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

• class of compounds known as squaraines [13][14][15][16][17][18]. Squaraines are a promising class of fluorescent dyes for PDT. In the past, squaraines showed a very low intersystem-crossing efficiency, leading to the premature conclusion that these dyes cannot be used in PDT [19]. Santos et al. showed

The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors

• Faith M. Akwi and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 1987–2004, doi:10.3762/bjoc.12.186

• principles of green chemistry [1][2] such as less hazardous chemical synthesis, efficient atom economy, reduction of waste produced, some alternative cleaner methods for the synthesis of azo dyes have been developed. These methods are however only representative of particular coupling agents and diazotized

• amines. Nonetheless they highlight the green benefits that they offer. For example Noroozi-Pesyan et al. synthesized azo dyes by grinding derivatives of aniline with solid sodium nitrite in the presence of p-toluenesulfonic acid [3]. It was found that the yield of isolated azo dyes obtained increased

• conjunction with the existing techniques. Microreactor technology is one such technology that can be used in the manufacture of these dyes. If used in conjunction with existing azo dye degradation techniques the amount of waste generated can easily be managed. Hisamoto et al., for example, used ‘phase

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• (DHQ) are heterocyclic scaffolds that are ubiquitous in natural products, therapeutics, fluorophores and dyes [1]. Both are structures of great versatility, and their physical and chemical properties can be finely tuned using synthetic chemistry. Methods for their synthesis have been well studied, and

• mildly red shifted (to 376 nm). This behaviour indicates that 1,4-DHQ structures of this type may function as more effective donor chromophores in dyes and fluorophores than the corresponding THQs due to improved orbital overlap between the nitrogen lone pair and the aromatic π-system by virtue of the

Cross-linked cyclodextrin-based material for treatment of metals and organic substances present in industrial discharge waters

• Élise Euvrard,
• Nadia Morin-Crini,
• Coline Druart,
• Justine Bugnet,
• Bernard Martel,
• Cesare Cosentino,
• Virginie Moutarlier and
• Grégorio Crini

Beilstein J. Org. Chem. 2016, 12, 1826–1838, doi:10.3762/bjoc.12.172

• cationic dyes. Zhang et al. [4] studied the removal of cobalt and 1-naphthol onto magnetic nanoparticles containing cyclodextrin and iron and Yang et al. [5] proposed a new nanocomposite adsorbent for the simultaneous removal of organic and inorganic substances from water. Here, we propose to use a single

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

• (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

Organic chemistry meets polymers, nanoscience, therapeutics and diagnostics

• Vincent M. Rotello

Beilstein J. Org. Chem. 2016, 12, 1638–1646, doi:10.3762/bjoc.12.161

• proteins (transferrin) and cationic nanoparticles to create stable capsules [62]. These capsules delivered hydrophobic drugs and dyes to cells very effectively. A puzzling question arose however: dyes were delivered into cells much faster than the particles on the outside of the capsule. Clearly, endosomal

From N-vinylpyrrolidone anions to modified paraffin-like oligomers via double alkylation with 1,8-dibromooctane: access to covalent networks and oligomeric amines for dye attachment

• Daniela Obels,
• Melanie Lievenbrück and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 1395–1400, doi:10.3762/bjoc.12.133

• reactive amino-functionalized oligomers. Further modification of the free amino groups with 1,4-difluoro-9,10-anthraquinone (DFA) yields red-colored oligomeric anthraquinone dyes. The final reaction of DFA-substituted N-VP oligomers with Jeffamine® M 600 leads to blue-colored and branched oligomers with

Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA

• Svetlana V. Vasilyeva,
• Vyacheslav V. Filichev and
• Alexandre S. Boutorine

Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128

• fluorescent probes via their labeling by commercial and "home-made" fluorescent dyes bearing azide groups. It was noted that yields of alkyne-modified MGBs were higher (50–83%) compared to those of azide modified MGBs (≈40%). The other variant for insertion of terminal azide or alkyne groups into the

Synthesis and fluorosolvatochromism of 3-arylnaphtho[1,2-b]quinolizinium derivatives

• Phil M. Pithan,
• David Decker,
• Manlio Sutero Sardo,
• Giampietro Viola and
• Heiko Ihmels

Beilstein J. Org. Chem. 2016, 12, 854–862, doi:10.3762/bjoc.12.84

• states. Keywords: fluorescence; heterocycles; quinolizinium; solvatochromism; Introduction Dyes that change their absorption and emission properties, especially their color, in different media are considered as helpful optical probes, because they may be applied for the characterization and

• observed for cationic dyes and explained with the high polarizability of these solvents [33][34]. Furthermore, the derivative 6e has a significantly red-shifted absorption in dimethoxyethane. Apart from these exceptional cases, however, the absorption properties depend only marginally on the solvent

• characteristic of donor–acceptor dyes, namely a cumulative red shift of the emission maximum with increasing solvent polarity, along with a broad, unstructured band structure [1][2]. To assess the effect of the solvent on the emission of compound 6e several different solvents were employed. Unfortunately, many

Indenopyrans – synthesis and photoluminescence properties

• Andreea Petronela Diac,
• Ana-Maria Ţepeş,
• Albert Soran,
• Ion Grosu,
• Anamaria Terec,
• Jean Roncali and
• Elena Bogdan

Beilstein J. Org. Chem. 2016, 12, 825–834, doi:10.3762/bjoc.12.81

• derivatives have been found to act as potential candidates for electroluminescent devices due to their fluorescent properties. Fluorescent dyes have lately attracted considerable interest owing to their wide range of applications in various fields. For example, naphthopyrans (e.g. 3,3-diphenyl-3H-naphtho[2,1

Creating molecular macrocycles for anion recognition

• Amar H. Flood

Beilstein J. Org. Chem. 2016, 12, 611–627, doi:10.3762/bjoc.12.60

• the creation and understanding of metal polypyridyl dyes [2] designed for use in solar cells [3]. I loved being in the laboratory doing research and I continued this work through my Ph.D. From Keith I learned the importance of designing function into molecules and exploiting them in a homologous

New synthetic strategies for xanthene-dye-appended cyclodextrins

• Milo Malanga,
• Andras Darcsi,
• Mihaly Balint,
• Gabor Benkovics,
• Tamas Sohajda and
• Szabolcs Beni

Beilstein J. Org. Chem. 2016, 12, 537–548, doi:10.3762/bjoc.12.53

• University, Hlavova 8, 12843 Prague 2, Czech Republic 10.3762/bjoc.12.53 Abstract Xanthene dyes can be appended to cyclodextrins via an ester or amide bridge in order to switch the fluorescence on or off. This is made possible through the formation of nonfluorescent lactones or lactams as the fluorophore

• inexpensive dyes, we prepared rhodamine- and fluorescein-appended cyclodextrins. The compounds were characterized by NMR and IR spectroscopy and MS spectrometry, their UV–vis spectra were recorded at various pH, and their purity was determined by capillary electrophoresis. Two potential models for the

• fluorophores for labeling in order to assess if these versatile molecules cross biological barriers (e.g., cell membrane, blood–brain barrier) and to follow their distribution in living matter [3]. Among the fluorescent dyes, the group of fluorophores based on xanthene scaffolds is one of the most popular. Two

Copper-mediated arylation with arylboronic acids: Facile and modular synthesis of triarylmethanes

• H. Surya Prakash Rao and
• A. Veera Bhadra Rao

Beilstein J. Org. Chem. 2016, 12, 496–504, doi:10.3762/bjoc.12.49

• triarylmethane motif are ubiquitous and found mainly in technologically and medicinally relevant molecules like dyes [6][7][8][9], pH indicators [10][11][12], fluorescent probes [13][14][15][16][17][18] and antibacterial drugs [19]. For example, malachite green (1) is a dye, cresol red (2) is a pH indicator and

Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• -soluble cyanine/β-CD derivatives have been efficiently prepared via CuAAC under simultaneous US/MW irradiation at 75 °C for 2 h (MW 15 W and US 20 W) in good yields (23% and 33%). These dyes were used as versatile carriers for drug delivery and optical imaging. Preparation of CD-grafted materials and CD

A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

• Steven C. Zimmerman

Beilstein J. Org. Chem. 2016, 12, 125–138, doi:10.3762/bjoc.12.14

• example, one summer that process involved taking J. D. Watson’s “Molecular Biology of the Gene” [5] on the subway to a Long Island beach on weekends. The beautiful structure of DNA and its intercalation complexes of aromatic dyes were especially intriguing. In broader reading, I sought to understand

Learning from the unexpected in life and DNA self-assembly

• Jennifer M. Heemstra

Beilstein J. Org. Chem. 2015, 11, 2713–2720, doi:10.3762/bjoc.11.292

• sensors. This was surprising, as the fluorophores are small molecules attached to the termini of much larger DNA molecules. However, we found this lesson very informative, as it showed that dyes and other functional groups that we frequently append to DNA are not as innocuous as we assume them to be

• chemical reactions [4]. In the context of this project, our unexpected observation regarding the impact of dyes on DNA assembly was something that we merely needed to overcome. However, this experience provided us with an improved understanding of the function of structure-switching sensors, which has

Smart molecules for imaging, sensing and health (SMITH)

• Bradley D. Smith

Beilstein J. Org. Chem. 2015, 11, 2540–2548, doi:10.3762/bjoc.11.274

• development of squaraine rotaxanes as a novel family of deep-red fluorescent dyes with extremely high brightness and stability [35][36]. A key finding was the importance of the interlocked rotaxane structure for protecting the encapsulated squaraine from chemical attack by water. Squaraine rotaxanes can be

• ]. Nanoparticles containing these self-illuminating molecules enable high sensitivity imaging of deep-tissue target sites in living subjects [40]. A recent spin-off from the squaraine rotaxane project uses homologous croconaine dyes to absorb 800 nm laser light and cleanly convert the energy into heat without

• producing reactive singlet oxygen [41][42][43]. The dyes enable new types of nanoscale heating technologies that release sensitive payload such as dyes, drugs, oligonucleotides, or proteins. The dyes can also be loaded into nanoparticles for anticancer photothermal therapy in preclinical animal models

Syntheses of 2-substituted 1-amino-4-bromoanthraquinones (bromaminic acid analogues) – precursors for dyes and drugs

• Enas M. Malik,
• Younis Baqi and
• Christa E. Müller

Beilstein J. Org. Chem. 2015, 11, 2326–2333, doi:10.3762/bjoc.11.253

• , Postal Code 123, Muscat, Oman 10.3762/bjoc.11.253 Abstract Anthraquinone (AQ) derivatives play a prominent role in medicine and also in textile industry. Bromaminic acid (1-amino-4-bromoanthraquinone-2-sulfonic acid) is an important precursor for obtaining dyes as well as biologically active compounds

• 1-amino-2,4-dibromoanthraquinone directly from 1-aminoanthraquinone in excellent yields (94–100%) and high purities. The synthesized brominated AQs are valuable precursors for the preparation of AQ drugs and dyes. Keywords: anthraquinone; bromaminic acid; drug synthesis; dyes; intermediates

• starting material for the synthesis of biologically active AQ derivatives as well as a large number of dyes. In fact, bromaminic acid is one of the most utilized intermediates for the synthesis of AQ derivatives, including acid dyes and reactive dyes, through replacement of the C4-bromine atom by an (ar

Copper-catalyzed aerobic radical C–C bond cleavage of N–H ketimines

• Ya Lin Tnay,
• Gim Yean Ang and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2015, 11, 1933–1943, doi:10.3762/bjoc.11.209

• proposal. Next, we turned our attention to apply the present copper-catalyzed aerobic C–C bond fission process in the electrophilic cyanation of Grignard reagents. As carbonitriles are omnipresent components in various natural products, dyes and potent pharmaceutical drugs [60][61][62], new and versatile

Star-shaped tetrathiafulvalene oligomers towards the construction of conducting supramolecular assembly

• Masahiko Iyoda and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2015, 11, 1596–1613, doi:10.3762/bjoc.11.175

• functional dyes [22][23]. Furthermore, various multifunctional TTF-based supramolecular architectures have been designed and synthesized to realize molecular sensors, redox switches, multi-input systems for logic gates, electrochemically-driven conformational controls, molecular clips and tweezers, and redox

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

• , uncommon reaction sequences. Homogeneous PRCs form one class that encompasses soluble organic dyes [1] as well as transition metal complexes; particularly those of Ru and Ir. Study of the latter markedly escalated from 2008 thanks to papers from the groups of MacMillan [2], Yoon [3] and Stephenson [4]. The

• opportunity for surface modification of the semiconductors with metals or dyes to extend the capability into the visible light region. This is a step nearer to directly channeling the Sun’s energy into synthetic chemistry. Though not proven beyond doubt, the likelihood is that surface OH groups on the

Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

• Mohamed Yacine Ameur Messaoud,
• Ghenia Bentabed-Ababsa,
• Madani Hedidi,
• Aïcha Derdour,
• Floris Chevallier,
• Yury S. Halauko,
• Oleg A. Ivashkevich,
• Vadim E. Matulis,
• Laurent Picot,
• Valérie Thiéry,
• Thierry Roisnel,
• Vincent Dorcet and
• Florence Mongin

Beilstein J. Org. Chem. 2015, 11, 1475–1485, doi:10.3762/bjoc.11.160

• , vincamine, ergotamine, lysergic acid), as well as in pharmaceuticals (e.g., indomethacin, iprindole), agrochemicals (e.g., auxins, pyroquilon), and dyes and pigments (e.g., indigo, indocyanines) [1][2]. The deprotonative metallation [3][4][5][6][7] is a valuable tool for the regioselective functionalization

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• gap energy values (Eg) ranging between 2.34 and 3.21 eV. Their catalytic activities were tested for the degradation of Eriochrome Blue Black B (a model of azo dyes) in the presence of an ecological oxidant (H2O2). The efficiency of the decolorization has been confirmed via UV–visible spectroscopic

• rise to more air- and possibly water-stable catalysts [9]. Commonly, difficulties arise when trying to treat waste waters containing dyes because the dyes are recalcitrant molecules, often resistant to aerobic digestion, and stable to light, heat, and oxidizing agents [10][11]. Recently, the catalytic

• oxidation was recognized as an effective method to treat colored waters [12]. In fact, the treatment of colored waters remains a serious environmental topic. Many industries such as textile, leather and paper discharge various dyes during their processing operations [13][14]. These dyes are toxic, mutagenic

A hybrid electron donor comprising cyclopentadithiophene and dithiafulvenyl for dye-sensitized solar cells

• Gleb Sorohhov,
• Chenyi Yi,
• Michael Grätzel,
• Silvio Decurtins and
• Shi-Xia Liu

Beilstein J. Org. Chem. 2015, 11, 1052–1059, doi:10.3762/bjoc.11.118

• ]. Although devices with the most commonly used dyes based on polypyridyl transition-metal complexes show excellent photovoltaic performances with high power conversion efficiencies of over 11% [4], metal-free organic dyes have significant advantages in several aspects. These comprise for example large molar

• extinction coefficients, ease of synthesis, fine-tuning of structural and electronic properties, and low-cost production [1][2][3][4]. Particularly, the hitherto best DSSC based on organic sensitizers shows an efficiency of 10.3% [5]. Among the most efficient organic dyes are those featured with an electron

• view, can be treated as half of a TTF unit. DTF-based D–π–A sensitizers have been proven quite promising with high power conversion efficiencies of up to 8.3% [18][19]. Taking into account all these considerations, we set ourselves the synthetic task to prepare two new molecular dyes (Figure 1

A new and convenient synthetic way to 2-substituted thieno[2,3-b]indoles

• Roman A. Irgashev,
• Arseny A. Karmatsky,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2015, 11, 1000–1007, doi:10.3762/bjoc.11.112

• compounds which can be applied in organic optoelectronic materials. Indeed, we have recently reported the synthesis of novel push–pull dyes IK-1,2 based on the thieno[2,3-b]indole ring system, as a donating part of dye-sensitized solar cells [8] (Figure 1). It should be noted that thieno[2,3-b]pyrrole and

• analogues. This two-step approach provides an easy access to compounds of the family of electron-rich thieno[2,3-b]indoles, which are regarded as promising building-blocks for the development of new photo- and electrosensitive molecules, e.g., novel push–pull dyes for dye-sensitized solar cells