Distinctive reactivity of N-benzylidene-[1,1'-biphenyl]-2-amines under photoredox conditions

• Shrikant D. Tambe,
• Kwan Hong Min,
• Naeem Iqbal and
• Eun Jin Cho

Beilstein J. Org. Chem. 2020, 16, 1335–1342, doi:10.3762/bjoc.16.114

• product 3a was unambiguously confirmed using X-ray crystallography [57]. To further extend the diversity of the reactivity of the imines in this process, we also attempted the use of a reducing agent in the reaction of 1a. Pleasingly, the reaction of 1a with 2 equivalents of the Hantzsch ester in CH3CN

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• emitting diodes (LEDs) were purchased from Topbright. X-ray crystallography Single crystals of 2c and 4a of suitable quality for X-ray diffraction measurements were grown by slow diffusion of n-pentane into CH2Cl2 solutions of the crude product at –18 °C for several weeks. One selected single crystal was

Copper catalysis with redox-active ligands

• Agnideep Das,
• Yufeng Ren,
• Cheriehan Hessin and
• Marine Desage-El Murr

Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77

• Chaudhuri on GAO mimics [11][12][13], Safaei and Storr have reported Cu(II) complexes bearing a non-innocent amidophenolate type benzoxazole ligand which was fully characterized by X-ray crystallography and other spectroscopic techniques (Scheme 1) [14]. These complexes were found to perform the aerobic

One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

• Ji Ma,
• Yubin Fu,
• Junzhi Liu and
• Xinliang Feng

Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72

• twofold [3 + 2] cyclopentannulation and subsequent twofold [4 + 2] benzannulation. The structure of 1 is unambiguously confirmed by X-ray crystallography; 1 adopted a twisted geometry due to the steric hindrance of the phenyl rings and the hydrogen substituents at the bay regions. Notably, compound 1

• 1 were obtained by slow evaporation from a carbon disulfide solution, allowing us to disclose the molecular structure by X-ray crystallography (Figure 2a). As shown in Figure 2a, the crystal structure of 1 clearly displayed a nonplanar conformation, resulting from steric repulsion between the phenyl

Reaction of indoles with aromatic fluoromethyl ketones: an efficient synthesis of trifluoromethyl(indolyl)phenylmethanols using K₂CO₃/n-Bu₄PBr in water

• Thanigaimalai Pillaiyar,
• Masoud Sedaghati and
• Gregor Schnakenburg

Beilstein J. Org. Chem. 2020, 16, 778–790, doi:10.3762/bjoc.16.71

• combination of 20 mol % of tetrabutylammonium bromide (TBAB) and NaOH (20 mol %) yielded the desired product, 2,2,2-trifluoro-1-(1H-indol-3-yl)ethan-1-ol (3a) in 93% yield (Table 1, entry 4). The product 3a was isolated by filtration and confirmed by NMR and X-ray crystallography analysis (CCDC-1973322, see

Synthesis of six-membered silacycles by borane-catalyzed double sila-Friedel–Crafts reaction

• Yafang Dong,
• Masahiko Sakai,
• Kazuto Fuji,
• Kohei Sekine and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2020, 16, 409–414, doi:10.3762/bjoc.16.39

• reaction between 1a with 2a proceeded to give phenoxasilin 3a in 60% yield (Table 1, entry 1). The structure of phenoxasilin 3a was confirmed using single-crystal X-ray crystallography (see Supporting Information File 1 for details) [42]. Upon increasing the reaction temperature to 140 °C, the yield of 3a

Six-fold C–H borylation of hexa-peri-hexabenzocoronene

• Mai Nagase,
• Kenta Kato,
• Akiko Yagi,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2020, 16, 391–397, doi:10.3762/bjoc.16.37

• -catalyzed six-fold C–H borylation of HBC was successfully achieved by screening solvents. The crystal structure of hexaborylated HBC was confirmed via X-ray crystallography. Optoelectronic properties of the thus-obtained hexaborylated HBC were analyzed with the support of density functional theory

• calculations. The spectra revealed a bathochromic shift of absorption bands compared with unsubstituted HBC under the effect of the σ-donation of boryl groups. Keywords: C–H borylation; hexa-peri-hexabenzocoronene; iridium catalyst; X-ray crystallography; Introduction Polycyclic aromatic hydrocarbons (PAHs

• hexaborylated HBC 1. The structure of thus-obtained 1 was confirmed by X-ray crystallography, and the electronic effects of the boryl groups were investigated through optoelectronic measurements and density functional theory (DFT) calculations. Results and Discussion We have examined the conditions for C–H

Synthesis and circularly polarized luminescence properties of BINOL-derived bisbenzofuro[2,3-b:3’,2’-e]pyridines (BBZFPys)

• Ryo Takishima,
• Yuji Nishii,
• Tomoaki Hinoue,
• Yoshitane Imai and
• Masahiro Miura

Beilstein J. Org. Chem. 2020, 16, 325–336, doi:10.3762/bjoc.16.32

• Information File 290: Summary of X-ray crystallography data, copy of NMR spectra, and copy of HPLC charts. Funding This work was supported by JSPS KAKENHI Grant No. JP 19K15586 (Grant-in-Aid for Young Scientists) to Y.N. and JP 17H06092 (Grant-in-Aid for Specially Promoted Research) to M.M.

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

• editing and proofreading of the manuscript. We also thank Dr. Su-Ching Lin, Ms. Yi-Ping Huang, and Ms. Mei-Man Chen for their help with NMR experiments, Dr. Yuh-Sheng Wen for the X-ray crystallography experiment, and Ms. Ping-Yu Lin for conducting mass spectrometry experiments. Funding This work was

• clearly showed that the NHAc group in position C-5 and the OH-4 group were oriented in a trans-diaxial configuration (Figure 2a). This enhanced the nucleophilicity of the OH-4 group due to the absence of hydrogen bonding between these moieties. After confirming the structure of 4 by single crystal X-ray

• crystallography, compounds 2 and 3 were acetylated with Ac2O in the presence of a catalytic amount of 4-(dimethylamino)pyridine (DMAP) in pyridine to give 5 [6] and 6 in 75 and 77% yield, respectively (Scheme 1), and the compatibility of acetyl protecting groups with the Lewis acids during acetolysis reactions

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

• 12 led to single crystals suitable for X-ray crystallography. Its analysis (Figure 3) not only confirmed the structure, but in addition showed a well-organized crystal packing (Figure 4) where the alternate disposition of the molecules displayed a parallelism between the p-bromophenyl groups as well

A chiral self-sorting photoresponsive coordination cage based on overcrowded alkenes

• Constantin Stuckhardt,
• Diederik Roke,
• Wojciech Danowski,
• Edwin Otten,
• Sander J. Wezenberg and
• Ben L. Feringa

Beilstein J. Org. Chem. 2019, 15, 2767–2773, doi:10.3762/bjoc.15.268

• corresponding stable isomer. Supporting Information Supporting Information File 538: Experimental procedures, compound characterization, CD spectroscopy, binding studies, NMR studies of the photochemical and thermal isomerizations, X-ray crystallography, computational details and Cartesian coordinates of DFT

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

• , 0.012 and 0.087 for 4pzMe-Cl2, 4pzMe-OMe2 and 4pzMe-Pyr2, respectively; see Figure 6 for 4pzH-F2 and 4pzH-Cl2). To experimentally compare the conformations of the E-isomers, we were able to characterize 4pzMe-F2, 4pzMe-Cl2 and 4pzH-F2 by X-ray crystallography (Figure 7). In agreement with the

• characterization and X-ray crystallography data. Supporting Information File 536: CIF files for 4pzMe-F2, 4pzMe-OMe2, 4pzMe-OMe2_diethylether and 4pzH-F2. Acknowledgements J.C. acknowledges the Generalitat Valenciana for the postdoctoral APOSTD/2017/081 fellowship. R.S.L.G would like to thank the Faculty of

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

• . Unexpectedly, dinuclear and tetranuclear iron(II) complexes were obtained, which were thoroughly characterized by X-ray crystallography, magnetic measurements, and Mössbauer spectroscopy. The formation of multinuclear complexes is facilitated by two coordination sites of the diarylethene, acting as a bridging

• condensation [33] of 3-(hydroxyimino)pentane-2,4-dione, aniline, and 2-pyridinecarboxaldehyde (Scheme 1). The structure of 1 was confirmed by X-ray crystallography [34]. The ketone 1 was subsequently used for the synthesis of desired photochromic ligands with cyclopentenone (3), cyclopentene (4), and

• 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

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

Reversible switching of arylazopyrazole within a metal–organic cage

• Anton I. Hanopolskyi,
• Soumen De,
• Michał J. Białek,
• Yael Diskin-Posner,
• Liat Avram,
• Moran Feller and
• Rafal Klajn

Beilstein J. Org. Chem. 2019, 15, 2398–2407, doi:10.3762/bjoc.15.232

• coordination. Owing to its high water solubility, the cage can solubilize the E isomer of arylazopyrazole, which, by itself, is not soluble in water. NMR spectroscopy and X-ray crystallography have independently demonstrated that each cage can encapsulate two molecules of E-arylazopyrazole. UV-induced

• host is small and is mostly related to the positions of the Pd centers (Figure S16, Supporting Information File 1). We were pleased to find that the structural features of (E-1)22 resolved by X-ray crystallography were in full agreement with a detailed analysis of the complex’s NOE spectra (see Figure

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• date, CotB2 represents the best studied bacterial diterpene synthase. Its reaction mechanism has been addressed by isoptope labeling, targeted mutagenesis and theoretical computations in the gas phase, as well as full enzyme molecular dynamic simulations. By X-ray crystallography different snapshots of

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

• , confirming the lactone moiety, and the DEPT spectrum showed a new aliphatic methine resonance at 25.2 ppm. By HRESIMS mass data (found: 404.2020 for [M + H]+) a molecular formula of C26H26FNO2 was confirmed, excluding incorporation of HCl into this artefact. Finally, X-ray crystallography structure analysis

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

• Arnault Heynderickx,
• Sébastien Nénon,
• Olivier Siri,
• Vladimir Lokshin and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2019, 15, 2059–2068, doi:10.3762/bjoc.15.203

• 1112 instrument. HRMS was made at the Spectropole (http://fr-chimie.univ-amu.fr/spectropole/). The X-ray crystallography data were collected on a Bruker-Nonius KappaCCD diffractometer with CCD detector using Mo Kα radiation, λ = 0.71073 Å. Crystallographic data (excluding structure factors) for the

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

• ability of 3a to bind various anion species in gas phase. To our delight, host molecule 3a co-crystalized with n-Bu4NX (X = Cl, Br) from diffusion of diethyl ether vapor into ethyl acetate solution at ambient temperature to give single crystals of the host–guest complexes (n-Bu4NX)3-3a (X = Cl, Br). X-ray

• crystallography then allowed us to understand the host–guest interactions at the molecular level. As illustrated in the molecular structures in Figure 4, above the centroid of each tetrazine ring there resided a chloride or a bromide. The distance of the anion to the centroid of tetrazine ranged from 3.060 Å to

2,3-Dibutoxynaphthalene-based tetralactam macrocycles for recognizing precious metal chloride complexes

• Li-Li Wang,
• Yi-Kuan Tu,
• Huan Yao and
• Wei Jiang

Beilstein J. Org. Chem. 2019, 15, 1460–1467, doi:10.3762/bjoc.15.146

• butyl methylene group next to the oxygen atoms. A single crystal (Figure 2) of 1, which was suitable for X-ray crystallography, was obtained by slow evaporation of its solution in CH3CN. The crystal structure clearly shows that 1 adopts a flattened chair conformation with the two naphthalenes in

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

• -butylnitrite, BTEAC and DABSO in the presence of CuCl2 provided an unexpected 3H-indazole product 8. The structure of the compound was determined by HRMS, IR, NMR and further confirmed by single crystal X-ray crystallography. The compound crystallises in the triclinic P-1 space group, with unit cell parameters

• over anhydrous sodium sulphate and the solvent was removed under reduced pressure to give the pure product 8 (0.226 g, 0.485 mmol, 96%). The 1H NMR spectrum of the crude product indicates that it is pure and required no further purification. X-ray crystallography A colourless plate-like crystal of 8

Bambusuril analogs based on alternating glycoluril and xylylene units

• Tomáš Lízal and
• Vladimír Šindelář

Beilstein J. Org. Chem. 2019, 15, 1268–1274, doi:10.3762/bjoc.15.124

• product. Two disastereomers of the macrocycle were separated and characterized by means of NMR spectroscopy and X-ray crystallography. Conformational changes of these diastereomers were investigated using DFT models and variable-temperature NMR. Keywords: bambusurils; conformers; glycolurils; macrocycles

Heck- and Suzuki-coupling approaches to novel hydroquinone inhibitors of calcium ATPase

• Robert J. Kempton,
• Taylor A. Kidd-Kautz,
• Soizic Laurenceau and
• Stefan Paula

Beilstein J. Org. Chem. 2019, 15, 971–975, doi:10.3762/bjoc.15.94

• cancer cells. Even though the Boc group of 14 would not be present in the final cleavage product, it has been demonstrated for TG-based inhibitors that its presence did not affect inhibitory potency [22]. In support of this observation, X-ray crystallography revealed the location of the Boc group in a

Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests

• Fangfang Pan,
• Mohadeseh Dashti,
• Michael R. Reynolds,
• Kari Rissanen,
• John F. Trant and
• Ngong Kodiah Beyeh

Beilstein J. Org. Chem. 2019, 15, 947–954, doi:10.3762/bjoc.15.91

• guest inclusion in solution. Keywords: capsule; dimeric assemblies; halogen bonding; host–guest chemistry; resorcinarene salts; X-ray crystallography; Introduction The construction of specific supramolecular assemblies based on the directional non-covalent bonding has been a central goal of

• potential inclusion guests (Figure 1). The flexibility imparted to the host due to the lack of a defined inclusion guest in these systems is considerable and led to many amorphous systems, as expected. However, two samples were successfully crystallized and structurally characterized by single X-ray

• crystallography: MeOH-MeCN@1&DIOFB and Water@2&DIOFB. These two structures, besides illustrating the potential of halogen bonding for organizing complex capsular systems, shed light on the importance of flexibility in affecting the self-assembled systems. Results and Discussion Single crystal X-ray diffraction

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

• were measured with Gallenkamp melting point devices. X-ray crystallography was performed using a Rigaku R-AXIS RAPID IP diffractometer. HRMS: electron-spray technique (M+/M−) from the solution in MeOH (Waters LCT PremierTM XE UPLC/MS TOF (Manchester, UK)). All the computations were performed using the