Oxidative and reductive cyclization in stiff dithienylethenes

• Michael Kleinwächter,
• Ellen Teichmann,
• Lutz Grubert,
• Martin Herder and
• Stefan Hecht

Beilstein J. Org. Chem. 2018, 14, 2812–2821, doi:10.3762/bjoc.14.259

• components for optical memories [3][4]. In addition to photochemistry, the isomerization of DAEs can also be triggered by electrochemical means, therefore providing a stimulus orthogonal to light [5]. Electrochemically induced isomerization of DAEs is almost exclusively based on oxidation. Either cyclization

• achieve cyclization, via both the oxidative and reductive pathway. Experimental A detailed description of the experimental conditions and applied analytical methods, including synthesis, photochemistry, and electrochemistry, can be found in Supporting Information File 1. Cyclic voltammograms of sDTE66-Me

Photocatalyic Appel reaction enabled by copper-based complexes in continuous flow

• Clémentine Minozzi,
• Jean-Christophe Grenier-Petel,
• Shawn Parisien-Collette and
• Shawn K. Collins

Beilstein J. Org. Chem. 2018, 14, 2730–2736, doi:10.3762/bjoc.14.251

• anhydrides. The protocol was also amendable and optimized under continuous flow conditions. Keywords: Appel; continuous flow; copper; halides; photocatalysis; Introduction Synthetic photochemistry and photocatalysis continues to influence molecular synthesis [1][2][3][4]. In exploring photochemical

Synthesis of aryl sulfides via radical–radical cross coupling of electron-rich arenes using visible light photoredox catalysis

• Amrita Das,
• Mitasree Maity,
• Simon Malcherek,
• Burkhard König and
• Julia Rehbein

Beilstein J. Org. Chem. 2018, 14, 2520–2528, doi:10.3762/bjoc.14.228

• ps/div, 10 ns/div, 10µs/div; tmax = 3.5 µs to 10 µs) provided information on photophysics and photochemistry of the single reactants. Figure 4 shows the strong luminescence of the catalyst (red line) that overlaps with the transient absorption of the postulated 1,3,5-TMB•+ in the 2-component mixture

Microfluidic light-driven synthesis of tetracyclic molecular architectures

• Javier Mateos,
• Nicholas Meneghini,
• Marcella Bonchio,
• Nadia Marino,
• Tommaso Carofiglio,
• Xavier Companyó and
• Luca Dell’Amico

Beilstein J. Org. Chem. 2018, 14, 2418–2424, doi:10.3762/bjoc.14.219

• molecules. Keywords: [4 + 2] photoenol; cycloaddition; flow chemistry; microfluidic photoreactor; photoredox catalysis; synthetic photochemistry; Introduction In recent years synthetic photochemistry has become highly sophisticated [1]. The opportunity of using renewable energy sources to transform and

Novel photochemical reactions of carbocyclic diazodiketones without elimination of nitrogen – a suitable way to N-hydrazonation of C–H-bonds

• Liudmila L. Rodina,
• Xenia V. Azarova,
• Jury J. Medvedev,
• Dmitrij V. Semenok and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2018, 14, 2250–2258, doi:10.3762/bjoc.14.200

• with up to 90–97% yield. Keywords: C–H insertion; diazo compounds; excited state; photochemistry; Wolff rearrangement; Introduction Photochemical reactions of diazocarbonyl compounds are well-known transformations in the synthesis of the diversified acyclic, carbo- and heterocyclic structures [1][2

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• damaging and toxic to various life forms. Photochemistry also offers benefits compared to conventional thermally driven processes. Several transformation processes that utilise sunlight as the energy source to drive a particular reaction have been reported and some reactions presented in this review

• Figure 2). It is ideal if a photocatalyst has a local absorbance maximum (λmax) at a relatively long wavelength. Lower energy photons avoid exciting other reactants and prevent competing photochemistry from occurring, cf. ultraviolet light. However, the energy of the absorbed photon also determines the

Diazirine-functionalized mannosides for photoaffinity labeling: trouble with FimH

• Femke Beiroth,
• Tomas Koudelka,
• Thorsten Overath,
• Stefan D. Knight,
• Andreas Tholey and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1890–1900, doi:10.3762/bjoc.14.163

• . They differ with respect to their steric properties, photochemistry, and reactivity. In order to be applied in a biological environment, the wavelength of the light required for activation of the photolabile ligand has to be biocompatible. Furthermore, small photophores are desirable. Diazirines meet

Synthesis and photophysical studies of a multivalent photoreactive Ru^II-calix[4]arene complex bearing RGD-containing cyclopentapeptides

• Sofia Kajouj,
• Lionel Marcelis,
• Alice Mattiuzzi,
• Adrien Grassin,
• Damien Dufour,
• Pierre Van Antwerpen,
• Didier Boturyn,
• Eric Defrancq,
• Mathieu Surin,
• Julien De Winter,
• Pascal Gerbaux,
• Ivan Jabin and
• Cécile Moucheron

Beilstein J. Org. Chem. 2018, 14, 1758–1768, doi:10.3762/bjoc.14.150

• a photoreactive [Ru(TAP)2phen]2+ complex tethered to a calix[4]arene platform bearing four c-[RGDfK] moieties [65] (Figure 1). Before studying this conjugate in vitro, it was first mandatory to check that the photochemistry of the RuII complex was not altered by the presence of the targeting

• the Ru complex and the cyclic peptides by the calixarene should be an advantage by preventing any negative effect of the RGD peptidic units on the photochemistry of the complex and, alternatively, prevents any influence of the complex on the affinity of the RGD patterns to interact with the targeted

An unusual thionyl chloride-promoted C−C bond formation to obtain 4,4'-bipyrazolones

• Gernot A. Eller,
• Gytė Vilkauskaitė,
• Algirdas Šačkus,
• Vytas Martynaitis,
• Ashenafi Damtew Mamuye,
• Vittorio Pace and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2018, 14, 1287–1292, doi:10.3762/bjoc.14.110

• nitrosation and subsequent heating [28], by heating with an aqueous NaHSO3 solution [29], and by photochemistry [30][31]. In nearly all cases these reactions have been carried out with 2-pyrazolin-5-ones unsubstituted at pyrazole C4 position or with derivatives carrying an alkyl or aryl substituent at the

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

Mechanochemistry of nucleosides, nucleotides and related materials

• Olga Eguaogie,
• Joseph S. Vyle,
• Patrick F. Conlon,
• Manuela A. Gîlea and
• Yipei Liang

Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81

• four taxa along with thermochemistry, electrochemistry and photochemistry [1]. A general definition commonly cited is that developed by The International Union of Pure and Applied Chemistry (IUPAC) to encompass both the chemical and physical effects of shearing, stretching or grinding polymeric

The photodecarboxylative addition of carboxylates to phthalimides as a key-step in the synthesis of biologically active 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones

• Ommid Anamimoghadam,
• Saira Mumtaz,
• Anke Nietsch,
• Gaetano Saya,
• Cherie A. Motti,
• Jun Wang,
• Peter C. Junk,
• Ashfaq Mahmood Qureshi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2017, 13, 2833–2841, doi:10.3762/bjoc.13.275

• ; arylmethylenedihydroisoindolinones; photochemistry; photodecarboxylation; phthalimide; Introduction Phthalimides and their related 3-alkyl- and 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones play an important role in medicinal chemistry due to their biological activities for a wide range of therapeutic applications [1][2][3][4

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• received the Nobel Prize in 1909, mentioned the term “Mechanochemistry” as, like a branch of physical chemistry, i.e., thermochemistry, photochemistry and electrochemistry [13][14]. He defined the subject as “Mechanochemistry is a branch of chemistry which is concerned with chemical and physio-chemical

Chemoselective synthesis of diaryl disulfides via a visible light-mediated coupling of arenediazonium tetrafluoroborates and CS₂

• Jing Leng,
• Shi-Meng Wang and
• Hua-Li Qin

Beilstein J. Org. Chem. 2017, 13, 903–909, doi:10.3762/bjoc.13.91

• has also been studied [14][15] by taking advantage of visible light as abundant and environmentally friendly energy source for organic syntheses. The photochemistry of diazonium salts has been widely studied since the early 19th century, at which time, it was noticed that benzenediazonium nitrate

How and why kinetics, thermodynamics, and chemistry induce the logic of biological evolution

• Addy Pross and
• Robert Pascal

Beilstein J. Org. Chem. 2017, 13, 665–674, doi:10.3762/bjoc.13.66

• origin of life that more or less correspond to the conditions for the development of life on the primitive Earth (organic chemistry, liquid water and visible or UV light). Here again, some recent experimental work has shown how photochemistry could lead to biochemical building blocks compatible with

Exploring endoperoxides as a new entry for the synthesis of branched azasugars

• Svenja Domeyer,
• Mark Bjerregaard,
• Henrik Johansson and
• Daniel Sejer Pedersen

Beilstein J. Org. Chem. 2017, 13, 644–647, doi:10.3762/bjoc.13.63

• these building blocks provided access to a variety of derivatives including tetrahydrofurans, epoxides and protected amino-tetraols. Keywords: azasugar; carbohydrate; cycloaddition; endoperoxide; photochemistry; Introduction Azasugars are small organic compounds that can mimic carbohydrates or their

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

• 43, Prague 2, Czech Republic Laboratory of Photochemistry, Department of Drug Sciences, University of Catania, I-95125 Viale A. Doria 6, Italy Department of Pharmacognosy, Semmelweis University, H-1085 Üllői út 26, Hungary STMicroelectronics, Stradale Primosole 50, I-95121, Catania, Italy 10.3762

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

• Flavio Fanelli,
• Giovanna Parisi,
• Leonardo Degennaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

• photochemistry got a sort of renaissance, emerging as useful approach in modern sustainable and green synthesis. Concerning the heterogeneous catalysis with palladium, practical procedures for recovering and reusing of the catalysts have been recently reported [51][52][53]. A versatile Pd-catalysed synthesis of

• prepared with this greener flow approach (Scheme 15) starting from mesitylene 13, and haloarenes using short irradiation times (<6 h), and a 5:1 MeCN/H2O mixture. The reported results show how photochemistry hold the potential to become a green tool for the development of sustainable photochemical flow

NMR reaction monitoring in flow synthesis

• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2017, 13, 285–300, doi:10.3762/bjoc.13.31

• (photochemistry, electrochemistry, microwave, ultrasound, etc.) [6][7][8][9]. In this regard, in a recent paper a compact reconfigurable flow system was described for the continuous flow production of pharmaceuticals. The system comprised different types of preparation, reaction and elaboration modules that could

Interactions between photoacidic 3-hydroxynaphtho[1,2-b]quinolizinium and cucurbit[7]uril: Influence on acidity in the ground and excited state

• Jonas Becher,
• Daria V. Berdnikova,
• Darinka Dzubiel,
• Heiko Ihmels and
• Phil M. Pithan

Beilstein J. Org. Chem. 2017, 13, 203–212, doi:10.3762/bjoc.13.23

• this ligand increase by about two to three orders of magnitude, respectively, when bound to CB[7]. Keywords: azoniahetarenes; cucurbit[7]uril; heterocycles; photoacids; supramolecular photochemistry; Introduction The complexation of ligands by macrocyclic host molecules, such as crown ethers

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

• cyclodextrin vesicle surface. The supramolecular immobilization was monitored by using fluorescence spectroscopy and microscopy and the photochemistry of the squaraine was investigated by using absorption spectroscopy. Keywords: cyclodextrin; host–guest chemistry; photodynamic therapy; self-assembly

• for the CDV without affecting its photochemistry. In addition, it is expected that the aggregation of squaraine will be supressed by immobilization at the CDV surface. Ultimately, the photoactive squaraine can be combined with other functional guests, such as targeting units and tracers, to further

• investigated the photochemistry of AdSq on CDV. To this end, AdSq was added to an aqueous dispersion of CDV exactly as described above. The solution was irradiated for 600 s and absorption spectra were taken at various time points. As shown before in the acetonitrile solution, also AdSq immobilized on CDV

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

• and Nobel Prize laureate 1909, chemistry can be divided into the four sub-disciplines thermochemistry, electrochemistry, photochemistry, and mechanochemistry, depending on the kind of energy involved in a chemical process [1]. Among these, mechanochemistry is nowadays a well-established method for the

• for mechanochemical syntheses include stoichiometric reactions such as the Knoevenagel condensation and the Wittig reaction, but also reactions catalyzed by metal catalysts, like the Sonogashira coupling and the Suzuki coupling [1]. Photocatalysis, as a part of Ostwald’s sub-discipline photochemistry

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

• operation of various other reactions at light/liquid/gas interfaces in student, research, and industrial laboratories. Keywords: biphasic reactions; flow chemistry; gas phase; microreactor; oxygen; photochemistry; Introduction The recent developments of microreactor technologies have significantly

• (with dyes of ε > 10,000 M−1 cm−1) and traditional photochemistry (involving mostly UV irradiation of colourless organic molecules of ε < 1,000 M−1 cm−1) [61]. The much lower molar attenuation coefficients of the majority of organic molecules which are directly irradiated by UV light in photochemical

Bright molecules for sensing, computing and imaging: a tale of two once-troubled cities

• A. Prasanna de Silva

Beilstein J. Org. Chem. 2015, 11, 2774–2784, doi:10.3762/bjoc.11.298

• , bad times and good times again. Through all these times, a bit of supramolecular photochemistry [1][2] kept happening and this is my story. My paternal grandfather was the schoolteacher in our Colombo suburb and so, the value of learning was instilled into me from age zero. A sharpening of the

• Belfast, but recruiting decent Ph.D. students to Belfast during the troubles had been hard. Ron Grigg was persuaded by Vincent Arkley to take on several Sri Lankans. I was fortunate to work with James Grimshaw who was hugely knowledgeable in electro- and photochemistry, while Ron Grigg also kept an eye

• beginnings At the time that I was studying for a Ph.D. in organic photochemistry [5], the field was in transition. The study of single functional groups was nearing completion and attention was shifting to the meeting of two functionalities in a photon field. One of the most influential concepts that emerged

Synthesis and structures of ruthenium–NHC complexes and their catalysis in hydrogen transfer reaction

• Chao Chen,
• Chunxin Lu,
• Qing Zheng,
• Shengliang Ni,
• Min Zhang and
• Wanzhi Chen

Beilstein J. Org. Chem. 2015, 11, 1786–1795, doi:10.3762/bjoc.11.194

• [8][9][10][11][12][13][14][15][16] have been reported. In the family of metal complexes supported by functionalized NHCs, ruthenium complexes have long been a research focus on various applications such as catalysis and photochemistry [17][18][19][20][21][22][23][24][25][26]. However, the majority of