Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

• Natalie Lagesse,
• Luca Pisciottani,
• Maxime Douarre,
• Pascale Godard,
• Brice Kauffmann,
• Vicente Martí-Centelles and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128

• analysis of the thread signals in the 1H NMR of the rotaxane showed a non-equivalency of both butyl chains indicating a slow rotation of the amide bond in the NMR timescale (Figure 4). One of these butyl chains is in close proximity to the macrocycle aromatic rings producing a shielding of the signals (j

Photocatalyzed syntheses of phenanthrenes and their aza-analogues. A review

• Alessandra Del Tito,
• Havall Othman Abdulla,
• Davide Ravelli,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 1476–1488, doi:10.3762/bjoc.16.123

• cyclization occurring in a biphenyl moiety or a related system containing two aromatic rings. Either carbon-centered radicals (e.g., imidoyl, α-aminoalkyl, or phenyl) or nitrogen-centered radicals (e.g., iminyl or amidyl) can be used for this purpose as shown in Figure 2. Accordingly, the azaarene may be

• (hetero)aromatic rings. Most of the protocols illustrated herein, however, involved the use of rather expensive transition-metal-based (e.g., on Ru or Ir) photocatalysts, that still represents an issue in terms of sustainability. In this context, the use of photoorganocatalysts [24] is a promising

Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

• Carlos H. Escalante,
• Eder I. Martínez-Mora,
• Carlos Espinoza-Hicks,
• Alejandro A. Camacho-Dávila,
• Fernando R. Ramos-Morales,
• Francisco Delgado and
• Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

• intermolecular interactions (NCIs) between aromatic rings (π···π) [58][59] and alkyl and aromatic ring (Csp3–H)···π stackings [59][60][61][62] are widely recognized, from both the experimental and theoretical viewpoint, as a major factor governing the conformational equilibrium, supramolecular assembly and

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

• of carboxyl groups, ketones or aldehydes, C=C double bonds, aromatic rings and ether C–O stretching bonds, respectively [65][82][115]. Changes of the surface properties due to the modification of the activated carbon samples can also be detected by FTIR measurements. Shafeeyan et al. investigated new

• ammonia due to the evolution of NH3 and HCN. Depending on the modification temperature, nitrogen is incorporated mainly to aromatic rings at higher temperatures, while less temperature-stable amide-like functionalities were formed at lower temperatures [129]. Composition of activated carbon Elemental

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• )-catalyzed oxidation of the adjacent C≡C bond, thereby allowing the isolation of the half-oxidized benzil derivative 2a. On the basis of this theoretical investigation, the unique reactivities of bistolanes with fluorinated and nonfluorinated aromatic rings toward oxidation by DMSO can be rationalized

Synthesis and properties of tetrathiafulvalenes bearing 6-aryl-1,4-dithiafulvenes

• Aya Yoshimura,
• Hitoshi Kimura,
• Kohei Kagawa,
• Mayuka Yoshioka,
• Toshiki Itou,
• Dhananjayan Vasu,
• Takashi Shirahata,
• Hideki Yorimitsu and
• Yohji Misaki

Beilstein J. Org. Chem. 2020, 16, 974–981, doi:10.3762/bjoc.16.86

• of 1,3-dithiole rings to aromatic rings appears very appealing since these allow to produce novel multistage redox systems. However, such molecules could formerly not be synthesized by conventional approaches. In 2011, a breakthrough synthesis of arylated TTF derivatives by a palladium-catalyzed

• direct C–H arylation was reported, and the structural and electrochemical properties of the products were clarified [30]. This motivated us to synthesize novel multistage redox-TTFs bearing 1,3-dithiole rings on aromatic rings, 1–3 (Figure 1). In addition, we focused on cross-conjugated systems with 1,3

• is participating in this redox process is surrounded by extended aromatic rings bearing 1,3-dithiol rings. Conclusion We have synthesized novel multistage TTF derivatives 1–4 bearing 6-aryl-1,4-dithiafulvene moieties by palladium-catalyzed direct C–H arylation. The DFT calculations revealed the

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• directly to the periphery of triptycene or via various linkers; arrays with six chromophores 3 have thus far eluded us [26][27]. While much work has been done on the functionalization of the aromatic rings of triptycene as in 2 or 3 [24][25][26][27][28][29][30], the attachment of chromophores at the

• molecule in the asymmetric unit with the bridgehead substituents being almost 180° to each other (Figure 2, for labelling see Figure S33 in Supporting Information File 1). Unlike the unsubstituted triptycene 1 crystal structure which exhibits a high degree of C–H···π interactions between the aromatic rings

• [43], there is a high degree of interdigitation between the aromatic rings of the triptycene unit (Figure 2b) akin to some triptycene-quinones [44]. This is due to two of the triptycene aromatic rings i [C8A to C8, centroid···centroid distance of 3.845(3) Å and shift distance of 1.507(5) Å] and ii

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

• Zeguo Fang,
• Nawaf Al-Maharik,
• Peer Kirsch,
• Matthias Bremer,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2020, 16, 674–680, doi:10.3762/bjoc.16.65

• core structures to enhance their LC potential. The birefringence Δn (Table 2) for compounds 8–11a was measured (Abbe refractometer). In all cases the Δn values were low, which is entirely consistent with their core aliphatic structures, unlike materials with aromatic rings. The differences for Δn for 8

Synthesis and herbicidal activities of aryloxyacetic acid derivatives as HPPD inhibitors

• Man-Man Wang,
• Hao Huang,
• Lei Shu,
• Jian-Min Liu,
• Jian-Qiu Zhang,
• Yi-Le Yan and
• Da-Yong Zhang

Beilstein J. Org. Chem. 2020, 16, 233–247, doi:10.3762/bjoc.16.25

• -dicarbonyl bidentate chelation with the active center metal, and 2) through favorable sandwich π–π stacking interactions between aromatic rings and the Phe360, Phe403 residues of the active site. Thus, 1,3-dicarbonyl and aromatic moieties are indispensable pharmacophores for potent HPPD-inhibiting compounds

• , the introduction of large groups on the benzene ring appears to be beneficial to the activity and deserves further structural optimization. The herbicidal activities of compounds containing other aromatic rings, compound II and III bearing a pyridine ring and a naphthalene ring, were examined. The

Synthesis, liquid crystalline behaviour and structure–property relationships of 1,3-bis(5-substituted-1,3,4-oxadiazol-2-yl)benzenes

• Afef Mabrouki,
• Malek Fouzai,
• Armand Soldera,
• Abdelkader Kriaa and
• Ahmed Hedhli

Beilstein J. Org. Chem. 2020, 16, 149–158, doi:10.3762/bjoc.16.17

• core, the obtained compounds do not exhibit mesomorphism, only crystal–isotropic transitions were observed [26]. The absence of mesophases is mainly due to the strong bend (134°) between the aromatic rings, which disturbs the linear shape of the whole molecule [27]. Herein we describe the synthesis and

• compounds 2 and 4 is constituted by a rigid core (three aromatic rings) to which are attached the terminal chains. Based on this structure, some liquid crystalline mesophases were expected. Differential scanning calorimetry (DSC), polarized optical microscopy (POM) and X-ray diffraction pattern analysis

The interaction between cucurbit[8]uril and baicalein and the effect on baicalein properties

• Xiaodong Zhang,
• Jun Xie,
• Zhiling Xu,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 71–77, doi:10.3762/bjoc.16.9

• ) was a simple superposition of BALE (a) and Q[8] (b), there was no interaction observed in the physical mixture. When compared to spectra (c) and (d), there were two absorption peaks observed at ≈3030 cm−1 corresponding to the stretching vibration of the two aromatic rings in BALE, but the complexes

Influence of the cis/trans configuration on the supramolecular aggregation of aryltriazoles

• Sara Tejera,
• Giada Caniglia,
• Rosa L. Dorta,
• Andrea Favero,
• Javier González-Platas and
• Jesús T. Vázquez

Beilstein J. Org. Chem. 2019, 15, 2881–2888, doi:10.3762/bjoc.15.282

• stacking interactions, in addition to hydrogen bonding, with the aromatic rings adopting a high degree of parallelism, as seen in crystal packings and ECD data. Furthermore, π–bromine interactions between the bromine atom of the aryl substituents and the triazole units might also contribute to an overall

• ) and its X-ray analysis was not accurate enough to resolve its structure. However, its crystal packing (Figure 5) deserves discussion. As with compound 12, this packing revealed a number of π–bromine interactions [19], together with a high degree of π–π stacking interactions between the aromatic rings

Carbazole-functionalized hyper-cross-linked polymers for CO₂ uptake based on Friedel–Crafts polymerization on 9-phenylcarbazole

• Dandan Fang,
• Xiaodong Li,
• Meishuai Zou,
• Xiaoyan Guo and
• Aijuan Zhang

Beilstein J. Org. Chem. 2019, 15, 2856–2863, doi:10.3762/bjoc.15.279

• . Chemical structure analysis FTIR spectra were measured to verify the structure of HCPs (Figure 1). The peak at 3100–3000 cm−1 correspond to the C–H stretching vibrations of the aromatic rings, which declined obviously in P1–P5 compared to monomer 9-PCz. The peak of the disubstituted phenyl ring in the 9

Photoreversible stretching of a BAPTA chelator marshalling Ca²⁺-binding in aqueous media

• Aurélien Ducrot,
• Arnaud Tron,
• Robin Bofinger,
• Ingrid Sanz Beguer,
• Jean-Luc Pozzo and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273

• cis and trans-forms [33][34]. Herein we describe a BAPTA host molecule 1, with an azobenzene moiety integrated in the tether linking both aromatic rings, as illustrated in Figure 1. The principle goal of the current work, with a long-term view of interfacing biological systems, was the development of

An improved, scalable synthesis of Notum inhibitor LP-922056 using 1-chloro-1,2-benziodoxol-3-one as a superior electrophilic chlorinating agent

• Nicky J. Willis,
• Elliott D. Bayle,
• George Papageorgiou,
• David Steadman,
• Benjamin N. Atkinson,
• William Mahy and
• Paul V. Fish

Beilstein J. Org. Chem. 2019, 15, 2790–2797, doi:10.3762/bjoc.15.271

• yields of the desired product 7 (ca. 15–32%) due to competing ring opening reactions of the 7-cyclopropyl group (Scheme 2). Clearly, a better procedure was required. A large number of electrophilic chlorinating reagents for the direct chlorination of aromatic rings have been reported [17]. Recently, Xue

A combinatorial approach to improving the performance of azoarene photoswitches

• Joaquin Calbo,
• Aditya R. Thawani,
• Rosina S. L. Gibson,
• Andrew J. P. White and
• Matthew J. Fuchter

Beilstein J. Org. Chem. 2019, 15, 2753–2764, doi:10.3762/bjoc.15.266

• applications. Experimental Computational details. Theoretical calculations were performed using the Gaussian 16 (revision A03) suite of programs [36]. Several rotational conformers of the studied compounds are available due to free rotation of the aromatic rings along single bonds linked to the azo bridge. All

A toolbox of molecular photoswitches to modulate the CXCR3 chemokine receptor with light

• Xavier Gómez-Santacana,
• Sabrina M. de Munnik,
• Tamara A. M. Mocking,
• Niels J. Hauwert,
• Shanliang Sun,
• Prashanna Vijayachandran,
• Iwan J. P. de Esch,
• Henry F. Vischer,
• Maikel Wijtmans and
• Rob Leurs

Beilstein J. Org. Chem. 2019, 15, 2509–2523, doi:10.3762/bjoc.15.244

• latter one. One of the main reasons is that an azobenzene has a relatively simple structure that can resemble various biaryl moieties of bioactive compounds: two aromatic rings linked with a bridge (e.g., amide, ether, alkane or alkyne) [8]. In the case of azobenzene the bridge is a diazene group (also

• alignment between trans-2a and the agonist 1e (Figure 2B), since the planar azobenzene is partially overlapping with the biaryl moiety. However, the two aromatic rings of both compounds can evidently not be in exactly the same plane because the azobenzene moiety is planar while the tilting of the dihedral

• -isomer, but it should be complemented with other strategies to further increase intrinsic activity. Substituent effects on the outer ring One of the postulated contributors to the CXCR3 agonism effect of parent biaryls such as 1d and 1e is the increased π-electron density of the aromatic rings [24]. A

Combining the Ugi-azide multicomponent reaction and rhodium(III)-catalyzed annulation for the synthesis of tetrazole-isoquinolone/pyridone hybrids

• Gerardo M. Ojeda,
• Prabhat Ranjan,
• Pavel Fedoseev,
• Lisandra Amable,
• Upendra K. Sharma,
• Daniel G. Rivera and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 2447–2457, doi:10.3762/bjoc.15.237

• synthesis of isoquinolones using an N-methoxyamide as directing group for the ortho-position and alkynyl bromide to achieve the regioselective cyclization (Scheme 1B) [31]. In parallel, our group has developed Ru(II) and Rh(III)-catalyzed inter- and intramolecular annulations of aromatic rings with alkynes

• explored with substrates bearing acyl groups other than benzoyl (Scheme 5). Compounds incorporating acrylamidomethyltetrazole fragments reacted with diphenylacetylene to form the tetrazole/pyridone hybrids 5a–c in good yields. In addition, very complex hybrid compounds based on heterocyclic, fused aromatic

• rings, such as furan, benzofuran, pyrrole, benzopyrrole, thiophene, benzothiophene and naphthalene were also successfully synthesized (5d–l) in moderate to very good yields. The exceptions were the cases of indolopyridone 5i and thiazolopyridone 5k, the latter one could not be obtained even after many

Effect of ring size on photoisomerization properties of stiff stilbene macrocycles

• Sandra Olsson,
• Óscar Benito Pérez,
• Magnus Blom and
• Adolf Gogoll

Beilstein J. Org. Chem. 2019, 15, 2408–2418, doi:10.3762/bjoc.15.233

• of the macrocyclic stiff stilbene diethers, a conformational analysis was undertaken (Figure 6). According to X-ray crystallography, in compound (E)-7 (Scheme 4) the aromatic rings of the two indane units are in the same plane (dihedral angle 180°), whereas in (Z)-7 this angle is 9.1° [21]. In the

• reaction (Figure S47, Supporting Information File 1). The differences in ring strain between the E- and Z-isomers show an exponential correlation to the linker length. Conformer ensembles for the macrocyclic stiff stilbene diethers 1a–d. Dihedral angles between the two aromatic rings are given in

Functionalization of 4-bromobenzo[c][2,7]naphthyridine via regioselective direct ring metalation. A novel approach to analogues of pyridoacridine alkaloids

• Benedikt C. Melzer,
• Alois Plodek and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2304–2310, doi:10.3762/bjoc.15.222

• , which undergo rearomatization as described above (Figure 2B). 4-Bromo-5-(methoxycarbonyl)benzo[c][2,7]naphthyridine generated this way gave, after Suzuki cross-coupling at C-4, intermediates for the synthesis of analogues of ascididemin (2) [16]. Introduction of (hetero)aromatic rings bearing ester

Click chemistry towards thermally reversible photochromic 4,5-bisthiazolyl-1,2,3-triazoles

• Chenxia Zhang,
• Kaori Morinaka,
• Mahmut Kose,
• Takashi Ubukata and
• Yasushi Yokoyama

Beilstein J. Org. Chem. 2019, 15, 2161–2169, doi:10.3762/bjoc.15.213

• among the photochromic families [1][2][3]. They are known to show thermally irreversible photochromism. However, some of them are thermally reversible [4]: (1) when the aromatic stabilization energy of the aromatic rings is large [5]; (2) when the substituent groups on the ring-closing carbon atoms are

• related families of diarylethenes, are largely thermally reversible [10][12] although some are irreversible when the aromatic stabilization energy of the aromatic rings is small [11]. Their syntheses are usually carried out by the sequential construction of the central aromatic ring at the final stage [10

• ] or the introduction of two aromatic rings to the central aromatic ring [11]. If the construction of three contiguous aromatic-ring arrays can be easily achieved, a new and facile synthesis method for the photochromic family which undergoes 6π-electrocyclization can be realized [13]. Early in the 21st

Multiple threading of a triple-calix[6]arene host

• Veronica Iuliano,
• Roberta Ciao,
• Emanuele Vignola,
• Carmen Talotta,
• Patrizia Iannece,
• Margherita De Rosa,
• Annunziata Soriente,
• Carmine Gaeta and
• Placido Neri

Beilstein J. Org. Chem. 2019, 15, 2092–2104, doi:10.3762/bjoc.15.207

• at 3.44/4.32, 3.39/4.22, and 3.58/4.66 ppm which were 1J correlated with carbon resonances at 27.7, 27.9, and 29.1 ppm, respectively, attributable to ArCH2Ar groups of calix[6]-wheels between syn oriented aromatic rings. Consequently, the three calix[6]-wheels in (7+)36 adopt a cone conformation

• evidences for the formation of the (4+)36 pseudo[4]rotaxanes was obtained by a 1H NMR study (Figure 8d). A careful analysis of the ArCH2Ar region of these spectra evidenced again a syn orientation of the aromatic rings of calix[6]-wheels corresponding to a cone conformation, which was also confirmed by the

Characterization of two new degradation products of atorvastatin calcium formed upon treatment with strong acids

• Jürgen Krauß,
• Monika Klimt,
• Markus Luber,
• Peter Mayer and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2085–2091, doi:10.3762/bjoc.15.206

• concentrated sulfuric acid, lactonization/dehydration is accompanied by complete loss of the carboxanilide residue to give pyrrole 7. Complete one-step removal of carboxamide residues from aromatic rings has been observed before in investigations of fragmentations of protonated species in mass spectrometry [21

Synthesis and anion binding properties of phthalimide-containing corona[6]arenes

• Meng-Di Gu,
• Yao Lu and
• Mei-Xiang Wang

Beilstein J. Org. Chem. 2019, 15, 1976–1983, doi:10.3762/bjoc.15.193

• heteroatoms and meta-(het)arenes in an alternative manner. Because of the interplay between heteroatoms and aromatic rings, heteracalixaromatics possess versatile molecular recognition properties and have found wide supramolecular applications. Very recently, we have devised coronarenes [22] simply through

• electrochemical result indicated the occurrence of electronic communication between aromatic rings. The potential for the first redox process (−811 mV) obtained from CV and DPV revealed the electron deficiency of the macrocycle. The resulting electron-deficient O6-corona[3]arene[3]tetrazines prompted us to

Installation of -SO₂F groups onto primary amides

• Jing Liu,
• Shi-Meng Wang,
• Njud S. Alharbi and
• Hua-Li Qin

Beilstein J. Org. Chem. 2019, 15, 1907–1912, doi:10.3762/bjoc.15.186

• excellent isolated yields. Both electron-withdrawing groups, such as halogen atoms (1b–d, 1j, 1m, and 1n), NO2 (1e, 1k) and CF3 (1f), and electron-donating groups, such as Me (1g, 1l, and 1o), tert-butyl (1h) and 2-naphthyl (1i) on the aromatic rings, were well tolerated under the optimized conditions. It