An easy assembled fluorescent sensor for dicarboxylates and acidic amino acids

• Xiao-bo Zhou,
• Yuk-Wang Yip,
• Wing-Hong Chan and
• Albert W. M. Lee

Beilstein J. Org. Chem. 2011, 7, 75–81, doi:10.3762/bjoc.7.11

• ) became magnetically non-equivalent. At the same time, the Ha, Hb and Hd protons of the host experienced an upfield shift of ~0.07 ppm, whereas the Hc protons were downfield shifted by 0.19 ppm. Conceivably, as a result of complexation, the spatial relationship between the mesitylene and the anthracene

Anthracene appended pyridinium amide–urea conjugate in selective fluorometric sensing of L-N-acetylvaline salt

• Kumaresh Ghosh,
• Tanmay Sarkar and
• Asoke P. Chattopadhyay

Beilstein J. Org. Chem. 2010, 6, 1211–1218, doi:10.3762/bjoc.6.139

• Kumaresh Ghosh Tanmay Sarkar Asoke P. Chattopadhyay Department of Chemistry, University of Kalyani, Kalyani-741235, India, Fax +91-33-25828282 10.3762/bjoc.6.139 Abstract A new anthracene labeled pyridinium amide–urea conjugate 1 has been designed and synthesized. The receptor shows a different

• to the charge–charge interaction and formation of unconventional hydrogen bonds with the anionic guests [27]. In order to explore this binding site for a wide range of substrates, especially for amino acid derivatives, we report here the design and synthesis of a new fluororeceptor 1 where anthracene

• -N-acetylvaline salt than with L-N-acetylalanine. This is attributed to the formation of a charge transfer complex between the excited state of anthracene and the electron deficient nitrophenyl urea during the interaction process. We believe that this characteristic feature with L-N-acetylvaline is

Conjugated polymers containing diketopyrrolopyrrole units in the main chain

• Bernd Tieke,
• A. Raman Rabindranath,
• Kai Zhang and
• Yu Zhu

Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92

• ]. The polymers consisted of dialkylated DPP units and carbazole, triphenylamine, benzo[2,1,3]thiadiazole, anthracene, or fluorene units in alternating fashion. They were prepared via Suzuki coupling, from the DPP monomers M-1 or DPP-3,6-diphenyl(4,4´-bis(pinacolato)boron ester. A number of readily

• 39 nm. The small shift of P-2 was ascribed to a large tilt angle between the π-planes of DPP and the adjacent comonomer units, in this case the anthracene unit, which strongly reduces the conjugation length [32]. EL devices prepared with P-4 exhibited an external quantum efficiency (EQE) of 0.5% and

Synthesis, electronic properties and self-assembly on Au{111} of thiolated (oligo)phenothiazines

• Adam W. Franz,
• Svetlana Stoycheva,
• Michael Himmelhaus and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2010, 6, No. 72, doi:10.3762/bjoc.6.72

• with the surface normal, and lAu–S = 2.1 Å is the Au–S bond length [57]. For φ, we refer to a recent electron spectroscopic analysis on similar aromatic systems, which determined φ = 23° for anthracene-2-thiol [58]. Using this value, we made the reasonable assumption that the Au–S–C bond is mainly

Anthracene functionalized terpyridines – synthesis and properties

• Falk Wehmeier and
• Jochen Mattay

Beilstein J. Org. Chem. 2010, 6, No. 54, doi:10.3762/bjoc.6.54

• (terpyridine)complexes 6a–b. Irradiation experiments were carried out with both the free ligands and an iron(II)-complex in order to investigate the photochemistry of the compounds. Keywords: anthracene; coordination chemistry; photochemistry; terpyridine; Introduction 2,2′:6′,2″-Terpyridines have been of

• diarylethenes [10][11]. There have also been reports about anthracene functionalized terpyridines in which an anthracene unit was used as a fluorescent sensor [12], spacer [13] or intercalator [14]. Herein we report the synthesis of two twofold anthracene functionalized terpyridines, their iron(II) complexes

• , and investigations regarding their photochemistry. Results and Discussion Synthesis of anthracene functionalized terpyridines We synthesized the terpyridine-4,4″-diacid 3, starting from methyl 2-acetylisonicotinate (1) and 4-tert-butylbenzaldehyde (2), by a one-pot combination of a Kröhnke type

9,10-Dioxa-1,2-diaza-anthracene derivatives from tetrafluoropyridazine

• Graham Pattison,
• Graham Sandford,
• Dmitrii S. Yufit,
• Judith A. K. Howard,
• John A. Christopher and
• David D. Miller

Beilstein J. Org. Chem. 2010, 6, No. 45, doi:10.3762/bjoc.6.45

• 3LE, U.K. GlaxoSmithKline R&D, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY, United Kingdom 10.3762/bjoc.6.45 Abstract Reaction of tetrafluoropyridazine with catechol gives a tricyclic 9,10-dioxa-1,2-diaza-anthracene system by a sequential nucleophilic aromatic

• substitution ring annelation process, further extending the use of perfluoroheteroaromatic derivatives for the synthesis of unusual polyfunctional heterocyclic architectures. The tricyclic scaffold reacts with amines and sodium ethoxide providing a short series of functional 9,10-dioxa-1,2-diaza-anthracene

• systems. Keywords: benzodioxinopyridazine; 9,10-dioxa-1,2-diaza-anthracene; heterocyclic synthesis; nucleophilic aromatic substitution; perfluoroheteroaromatic; tetrafluoropyrazine; Introduction Drug discovery programmes are continually searching for viable synthetic routes to highly novel classes of

Anthracene coupled adenine for the selective sensing of copper ions

• Kumaresh Ghosh and
• Tanushree Sen

Beilstein J. Org. Chem. 2010, 6, No. 44, doi:10.3762/bjoc.6.44

• Kumaresh Ghosh Tanushree Sen Department of Chemistry, University of Kalyani, Kalyani-741235, India 10.3762/bjoc.6.44 Abstract Anthracene-based adenines 1 and 2 have been designed and synthesized, and their metal ion recognition properties have been established fluorometrically. Both molecules

• exhibit Cu2+ induced ON-OFF type signaling patterns over the other representative metal ions studied. Compound 1 exhibits 97% quenching of emission in the presence of Cu2+ whilst derivative 2 shows 81% quenching under similar experimental conditions. Keywords: adenine-based anthracene; copper ion

• sensor, shown in Figure 1. In both 1 and 2, adenine is defined as the binding site, which is connected to the anthracene probe via –CH2– spacer at the different regions of adenine. In order to find out the possible site for binding of metal ions, we optimized the geometries of both 1 and 2 at AM1 level

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

• potential use of these peptide nanostructures is as pro-drugs that may be activated by a specific proteolytic enzyme to target selectively and destroy undesirable cells [190]. Kim et al. reported two bis(azacrown)anthracene derivatives 48a and 48b (Figure 30) for the recognition and detection of

• alkyldiammonium ions in ethanol or in a chloroform/methanol mixture (9:1) based on the PET principle [191]. The fluorescence of the anthracene function is quenched by the free electron pairs of the nitrogen atoms. When hydrogen bonds are formed by both nitrogen atoms to the bis-ammonium guests, the photoinduced

Templated versus non-templated synthesis of benzo-21-crown-7 and the influence of substituents on its complexing properties

• Wei Jiang and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2010, 6, No. 14, doi:10.3762/bjoc.6.14

• with the larger anthracene π-system in 5-H•PF6. Analogously, stronger binding of C7 would be expected with 7-H•PF6 as compared to 6-H•PF6. Surprisingly, the binding affinities of C7 or 4 toward anthracenyl methyl-substituted 7-H•PF6 turn out to be lower than to benzyl-substituted 6-H•PF6. There are two

• dialkylammonium guests significantly alter the binding ability. Replacing a benzyl stopper on the axle by an anthracenyl methyl group even changes the binding mode: Formation of C-H•••O hydrogen bonds is hampered for the methylene group between the anthracene and the ammonium. Compared to DB24C8, the complexing

A stable enol from a 6-substituted benzanthrone and its unexpected behaviour under acidic conditions

• Marc Debeaux,
• Kai Brandhorst,
• Peter G. Jones,
• Henning Hopf,
• Jörg Grunenberg,
• Wolfgang Kowalsky and
• Hans-Hermann Johannes

Beilstein J. Org. Chem. 2009, 5, No. 31, doi:10.3762/bjoc.5.31

• [benzo[de]anthracene-6,9′-fluoren]-7-ol (11), Bicyclo[4.3.1]decane derivative 12, and 6-(Biphenyl-2-yl)-5,6-dihydro-4H-benzo[de]anthracen-7-ol (13) The enol 4 (500 mg, 1.30 mmol) was dissolved in warm toluene (20 mL). Phosphoric acid (0.5 mL) and silica gel (1.0 g) were added and the mixture was stirred

Synthesis of rigidified flavin–guanidinium ion conjugates and investigation of their photocatalytic properties

• Harald Schmaderer,
• Mouchumi Bhuyan and
• Burkhard König

Beilstein J. Org. Chem. 2009, 5, No. 26, doi:10.3762/bjoc.5.26

• for the cycloaddition of maleimide to anthracene in toluene (Scheme 5). Table 3 summarizes the results. A significantly higher yield of the cycloaddition product was obtained after 8 h at 40 °C in the presence of compound 2 (entry 3), if compared to the control reaction (entry 6). Upon irradiation

• reaction (entry 4). Blue light irradiated flavins accelerate the anthracene maleimide cycloaddition significantly, but flavins 1 and 2 do not provide additional benefit if compared to tetraacetyl flavin 3. Conclusion We have prepared new flavin derivatives that bear an acyl guanidinium group, which is

• )2, mono-Boc guanidine, CH2Cl2, rt, 20 h, 58–82%, (iii) HCl/Et2O, CH2Cl2/CHCl3, rt, 24 h, 83–90%. Oxidative photocleavage of dibenzyl phosphate. Photoreduction of 4-nitrophenyl phosphate. Photo Diels–Alder-reaction of anthracene with N-methyl-maleinimide. Oxidative photocleavage of dibenzyl phosphate

Reversible intramolecular photocycloaddition of a bis(9-anthrylbutadienyl)paracyclophane – an inverse photochromic system. (Photoactive cyclophanes 5)

• Henning Hopf,
• Christian Beck,
• Jean-Pierre Desvergne,
• Henri Bouas-Laurent,
• Peter G. Jones and
• Ludger Ernst

Beilstein J. Org. Chem. 2009, 5, No. 20, doi:10.3762/bjoc.5.20

• cycles were recorded but the photoproduct could not so far be isolated. It occurred to us that the performance of these systems could be improved by incorporating the anthracene substrate, well known for its ability to generate definite photodimers [10][11][12][13][14][15], in the pseudo-gem positions of

• diffusion of pentane vapour. The molecular structure of 2 is presented in Figure 4. The double bonds are clearly all-trans and their average planes form twist angles with the two anthracene nuclei of 47° and 44°,respectively; the two ethylenic systems are also not parallel to each other but subtend twist

• angles of 42–43° (see Table 1). Finally, the interplanar angle between the two anthracene substrates is ca 4.5° (Table 1). Consequently, the inter-ring distance varies between 3.40 and 3.80 Å. Two lateral anthracene nuclei are thus in close proximity (see Figure 5), in which two carbons are separated by

Highly brominated anthracenes as precursors for the convenient synthesis of 2,9,10-trisubstituted anthracene derivatives

• Osman Cakmak,
• Leyla Aydogan,
• Kiymet Berkil,
• Ilhami Gulcin and
• Orhan Buyukgungor

Beilstein J. Org. Chem. 2008, 4, No. 50, doi:10.3762/bjoc.4.50

• tribromide 12 was transformed to trimethoxy compound 13 and trinitrile 14 by copper-assisted nucleophilic substitution reactions. Keywords: anthracene derivative; bromination; bromoanthracene; cyanoanthracene; methoxyanthracene; Introduction Anthracene derivatives have been extensively investigated in many

• biological systems, anthracene skeletal compounds are also useful for probing DNA cleavage [17]. Bromoanthracenes have become increasingly important in the synthesis of anthracene derivatives [18]. For example, new anthracene derivatives used as light emitting material in a non-doped organic light-emitting

• diode (OLED) were synthesized from the corresponding bromo derivatives by substitution [19][20][21][22][23]. Recently we succeeded in the bromination of anthracene to give hexabromides 3 and 4 which were used in the selective and specific preparation of anthracene oxides and anthracene derivatives

Synthesis of 2,3,6,7-tetrabromoanthracene

• Christian Schäfer,
• Friederike Herrmann and
• Jochen Mattay

Beilstein J. Org. Chem. 2008, 4, No. 41, doi:10.3762/bjoc.4.41

• . Keywords: anthracene; arenes; cyclizations; polycycles; ring closure; 2,3,6,7-tetrabromoanthracene; Introduction Anthracene and its derivatives are long known polycyclic aromatic compounds showing a high potential for use in materials science (e.g. fluorescence probing, photochromic systems

• , electroluminescence) and several reviews have been published so far [1][2][3]. Anthracenes may be readily functionalized in positions 9 and 10 due to their exceptional reactivity. The outer rings, however, can not be functionalized easily. There are some anthracene compounds available with one or two substituents at

• -cyclohexadiene as hydrogen donor. In this case, the structure and the purity of 4 were proven by NMR and high resolution mass spectrometry. The UV/VIS-spectra of 2,3,6,7-tetrabromoanthracene and anthracene in cyclohexane are shown in Figure 1. At first glance, both spectra resemble each other; however, all

The role of an aromatic group in remote chiral induction during conjugate addition of α-sulfonylallylic carbanions to ethyl crotonate

• Shlomo Levinger,
• Ranjeet Nair and
• Alfred Hassner

Beilstein J. Org. Chem. 2008, 4, No. 32, doi:10.3762/bjoc.4.32

• ]. 9-Acetylanthracene does not lend itself to the Borch reductive amination, which entails a nucleophilic addition step of ammonia (or amine) to the carbonyl function [7]. Conjugation between the anthracene nucleus and an acyl substituent at position 9 is sterically inhibited by the flanking hydrogen

• for orthogonality between the planar function and the aromatic nucleus in the nitrogen derivatives of 9-acylanthracenes has been corroborated spectroscopically (lack of conjugation in the semicarbazide and the oxime). Furthermore, steric hindrance to attack at the cyano group of anthracene-9

• anthracene) is also worth noting in this context. Restricted rotation in acylnaphthalenes has been extensively studied [11]. Amino-substituted allyl sulfones 1 were deprotonated with LDA at −78 °C in THF and the lithio derivative obtained was allowed to react for a specified time at that temperature with