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

• , and high-yielding synthesis of HITub-4. Chemical structures of HITubs. Key variations with respect to HITub-4 are highlighted in dashed boxes. Photocharacterisation of HITub-4. a) Photochemical and thermal isomerisation. b) UV–vis spectra after saturating illumination at λ = 450, 505, and 530 nm

The interaction between cucurbit[8]uril and baicalein and the effect on baicalein properties

• Xiaodong Zhang,
• Jun Xie,
• Zhiling Xu,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 71–77, doi:10.3762/bjoc.16.9

• concentrations of Q[8] were recorded (Figure 4A–C). Figure 4 shows the changes in the UV–vis spectra of BALE upon the gradual addition of Q[8]. The maximum absorption wavelength of BALE was at 270 nm and the host showed no absorbance in the range of >210 nm. The absorption spectra of the guest exhibited a

Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes

• Andreas H. Heindl and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4

• and 3b showed characteristic UV–vis spectra of ABs with strong π–π* absorption, having their absorption maxima at 337 nm (3a) and 349 nm (3b), respectively (Figure 2a). In contrast to AB, the π–π* and n–π* bands of both compounds overlapped, forming shoulders at ca. 450 nm. The samples were irradiated

• switchable multistate photoswitches: previous [11][12] and present work. a) UV–vis spectra of tris(arylazo)benzenes 3a/3b in ethanol. b) Reversible photoisomerization of 3a and c) 3b using light of 365 nm wavelength to induce E→Z isomerization and of 448 nm wavelength for photochemical back-conversion

Synthesis and characterization of bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives

• David Martínez-López,
• Amirhossein Babalhavaeji,
• Diego Sampedro and
• G. Andrew Woolley

Beilstein J. Org. Chem. 2019, 15, 3000–3008, doi:10.3762/bjoc.15.296

• , 2H), 4.11 (s, 6H), 3.45 (m, 8H), 3.00 (m, 8H); 13C NMR (126 MHz, DCM-d2) δ 158.9, 154.0, 140.2, 123.0, 111.5, 107.2, 66.9, 57.3, 45.1; HRMS (m/z): [M + H]+ calcd for C22H29Br2N6O2, 567.0719; found, 567.0713. UV–vis spectroscopy UV–vis spectra were recorded on a PerkinElmer LAMBDA 35, Shimadzu UV

• experiments. Estimates of the percentage of cis/trans isomers in PSSs Based on NMR spectra, we assumed that the fraction of Z-isomer present at equilibrium in the dark was negligible. Since UV–vis spectra obtained during thermal reversion exhibited an isosbestic point, we assumed that only E- and Z-isomers

• subjected to TD-SCF calculations using the same functionals and basis set, assuming the first 15 singlet excitations, and by applying a SMD (assuming water as the solvent) to implicitly approximate the effect of the solvent [29]. TD-SCF data were used to generate the simulated UV–vis spectra by applying a

Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• Supporting Information File 1. Absorption spectroscopy UV–vis spectra were recorded using a Cary 50 spectrophotometer (Agilent, Santa Clara, CA, USA) at rt in quartz cuvettes with a 1 cm path length in HEPES buffer at pH 7.4. UPLC Chromatography was performed using a Waters Acuity Arc using Cortecs C-18

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

• range: 100–2500 m/z, capillary voltage: 4500 V, drying temperature: 200 °C). UV–vis spectra were recorded with a Shimadzu UV-2450 UV–vis spectrophotometer. The chromatogram in Figure 1 was recorded on a Bruker Agilent 1260 Infinity Series equipped with DAD and an ESI ion trap mass spectrometer (amaZon

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

• 4pzMe-F2 (left), 4pzH-F2 (middle) and 4pzMe-OMe2 (right). Experimental UV–vis spectra of 4pzMe-F2, 4pzMe-Cl2, 4pzMe-OMe2 and 4pzH-F2 in MeCN at 25 µM. Theoretical half-lives (t1/2, theor in hours and days) calculated at the PBE0-D3/6-31G** level of theory for ortho-substituted arylazopyrazoles 4pzH-X

A photochemical determination of luminescence efficiency of upconverting nanoparticles

• Baptiste Amouroux,
• Clément Roux,
• Jean-Claude Micheau,
• Fabienne Gauffre and
• Christophe Coudret

Beilstein J. Org. Chem. 2019, 15, 2671–2677, doi:10.3762/bjoc.15.260

• length L of 9 cm, most of the light escapes the cuvette and no simplification can be done. Thus, privileging the spectral information (clear UV–vis spectra are indeed monitored) lead to a loss of information; another photoreactor design would then be necessary. Conclusion We have demonstrated that the

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

• geometry of BTD-4APTEG (implicit DMSO). (B) TD-DFT UV–vis spectra of BTD-4APTEG calculated at the PBE1PBE/6-311+G(2d,p) level of theory. Solvent effects were estimated under the IEF-PCM formalism. (C) PBE1PBE/6-311+G(2d,p)//CAM-B3LYP/6-311+G(d) HOMO and LUMO orbitals of BTD-4APTEG in DMSO involved in the

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

• General experimental details Optical rotations were acquired in MeOH on a Perkin-Elmer Model 341 polarimeter in a 50 × 5 mm cell or on a Jasco P-1010 polarimeter in a 100 × 3.5 mm cell. UV–vis spectra were acquired in MeCN on a Varian Cary 4000 spectrophotometer or a Jasco V-760 spectrophotometer in a 10

A toolbox of molecular photoswitches to modulate the CXCR3 chemokine receptor with light

• Xavier Gómez-Santacana,
• Sabrina M. de Munnik,
• Tamara A. M. Mocking,
• Niels J. Hauwert,
• Shanliang Sun,
• Prashanna Vijayachandran,
• Iwan J. P. de Esch,
• Henry F. Vischer,
• Maikel Wijtmans and
• Rob Leurs

Beilstein J. Org. Chem. 2019, 15, 2509–2523, doi:10.3762/bjoc.15.244

• which was followed by methylation to afford 6f–h as orange solids with ≥98% trans-isomer. The synthetic strategies for the synthesis of compound 6i were reported in our previous communication [7]. In the subseries depicted in Table 3, several notable differences in both the UV–vis spectra (Figure S1

In search of visible-light photoresponsive peptide nucleic acids (PNAs) for reversible control of DNA hybridization

• Lei Zhang,
• Greta Linden and
• Olalla Vázquez

Beilstein J. Org. Chem. 2019, 15, 2500–2508, doi:10.3762/bjoc.15.243

• irradiated to obtain maximal cis (oF4Azo, 520 nm, 10 min) or trans (HTI, 405 nm, 2 min) and stored in the dark. PNA12(oF4Azo) (3) was also measured with continuous heating at 90 °C (gray squares). UV–vis spectra were collected at different time points during 10 h. Curves derived were calculate from two

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

• assignment. UV–vis spectra taken of eLW solutions generated by bulk electrolysis in acetonitrile and acetonitrile-d3 were compared against photoirradiated (pLW) solutions. No difference was observed in the UV–vis spectrum of the LW isomer prepared from either photolysis or electrolysis of solutions of 1b (as

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

• a previously reported procedure [29]. Its UV–vis spectra were recorded on a Shimadzu UV-1800 UV–vis spectrophotometer. A Photon Technology International QuantaMaster 4 spectrofluorometer outfitted with a LPS-100 lamp power supply and Xenon arc lamp housing, ASOC-10 electronics interface, MD-4 motor

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

• determined and from it the distance rAB calculated assuming rAB = rref(σref/σAB)1/6. Mass spectra were obtained on an Advion Expression-L CMS with APCI+ interface. High-resolution mass spectra were obtained on a Thermo Scientific Q-Exactive instrument in APCI positive mode. UV–vis spectra were recorded on a

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

• and spectra. Upon exposure of 2b to radiation of 365 nm, changes in the UV–vis spectra proceeded slowly, due to the low absorbance of 2b in this wavelength region. However, shorter wavelengths, i.e. 254 nm, revealed fast and dramatic changes (Figure 2). After an initial decline and blue shift of the

• provided deeper insights and clarified the differential behaviour observed in the UV–vis spectra of 2b and 2f after UV irradiation. As anticipated, UV irradiation lead to E→Z isomerization of the C=C double bond in both compounds. The (Z)-isomers were found to be slightly more polar than the respective (E

• )-isomers and their absorption maxima appeared blue shifted as demonstrated by the UV–vis spectra extracted from the LC runs. Unfortunately, the amount of photoisomerization was only moderate, since after 100 minutes of continuous irradiation still substantial amounts of the (E)-isomers were present in the

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

• replacement of methoxy groups by hydroxy groups formed under ether-cleavage conditions. UV–vis spectra in MeCN: S3-(DMP)3C+ (1, red), S2-(DMP)3C+ (2, green), and S1-(DMP)3C+ (3, blue). UV–vis spectra in MeCN: S3-acridinium (4a, black) and S3-xanthenium (7, red). Inset: The 3D structure of 4a with indication

• of the principle axes of the electronic transitions. UV–vis spectra in CH2Cl2: S1-TOTA+ (9, blue line), S2-TOTA+ (8, red line), and S3-TOTA+ (6, black line). UV–vis absorption and fluorescence spectra (λex = 485 nm) of 5a in CH2Cl2 solution. Calculated molecular orbital contour plots (semi-empirical

Friedel–Crafts approach to the one-pot synthesis of methoxy-substituted thioxanthylium salts

• Kenta Tanaka,
• Yuta Tanaka,
• Mami Kishimoto,
• Yujiro Hoshino and
• Kiyoshi Honda

Beilstein J. Org. Chem. 2019, 15, 2105–2112, doi:10.3762/bjoc.15.208

• salts has been developed. The reaction of diaryl sulfides with benzoyl chlorides in the presence of TfOH smoothly proceeded to give the desired thioxanthylium salts in good yields. In their UV–vis spectra, the maximum absorption wavelengths of methoxy-functionalized thioxanthylium salts were observed at

• -withdrawing groups. Subsequently, we measured the UV–vis spectra of thioxanthylium salts. As shown in Figure 2, almost all measured UV–vis spectra are nearly identical in spite of different substituents on the benzene ring at the 9-position of the thioxanthylium core. Moreover, when the solvent effects were

• electron-withdrawing groups can be applied to the reaction. It was found that the main absorption of thioxanthylium salts around 460 nm in UV–vis spectra would be due to π–π* transitions, which was supported by DFT calculations. The present reaction provides a versatile access to functionalized

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

• coupling constants (Table 1), NOESY correlations (Figure 3) and ECD spectra (Figure 4). Bipolenin N (4) was acquired as a colourless oil. Its molecular formula was determined to be C15H28O4 from the HRESIMS [M + H − 2H2O]+ ion at m/z 237.1859 (calcd for C15H25O2+, 237.1849). The UV–vis spectra of 1–3

Morphology-tunable and pH-responsive supramolecular self-assemblies based on AB₂-type host–guest-conjugated amphiphilic molecules for controlled drug delivery

• Yang Bai,
• Cai-ping Liu,
• Di Chen,
• Long-hai Zhuo,
• Huai-tian Bu and
• Wei Tian

Beilstein J. Org. Chem. 2019, 15, 1925–1932, doi:10.3762/bjoc.15.188

• . 1H NMR spectra of β-CD-BM2-based supramolecular self-assemblies in DMSO-d6 (a), D2O (b) and DCl/D2O (c), respectively. 2D NMR NOESY spectra in D2O (a) and D2O/DCl (b), UV–vis spectra (c) and fluorescence spectra (d) of β-CD-BM2-based supramolecular self-assemblies at pH 7.4 and 5.0. Cumulative

Norbornadiene-functionalized triazatriangulenium and trioxatriangulenium platforms

• Roland Löw,
• Talina Rusch,
• Tobias Moje,
• Fynn Röhricht,
• Olaf M. Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1815–1821, doi:10.3762/bjoc.15.175

• platform 2 (44%). The photophysical properties and the switching behaviour of 1, 2 and 3 were determined in solution (THF). The UV–vis spectra of the norbornadienes (NBD, black, 1a, 2a, 3a) and quadricylanes (QC, red, 1b, 2b, 3b) and the spectra of the QCs after irradiation with 311 nm for 1b and 2b or 254

• geometry coordinates and further details see Supporting Information File 1). The norbornadiene isomerizes upon irradiation with 385 nm to the quadricyclane 1b. Back-isomerization to the norbornadiene 1a is achieved upon irradiation with 311 nm or thermochemically with a half-life of 31 days. UV–vis spectra

Host–guest interactions in nor-seco-cucurbit[10]uril: novel guest-dependent molecular recognition and stereoisomerism

• Xiaodong Zhang,
• Wei Wu,
• Zhu Tao and
• Xin-Long Ni

Beilstein J. Org. Chem. 2019, 15, 1705–1711, doi:10.3762/bjoc.15.166

• ad host-2 were further studied by UV–vis spectra (Supporting Information File 1, Figure S3) and Job plot (Supporting Information File 1, Figure S4). In order to obtain detailed information on the mechanism of the complexation of G2 with host-1 and -2, 1H NMR titration experiments in acidic aqueous

Synthesis, enantioseparation and photophysical properties of planar-chiral pillar[5]arene derivatives bearing fluorophore fragments

• Guojuan Li,
• Chunying Fan,
• Guo Cheng,
• Wanhua Wu and
• Cheng Yang

Beilstein J. Org. Chem. 2019, 15, 1601–1611, doi:10.3762/bjoc.15.164

• ). These results demonstrated that the bulky substituents DPA or perylene effectively prevent the ring rotations, and therefore making the separation of Rp and Sp conformers possible. Figure 3d and e show the circular dichroism (CD) and UV–vis spectra of each fraction for P5A-DPA. The CD signals of both

• DPA is responsible for the red-shift of the absorption. For P5A-Py, however, adding water to the THF solution led to a continuous red-shifting of the UV–vis spectra and increasing of CD signal, which is reasonable, as the planar structure of Py tends more to get aggregated in water by π–π stacking

• ) apparatus. UV–vis spectra were obtained on a JASCO v-650 spectrometer. Fluorescence spectra and fluorescence lifetime decay measurements were recorded on a HORIBA FluoroMax–4 (TCSPC) spectrofluorimeter. Circular dichroism spectra were measured on a JASCO J-1500 spectrometer using a quartz cuvette of 1 cm

Diazocine-functionalized TATA platforms

• Roland Löw,
• Talina Rusch,
• Fynn Röhricht,
• Olaf Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1485–1490, doi:10.3762/bjoc.15.150

• ). The UV–vis spectra of 1 and 2 are shown before and after irradiation with 405 nm and 525 nm. Both diazocine-TATAs 1 and 2 exhibit similar UV spectra. The n→π* transition of cis-1 appears at 403 nm and at 494 nm in the trans-isomer. The corresponding absorption maxima in diazocine-TATA 2 are 409 nm

• -diazocines (1b, 2b) and with 525 nm or thermally back to the cis-diazocines (1a, 2a). UV–vis spectra of 1 (left) and 2 (right) in THF at room temperature. Black: as synthesized, red: after irradiation with 405 nm, and blue: after irradiation with 525 nm. STM images (30 × 30 nm², Ubias = 0.3 V, It = 40 pA) of

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

• the silyl ethers. Unlike in the solution reaction, the HEBM isolated reaction products of β-CD were almost completely insoluble in water, while the γ-CD derivative was somehow soluble or solubilised, as seen in the UV–vis spectra. Both the β- and γ-CD derivatives showed high complexation affinity

• with the front, and they were found to be very poorly charrable. While it is not clear whether the product itself was dissolved or whether the particle size was smaller than <0.22 µm, the UV–vis spectra clearly show the hypsochromic shift that was caused by complexation with increasing amounts of added

• (Table 3, entry 9) and γ-CDP (Table 3, entry 12) prepared in a ball mill on 2 mmol scale. Normalised particle-size distribution of insoluble CD polymers (entries 9, 10, and 12 of Table 3). UV–vis spectra and adsorption isotherm of the insoluble β-CDP polymer in 10 ml 0.050 mM MO solution (entry 10 of