Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[b]quinolizinium derivatives by Palladium-mediated cross-coupling reactions

• Siva Sankar Murthy Bandaru,
• Darinka Dzubiel,
• Heiko Ihmels,
• Mohebodin Karbasiyoun,
• Mohamed M. A. Mahmoud and
• Carola Schulzke

Beilstein J. Org. Chem. 2018, 14, 1871–1884, doi:10.3762/bjoc.14.161

• aromatic character of the substituent and its engagement in the π···π interaction also brings the two phenyl rings of adjacent benzo[b]quinolizinium moieties in close proximity, which can now also interact in an off-set π···π fashion. The contribution of the charge repulsion has, hence, to be less

• . Notably, for 2b the phenyl to phenyl π···π interaction of one molecule is not with the same neighbor as the π···π donor–acceptor attraction between the phenyl and pyridinium rings. Therefore, these two distinct π-system-based attractions alternate and form infinite chains of molecules roughly protruding

Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2698–2709, doi:10.3762/bjoc.13.268

• , indeed, the inclusion seems controlled by a fine compromise between different factors. Two main driving forces of the inclusion process can be identified, namely: i) π–π interaction between the aromatic moiety of the guest and the host cavity, as accounted for by the scarce or negligible affinity

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• and B) are 61.1(1)° and 66.8(1)°, respectively (Figure 2, left part). Interestingly, the crystal structure of 5 shows centrosymmetric dimers, formed by a close π–π interaction of the planar naphthyl moieties (Figure 2, right part). The intermolecular distance of the naphthalene moieties of the two

• molecules accounts to 3.435(7) Å. This intermolecular plane distance of the two adjacent naphthyl moieties (C2–C11) must be understood as a π–π interaction of two fused aromatic systems [51]. The twist angle of the attached phenyl substituent (ring B) of the asymmetric unit of the crystal structure 6 were

Regioselective (thio)carbamoylation of 2,7-di-tert-butylpyrene at the 1-position with iso(thio)cyanates

• Anna Wrona-Piotrowicz,
• Marzena Witalewska,
• Janusz Zakrzewski and
• Anna Makal

Beilstein J. Org. Chem. 2017, 13, 1032–1038, doi:10.3762/bjoc.13.102

• , for the reaction with p-methoxyphenyl isothiocyanate we were able to obtain, by crystallization, the major product, C(1)-substituted thioamide 3n, contaminated with only ≈5% of its C4-substituted counterpart. We tentatively explain this poorer regioselectivity by possible π–π interaction of pyrene

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

• of equilibriums of at least four different conformations: π-stacked and face-to-edge, each of them in an s-cis/s-trans conformation. The results show that the stabilization produced by the π–π interaction makes the π-stacked conformation predominant in solution and this stabilization is slightly

• planned to synthesize the acrylic esters, structurally related to the previously reported acrylate, with CF3 and OMe groups in the para position of the phenoxy group as representative electron-withdrawing and releasing groups, respectively. The π–π interaction was studied by combining experimental

• complexes in s-cis conformation, the π–π interaction energy computed at the M06-2X/6-31+G(d) level is −7.2 kcal/mol for 7 + 8, −6.9 kcal/mol for 7 + 9 and −6.5 kcal/mol for 7 + 10 (similar values were computed for 7 in its s-trans conformation, see Supporting Information File 1). Similar trends were found

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

Are D-manno-configured Amadori products ligands of the bacterial lectin FimH?

• Tobias-Elias Gloe,
• Insa Stamer,
• Cornelia Hojnik,
• Tanja M. Wrodnigg and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2015, 11, 1096–1104, doi:10.3762/bjoc.11.123

• has a slightly higher inhibitory power than the Amadori product 10, having a phenyl-containing aglycone. This again shows, that the tilted complexation mode apparently compromises the possibility of favorable π–π interaction. Conclusion The Amadori rearrangement has the potential as a straight forward

A one-pot multistep cyclization yielding thiadiazoloimidazole derivatives

• Debabrata Samanta,
• Anup Rana,
• Jan W. Bats and
• Michael Schmittel

Beilstein J. Org. Chem. 2014, 10, 2989–2996, doi:10.3762/bjoc.10.317

• dihedral angles in red (unit: deg). (c) represents the unit cell packing (Z = 4) showing the π···π interaction distances. Optimized structures of 3, TS3→5‡ and 5 at B3LYP/6-31+G*. Free energies are reported in kcal mol−1 at 25 °C and distances are shown in angstrom (italics). Optimized geometries of 9‡ and

Molecular ordering at electrified interfaces: Template and potential effects

• Thanh Hai Phan and
• Klaus Wandelt

Beilstein J. Org. Chem. 2014, 10, 2243–2254, doi:10.3762/bjoc.10.233

• +• species on Cl/Cu(111). Both the individual monocation radicals as well as the stripe propagation direction are aligned in directions, molecules in adjacent rows being rotated by 120°. The intermolecular distance of 0.43 nm within the rows, though still consistent with π–π interaction, equals precisely

Triphenylene discotic liquid crystal trimers synthesized by Co₂(CO)₈-catalyzed terminal alkyne [2 + 2 + 2] cycloaddition

• Bin Han,
• Ping Hu,
• Bi-Qin Wang,
• Carl Redshaw and
• Ke-Qing Zhao

Beilstein J. Org. Chem. 2013, 9, 2852–2861, doi:10.3762/bjoc.9.321

• polymers, the most important parameter in determining the device performance, as the discotic unites can still self-assemble to higher order through the π–π interaction. In addition, DLC oligomers similar to polymers can be processed on flexible substrates by spin-casting, screen printing, doctor-blading

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• single crystal X-ray structure of carmegliptin bound in the human DPP-4 active site has been published indicating how the fluoromethylpyrrolidone moiety extends into an adjacent lipophilic pocket [81]. Additional binding is provided by π–π interaction between the aromatic substructure and an adjacent

Ring-opening reaction of 2,5-dioctyldithieno[2,3-b:3',2'-d]thiophene in the presence of aryllithium reagents

• Hao Zhong,
• Jianwu Shi,
• Jianxun Kang,
• Shaomin Wang,
• Xinming Liu and
• Hua Wang

Beilstein J. Org. Chem. 2013, 9, 767–774, doi:10.3762/bjoc.9.87

• ) of 55.4° and a dihedral angle of 56.1°. The pyrenylsulfanyl group is not coplanar to the neighboring thiophene ring with a dihedral angle of 79.5° and a torsion angle (C5–C6–S2–C10) of 89.7°. There are short contacts of hydrogen bonding found in the crystal packing. However, no π–π interaction was

Double N-arylation reaction of polyhalogenated 4,4’-bipyridines. Expedious synthesis of functionalized 2,7-diazacarbazoles

• Mohamed Abboud,
• Emmanuel Aubert and
• Victor Mamane

Beilstein J. Org. Chem. 2012, 8, 253–258, doi:10.3762/bjoc.8.26

• stacking, forming infinite columns in which molecules interact through diazacarbazole moieties (interplanar distances are 3.558 Å for 3b, 3.270 Å and 3.404 Å for 12c). The methoxyphenyl group is also involved in this π–π interaction in 3b (interplanar distance of 3.415 Å) but not in 12c: In this latter

Photochemical and thermal intramolecular 1,3-dipolar cycloaddition reactions of new o-stilbene-methylene-3-sydnones and their synthesis

• Kristina Butković,
• Željko Marinić,
• Krešimir Molčanov,
• Biserka Kojić-Prodić and
• Marija Šindler-Kulyk

Beilstein J. Org. Chem. 2011, 7, 1663–1670, doi:10.3762/bjoc.7.196

• energetically favoured transition state due to a possible secondary π–π interaction of the tolyl and carbonyl groups. Conclusion In photochemical and thermal intramolecular reactions the investigated compounds 3a and 3b, in which the stilbene and sydnone ring are bridged by a methylene group, show the

Towards racemizable chiral organogelators

• Jian Bin Lin,
• Debarshi Dasgupta,
• Seda Cantekin and
• Albertus P. H. J. Schenning

Beilstein J. Org. Chem. 2010, 6, 960–965, doi:10.3762/bjoc.6.107

• that these hydrogen-bonded dimers or tetramers subsequently stack via π-π interaction and via van der Waals interactions into bundled fibers. Racemization The racemization of R-3 was investigated by chiral HPLC. After adding 1 equivalent of DBU to a solution of R-3 in octane at room temperature

Preparation, structures and preliminary host–guest studies of fluorinated syn-bis-quinoxaline molecular tweezers

• Markus Etzkorn,
• Jacob C. Timmerman,
• Matthew D. Brooker,
• Xin Yu and
• Michael Gerken

Beilstein J. Org. Chem. 2010, 6, No. 39, doi:10.3762/bjoc.6.39

• framework 16c differ only slightly from the parameters of the non-fluorinated compound 4a, although the latter does not include any solvent in the cleft and, furthermore, lacks the interpenetrating self-association displayed in 16c [19]. Conversely, 4a shows π-π–interaction of two adjacent molecules by

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

• ]. The higher enantioselectivity was rationalized by the stronger π–π-interaction of the extended π-system of the acridine unit and the more rigid conformation of host molecule. An interesting application was demonstrated by Lakatos: Molecule 22 was attached to a silica gel surface to produce a

• for the potassium salt of S-Phe. The cavity of the macrocycle plays an important role in recognition: A dibenzo substitution on the diazacrown ether may close the cavity due to steric hindrance of the arene units on the ring and the resulting π–π-interaction between the two aromatic moieties on the

• and enantiomeric selectivities were obtained for the R-enantiomers of tyrosine and its potassium salt. The more pronounced enantioselectivity of tyrosine may be explained by hydrogen bonding and the favorable π–π interaction between the hosts’ side arm and the aromatic moiety of guests. The higher

Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules

• Matthias Lehmann and
• Jens Seltmann

Beilstein J. Org. Chem. 2009, 5, No. 73, doi:10.3762/bjoc.5.73

• obtained previously in the series of fluorenone derivatives, in which the π–π interaction increased with decreasing temperature and moderated the uniaxial to biaxial transition [25]. X-ray diffraction shows the orientation of two molecular axes in this mesogen family, which may be an indication for phase

Novel banana-discotic hybrid architectures

• Hari Krishna Bisoyi,
• H. T. Srinivasa and
• Sandeep Kumar

Beilstein J. Org. Chem. 2009, 5, No. 52, doi:10.3762/bjoc.5.52

• the other hand, most of the discotic liquid crystalline compounds form columnar phases because of the strong π-π interaction of poly aromatic cores. In the columnar mesophases, the discotic molecules stack one on top of the other to form columns and the columns so formed arrange themselves in various

Synthesis of thienyl analogues of PCBM and investigation of morphology of mixtures in P3HT

• Fukashi Matsumoto,
• Kazuyuki Moriwaki,
• Yuko Takao and
• Toshinobu Ohno

Beilstein J. Org. Chem. 2008, 4, No. 33, doi:10.3762/bjoc.4.33

• a crystal state, additional peaks are observed at a higher wavelength because of the π-π interaction between its polymer chains. Therefore, the P3HT contained in the films of PCBM and ThCBM is in a more crystalline state than that contained in the films of 2-BThCBM (3a) and es-TThCBM (3d), which is