Photochromic diarylethene ligands featuring 2-(imidazol-2-yl)pyridine coordination site and their iron(II) complexes

• Andrey G. Lvov,
• Max Mörtel,
• Anton V. Yadykov,
• Frank W. Heinemann,
• Valerii Z. Shirinian and
• Marat M. Khusniyarov

Beilstein J. Org. Chem. 2019, 15, 2428–2437, doi:10.3762/bjoc.15.235

• successfully applied for the synthesis of a new family of photochromic ligands. The structures of the synthesized diarylethene-based ligands 3, 4, 6, and 7 were confirmed by 1H and 13C NMR spectroscopy and mass spectrometry. The molecular structure of 6 was additionally confirmed by X-ray crystallography. In

• irradiation (313 nm, toluene, c = 3.4 × 10−5 M). Inset: fatigue resistance upon multiple subsequent irradiation with UV (365 nm) and visible light (green LED) in acetonitrile. Molecular structure of complexes 8 (top) and 9 (bottom) at 100 K. The H atoms are omitted for clarity; the thermal ellipsoids are

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

• ]. For example, each CH2 signal is generated by four CH2 protons which are chemically equivalent in the averaged chemical structure (≈ the 2D molecular structure) but not in individual conformers. They cannot be distinguished on the NMR timescale. Therefore, the calculated distances rave, being averages

In water multicomponent synthesis of low-molecular-mass 4,7-dihydrotetrazolo[1,5-a]pyrimidines

• Irina G. Tkachenko,
• Sergey A. Komykhov,
• Vladimir I. Musatov,
• Svitlana V. Shishkina,
• Viktoriya V. Dyakonenko,
• Vladimir N. Shvets,
• Mikhail V. Diachkov,
• Valentyn A. Chebanov and
• Sergey M. Desenko

Beilstein J. Org. Chem. 2019, 15, 2390–2397, doi:10.3762/bjoc.15.231

• ); EIMS (70 eV, m/z (%)): 295 (15) [M+], 294 (100), 277 (12), 276 (60), 180 (25); Anal. calcd for С9Н12F3N5O3 (295.23): C, 36.62; H, 4.10; F, 19.31; N, 23.72%; found: C, 36.53; H, 4.21; F, 19.20; N, 23.84%. Molecular structure of 9a according to X-ray data. Displacement ellipsoids are shown at the 50

Excited state dynamics for visible-light sensitization of a photochromic benzil-subsituted phenoxyl-imidazolyl radical complex

• Yoichi Kobayashi,
• Yukie Mamiya,
• Katsuya Mutoh,
• Hikaru Sotome,
• Masafumi Koga,
• Hiroshi Miyasaka and
• Jiro Abe

Beilstein J. Org. Chem. 2019, 15, 2369–2379, doi:10.3762/bjoc.15.229

• photoswitch molecules, the phenoxyl-imidazolyl radical complex (PIC) is a recently developed thermally reversible photochromic molecule whose thermal back reaction can be tuned from tens of nanoseconds to tens of seconds by rational design of the molecular structure. While the wide range of tunability of 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

• treatment with acids: lactone 2, dehydrated lactone 3, α,β-unsaturated carboxylic acid 4, and carboxylic acid 5 (resulting from postulated anilide hydrolysis). Top: Molecular structure of artefact 6. Shown here is the molecular structure of one of three independent molecules in 6 drawn at the 50% ellipsoid

• probability level. Bottom: Molecular structure of artefact 7 (drawn at the 50% ellipsoid probability level). Separation of atorvastatin (1; retention time: 5.8 min) from the four decomposition products 2 (retention time: 9.2 min), 3 (retention time: 15.6 min), 6 (retention time: 21.4 min) and 7 (retention

Synthesis of benzo[d]imidazo[2,1-b]benzoselenoazoles: Cs₂CO₃-mediated cyclization of 1-(2-bromoaryl)benzimidazoles with selenium

• Mio Matsumura,
• Yuki Kitamura,
• Arisa Yamauchi,
• Yoshitaka Kanazawa,
• Yuki Murata,
• Tadashi Hyodo,
• Kentaro Yamaguchi and
• Shuji Yasuike

Beilstein J. Org. Chem. 2019, 15, 2029–2035, doi:10.3762/bjoc.15.199

• group having bromine to generate the tetracyclic target molecule. Conclusion Benzo[d]imidazo[2,1-b]benzoselenoazoles were prepared via Cs2CO3-mediated tandem cyclization followed by reaction of 1-(2-bromoaryl)benzimidazoles with Se powder without a transition metal catalyst. The molecular structure of

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

• , 1325, 1228, 1113, 1066. HRMS-APCI: [M − H]− calcd for C63H41N21O15F9, 1502.2953; found, 1502.2972; anal. calcd for C63H42F9N21O15·H2O: C, 49.71; H, 2.91; N, 19.32. found: C, 49.42; H, 3.04; N, 19.01. X-ray molecular structure of 3a (CCDC 1913907) with side (left) and top (right) views. All solvent

Identification of optimal fluorescent probes for G-quadruplex nucleic acids through systematic exploration of mono- and distyryl dye libraries

• Xiao Xie,
• Michela Zuffo,
• Marie-Paule Teulade-Fichou and
• Anton Granzhan

Beilstein J. Org. Chem. 2019, 15, 1872–1889, doi:10.3762/bjoc.15.183

• common feature of mono- and distyryl dyes, including long-known mono-styryl dyes used as mitochondrial probes or protein stains. However, the magnitude of the G4-induced “light-up” effect varies drastically, as a function of both the molecular structure of the dyes and the nature or topology of G4

• to the molecular structure of dyes, it may be concluded that lipophilic substituents (1c, 1d, 1ð, 1y, 1Þ) and/or π-expanded heterocyclic cores (9a, 10a, 12a, 14p) promote the dye aggregation, but the nature of the resulting aggregate (H vs J) is unpredictable. Conversely, small or hydrophilic

• solvents (MeOH, DMSO) and in aqueous buffer, as assessed by visual inspection of the respective solutions. In non-aggregating conditions, the influence of the molecular structure of the dyes on their absorption bands can be clearly observed. Thus, when Ar contains poor electron-donating substituents (1g–1j

Cyclobutane dication, (CH₂)₄²⁺: a model for a two-electron four-center (2e-4c) Woodward–Hoffmann frozen transition state

• G. K. Surya Prakash and
• Golam Rasul

Beilstein J. Org. Chem. 2019, 15, 1475–1479, doi:10.3762/bjoc.15.148

• . This type of bonding could occur in rigid frameworks such as in 1,3-dehydro-5,7-adamantanediyl dication (iii) [7] and pagodane dication (iv) [8]. The question is can a 2e-4c bond exist in a molecular structure involving four atoms without any rigid frameworks such as in the diprotonated hydrogen (H42

One-pot activation–alkynylation–cyclization synthesis of 1,5-diacyl-5-hydroxypyrazolines in a consecutive three-component fashion

• Christina Görgen,
• Katharina Boden,
• Guido J. Reiss,
• Walter Frank and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2019, 15, 1360–1370, doi:10.3762/bjoc.15.136

• intermediate 5a could be a 1,5-diacylpyrazole. However, upon performing the terminal cyclization step starting from 1,4-diphenylbut-3-yne-1,2-dione (3a) and Boc-hydrazine (4a) under identical conditions 1-Boc-5-benzoyl-5-hydroxypyrazoline was isolated in 83% yield (Scheme 3). The molecular structure was

Formation of an unexpected 3,3-diphenyl-3H-indazole through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate

• Andrew T. King,
• Hugh G. Hiscocks,
• Lidia Matesic,
• Mohan Bhadbhade,
• Roger Bishop and
• Alison T. Ung

Beilstein J. Org. Chem. 2019, 15, 1347–1354, doi:10.3762/bjoc.15.134

• (H···H = 2.48 Å) there is also a linear C6D–H6D···H6D–C6D close contact (H···H = 2.37 Å) around a further inversion centre. These two motifs alternate along the a axis to produce infinite hydrocarbon tapes with inversion centres separated by a/2 (Figure 6). The molecular structure of 8 precludes

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

• Alexander N. Reznikov,
• Anastasiya E. Sibiryakova,
• Marat R. Baimuratov,
• Eugene V. Golovin,
• Victor B. Rybakov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127

• suitable for X-ray analysis were obtained for compound 8d (which is formed as an individual diastereomer). This made it possible to determine its absolute (2R,3S)-configuration, as well as to assign the absolute configuration for the other compounds obtained. The molecular structure of compound 8d is shown

Doebner-type pyrazolopyridine carboxylic acids in an Ugi four-component reaction

• Maryna V. Murlykina,
• Oleksandr V. Kolomiets,
• Maryna M. Kornet,
• Yana I. Sakhno,
• Sergey M. Desenko,
• Victoriya V. Dyakonenko,
• Svetlana V. Shishkina,
• Oleksandr A. Brazhko,
• Vladimir I. Musatov,
• Alexander V. Tsygankov,
• Erik V. Van der Eycken and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2019, 15, 1281–1288, doi:10.3762/bjoc.15.126

• 70 °C) and a small focused library of 23 Ugi products was created. The target compounds containing two pharmacophore pyrazolopyridine and peptidomimetic moieties were screened for their antibacterial activity and demonstrated weak antibacterial effect. Molecular structure of N-(2-(tert-butylamino)-1

Insertion of [1.1.1]propellane into aromatic disulfides

• Robin M. Bär,
• Gregor Heinrich,
• Martin Nieger,
• Olaf Fuhr and
• Stefan Bräse

Beilstein J. Org. Chem. 2019, 15, 1172–1180, doi:10.3762/bjoc.15.114

• peroxide, DTBP) led to increased amounts of insoluble polymer. Molecular structure of 6a (displacement parameters are drawn at 50% probability level), distance C1–C3 1.844(3) Å. NMR spectra of pure 6a (green) and 6d (red) and the obtained mixture with the new compound 15 (blue). Summary of the most recent

Novel (2-amino-4-arylimidazolyl)propanoic acids and pyrrolo[1,2-c]imidazoles via the domino reactions of 2-amino-4-arylimidazoles with carbonyl and methylene active compounds

• Victoria V. Lipson,
• Tetiana L. Pavlovska,
• Nataliya V. Svetlichnaya,
• Anna A. Poryvai,
• Nikolay Yu. Gorobets,
• Erik V. Van der Eycken,
• Irina S. Konovalova,
• Svetlana V. Shiskina,
• Alexander V. Borisov,
• Vladimir I. Musatov and
• Alexander V. Mazepa

Beilstein J. Org. Chem. 2019, 15, 1032–1045, doi:10.3762/bjoc.15.101

• structure of 1-([1,1'-biphenyl]-4-yl)-5-oxo-7-phenyl-6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-3-aminium 2,2,2-trifluoroacetate 9i according to X-ray diffraction data. Thermal ellipsoids of atoms are shown at 50% probability level. Molecular structure of 3-(2-amino-4-phenyl-1H-imidazol-5-yl)-3-(p-tolyl

• )propanoic acid 11b according to X-ray diffraction data. Thermal ellipsoids of atoms are shown at 50% probability level. Molecular structure of aminoimidazo[1,2-c]pyrrole 16a according to X-ray diffraction data. Thermal ellipsoids of atoms are shown at 50% probability level. 3,3’-Spirooxindole alkaloids

• . Molecular structure of aminoimidazo[1,2-c]pyrrole 19a according to X-ray diffraction data. Thermal ellipsoids of atoms are shown at 50% probability level. The three component condensation of imidazo[1,2-a]pyridine, aldehydes and Meldrum’s acid described by Gerencsér at al. [31]. Two forms of cation 9i

Fabrication, characterization and adsorption properties of cucurbit[7]uril-functionalized polycaprolactone electrospun nanofibrous membranes

• Changzhong Chen,
• Fengbo Liu,
• Xiongzhi Zhang,
• Zhiyong Zhao and
• Simin Liu

Beilstein J. Org. Chem. 2019, 15, 992–999, doi:10.3762/bjoc.15.97

• present in the molecular structure. Combined with merits of host molecules and electrospun nanofibers, the supramolecular host functionalized nanofibers have been widely reported in recent years as efficient molecular filters and absorbent for the removal of hazardous chemicals or polluting substances. A

Diaminoterephthalate–α-lipoic acid conjugates with fluorinated residues

• Leon Buschbeck,
• Aleksandra Markovic,
• Gunther Wittstock and
• Jens Christoffers

Beilstein J. Org. Chem. 2019, 15, 981–991, doi:10.3762/bjoc.15.96

• ), which is expected from the molecular structure of compounds 3 and 7, may be caused by residual adsorbed water that also causes an O 1s component at 533.0–533.5 eV [57][58]. The main doublet in the S 2p spectra of both monolayers at 161.8 eV corresponds to sulfur bound to gold [59]. Although, S 2p

An anomalous addition of chlorosulfonyl isocyanate to a carbonyl group: the synthesis of ((3aS,7aR,E)-2-ethyl-3-oxo-2,3,3a,4,7,7a-hexahydro-1H-isoindol-1-ylidene)sulfamoyl chloride

• Aytekin Köse,
• Aslı Ünal,
• Ertan Şahin,
• Uğur Bozkaya and
• Yunus Kara

Beilstein J. Org. Chem. 2019, 15, 931–936, doi:10.3762/bjoc.15.89

• for C10H13ClN2O3S, 276.7350; found, 277.0434. The dipolar intermediate formed in the reaction of CSI with olefins. (a) Molecular structure of racemic molecule 10 (asymmetric unit). Thermal ellipsoids are drawn at the 30% probability level. (b) Geometric parameter with H-bonded geometry. Hydrogen bonds

Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands

• Jennifer Klose,
• Tobias Severin,
• Peter Hahn,
• Alexander Jeremies,
• Jens Bergmann,
• Daniel Fuhrmann,
• Jan Griebel,
• Bernd Abel and
• Berthold Kersting

Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81

• ·8EtOH (7·8EtOH). Only one orientation of the disordered azo-carboxylato co-ligand is displayed. Hydrogen atoms omitted for clarity. Thermal ellipsoids are drawn at the 50% probability level. Left: ORTEP representation of the molecular structure of the [Cd2L(μ-azo-CO2Me)]+ cation in crystals of 8·MeCN

Catalyst-free assembly of giant tris(heteroaryl)methanes: synthesis of novel pharmacophoric triads and model sterically crowded tris(heteroaryl/aryl)methyl cation salts

• Rodrigo Abonia,
• Luisa F. Gutiérrez,
• Braulio Insuasty,
• Jairo Quiroga,
• Kenneth K. Laali,
• Chunqing Zhao,
• Gabriela L. Borosky,
• Samantha M. Horwitz and
• Scott D. Bunge

Beilstein J. Org. Chem. 2019, 15, 642–654, doi:10.3762/bjoc.15.60

• reactions could also be carried out in water (at circa 80 °C) but with chemoselectivity favoring (Ar1Ar1Ar2)CH over (Ar1Ar2Ar3)CH. The molecular structure of a representative (Ar1Ar2Ar3)CH triad was confirmed by X-ray analysis. Model tris(heteroaryl/aryl)methylium salts were generated by reaction with DDQ

Synthesis of a tubugi-1-toxin conjugate by a modulizable disulfide linker system with a neuropeptide Y analogue showing selectivity for hY1R-overexpressing tumor cells

• Rainer Kufka,
• Robert Rennert,
• Goran N. Kaluđerović,
• Lutz Weber,
• Wolfgang Richter and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2019, 15, 96–105, doi:10.3762/bjoc.15.11

• targeting of the conjugate towards a specific molecular structure that has been identified to be characteristic for a diseased state of cells and tissues. Particularly G protein-coupled receptors (GPCRs) that are endogenously activated by agonistic peptide or protein ligands can be suitable target

N-Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes

• Fabienne Speck,
• David Rombach and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 52–59, doi:10.3762/bjoc.15.5

• reduction potential interestingly is higher than in the parent compound 1 although there are electron-donating alkyl groups present in the molecular structure. This can be explained by a twist of the arene moieties due to steric bulk causing an interruption of the delocalization. The electron transfer is

1,8-Bis(dimethylamino)naphthyl-2-ketimines: Inside vs outside protonation

• A. S. Antonov,
• A. F. Pozharskii,
• P. M. Tolstoy,
• A. Filarowski and
• O. V. Khoroshilova

Beilstein J. Org. Chem. 2018, 14, 2940–2948, doi:10.3762/bjoc.14.273

• case, we were able to experimentally observe the simultaneous out-inversion and protonation of the 1-NMe2 group for the first time. C=NH Signal regions of temperature-depending 1H NMR spectra for compounds 4a–7a, acetone-d6. Molecular structure of imines 6a (a) and 4a (b). The H···O distance for 6a is

• ΔE = Eb’ – Eb (kcal/mol) for different sites of protonation of the studied imines (B3LYP/6-311+G(d,p)). Molecular structure of protonated imines 4a·HClO4 (a) and 6b·EtOH (b). C=NH2+ Signal regions of temperature-depending spectra for compounds 4c–7c, acetone-d6. Molecular structure of dication 6с

Oxidative and reductive cyclization in stiff dithienylethenes

• Michael Kleinwächter,
• Ellen Teichmann,
• Lutz Grubert,
• Martin Herder and
• Stefan Hecht

Beilstein J. Org. Chem. 2018, 14, 2812–2821, doi:10.3762/bjoc.14.259

• [5][6][7][8][9][10][11][12][13] or cycloreversion [14][15][16][17][18][19][20][21] can be observed, while correlation of both reaction modes to the molecular structure is still under discussion [22][23][24][25][26]. There are only few reports about reductive isomerization, each involving the ionic

Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1H-pyrazoles

• Camila S. Pires,
• Daniela H. de Oliveira,
• Maria R. B. Pontel,
• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Diego Alves,
• Raquel G. Jacob and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2018, 14, 2789–2798, doi:10.3762/bjoc.14.256

• copper salt. To confirm the structure of 6, its molecular structure was also analyzed by single-crystal X-ray diffraction (CCDC: 1853770). The molecular structure is demonstrated in Figure 1. Conclusion A variety of 4-(arylselanyl)-1H-pyrazol-5-amines was prepared in a one-pot multicomponent procedure

• . Molecular structure of compound 6. The hydrogen atoms are omitted for clarity [27]. Synthesis of selanyl-pyrazoles and their derivatives previously described. Multicomponent reaction proposed in this work. Direct selanylation reaction of 5-amino-pyrazole 5a with diphenyl diselenide (3a) under the optimized