Novel β-cyclodextrin–eosin conjugates

• Gábor Benkovics,
• Damien Afonso,
• András Darcsi,
• Szabolcs Béni,
• Sabrina Conoci,
• Éva Fenyvesi,
• Lajos Szente,
• Milo Malanga and
• Salvatore Sortino

Beilstein J. Org. Chem. 2017, 13, 543–551, doi:10.3762/bjoc.13.52

• successfully utilized in photodynamic therapy (PDT). This minimally invasive therapeutic approach has proven to be very well-suited for cancer and bacterial diseases treatment. The PDT is based on the combination of three main components: visible light, a photosensitizer (PS) and molecular oxygen [4][5]. After

• being excited with visible light, the PS – while reverting to the ground state – transfers the energy of its lowest excited triplet state to nearby molecular oxygen. This leads to an in situ generation of singlet oxygen (1O2), which is the main responsible species for cytotoxic reactions in cells [6

• nitric oxide under illumination with visible light, resulting in amplified cancer-cell mortality [9]. By attaching porphyrin to γ-CD and dimeric β-CD, which are both able to form inclusion complexes with cytotoxic drug molecules such as doxorubicin and paclitaxel, nanocarriers with multimodal therapeutic

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

• Andrew J. Capel,
• Andrew Wright,
• Matthew J. Harding,
• George W. Weaver,
• Yuqi Li,
• Russell A. Harris,
• Steve Edmondson,
• Ruth D. Goodridge and
• Steven D. R. Christie

Beilstein J. Org. Chem. 2017, 13, 111–119, doi:10.3762/bjoc.13.14

• ) being picked up by the detector when the light source was inactive (Figure 2). This demonstrated that due to the transparency of the Accura 60 resin to visible light, even though the part would be housed inside a dark chamber, ideally the detection wavelengths for this material should be kept below 400

Copper-catalyzed asymmetric sp³ C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

• Pierre Querard,
• Inna Perepichka,
• Eli Zysman-Colman and
• Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

• catalysts provide a mild and highly effective sp3 C–H asymmetric arylation of THIQs. Keywords: C–H arylation; copper catalyst; enantioselectivity; visible light; Introduction Functionalization of sp3 C–H bonds is a unique and powerful transformation in modern organic synthesis, which remains a challenging

• [2]. The emerging and expanding field of visible-light-mediated photoredox catalysis presents unique opportunities for the conception of new synthetic routes [3][4][5][6][7][8][9][10][11][12]. Upon exposure to visible light, photoredox catalysts can function as both reductant and oxidant, thereby

• allow us to design a visible-light-mediated photoredox asymmetric arylation of tetrahydroisoquinolines (THIQs) [15][16][17][18][19][20]. During the last decade, numerous examples of sp3 C–H bond arylation procedures have been developed [1][21][22][23][24][25][26][27][28][29]. In 2008, our group

A self-assembled cyclodextrin nanocarrier for photoreactive squaraine

• Ulrike Kauscher and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2016, 12, 2535–2542, doi:10.3762/bjoc.12.248

• , which have the disadvantage of an absorption wavelength in the range of visible light [8][9]. Visible light is scattered and absorbed by the inhomogeneous biological tissue. In order to optimise efficiency, it is vital to skew the absorption range of the PS towards the near infrared range. Then, the

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

• Donghui Pan,
• Yanbin Wang and
• Guomin Xiao

Beilstein J. Org. Chem. 2016, 12, 2443–2449, doi:10.3762/bjoc.12.237

• was induced by adding 3 mol % of radical initiator (DBP or AMPA) and proceeded at 75 °C for 4 h (Table 1, entries 3 and 4). Though the yields in both processes increased, the selectivity of 2a decreased due to the formation of some excessive brominated byproducts. Then, we tried visible light as

• visible-light induced bromination with the H2O2–HBr system Analogous as described in [16], substituted p-xylene (1.0 mmol) was added to 2.0 mL solution (CCl4 or water) of 2.0 mmol of H2O2 (0.23 g, 30% H2O2 aqueous) and 1.1 mmol of HBr (0.22 g, 30% HBr aqueous). The mixture was stirred at 300 rpm at

• bromides from substituted (4-methylbenzyl)bromides. Bromination of 2,5-dichloro-p-xylene (1) with H2O2–HBr. Visible-light induced free-radical bromination of substituted p-xylenes with H2O2–HBr. Synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane 16 from 11. Synthesis of substituted [2.2]paracyclophanes

Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

• Martin Obst and
• Burkhard König

Beilstein J. Org. Chem. 2016, 12, 2358–2363, doi:10.3762/bjoc.12.229

• reaction mixture. The corresponding carbonyl compounds were obtained in moderate to good yields. Keywords: benzylic alcohol; oxidation; photocatalysis; solvent free; visible light; Introduction According to a classification made by Wilhelm Ostwald, one of the pioneers in the field of physical chemistry

• , is a rather new field of great academic interest. Namely, visible-light photocatalysis applying an organic, redox-active catalyst allows mild and efficient transformations. By exciting the photocatalyst, which then exchanges electrons with the substrate, light energy is converted into chemical energy

• substrates would be grinded under visible light irradiation. In contrast to mechanochemistry, the process would be driven by light energy and not by mechanical energy, but profit from the absence of toxic solvents, high concentrations of the substrate, and easy work-up. Furthermore, undesired effects of the

Enantioconvergent catalysis

• Justin T. Mohr,
• Jared T. Moore and
• Brian M. Stoltz

Beilstein J. Org. Chem. 2016, 12, 2038–2045, doi:10.3762/bjoc.12.192

• visible light (Scheme 4) [27]. Although the mechanism continues to be studied, it is hypothesized that irradiation of the copper–carbazole complex leads to an excited-state adduct that is capable of generating achiral tertiary alkyl radical intermediates through electron transfer with a racemic alkyl

A flow reactor setup for photochemistry of biphasic gas/liquid reactions

• Josef Schachtner,
• Patrick Bayer and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2016, 12, 1798–1811, doi:10.3762/bjoc.12.170

• especially evident from a consideration of the extent of light attenuation when passing through condensed matter. The molar attenuation coefficients of common organic photosensitizers are in the range of 20,000–500,000 M−1 cm−1 (Table 1) which significantly limits the penetration depth of visible light into

• reactor parameters. The length of the tubing coil directly determines the residence time in the reactor. The FEP tubing does not exhibit a significant absorption of visible light [68]; furthermore, the reaction temperature can be easily set and controlled by immersing the reactor coil into a thermostat

• selective oxidations of various organic molecules (Scheme 5). From a conceptual point of view, the combination of two of the most abundant “reagents” on the surface of our planet, oxygen and visible light, with a safe, scalable, and efficient reactor technology for chemical reactions constitutes an approach

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells

• Hideaki Komiyama,
• Chihaya Adachi and
• Takuma Yasuda

Beilstein J. Org. Chem. 2016, 12, 1459–1466, doi:10.3762/bjoc.12.142

• ability, and good miscibility with a fullerene derivative as an acceptor. Moreover, strong visible light photoabsorption ability for visible light is vital for the donor materials. Star-shaped molecules tethering multiple π-conjugated arms are capable of harvesting incident light effectively owing to

The role of alkyl substituents in deazaadenine-based diarylethene photoswitches

• Christopher Sarter,
• Michael Heimes and
• Andres Jäschke

Beilstein J. Org. Chem. 2016, 12, 1103–1110, doi:10.3762/bjoc.12.106

• isomer, BP: byproduct. Thermostability measurements of the 7-deazaadenosine nucleosides. A 60 µM solution of the compound in acetonitrile was irradiated with UV light until the (pseudo)-photostationary state was reached. Then UV irradiation was switched off and the absorption at the visible light maximum

Opportunities and challenges for direct C–H functionalization of piperazines

• Zhishi Ye,
• Kristen E. Gettys and
• Mingji Dai

Beilstein J. Org. Chem. 2016, 12, 702–715, doi:10.3762/bjoc.12.70

• starting materials. The reaction proceeds with excellent regio- and diastereoselectivity which is presumably due to a regio- and stereoselective alkene insertion into the strained metalla-aziridine intermediate 84. Photoredox catalysis Visible-light photoredox catalysis has emerged as a powerful platform

Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• photo-responsive small molecules are azobenzene and its derivatives which isomerize from trans to cis and from cis to trans under irradiation with UV and visible light, respectively, and are potentially components of photo-responsive materials. In 2005, Harada et al. constructed a photo-responsive

• PAA3α-CD/PAAAzo and PAA6α-CD/PAAAzo host–guest complexation between the α-CD and azobenzene substituents are characterized by complexation constants, K = 1.4 × 102 and 1.2 × 104 M−1, respectively. Under visible light the viscosities of PAA3α-CD/PAAAzo and PAA6α-CD/PAAAzo are 6.5 × 10−1 and 2.5 × 102

Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

• A. John Blacker and
• Katherine E. Jolley

Beilstein J. Org. Chem. 2015, 11, 2408–2417, doi:10.3762/bjoc.11.262

• organozinc reagents to give amines [1]; iii) aldehydes to give amides [5][6][7]; iv) base to give imines [8]; v) alkyl and aryl C–H bonds in the presence of acid and visible light to form heterocycles [9][10]. Furthermore they have also been used for chlorination of aromatics in the presence of acid [11

Biocatalysis for the application of CO₂ as a chemical feedstock

• Apostolos Alissandratos and
• Christopher J. Easton

Beilstein J. Org. Chem. 2015, 11, 2370–2387, doi:10.3762/bjoc.11.259

• CODH and photosensitised with a Ru dye to catalyse the reduction of CO2 using visible light. Further to this, the reported ability of a V-dependent nitrogenase to slowly reduce CO to various small-chain hydrocarbons holds much promise for the development of enzymatic processes to further transform CO

Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II)-ethylenediamine precatalyst

• Redouane Beniazza,
• Natalia Bayo,
• Florian Molton,
• Carole Duboc,
• Stéphane Massip,
• Nathan McClenaghan,
• Dominique Lastécouères and
• Jean-Marc Vincent

Beilstein J. Org. Chem. 2015, 11, 1950–1959, doi:10.3762/bjoc.11.211

• experiments were carried out in quartz cuvettes to follow the disappearance of the low-energy visible light absorption band (550–600 nm) ascribed to a d–d electronic transition, which is typical for CuII complexes (d9). The reductions were typically conducted under strictly anaerobic conditions, deaeration of

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• popularity of homogeneous PRCs is due to their ease of synthesis and stability as well as their excellent photoredox properties. Furthermore, they can be activated by visible light, precluding the requirement for specialized irradiation setups, and their reactivity can be tuned by altering the substitution

• excitation wavelength 385 nm, band gap 3.2 eV). Whilst this is less convenient than visible light, the band edge positions are consequently more powerful redox agents. Of the naturally occurring crystal structures of TiO2, anatase is superior to rutile for photocatalytic activity [12]. For semiconductor

• catalysts visible light can be used [15][16]. Following this the P25 can be removed by filtration through a Celite pad, or by centrifugation, and can usually be reused. Alternatively, glass beads coated with TiO2 can be used but these tend to rise to the solvent surface thus making irradiation less

Synthesis of photoresponsive cholesterol-based azobenzene organogels: dependence on different spacer lengths

• Yuchun Ren,
• Bin Wang and
• Xiuqing Zhang

Beilstein J. Org. Chem. 2015, 11, 1089–1095, doi:10.3762/bjoc.11.122

• intermolecular H-bonding, the solvents and van der Waals interaction are the main contributions to the specific superstructure. Results and Discussion To investigate the photoresponsiveness of these compounds, the dilute THF solution of compounds were irradiated by UV and visible light. Figure 1a shows an

• obvious increase in the peak at 258 nm and a concurrent decrease in the strong peak at 358 nm. The photostationary state was attained after 94 min of irradiation and the spectral changes are attributable to the trans-to-cis isomerization under UV light irradiation. Further visible light (450 nm

• organogelators and soft matter. Changes in the absorption over time in the UV–vis spectra of dilute THF solution of M0: (a) upon UV-light irradiation (λ = 365 nm) and (b) upon visible-light irradiation (λ = 450 nm) of the solution obtained after irradiation of 365 nm. DSC thermogram of the compounds M0-n

Impact of multivalent charge presentation on peptide–nanoparticle aggregation

• Daniel Schöne,
• Boris Schade,
• Christoph Böttcher and
• Beate Koksch

Beilstein J. Org. Chem. 2015, 11, 792–803, doi:10.3762/bjoc.11.89

• (C) R2A2 in the presence of 0.05 µM Au/MUA nanoparticles at pH 9 visualised by UV light (left) and visible light (right). Cryo TEM images of 100 µM R2A2 and 0.05 µM Au/MUA nanoparticles at pH 9 at a defocus of (A) −1.2 µm, (B) −1.8 µm and (D) after pH switch from 11 to 9 at a defocus of −1.8 µm. (C

Metal-free one-pot synthesis of 2-substituted and 2,3-disubstituted morpholines from aziridines

• Hongnan Sun,
• Binbin Huang,
• Run Lin,
• Chao Yang and
• Wujiong Xia

Beilstein J. Org. Chem. 2015, 11, 524–529, doi:10.3762/bjoc.11.59

• temperatures in the initial stage. Thus, the discovery of an operationally simple and eco-friendly synthetic approach is a desirable complement to current methodologies. Recently we have reported the visible light-mediated ring opening of aziridines by a number of nucleophiles, such as LiBr, NaN3 and alcohols

Eosin Y-catalyzed visible-light-mediated aerobic oxidative cyclization of N,N-dimethylanilines with maleimides

• Zhongwei Liang,
• Song Xu,
• Wenyan Tian and
• Ronghua Zhang

Beilstein J. Org. Chem. 2015, 11, 425–430, doi:10.3762/bjoc.11.48

• Engineering, Jiaxing University, Jiahang Road 118, Zhejiang 314001, China 10.3762/bjoc.11.48 Abstract A novel and simple strategy for the efficient synthesis of the corresponding tetrahydroquinolines from N,N-dimethylanilines and maleimides using visible light in an air atmosphere in the presence of Eosin Y

• catalysis; visible light; Introduction Over the past several years, visible light photoredox catalysis has become a powerful and promising tool and has been productively used to drive chemical transformations in the field of organic synthesis [1][2][3][4][5][6]. The approach takes full advantage of visible

• light, which is clean, abundant, and renewable. The pioneering work in this research area, reported by the groups of MacMillan [7][8][9], Yoon [10][11], Stephenson [12][13] and others [14][15][16][17][18], has demonstrated that ruthenium and iridium complexes as visible light photoredox catalysts are

Functionalized branched EDOT-terthiophene copolymer films by electropolymerization and post-polymerization “click”-reactions

• Miriam Goll,
• Adrian Ruff,
• Erna Muks,
• Felix Goerigk,
• Beatrice Omiecienski,
• Ines Ruff,
• Rafael C. González-Cano,
• Juan T. Lopez Navarrete,
• M. Carmen Ruiz Delgado and
• Sabine Ludwigs

Beilstein J. Org. Chem. 2015, 11, 335–347, doi:10.3762/bjoc.11.39

• visible (light areas in the microscope images; green and blue spots in the IR map. Note that the background of the single IR spectra is about 70–80%), for the modified P(EDOT-clickSO3Na-co-3T)-1:1 nearly no azide band intensity can be observed. This provides information about the integrity of the

Photovoltaic-driven organic electrosynthesis and efforts toward more sustainable oxidation reactions

• Bichlien H. Nguyen,
• Robert J. Perkins,
• Jake A. Smith and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2015, 11, 280–287, doi:10.3762/bjoc.11.32

• Bichlien H. Nguyen Robert J. Perkins Jake A. Smith Kevin D. Moeller Washington University in Saint Louis, Saint Louis, Missouri 63130, United States 10.3762/bjoc.11.32 Abstract The combination of visible light, photovoltaics, and electrochemistry provides a convenient, inexpensive platform for

• . Keywords: electrochemistry; sustainable oxidation reactions; visible light; Introduction Organic electrochemistry is an extremely versatile tool for conducting a wide variety of chemical reactions [1][2][3]. This versatility stems from both the gentle, acid/base neutral reaction conditions employed for

• visible light into electricity, two of which are shown in Figure 1 [9]. The first is a portable photovoltaic device capable of generating a potential large enough to recharge a wide variety of batteries. The second is a much less expensive alternative that is sold for use in connection with science fair

An improved procedure for the preparation of Ru(bpz)₃(PF₆)₂ via a high-yielding synthesis of 2,2’-bipyrazine

• Danielle M. Schultz,
• James W. Sawicki and
• Tehshik P. Yoon

Beilstein J. Org. Chem. 2015, 11, 61–65, doi:10.3762/bjoc.11.9

• Danielle M. Schultz James W. Sawicki Tehshik P. Yoon Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, WI 53706, USA 10.3762/bjoc.11.9 Abstract There has been a recent surge of interest in the use of transition metal polypyridyl complexes as visible light

• ; palladium; photocatalysis; reductive coupling; Findings Visible light-photoredox catalysis using transition metal chromophores is rapidly becoming recognized as an important strategy in organic synthesis [1][2][3][4][5]. This approach towards reaction design enables the facile generation and exploitation

• , we have developed an improved, Pd-catalyzed method for the synthesis of 2,2’-bipyrazine, an important ligand with growing utility in the context of visible light photocatalysis. This method is readily scalable to enable the gram-scale preparation of 2,2’-bipryazine, which facilitates the preparative

Visible-light-induced bromoetherification of alkenols for the synthesis of β-bromotetrahydrofurans and -tetrahydropyrans

• Run Lin,
• Hongnan Sun,
• Chao Yang,
• Youdong Yang,
• Xinxin Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2015, 11, 31–36, doi:10.3762/bjoc.11.5

• Run Lin Hongnan Sun Chao Yang Youdong Yang Xinxin Zhao Wujiong Xia State Key Lab of Urban Water Resource and Environment, the Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080, P. R. China 10.3762/bjoc.11.5 Abstract A visible-light-induced

• . Keywords: alkenols; bromoetherification; photoredox catalysis; visible light; Introduction The halocyclization of alkenes provides an excellent synthetic method for halogenated heterocycles [1][2][3]. In recent years, haloaminocyclization [4][5], halolactonization [6][7] and haloetherification [8][9] of

• reported that visible-light-induced photoredox catalysis could serve as a more environmental-friendly alternative reaction system to obtain Br2 in situ from CBr4, an oxidative quencher of photoredox catalyst [16][17][18][19][20][21][22]. Thus, as part of difunctionalization of alkenes, with our continuous