Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• be realized by totally blocking the structure, what was done with B9 and B10 in which two of the three aromatic rings of triphenylamine were connected to the boron center [39]. By elongating the π-conjugation of the electron-donating group in B10 compared to B9, a more delocalized HOMO level could be

• blue TADF emitters can be cited, the molecules differing by the strategy used to connect the donor(s) to triazine. However, contrarily to azasiline that possesses a six-membered central ring, carbazole only possesses a five-membered central ring, inducing a deviation of the two adjacent aromatic rings

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

• duplexes and shows a large fluorescence enhancement upon binding [158]. PNA–DNA hybridization facilitates the binding of TO to the PNA–DNA duplexes, resulting in a fluorescence enhancement due to the increased co-planarity and restricted motion of the two conjugated aromatic rings in the TO (Figure 19

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• (CF3SO2)2Zn, which demonstrated great efficiency in introducing the CF3 moiety on (hetero)aromatic rings [34]. Trifluoromethylation of olefins: In 2005, Vogel and co-workers showed that terminal alkenes could be trifluoromethylated by means of CF3SO2Cl via a palladium-catalysed desulfitative Mizoroki–Heck

Development of a fluorogenic small substrate for dipeptidyl peptidase-4

• Futa Ogawa,
• Masanori Takeda,
• Kanae Miyanaga,
• Keita Tani,
• Ryuji Yamazawa,
• Kiyoshi Ito,
• Atsushi Tarui,
• Kazuyuki Sato and
• Masaaki Omote

Beilstein J. Org. Chem. 2017, 13, 2690–2697, doi:10.3762/bjoc.13.267

• probes can act as good sensors for enzymes but the fluorophore unit is usually large because fused aromatic rings and an elongated π-conjugated system are necessary to impart appropriate fluorescent properties to the probe [14]. The molecular size of the fluorescent probe is therefore large, which is

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• S15–S19 in Supporting Information File 1. Raman spectra of all studied compounds, the alkyne 4 and the isolated products 5–8, are characterized by strong bands assigned to various vibrations of aromatic rings (Figure 1 and Supporting Information File 1, Table S1). Dried aryl azides were excluded from

Curcuminoid–BF₂ complexes: Synthesis, fluorescence and optimization of BF₂ group cleavage

• Henning Weiss,
• Jeannine Reichel,
• Helmar Görls,
• Kilian Rolf Anton Schneider,
• Mathias Micheel,
• Michael Pröhl,
• Michael Gottschaldt,
• Benjamin Dietzek and
• Wolfgang Weigand

Beilstein J. Org. Chem. 2017, 13, 2264–2272, doi:10.3762/bjoc.13.223

• is in the more favoured anti/anti conformation (Figure 1b) with the torsion angles only slightly differing from the ideal 60° or 180°, respectively. The aromatic rings are almost coplanar with the backbone. In both cases, one of the longer side chains lays mostly within the molecule plane, while the

Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound

• Joana M. Pais,
• Maria João Barroca,
• Maria Paula M. Marques,
• Filipe A. Almeida Paz and
• Susana S. Braga

Beilstein J. Org. Chem. 2017, 13, 2138–2145, doi:10.3762/bjoc.13.212

• such as the carbonyl group or the vibrational modes of the aromatic ring. In the γ-CD·fisetin compound the most relevant shifts are associated with the stretching modes of the aromatic rings, as shown in Table 1 (note: for a full list of vibrational bands, see the experimental section). The observation

Novel approach to hydroxy-group-containing porous organic polymers from bisphenol A

• Tao Wang,
• Yan-Chao Zhao,
• Li-Min Zhang,
• Yi Cui,
• Chang-Shan Zhang and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 2131–2137, doi:10.3762/bjoc.13.211

• that are enhanced by weak supramolecular interactions with C–H atoms on the aromatic rings of the polymers [38]. The isosteric heat of adsorption for carbon dioxide is calculated from adsorption data collected at 273 and 298 K using a virial method and the Clausius–Clapeyron equation [39] (Supporting

Complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives

• Leonid S. Kikot',
• Catherine Yu. Kulygina,
• Alexander Yu. Lyapunov,
• Svetlana V. Shishkina,
• Roman I. Zubatyuk,
• Tatiana Yu. Bogaschenko and
• Tatiana I. Kirichenko

Beilstein J. Org. Chem. 2017, 13, 2056–2067, doi:10.3762/bjoc.13.203

• complexation constant of the clip 6 with paraquat (7), which was: lgK = 1.46 ± 0.01 (−ΔG = 1.96 ± 0.02 kcal/mol). The complex of clip 6 with paraquat (7) may be stabilized through π–π stacking interactions of the electron-deficient aromatic rings of paraquat and the electron donating veratrol fragments of the

p-tert-Butylthiacalix[4]arenes functionalized by N-(4’-nitrophenyl)acetamide and N,N-diethylacetamide fragments: synthesis and binding of anionic guests

• Alena A. Vavilova and
• Ivan I. Stoikov

Beilstein J. Org. Chem. 2017, 13, 1940–1949, doi:10.3762/bjoc.13.188

• containing only one amide fragment binds to F−, CH3CO2− and H2PO4− ions. Probably, the aromatic rings of the macrocycle with free phenolic groups are arranged in such a manner that the hydroxy groups are located near the amide thereby forming a cavity complementary to the anions studied. In this case

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

• ). However, NCS-cericammonium nitrate (CAN) successfully yielded mono-chlorinated products [88]. Consecutively, the same group reported metal-free oxidative iodination of electron rich aromatic rings with molecular iodine and oxone (Scheme 25) [98]. This method proved to be highly chemoselective and no

Accessing simply-substituted 4-hydroxytetrahydroisoquinolines via Pomeranz–Fritsch–Bobbitt reaction with non-activated and moderately-activated systems

• Marco Mottinelli,
• Mathew P. Leese and
• Barry V. L. Potter

Beilstein J. Org. Chem. 2017, 13, 1871–1878, doi:10.3762/bjoc.13.182

• . Compound 18 (Scheme 7) was generated via a double reductive amination, in analogy to the syntheses of compounds 9a–q. Because none of the aromatic rings contained any activating group, the cyclization was performed with 70% HClO4 as catalyst. However, in the experimental conditions used it was not possible

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• were screened with electron-donating and electron-withdrawing groups attached to aromatic rings. The reactions were performed in a 1:1 stoichiometry by manual grinding in a mortar and by automated ball milling in a laboratory mixer mill. Also, the performance of solvent-free or neat grinding was

Inclusion complexes of β-cyclodextrin with tricyclic drugs: an X-ray diffraction, NMR and molecular dynamics study

• Franca Castiglione,
• Fabio Ganazzoli,
• Luciana Malpezzi,
• Andrea Mele,
• Walter Panzeri and
• Giuseppina Raffaini

Beilstein J. Org. Chem. 2017, 13, 714–719, doi:10.3762/bjoc.13.70

• formulae and atom numbering of cyclobenzaprine (1, left) and amitriptyline (2, right). E and Z symbols are arbitrarily introduced to identify the two aromatic rings. Left: Job’s plot for H3’ chemical shift variations of the complex β-CD/1. Right: Job’s plot for H11 (see Figure 1 for atom numbering

Synthesis and optical properties of new 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles

• Anastasia S. Kostyuchenko,
• Tatyana Yu. Zheleznova,
• Anton J. Stasyuk,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2017, 13, 313–322, doi:10.3762/bjoc.13.34

• ) The ethyl esters of 2,2'-bithiophenes 7 having no (7a), an alkyl (7b), or a thienyl (7c) substituent in the C-5' position can be easily obtained by this method. On the other hand, the substitution of the thiophene ring with phenyl or fused aromatic rings is much more challenging and requires the

Spectral and DFT studies of anion bound organic receptors: Time dependent studies and logic gate applications

• Srikala Pangannaya,
• Neethu Padinchare Purayil,
• Shweta Dabhi,
• Venu Mankad,
• Prafulla K. Jha,
• Satyam Shinde and
• Darshak R. Trivedi

Beilstein J. Org. Chem. 2017, 13, 222–238, doi:10.3762/bjoc.13.25

• was found that there were no conformational changes observed in receptors R1 and R2 in the presence of anions indicating the structural stability of the receptor–anion complex. The results show that the HOMOs and LUMOs are spread over both aromatic rings due to the presence of the electron-withdrawing

Phosphated cyclodextrins as water-soluble chiral NMR solvating agents for cationic compounds

• Cira Mollings Puentes and
• Thomas J. Wenzel

Beilstein J. Org. Chem. 2017, 13, 43–53, doi:10.3762/bjoc.13.6

• cationic form were individually tested with six different P-CDs at cyclodextrin concentrations of 5, 10 and 20 mM. All substrates, except for 14, have aromatic rings in their structures. Previous studies [21][31][32] and observations made herein with the P-CDs indicate that host–guest complexes through

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

• Pavel Nagorny and
• Zhankui Sun

Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283

• acceptors and also act as electron-withdrawing substituents when attached to other aromatic rings thus enhancing benzene’s ring C–H hydrogen bonding [29][30][31]. Recent studies by the Flood group and the Craig group suggested that receptors containing arylated 1,2,3-triazoles could form stable

Synthesis of spiro[isoindole-1,5’-isoxazolidin]-3(2H)-ones as potential inhibitors of the MDM2-p53 interaction

• Salvatore V. Giofrè,
• Santa Cirmi,
• Raffaella Mancuso,
• Francesco Nicolò,
• Giuseppe Lanza,
• Laura Legnani,
• Agata Campisi,
• Maria A. Chiacchio,
• Michele Navarra,
• Bartolo Gabriele and
• Roberto Romeo

Beilstein J. Org. Chem. 2016, 12, 2793–2807, doi:10.3762/bjoc.12.278

• moiety. The possibility, in the endo TSs, of stacking interactions between aromatic rings, as hypothesized in the literature [45], was taken into account, but the corresponding geometries are too high in energy and evolve to the TSs reported in Figure 5. The profiles of the four reactions are shown in

Continuous-flow synthesis of primary amines: Metal-free reduction of aliphatic and aromatic nitro derivatives with trichlorosilane

• Riccardo Porta,
• Alessandra Puglisi,
• Giacomo Colombo,
• Sergio Rossi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2016, 12, 2614–2619, doi:10.3762/bjoc.12.257

• aromatic rings followed by reduction is the most classical entry for the preparation of anilines [1][2]. Lately, also aliphatic nitro derivatives have become more and more popular: a wide variety of highly functionalized and chiral aliphatic nitro compounds, precursors of the corresponding chiral amines

Facile synthesis of indolo[3,2-a]carbazoles via Pd-catalyzed twofold oxidative cyclization

• Chao Yang,
• Kai Lin,
• Lan Huang,
• Wei-dong Pan and
• Sheng Liu

Beilstein J. Org. Chem. 2016, 12, 2490–2494, doi:10.3762/bjoc.12.243

• substituents to aromatic rings was also inconvenient. It could still be necessary to exploit more practical methods and economic procedures to assemble these polycyclic molecules. In this paper, we describe a concise, 3 to 4 steps procedure for the synthesis of indolo[3,2-a]carbazoles via palladium-catalyzed

• materials. The operational simplicity combined with the convenience for introducing substituents to the aromatic rings makes this method useful. Natural indolo[3,2-a]carbazole alkaloids. Retrosynthetic analysis of indolo[3,2-a]carbazoles. Reagents and conditions: (a) H2SO4, MeOH; (b) Ar-NH2, Pd(OAc)2, BINAP

Hydroxy-functionalized hyper-cross-linked ultra-microporous organic polymers for selective CO₂ capture at room temperature

• Partha Samanta,
• Priyanshu Chandra and
• Sujit K. Ghosh

Beilstein J. Org. Chem. 2016, 12, 1981–1986, doi:10.3762/bjoc.12.185

• two hydroxy-functionalised hyper-cross-linked microporous organic polymers for selective CO2 capture at room temperature. Both compounds (HCP-91 and HCP-94) were synthesized via hyper-cross-linked C–C coupling of hydroxyl-functionalised aromatic rings by using a Friedel–Craftys reaction. At different

Experimental and theoretical insights in the alkene–arene intramolecular π-stacking interaction

• Valeria Corne,
• Ariel M. Sarotti,
• Carmen Ramirez de Arellano,
• Rolando A. Spanevello and
• Alejandra G. Suárez

Beilstein J. Org. Chem. 2016, 12, 1616–1623, doi:10.3762/bjoc.12.158

• aromatic rings. This can be useful in several fields, such as supramolecular chemistry, biology and material science and, in particular, in the area of asymmetric synthesis for the rational design of new elements of stereocontrol. Intramolecular aryl–vinyl π-stacking interaction of a levoglucosenone

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

• Tai Nguyen Van,
• Audrey Hospital,
• Corinne Lionne,
• Lars P. Jordheim,
• Charles Dumontet,
• Christian Périgaud,
• Laurent Chaloin and
• Suzanne Peyrottes

Beilstein J. Org. Chem. 2016, 12, 1476–1486, doi:10.3762/bjoc.12.144

• , the NOESY spectrum showed correlation between the H5 of the triazole ring and the aromatic proton in ortho (Ho), whereas rotation about the C–C bond linking the triazole and the aromatic rings would lead to the disappearance of this correlation peak. In addition, the HMBC spectrum is showing only one

• formation of a strong H-bond and the C–C bond linking the triazole and the aromatic rings is free to rotate. To our surprise, a cross-peak between the H5 of the triazole and the H3’ was observed (as well as with the anomeric proton), indicating that both syn- and anti-conformers may be present. Enzyme

Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization

• Barry M. Trost,
• Michael C. Ryan and
• Meera Rao

Beilstein J. Org. Chem. 2016, 12, 1136–1152, doi:10.3762/bjoc.12.110

• could also be isolated with similar results, although the catalyst loading for this substrate had to be increased to 7.5 mol %. This is most likely due to the tendency of ruthenium to coordinate to certain aromatic rings in a η6 fashion. There were a few substrate classes that were not amenable to redox

• , we decided to try the same reactions in acetone. Pleasingly, exceptional yields and enantioselectivities of 37 and 39 were obtained in this solvent, surpassing those obtained for 35. Catalyst 1 exhibits excellent functional group compatibility. Substrates containing remote electron-neutral aromatic

• rings 40, alkenes 42, and alkynes 44 are all tolerated and remain intact under the reaction conditions. The reaction can also tolerate branching at the internal position of the pendant olefin, as polycyclic 46 and 48 displayed excellent enantiomeric ratios. It is also important to point out that no ring