Revisiting ring-degenerate rearrangements of 1-substituted-4-imino-1,2,3-triazoles

• James T. Fletcher,
• Matthew D. Hanson,
• Joseph A. Christensen and
• Eric M. Villa

Beilstein J. Org. Chem. 2018, 14, 2098–2105, doi:10.3762/bjoc.14.184

• -formyltriazole analogs via ring-degenerate rearrangement of 1-substituted-4-imino-1,2,3-triazoles as first described by L’abbé [42]. ORTEP structure of 2cc’. Thermal ellipsoids shown at 25% probability. 1H NMR aromatic region of a product mixture compared with reference imine analogs. Singlets appearing from 8.5

D-Fructose-based spiro-fused PHOX ligands: synthesis and application in enantioselective allylic alkylation

• Michael R. Imrich,
• Jochen Kraft,
• Cäcilia Maichle-Mössmer and
• Thomas Ziegler

Beilstein J. Org. Chem. 2018, 14, 2082–2089, doi:10.3762/bjoc.14.182

• ligands 2 and 3 and spiro-fused PyOx and PHOX ligands 4 and 5. Molecular structure of 10j. Ellipsoids are given at the 50% probability level. Grey = carbon, red = oxygen, white = hydrogen, purple = nitrogen, orange = bromine. Preparation of 1,2-isopropylidene-protected D-fructose derivatives with

Chiral bisoxazoline ligands designed to stabilize bimetallic complexes

• Deepankar Das,
• Rudrajit Mal,
• Nisha Mittal,
• Zhengbo Zhu,
• Thomas J. Emge and
• Daniel Seidel

Beilstein J. Org. Chem. 2018, 14, 2002–2011, doi:10.3762/bjoc.14.175

• the development of new catalytic enantioselective transformations. Examples of chiral bimetallic complexes utilized in asymmetric catalysis. Previously reported bisoxazoline ligands capable of stabilizing bimetallic complexes. Thermal ellipsoid plot (50% probability) of the molecular structure of 16

• with a = 14.1829(5) Å, b = 14.8645(6) Å, c = 25.2342(10) Å, α = 90°, β = 90°, γ = 90°, V = 5319.9(4) Å3, Z = 4, Dc = 1.450 mg m−3 and μ(Mo Kα) = 1.017 mm−1. Thermal ellipsoid plot (50% probability) of the molecular structure of 25·Ni2(OAc). Hydrogen and solvate atoms have been omitted for clarity: (A

• (2)°, γ = 90°, V = 1759.0(3) Å3, Z = 2, Dc = 1.614 mg m−3 and μ(Mo Kα) = 1.281 mm−1. Thermal ellipsoid plot (50% probability) of the molecular structure of 30·Pd2Br. Hydrogen and solvate atoms have been omitted for clarity: (A) view normal to the mean molecular plane; (B) side view nearly

Synthesis and characterization of π–extended “earring” subporphyrins

• Haiyan Guan,
• Mingbo Zhou,
• Bangshao Yin,
• Ling Xu and
• Jianxin Song

Beilstein J. Org. Chem. 2018, 14, 1956–1960, doi:10.3762/bjoc.14.170

• . Thermal ellipsoids are drawn at the 50% probability level. All hydrogens on tolyl groups are omitted for clarity. Partial 1H NMR spectrum of 3Pd. X-ray crystal structures of 3Pd: a) top view; b) side view. Thermal ellipsoids are at the 30% probability level. All hydrogens on tolyl are omitted for clarity

Diazirine-functionalized mannosides for photoaffinity labeling: trouble with FimH

• Femke Beiroth,
• Tomas Koudelka,
• Thorsten Overath,
• Stefan D. Knight,
• Andreas Tholey and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1890–1900, doi:10.3762/bjoc.14.163

• of the mannoside are varied. In 5 a bis-diazirine functionalization is suggested to increase labeling probability. Connolly representation of photolabile α-D-mannoside 3 in the closed gate (A, PDB code 1UWF) and open gate crystal structure of FimH (B, PDB code 1KLF) [24]. The surface is colored

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

• tuning of the stereoelectronic or steric properties of substituents. Structures of 9-substituted benzo[b]quinolizinium derivatives 1 and 2. Molecular structures of derivatives 2a (top) and 2b (bottom) in the solid state. Ellipsoids are shown at the 50% probability level. The counter anions and solvent

Water-soluble SNS cationic palladium(II) complexes and their Suzuki–Miyaura cross-coupling reactions in aqueous medium

• Alphonse Fiebor,
• Richard Tia,
• Banothile C. E. Makhubela and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1859–1870, doi:10.3762/bjoc.14.160

• in literature [40]. The crystal structure of 17d also shows a static disorder of a CH2 carbon of one of the sec-butyl groups (C14). The atom site occupancy factors of the two positions of the CH2 carbon atom was refined to 0.571(11) and 0.429(11). This shows that the carbon atom has equal probability

First thia-Diels–Alder reactions of thiochalcones with 1,4-quinones

• Grzegorz Mlostoń,
• Katarzyna Urbaniak,
• Paweł Urbaniak,
• Anna Marko,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2018, 14, 1834–1839, doi:10.3762/bjoc.14.156

• (for C26H20O2S): 395 (100, [M − 1]−). ORTEP plot [29] of the molecular structure of 4k showing the major conformation of the disordered thiophene ring (50% probability ellipsoids; arbitrary numbering of the atoms). Products of the reactions of thiochalcones 1a and 1b with 1,4-benzoquinone (2a) and of

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3⁺ + 2]-cycloaddition/rearrangement reactions

• Lin-bo Luan,
• Zi-jie Song,
• Zhi-ming Li and
• Quan-rui Wang

Beilstein J. Org. Chem. 2018, 14, 1826–1833, doi:10.3762/bjoc.14.155

• present synthetic protocol paves the way for further applications in drug-discovery research. Examples of marketed pharmaceutical 1,2,4-triazolobenzodiazepines. Crystal structure of salt 10k. The displacement ellipsoids are drawn at the 30% probability level. Crystal structure of the free base 13e. The

• displacement ellipsoids are drawn at the 30% probability level. Preparation of N-acylated 2,3-dihydro-4(1H)-quinolones 6. Synthesis of α-acetoxyazo compounds 8a–g. Reaction conditions: for synthesis of 8a: 7a (10.42 mmol), PhI(OAc)2 (12.50 mmol), AcOH (10 mL); for synthesis of 8b–g: 7b–g (0.71 mmol), PhI(OAc)2

Synthesis of pyrimido[1,6-a]quinoxalines via intermolecular trapping of thermally generated acyl(quinoxalin-2-yl)ketenes by Schiff bases

• Svetlana O. Kasatkina,
• Ekaterina E. Stepanova,
• Maksim V. Dmitriev,
• Ivan G. Mokrushin and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2018, 14, 1734–1742, doi:10.3762/bjoc.14.147

• under solvent-free conditions. ORTEP drawing of compound 3g (CCDC 1834011) showing thermal ellipsoids at the 30% probability level. ORTEP drawing of compound 3j (CCDC 1834012) showing thermal ellipsoids at the 30% probability level. Thermolysis of five-membered 2,3-dioxoheterocycles resulting in acyl

Synthesis of pyrazolopyrimidinones using a “one-pot” approach under microwave irradiation

• Mark Kelada,
• John M. D. Walsh,
• Robert W. Devine,
• Patrick McArdle and
• John C. Stephens

Beilstein J. Org. Chem. 2018, 14, 1222–1228, doi:10.3762/bjoc.14.104

• of versatile 5-aminopyrazoles is reported. Bioactive pyrazolo[1,5-a]pyrimidinones. X-ray crystal structure of pyrazolo[1,5-a]pyrimidinone 3m with ellipsoids at 50% probability. Synthesis of 5-aminopyrazoles. Reaction conditions: ketonitrile (2.0 mmol, 1.0 equiv), hydrazine (2.6 mmol, 1.3 equiv), MeOH

Preparation, structure, and reactivity of bicyclic benziodazole: a new hypervalent iodine heterocycle

• Akira Yoshimura,
• Michael T. Shea,
• Cody L. Makitalo,
• Melissa E. Jarvi,
• Gregory T. Rohde,
• Akio Saito,
• Mekhman S. Yusubov and
• Viktor V. Zhdankin

Beilstein J. Org. Chem. 2018, 14, 1016–1020, doi:10.3762/bjoc.14.87

• assisted coupling of carboxylic acids with alcohols or amines to afford the corresponding esters or amides in moderate to good yields. X-ray crystal structure of compound 7a. Ellipsoids are drawn to the 50% probability level. Selected bond lengths and angles: I(1)–C(1) 2.040 (4) Å; I(1)–N(1) 2.184 (4) Å; I

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• substrates through the hydrogels and increased the probability of the reactant to be in contact with the catalyst (Ag NPs). Conclusion In this review we have discussed the utility of supramolecular polymersomes, micelles, dendrimers and nanogels in catalysis. Over the past decades, many groups have

Enhanced quantum yields by sterically demanding aryl-substituted β-diketonate ancillary ligands

• Rebecca Pittkowski and
• Thomas Strassner

Beilstein J. Org. Chem. 2018, 14, 664–671, doi:10.3762/bjoc.14.54

• ); 195Pt NMR (CDCl3, 64.52 MHz) δ (ppm) −3383; ESIMS m/z = 688.4 [M + H]+; anal. calcd for C33H36N2O2Pt: C, 57.63; H, 5.28; N, 4.07; found: C, 57.93; H, 5.46; N, 3.82. ORTEP representation of 3. Thermal ellipsoids are drawn at the 50% probability level. Selected bond lengths (Å) and angles (deg): C(1)–Pt(1

Sequential Ugi reaction/base-induced ring closing/IAAC protocol toward triazolobenzodiazepine-fused diketopiperazines and hydantoins

• Robby Vroemans,
• Fante Bamba,
• Jonas Winters,
• Joice Thomas,
• Jeroen Jacobs,
• Luc Van Meervelt,
• Jubi John and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 626–633, doi:10.3762/bjoc.14.49

• examples. X-ray crystal structure of hydantoin-fused triazolobenzodiazepine 10a. (Displacement ellipsoids are drawn at the 30% probability level.) Retrosynthetic analysis towards 2,5-diketopiperazine fused triazolobenzodiazepine. Ugi 4-CR reaction. Synthesis of diketopiperazine-fused triazolobenzodiazepine

An air-stable bisboron complex: a practical bidentate Lewis acid catalyst

• Longcheng Hong,
• Sebastian Ahles,
• Andreas H. Heindl,
• Gastelle Tiétcha,
• Andrey Petrov,
• Zhenpin Lu,
• Christian Logemann and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2018, 14, 618–625, doi:10.3762/bjoc.14.48

• distilled off from the resulting mixture in vacuo. The residue was purified by column chromatography over SiO2 (ethyl acetate/cyclohexane 1:1) to obtain the product. Time-dependent 1H NMR spectra of the air-exposed complex B. ORTEP drawing (50% probability) of complex B. UV–vis spectrum of complex B was

Carbohydrate inhibitors of cholera toxin

• Vajinder Kumar and
• W. Bruce Turnbull

Beilstein J. Org. Chem. 2018, 14, 484–498, doi:10.3762/bjoc.14.34

• ligand group dissociates from the protein, then the others will continue to make contact between the protein and the inhibitor, thus maintaining a high effective concentration of the dissociated ligand group in the vicinity of the binding site and increasing the probability of rebinding occurring. The

Preparation of trinucleotide phosphoramidites as synthons for the synthesis of gene libraries

• Ruth Suchsland,
• Bettina Appel and
• Sabine Müller

Beilstein J. Org. Chem. 2018, 14, 397–406, doi:10.3762/bjoc.14.28

• trinucleotide mixture, to ensure that each of the trinucleotides is coupled with identical statistical probability, or alternatively, to adjust the trinucleotide mixture to a desired amino acid distribution at the respective position. Thus, the application of trinucleotide building blocks for the synthesis of

Synthesis of fluoro-functionalized diaryl-λ³-iodonium salts and their cytotoxicity against human lymphoma U937 cells

• Prajwalita Das,
• Etsuko Tokunaga,
• Hidehiko Akiyama,
• Hiroki Doi,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2018, 14, 364–372, doi:10.3762/bjoc.14.24

• . Briefly, U937 cells (1 × 104 cells/mL) were incubated with each test compound at 1 μM and 5 μM for 24 h. Cells were stained with annexin V and propidium iodide (PI). The data shown is the mean ± SD (n = 3). X-ray crystallographic structure of 3p drawn at 50% probability (CCDC 1573953). Ortho-SF5 phenyl

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

• operated at high voltages [17]. Second, and still related to their wide bandgaps, the probability to transfer an electron from the ground to the excited stable state is considerably reduced, providing materials displaying PLQY greatly reduced compared to that observed for the other colors [18][19]. To end

Nucleophilic dearomatization of 4-aza-6-nitrobenzofuroxan by CH acids in the synthesis of pharmacology-oriented compounds

• Alexey M. Starosotnikov,
• Dmitry V. Shkaev,
• Maxim A. Bastrakov,
• Ivan V. Fedyanin,
• Svyatoslav A. Shevelev and
• Igor L. Dalinger

Beilstein J. Org. Chem. 2017, 13, 2854–2861, doi:10.3762/bjoc.13.277

• drawn at 50% probability; a DMF molecule is omitted for clarity. Partial 1H NMR spectrum of compound 15 in DMSO-d6. General view of molecule 15 in crystal. Anisotropic displacement parameters for non-hydrogen atoms are drawn at 50% probability; a DMSO molecule and the minor component of the disordered

The use of 4,4,4-trifluorothreonine to stabilize extended peptide structures and mimic β-strands

• Yaochun Xu,
• Isabelle Correia,
• Tap Ha-Duong,
• Nadjib Kihal,
• Jean-Louis Soulier,
• Julia Kaffy,
• Benoît Crousse,
• Olivier Lequin and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2017, 13, 2842–2853, doi:10.3762/bjoc.13.276

• the aforementioned extended conformations. More specifically, the probability of each residue to be in α- or β-conformation can be quantified by calculating the area under the peaks of the ψ distribution functions centered around −30° or +140°, respectively. The probability of the three central

• CSDs and 3JHN-Hα coupling constant values. The probability of each peptide to have all its three central residues in β-conformation (which is equal to the product of the three central residue probabilities) is a good indication of its propensity to adopt a global extended structure. According to this

• -protected pentapeptides 1a–4a and free amine pentapeptides 1b–4b. Probability distribution of the peptide conformations as a function of end-to-end distance (defined as the distance between the nitrogen of residue Ala1 and the carbon of the C-terminal carbonyl). Probability distribution of the peptide

Ring-size-selective construction of fluorine-containing carbocycles via intramolecular iodoarylation of 1,1-difluoro-1-alkenes

• Takeshi Fujita,
• Ryo Kinoshita,
• Tsuyoshi Takanohashi,
• Naoto Suzuki and
• Junji Ichikawa

Beilstein J. Org. Chem. 2017, 13, 2682–2689, doi:10.3762/bjoc.13.266

• probability. ORTEP diagram of 6a with 50% ellipsoid probability. Intramolecular site-selective iodoarylation of 1,1-difluoro-1-alkenes bearing a biaryl group. Mechanism for formation of 3a. Transformation of a CF2I group of 2a into a CHF2 group. Construction of seven-membered carbocycles via iodoarylation of

A Brønsted base-promoted diastereoselective dimerization of azlactones

• Danielle L. J. Pinheiro,
• Gabriel M. F. Batista,
• Pedro P. de Castro,
• Leonã S. Flores,
• Gustavo F. S. Andrade and
• Giovanni W. Amarante

Beilstein J. Org. Chem. 2017, 13, 2663–2670, doi:10.3762/bjoc.13.264

• dimer. X-ray crystallographic structure of 2a (30% ellipsoids probability). Plausible mechanism for the dimerization of azlactone. Plot of vs time for the dimerization of azlactone 1a. X-ray crystallographic structure of 6 (30% ellipsoids probability). Diastereoselective dimerization of azlactones

Regioselective decarboxylative addition of malonic acid and its mono(thio)esters to 4-trifluoromethylpyrimidin-2(1H)-ones

• Sergii V. Melnykov,
• Andrii S. Pataman,
• Yurii V. Dmytriv,
• Svitlana V. Shishkina,
• Mykhailo V. Vovk and
• Volodymyr A. Sukach

Beilstein J. Org. Chem. 2017, 13, 2617–2625, doi:10.3762/bjoc.13.259

• heterochiral dimer in the crystal state. Intermolecular hydrogen bonds in the dimer are shown as dashed lines. Thermal ellipsoids are defined at 50% probability. Hydrogenation of compounds 4–6 and preparation of N1(3)-unsubstituted compounds 9–11d. Screening of the reaction conditions for organic base