-[amino(phenyl)methylidene]-1,3-dihydro-2H-indol-2-ones using an Eschenmoser coupling reaction

• Lukáš Marek,
• Lukáš Kolman,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2021, 17, 527–539, doi:10.3762/bjoc.17.47

• ) and 39.6 ppm (13C). High-resolution mass spectra were recorded on a MALDI LTQ Orbitrap XL equipped with a nitrogen UV laser (337 nm, 60 Hz, 8–20 μJ) in the positive ion mode. For the CID experiment using the linear trap quadrupole (LTQ) helium was used as the collision gas and 2,5-dihydroxybenzoic

Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies

• Alexander Zika and
• Franziska Gröhn

Beilstein J. Org. Chem. 2021, 17, 166–185, doi:10.3762/bjoc.17.17

• , Langen, Germany), an ALV CGS 3 goniometer, and a red HeNe laser (λ = 632.8 nm, 20 mW). The samples were measured over a scattering angular range of 30° ≤ θ ≤ 150° in steps of 10° for a duration of 50 seconds. Via the Siegert relation the intensity autocorrelation function g2(τ) was transferred into the

• volumes of the AFM structures have been calculated using a spherical cap as model structure. ζ-Potential measurements were carried out with a Zetasizer Nano ZS analyzer with a 4 mW HeNe laser (λ = 633 nm; Malvern Instruments Ltd., U.K.). The solutions were placed in folded capillary cells (DTS 1070

• ). After applying an electric field across the sample solution, the electrophoretic mobility was measured by using the technique of laser Doppler anemometry. By using the Smoluchowski approximation, the ζ-potential is calculated from the electrophoretic mobility. The measurements were performed at 20 °C

Control over size, shape, and photonics of self-assembled organic nanocrystals

• Chen Shahar,
• Yaron Tidhar,
• Yunmin Jung,
• Haim Weissman,
• Sidney R. Cohen,
• Ronit Bitton,
• Iddo Pinkas,
• Gilad Haran and
• Boris Rybtchinski

Beilstein J. Org. Chem. 2021, 17, 42–51, doi:10.3762/bjoc.17.5

• Spitfire ACE). The pulses are first stretched, then regeneratively amplified in a Ti:sapphire cavity, pumped by a pulsed Nd:YLF laser (Spectra Physics Empower 45) operating at 1 kHz. After the pulse has been amplified and recompressed, the energy is about 5.0 mJ in a train of 1 kHz pulses and about 1 mJ is

• pump power for studying the power dependence. The pump power intensities were measured using an Ophir powermeter with a photodiode sensor in proximity to the sample. The excitation densities were calculated for a laser spot of 300 μm diameter on the sample. This diameter was measured by placing a

• different laser powers probed at 755 nm (1 × 10−4 M solution at pH 10): A) 5% THF solution and B) 10% THF solution. Diffusion coefficient and exciton diffusion length. Supporting Information Supporting Information File 92: General information, synthesis, molecular modeling, and further experimental details

Selected peptide-based fluorescent probes for biological applications

• Debabrata Maity

Beilstein J. Org. Chem. 2020, 16, 2971–2982, doi:10.3762/bjoc.16.247

• . Thus, it acts as inhibitor by preventing the substrate to reach the active sites in β-tryptase. Confocal laser scanning microscopy (CLSM) confirms that peptide 9 is mast-cell permeable and exhibits inhibitory activity within cells by suppressing their growth (Figure 8B). Heparin detection Heparin is a

• laser scanning microscopy images of CHMAS cells treated with 10 μM peptide 9 for 30 min. Reproduced from [51], “A fluorescent light-up probe as an inhibitor of intracellular β-tryptase”, © 2014 Wang et al., licensed under a Creative Commons Attribution 3.0 Unported Licence, https://creativecommons.org

Construction of pillar[4]arene[1]quinone–1,10-dibromodecane pseudorotaxanes in solution and in the solid state

• Xinru Sheng,
• Errui Li and
• Feihe Huang

Beilstein J. Org. Chem. 2020, 16, 2954–2959, doi:10.3762/bjoc.16.245

• . Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI–TOF MS) was conducted to investigate the complexation properties. However, no signal related to the complex but only peaks of H were found, implying weak host–guest interactions between H and G (Figures S3 and S4