Influence of perylenediimide–pyrene supramolecular interactions on the stability of DNA-based hybrids: Importance of electrostatic complementarity

• Christian B. Winiger,
• Simon M. Langenegger,
• Oleg Khorev and
• Robert Häner

Beilstein J. Org. Chem. 2014, 10, 1589–1595, doi:10.3762/bjoc.10.164

• (Table 1, hybrids 1*2 and 7*6) than hybrids containing both types of aromatic compounds. Although the actual stability of such duplexes strongly depends on several parameters like, e.g., the geometry of the building blocks and the flexibility of the linkers, a general trend can be deduced from the

Streptopyridines, volatile pyridine alkaloids produced by Streptomyces sp. FORM5

• Ulrike Groenhagen,
• Michael Maczka,
• Jeroen S. Dickschat and
• Stefan Schulz

Beilstein J. Org. Chem. 2014, 10, 1421–1432, doi:10.3762/bjoc.10.146

• compounds with bouquets composed of up to 100 different compounds [1][2][3][4][5][6]. Major volatile classes comprise aliphatic compounds derived from fatty acid metabolism, terpenes, aromatic compounds, sulfur compounds, and pyrazines [1]. Apart from pyrazines, indole, and a few strain specific compounds

• tetrasulfide (37), and S-methyl methanethiosulfonate (50). The hydroxyketones acetoin (40), and longer variants 38, 39, 41, and 42 occur often in bacteria and are precursors of alkylated pyrazines [29] like 2,5-dimethylpyrazine (44). Aldehydes, ketones, and aromatic compounds commonly found as volatiles from

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• electronegative fluorine atom is needed for the SNAr reaction to take place, even though the arenechromium complexes are already very electron-deficient aromatic compounds. The same group also developed a P-chiral ligand, QuinoxP 74, via deprotonation of chiral secondary phosphine borane 13d with n-butyllithium

Columnar/herringbone dual crystal packing of pyrenylsumanene and its photophysical properties

• Binod Babu Shrestha,
• Shuhei Higashibayashi and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2014, 10, 841–847, doi:10.3762/bjoc.10.80

• of the columns: unidirectional (Figure 1a) and opposite (Figure 1b). These columnar structures allow buckybowls to exhibit specific solid-state properties, including high electron conductivity and solid-state emission [14][15][16][17][18]. In contrast, planar π-conjugated aromatic compounds tend to

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

• reactions are fast and highly exothermic. Typically, the nitration of aromatic compounds is acid-catalyzed and it involves an electrophilic substitution where the nitronium ion (NO2+) acts as the reactive species [4][5][6]. Based on estimations of 2007 and the proposed world production capacity, the overall

• world production of nitric acid in 2012 is assumed to be close to 78 Mi TPA, of which 85% is used for the production of ammonium nitrate as fertilizer and 6% for production of nylon. The remaining 9% – that is about 8 Mi TPA – are used for the nitration of aromatics [7]. Nitro derivatives of aromatic

• compounds are used in variety of basic chemicals, specialty chemicals, and knowledge chemicals. They are also employed in dyes, perfumes, pharmaceuticals, explosives [8], intermediates, colorants, and pesticides. In general, the annual demand for nitric acid grows in the range of 3 to 6%. A large proportion

The Flögel-three-component reaction with dicarboxylic acids – an approach to bis(β-alkoxy-β-ketoenamides) for the synthesis of complex pyridine and pyrimidine derivatives

• Mrinal K. Bera,
• Moisés Domínguez,
• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 394–404, doi:10.3762/bjoc.10.37

• these enamides to 4-hydroxypyridine derivatives or to functionalized pyrimidines efficiently provided symmetrically and unsymmetrically substituted fairly complex (hetero)aromatic compounds containing up to six conjugated aryl and hetaryl groups. In addition, subsequent functionalizations of the

• -ketoenamides) are only moderate when dicarboxylic acids are used the simplicity of the processes and the diversity of the products accessible is impressive. The described methods allow the preparation of oligo(hetero)aromatic compounds not available by alternative procedures. Experimental General methods

Novel supramolecular affinity materials based on (−)-isosteviol as molecular templates

• Christina Lohoelter,
• Malte Brutschy,
• Daniel Lubczyk and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2013, 9, 2821–2833, doi:10.3762/bjoc.9.317

• significant application as receptors and chemical sensors in the detection of aromatic compounds [16][17][18][19][20]. Thus, the first artificial receptor for caffeine had been established [21][22]. The introduction of chiral information onto a supramolecular entity gave rise for enantiofacial differentiation

• ][34], compounds based on (−)-isosteviol have found application in various fields of synthetic chemistry [35], including the construction of tweezer-like supramolecular transporters for amino acids [36], chiral organocatalysts in aldol reactions [37], or the complex formation with aromatic compounds

• model compound 7 were subjected to QCM measurements in order to evaluate their properties to serve as affinity materials in the tracing of volatile aromatic compounds. For this purpose, a collection of chemically related aromatic analytes were screened. The analytes range from benzene to pseudocumene

Diastereoselectivity in the Staudinger reaction of pentafluorosulfanylaldimines and ketimines

• Alexander Penger,
• Cortney N. von Hahmann,
• Alexander S. Filatov and
• John T. Welch

Beilstein J. Org. Chem. 2013, 9, 2675–2680, doi:10.3762/bjoc.9.303

• ]. Given the unique potential of the SF5 group, the rarity of its application in medicinal or agrochemical materials may be surprising. However, synthesis of aliphatic SF5-containing building blocks (SF5-substituted aromatic compounds are more accessible) [1][6], is challenging and often beset by confusing

Gold(I)-catalyzed domino cyclization for the synthesis of polyaromatic heterocycles

• Mathieu Morin,
• Patrick Levesque and
• Louis Barriault

Beilstein J. Org. Chem. 2013, 9, 2625–2628, doi:10.3762/bjoc.9.297

• charge build-up at the cationic cyclization transition state. Substituted aromatic compounds have a fundamental importance in organic and medicinal chemistry as well as in materials. Although there are many methods to functionalize aromatic rings, one can recognize that the above transformation

• = Ph and R2 = Me) provided the corresponding benzothiophenes 12h and 12i in 91% and 87% yield, respectively. Conclusion In summary, we have developed a mild and efficient gold(I)-catalyzed 5-exo-dig polycyclization cascade to prepare an array of substituted aromatic compounds such as benzofuran

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• trifluoromethylation of aromatic compounds has been extensively reviewed in recent years by several authors [23][24][25][26][27][28][63][64]. Nevertheless, aromatic trifluoromethylations catalytic in metal are still rare. This section reviews recent advances in this area and classifies the reactions according to metal

• coworkers reported on the first Pd-catalyzed trifluoromethylation at C–H positions in aromatic compounds (Table 5) [67]. Pd(OAc)2 (10 mol %) was used as the catalyst, and Umemoto’s sulfonium tetrafluoroborate salt as the CF3 source rather than its triflate analogue. Trifluoroacetic acid and copper(II

Crystal design using multipolar electrostatic interactions: A concept study for organic electronics

• Peer Kirsch,
• Qiong Tong and
• Harald Untenecker

Beilstein J. Org. Chem. 2013, 9, 2367–2373, doi:10.3762/bjoc.9.272

• demonstrated by Watson et al. [10] with bipolar, partially fluorinated aromatic compounds, which form closely packed 1D stacks through self-complementary structure of their electrostatic potential surface. Chemically, the electrostatic potential surface can be modelled very efficiently with partially

Flow synthesis of phenylserine using threonine aldolase immobilized on Eupergit support

• Jagdish D. Tibhe,
• Hui Fu,
• Timothy Noël,
• Qi Wang,
• Jan Meuldijk and
• Volker Hessel

Beilstein J. Org. Chem. 2013, 9, 2168–2179, doi:10.3762/bjoc.9.254

• reaction [43]. The same group also investigated the effect of ring-sided substituents of benzaldehyde on the product yield, revealing that TA accepts aromatic compounds having electron withdrawing groups as a substrate [44]. Aldolases are known to be hampered by thermodynamic and kinetic limitations, such

Structure elucidation of β-cyclodextrin–xylazine complex by a combination of quantitative ¹H–¹H ROESY and molecular dynamics studies

• Syed Mashhood Ali,
• Kehkeshan Fatma and
• Snehal Dhokale

Beilstein J. Org. Chem. 2013, 9, 1917–1924, doi:10.3762/bjoc.9.226

• molecular dynamics results in vacuum though it does not fully simulate the experimental conditions. Results and Discussion 1H NMR studies Demarco and Thakkar first observed the chemical shift changes of the H-3’ and H-5’ protons, positioned inside the cavity of β-CD, in the presence of aromatic compounds

Damage of polyesters by the atmospheric free radical oxidant NO₃^•: a product study involving model systems

• Catrin Goeschen and
• Uta Wille

Beilstein J. Org. Chem. 2013, 9, 1907–1916, doi:10.3762/bjoc.9.225

• revealed that N2O5 reacts with unsaturated compounds several orders of magnitude slower than NO3• [16] and does not readily nitrate deactivated aromatic compounds in solution [17]. In all experiments we have used NO3• in excess in order to obtain sufficient amounts of material to enable product separation

• hydroxylated products of type 14 in the reaction of NO3• with aromatic compounds is unprecedented. We propose that these compounds result from hydrolysis of the corresponding nitrates 18 during work-up and/or HPLC purification. Potential pathways to the latter could involve either trapping of the radical

• isolation. However, this outcome is not unexpected, since the reactivity of NO2• is much lower than that of NO3•. In particular, the oxidation power of NO2• is not sufficient to induce ET in deactivated aromatic compounds [31]. Likewise, although O3 is a strong oxidant, it does not react via ET transfer

Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2013, 9, 1858–1866, doi:10.3762/bjoc.9.217

Gold(I)-catalyzed formation of furans from γ-acyloxyalkynyl ketones

• Marie Hoffmann,
• Solène Miaskiewicz,
• Jean-Marc Weibel,
• Patrick Pale and
• Aurélien Blanc

Beilstein J. Org. Chem. 2013, 9, 1774–1780, doi:10.3762/bjoc.9.206

• aromatic compounds. They are found in many natural products, in pharmaceutical and agrochemical compounds as well as in flavor and fragrance industries [1]. Furans are also routinely used as building blocks in organic synthesis [2][3]. Therefore, a large number of synthetic methods has been developed to

Molecular assembly of amino acid interlinked, topologically symmetric, π-complementary donor–acceptor–donor triads

• M. B. Avinash,
• K. V. Sandeepa and
• T. Govindaraju

Beilstein J. Org. Chem. 2013, 9, 1565–1571, doi:10.3762/bjoc.9.178

• (Qzz) of +18.6 B (Buckinghams), which is in the range of the explosive TNT [34]. This π-acidic behaviour of NDI is an interesting property, because most of the aromatic compounds are π-basic, viz., benzene has Qzz = −8.5 B, whereas pyrene has Qzz = −13.8 B. Thus, pyrene and NDI represent a unique D-A

True and masked three-coordinate T-shaped platinum(II) intermediates

• Manuel A. Ortuño,
• Salvador Conejero and
• Agustí Lledós

Beilstein J. Org. Chem. 2013, 9, 1352–1382, doi:10.3762/bjoc.9.153

• those reported by Baratta [39]. Low electron-count species can also be prepared by C–H bond-activation reactions from coordinatively unsaturated compounds in a way similar to the addition of H2 to Pt–Calkyl bonds mentioned above. The cyclometalated complex T5a shown in Scheme 5 reacts with aromatic

• compounds to yield the corresponding aryl complexes while keeping the unsaturated nature at the platinum atom. The complexes thus synthesized are not stabilized by agostic interactions according to spectroscopic (NMR), crystallographic and theoretical methods [28]. Spencer et al. reported that the formation

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• reported the efficient air-assisted nitration of alkanes [24] and alkyl side-chain aromatic compounds [25] by nitrogen dioxide and nitric acid, under NHPI catalysis (Scheme 8). Both HNO3 and NO2 are able to promote the formation of PINO according to path (a) and (b) reported in Scheme 9. These initiation

Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria

• Nelson L. Brock,
• Christian A. Citron,
• Claudia Zell,
• Martine Berger,
• Irene Wagner-Döbler,
• Jörn Petersen,
• Thorsten Brinkhoff,
• Meinhard Simon and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2013, 9, 942–950, doi:10.3762/bjoc.9.108

• clade within the class of alphaproteobacteria is found both in seawater and marine sediments and occurs often in association with marine algae [1]. Genome data from sequenced clade members revealed that pathways for the degradation of aromatic compounds and sulfur metabolic pathways are widespread [2

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

• Maurizio Fagnoni,
• Stefano Protti,
• Davide Ravelli and
• Angelo Albini

Beilstein J. Org. Chem. 2013, 9, 800–808, doi:10.3762/bjoc.9.91

• aromatic compounds known to participate in photosubstitution or photocatalytic alkylation reactions. It was proposed to ascertain whether these may accumulate, as often observed in electrochemistry [33][34] and by pulse radiolysis [35], but rarely in photochemistry. Results The acceptors chosen for this

High-spin intermediates of the photolysis of 2,4,6-triazido-3-chloro-5-fluoropyridine

• Sergei V. Chapyshev,
• Denis V. Korchagin,
• Patrik Neuhaus and
• Wolfram Sander

Beilstein J. Org. Chem. 2013, 9, 733–742, doi:10.3762/bjoc.9.83

• -spin intermediates formed during the photolysis of asymmetric triazide 11, providing the first information about selective photochemical decomposition of three nonequivalent azido groups in monocyclic aromatic compounds. Results and Discussion Brief UV irradiation (2 min, λ = 260–320 nm) of triazide 11

Efficient Cu-catalyzed base-free C–S coupling under conventional and microwave heating. A simple access to S-heterocycles and sulfides

• Silvia M. Soria-Castro and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2013, 9, 467–475, doi:10.3762/bjoc.9.50

• mechanism), as a “one-pot” method for the synthesis of several sulfur aromatic compounds in moderate to good yields. A common feature of these reactions concerns the formation of arylthiolate anions as intermediates, offering a viable alternative for the introduction of sulfur functionalities in aryl

Iron-containing mesoporous aluminosilicate catalyzed direct alkenylation of phenols: Facile synthesis of 1,1-diarylalkenes

• Satyajit Haldar and
• Subratanath Koner

Beilstein J. Org. Chem. 2013, 9, 49–55, doi:10.3762/bjoc.9.6

• reagents to afford 1,1-disubstituted olefins [27]. Alternatively, Friedel–Crafts-type alkenylation could be a better choice to prepare such regiospecific vinyl aromatic compounds. Yamaguchi et al. reported a direct ortho alkenylation of phenols with 1-alkynes using SnCl4 and Bu3N in acetonitrile under

Polar reactions of acyclic conjugated bisallenes

• Reiner Stamm and
• Henning Hopf

Beilstein J. Org. Chem. 2013, 9, 36–48, doi:10.3762/bjoc.9.5

• converted into 54. Proton loss of this σ-complex yields the isolated aromatic product 57 in the last step. Thermal cyclizations of tetraenes such as 51 to aromatic compounds have been reported in the literature [31]. For the interception of the cations in Scheme 11 by bromide very similar results are