Reversible photoswitching of the DNA-binding properties of styrylquinolizinium derivatives through photochromic [2 + 2] cycloaddition and cycloreversion

• Sarah Kölsch,
• Heiko Ihmels,
• Jochen Mattay,
• Norbert Sewald and
• Brian O. Patrick

Beilstein J. Org. Chem. 2020, 16, 111–124, doi:10.3762/bjoc.16.13

• nm in H2O (B). ORTEP drawings of cyclobutane derivatives 4b (A) and 4c (B) in the solid state (thermal ellipsoids indicate 50% probability). The tetrafluoroborate counterions were omitted for clarity. A) Spectrophotometric titration of ct DNA to dimer 4b in BPE buffer (cL = 20 µM, cct DNA = 1.45 mM

SnCl₄-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives

• Kesatebrhan Haile Asressu and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2019, 15, 2990–2999, doi:10.3762/bjoc.15.295

• thiosialoside and sialyl halide donors in order to serve as alternative building blocks for the synthesis of sialic acid-containing glycans. Representative structures of bacterial glycans containing sialic acid. a) ORTEP diagram of compound 4. Thermal ellipsoids indicate 50% probability. b) HMBC spectrum of 6

Two new aromatic polyketides from a sponge-derived Fusarium

• Mada Triandala Sibero,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Ocky K. Karna Radjasa,
• Agus Sabdono,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2941–2947, doi:10.3762/bjoc.15.289

• , C8, C8a, C9, C10, and C10a) were significantly smaller for structure a than structure b (Table 2). Then, DP4+ was used to quantify this calculated result [25]. DP4+ probability analysis provides reliable guidance on the correct structure among several possible isomers. The developers recommend to use

• the combination of 1H and 13C data for enhancement of DP4+ performance. In this study, the DP4+ probability using only 1H data or only 13C data gave an inconsistent result, but the DP4+ probability using both 1H and 13C data supported the structure a, in which the methoxy group was present at C7, as a

One-pot synthesis of substituted pyrrolo[3,4-b]pyridine-4,5-diones based on the reaction of N-(1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-oxo-2-arylethyl)acetamide with amines

• Valeriya G. Melekhina,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Vitaly S. Mityanov,
• Artem N. Fakhrutdinov,
• Arkady A. Dudinov,
• Vasily A. Migulin,
• Yulia V. Nelyubina,
• Elizaveta K. Melnikova and
• Michail M. Krayushkin

Beilstein J. Org. Chem. 2019, 15, 2840–2846, doi:10.3762/bjoc.15.277

• ellipsoids indicate 50% probability. Solvent molecules have been omitted for clarity. General synthetic pathway to 1. Synthesis of acetamides 2. Possible reaction pathways for the formation of enaminone 7. Possible reaction pathways for the formation of pyrrolo[3,4-b]pyridin-5-one derivatives 1. Tautomeric

Synthesis of aryl-substituted thieno[3,2-b]thiophene derivatives and their use for N,S-heterotetracene construction

• Nadezhda S. Demina,
• Nikita A. Kazin,
• Nikolay A. Rasputin,
• Roman A. Irgashev and
• Gennady L. Rusinov

Beilstein J. Org. Chem. 2019, 15, 2678–2683, doi:10.3762/bjoc.15.261

• synthesized in this work. ORTEP diagram for the X-ray structure of compound 7d. Thermal ellipsoids of 50% probability are shown. Synthesis of aryl-substituted TT derivatives 3a–k, product scope, and yields. Synthesis of thieno[3,2-b]thiophen-3(2H)-one 4a–k, product scope, and yields. Synthesis of TTI

Formation of alkyne-bridged ferrocenophanes using ring-closing alkyne metathesis on 1,1’-diacetylenic ferrocenes

• Celine Bittner,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2019, 15, 2534–2543, doi:10.3762/bjoc.15.246

• sensing. ORTEP diagram of 1a with thermal displacement parameters drawn at 50% probability; hydrogen atoms are omitted for clarity; occupation Fe 74%, Fe’ 26%. Selected bond lengths [Å] and angles [°]: Fe–Ct1 1.6947(12), Fe-Ct11 1.6695(12), Ct1-Fe-Ct11 176.96(8), C9–C10 1.186(11), C8–C9–C10 177.2(9), C19

• –C20 1.165(12), C18–C19–C20 178.1(10). ORTEP diagram of 1b with thermal displacement parameters drawn at 50% probability; hydrogen atoms are omitted for clarity. Selected bond lengths [Å] and angles [°]: Fe–Ct 1.6523(7), Ct–Fe–Ct‘ 180.0, C10–C11 1.127(2), C9–C10–C11 176.3(2). ORTEP diagram of 2a with

• thermal displacement parameters drawn at 50% probability; hydrogen atoms are omitted for clarity. Selected bond lengths [Å] and angles [°]: Fe–Ct 1.6414(6), Ct–Fe–Ct’ 178.809(1), C9–C9‘ 1.193(2), C8–C9–C9‘ 172.1(2). ORTEP diagram of 2b (one of two molecules of the asymmetric unit) with thermal

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

• drawn at the 50% probability level. Variable temperature χT product (blue) and χ (green) of 8 (top) and 9 (bottom) measured at an external magnetic field of 1 T in the heating mode (see Supporting Information File 1 for fitting parameters). Synthesis of photochromic ligands. Reversible photocyclization

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

• % probability level. Three synthetic approaches to dihydrotetrazolo[1,5-a]pyrimidines. Three-component reaction of 1, 7a,b and 8a–d in water. Three-component reaction of 5-aminotetrazole (1) with formaldehyde (7a) and acetylacetone (10). a) Three-component reaction of 5-aminotetrazole (1) with acetaldehyde (7b

An overview of the cycloaddition chemistry of fulvenes and emerging applications

• Ellen Swan,
• Kirsten Platts and
• Anton Blencowe

Beilstein J. Org. Chem. 2019, 15, 2113–2132, doi:10.3762/bjoc.15.209

• reactive, is prone to dimerization and polymerisation [59][111]. If the reaction is conducted under aqueous conditions, the probability of dimerization has been reported to increase further due to hydrophobic packing of the fulvene molecules [120][121]. Intramolecular cycloadditions Whilst not as widely

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

• 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

• residue was purified by silica gel chromatography (n-hexane/AcOEt). (a) Ortep drawing of 2a (50% probability, only one of two independent molecules is shown) and (b) packing structure. The component based solvent was omitted for clarity. Cs2CO3-mediated cyclization of 1-(2-bromoaryl)imidazoles with Se

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• devices sensitized with BOD-TTPA-alk are slightly higher compared to the ones prepared out of BOD-TTPA. This could be explained by the presence of the alkyl chains on the TPA units that are known to prevent the redox mediator to interact with the TiO2 surface thus reducing the probability to observe a

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• aliphatic alkynes gave an optimal yield of the final product in the range of 50–78%. Successful formation of the product on application of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO: a radical scavenger) has nullified the probability of radical pathway. It was thought to be initiated by the coordination of

Transient and intermediate carbocations in ruthenium tetroxide oxidation of saturated rings

• Manuel Pedrón,
• Laura Legnani,
• Maria-Assunta Chiacchio,
• Pierluigi Caramella,
• Tomás Tejero and
• Pedro Merino

Beilstein J. Org. Chem. 2019, 15, 1552–1562, doi:10.3762/bjoc.15.158

• attractors [74], that are the areas in which the probability of finding an electron pair is maximal. Monosynaptic and disynaptic basins correspond to separate atoms and bonds, respectively. When a bond is formed, two monosynaptic basins merge into a new disynaptic basin. The complete ELF analyses of the IRCs

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

• ) and antibacterial activity (center and right). ORTEP plot of 5-benzoyl-3-phenyl-1H-pyrazole (6a) (thermal ellipsoids at 30% probability); the direction of intermolecular N−H···O hydrogen bonding is indicated by dashed lines. Ellipsoid plot of 1-Boc-5-benzoyl-5-hydroxypyrazoline 5a. ORTEP plot and

• dimer of compound 5r (thermal ellipsoids at 30% probability). Glyoxylation–alkynylation (GA) and activation–alkynylation (AA) synthesis of alkynediones in a one-pot fashion. Consecutive three-component synthesis to give 5-benzoyl-3-phenyl-1H-pyrazole (6a) after alkaline deacylation of intermediate 5a

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

• . Possible compounds with the molecular formula C33H26N2O (structure 7 contains 27 hydrogen atoms). ORTEP view of the molecule 8 showing the atom labelling (ellipsoids are drawn at 50% probability level). Significant intermolecular interactions made by the benzhydryl group (a, upper) and the gem-diphenyl

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

• -(4-chlorophenyl)-2-oxoethyl)-6-(4-methoxyphenyl)-3-methyl-N-p-tolyl-1H-pyrazolo[3,4-b]pyridine-4-carboxamide (11n) according to X-ray diffraction data. Non-hydrogen atoms are presented as thermal ellipsoids with 50% probability. An overview of heterocyclic acids used in the Ugi reaction. Synthesis of

Understanding the unexpected effect of frequency on the kinetics of a covalent reaction under ball-milling conditions

• Ana M. Belenguer,
• Adam A. L. Michalchuk,
• Giulio I. Lampronti and
• Jeremy K. M. Sanders

Beilstein J. Org. Chem. 2019, 15, 1226–1235, doi:10.3762/bjoc.15.120

• the temperature term of the traditional Arrhenius equation can be (to a first approximation) replaced by the rate of supply of mechanical energy, W [29], (Equation 2) Hence, k2 represents the ‘per impact’ probability of reaction. We note that the individual terms of Equation 2 are indeed expected to

• ) can dominate subsequent stages of the transformation, as the probability of contact formation decreases. While further work is required to capture detailed mechanistic insight, we can suggest that kinetic modelling of covalent mechanochemical reactions likely requires a model that accounts for both

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

• structure of 14 could be proven by single-crystal X-ray diffraction (displacement parameters are drawn at 50% probability level). Reaction of propellane (1) with the two disulfides 10a and 10d. When two different disulfides were used, all three possible products were obtained. The yields were determined by

• by single-crystal X-ray diffraction (displacement parameters are drawn at 50% probability level). Results of the insertion of 1 into aromatic disulfide bonds. The ratio of 1:10 determines the amount of [2]staffane formed. Supporting Information Full experimental details and analytical data (1H NMR

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• Heck cyclization reaction between the substituted alkyne and aryl bromide in 133 takes place to form a cyclic palladium intermediate 134 with E-configuration, resulting from a syn-addition mechanism of this step. The addition of a silver salt reduces the probability of isomerization of the double bond

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

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

Efficient synthesis of pyrazolopyridines containing a chromane backbone through domino reaction

• Razieh Navari,
• Saeed Balalaie,
• Saber Mehrparvar,
• Fatemeh Darvish,
• Frank Rominger,
• Fatima Hamdan and
• Sattar Mirzaie

Beilstein J. Org. Chem. 2019, 15, 874–880, doi:10.3762/bjoc.15.85

• molecules based on the pyrazolopyridine framework. ORTEP Structure of compound 4a and intermolecular hydrogen bonding; the ellipsoid probability level of each ORTEP diagram is 50%. Structures of synthesized pyrazolopyridines 4a–m. Reaction conditions: 3-formylchromone derivatives (1 mmol), primary amine

Photochemical generation of the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical from caged nitroxides by near-infrared two-photon irradiation and its cytocidal effect on lung cancer cells

• Ayato Yamada,
• Manabu Abe,
• Yoshinobu Nishimura,
• Shoji Ishizaka,
• Masashi Namba,
• Taku Nakashima,
• Kiyofumi Shimoji and
• Noboru Hattori

Beilstein J. Org. Chem. 2019, 15, 863–873, doi:10.3762/bjoc.15.84

• excitation is possible because the probability of TP excitation is proportional to the square of the light intensity [46]. The light-induced generation of nitroxides using the TP excitation technique, i.e., the concentration jump of nitroxides, is one promising method of exploring the role of these species

Synthesis of a novel category of pseudo-peptides using an Ugi three-component reaction of levulinic acid as bifunctional substrate, amines, and amino acid-based isocyanides

• Maryam Khalesi,
• Azim Ziyaei Halimehjani and
• Jürgen Martens

Beilstein J. Org. Chem. 2019, 15, 852–857, doi:10.3762/bjoc.15.82

• . cIsolated yield of one of the diastereomers as pure stereoisomer after several recrystallization steps. ORTEP representation of compound (R*,S*)-4a with thermal ellipsoids at 50% probability. Opposite enantiomer is omitted for clarity. The atom numbering does not follow IUPAC nomenclature. Synthesis of