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

• NMR spectroscopy, HRMS data and X-ray crystal structure analysis. Keywords: atorvastatin; crystal structure; cyclization; degradation products; fragmentation; stress test; Introduction Over the past decades, the general trend toward globalization of the supply chains for active pharmaceutical

• isopropyl residue, originally located at C-2 of the pyrrole, is shifted to C-3, rendering the annulated, tetrasubstituted pyrrole 6. The structure of 6 was confirmed by X-ray crystal structure analysis. However, most likely cleavage of the carboxanilide moiety (compare formation of 7 from atorvastatin with

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

• . Cyclization of 1-(2-bromophenyl)benzimidazoles with chalcogen elements.a Absorption spectroscopy dataa. Supporting Information Supporting Information File 401: Experimental details and analytical data, copies of absorption and NMR spectra. Supporting Information File 402: X-ray crystal structure of 2a

Fluorinated azobenzenes as supramolecular halogen-bonding building blocks

• Esther Nieland,
• Oliver Weingart and
• Bernd M. Schmidt

Beilstein J. Org. Chem. 2019, 15, 2013–2019, doi:10.3762/bjoc.15.197

• to facilitate readability. a) Space-filling model of U1···A2. The kinked alignment of both the lutidine units of U1 and the azobenzenes A2 can be seen. b) Part of the X-ray crystal structure showing the halogen bonding azobenzene A2 in detail. Selected bond lengths: N3–I1 2.7810(2), I2–N4 2.816(2) Å

Inherent atomic mobility changes in carbocation intermediates during the sesterterpene cyclization cascade

• Hajime Sato,
• Takaaki Mitsuhashi,
• Mami Yamazaki,
• Ikuro Abe and
• Masanobu Uchiyama

Beilstein J. Org. Chem. 2019, 15, 1890–1897, doi:10.3762/bjoc.15.184

• terpene cyclase active site [3][5][6]. Although many terpene cyclases are known [6][7][8][9][10], it is still challenging to identify the precise initial conformation of the oligoprenyl diphosphate substrate in the active site, even by X-ray crystal structure determination. This is because the substrate

Molecular basis for the plasticity of aromatic prenyltransferases in hapalindole biosynthesis

• Takayoshi Awakawa and
• Ikuro Abe

Beilstein J. Org. Chem. 2019, 15, 1545–1551, doi:10.3762/bjoc.15.157

• (Figure 2B). Remarkably, AmbP3 also accepts (10S)-hapalindole A (HA), and transfers the dimethylallyl group onto the C-2 carbon of hapalindole A in normal prenylation mode to yield compound 3 (Figure 2B). X-ray crystal structure analysis of AmbP1 To understand the effect of Mg2+ ions on the AmbP1 reaction

• PTases that utilize a Mg2+ ion to reorganise the active site cavity to control the regiospecificity of the prenylation reaction. X-ray crystal structure analysis of AmbP3 The crystal structures of AmbP3 complexed with DMSPP/hapalindole U (HU structure) and A (HA structure) were each solved at 2.00 Å [14

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

• signals. X-ray crystal structure of 1b-1 (left), layered structure of crystal packing (right). Reaction of 2,4-dimethylglycoluril and m-xylylene dibromide. Supporting Information Supporting Information File 273: MS and NMR spectra, computational details and crystallographic data for macrocycles 1a and 1b

Molecular recognition using tetralactam macrocycles with parallel aromatic sidewalls

• Dong-Hao Li and
• Bradley D. Smith

Beilstein J. Org. Chem. 2019, 15, 1086–1095, doi:10.3762/bjoc.15.105

• shown that members of this tetralactam family are effective receptors for saccharides in water [65]. As shown by the X-ray crystal structure in Figure 7a, water-soluble versions of tetralactam B can nicely accommodate β-glucopyranose within the cavity [66]. There is a combination of hydrogen bonding

• inside tetralactam B. In (b) is an X-ray crystal structure of a complex comprised of a squaraine guest encapsulated by tetralactam B (X = CH, Z = t-Bu) in a flattened chair conformation [33]. In (c) and (d) are calculated structures (semiempirical, PM7) of complexes comprised of a thiosquaraine or

• croconaine, respectively, encapsulated by tetralactam B (X = CH, Z = t-Bu) in a boat conformation [57][58][59]. In (e) is an X-ray crystal structure of an azaacene guest encapsulated by tetralactam B (X = N, Z = H) in a boat conformation [25]. (a) Shape and electrostatic comparison of squaraine C4O2 core

Catalytic asymmetric oxo-Diels–Alder reactions with chiral atropisomeric biphenyl diols

• Chi-Tung Yeung,
• Wesley Ting Kwok Chan,
• Wai-Sum Lo,
• Ga-Lai Law and
• Wing-Tak Wong

Beilstein J. Org. Chem. 2019, 15, 955–962, doi:10.3762/bjoc.15.92

• Polytechnic University, Hung Hom, Kowloon, Hong Kong 10.3762/bjoc.15.92 Abstract New chiral atropisomeric biphenyl diols 3, 4 and 6 containing additional peripheral chiral centers with different steric bulkiness and/or electronic properties were synthesized. The X-ray crystal structure of 3 shows the

• Information File 1). Homo-coupling of (S)-b with Ni(COD)2 was achieved with very high diastereoselectivity and only a single atropisomer was formed. The X-ray crystal structure showed that it is (M)-(S,S)-3 (Figure 1). This high atropstereoselectivity is believed to be due to the energetically unfavorable

• formation of the other atropisomer (P)-(S,S)-3 as a higher steric repulsion is generated during the close approach of two bulky phenyl peripheral substituents. The X-ray crystal structure also reveals that an alternative formation of intra- and intermolecular hydrogen bonds [intra- D(OH···O): 1.951(3) Å

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

• spectroscopy) and in case of 3' and 5–8 also by X-ray crystal structure analysis. Characterization of complexes IR and NMR spectroscopy Table 1 lists selected analytical data for the synthesized compounds. The infrared spectra of 1–9 were recorded in the 4000–400 cm−1 spectral range. The IR spectra display in

A diastereoselective approach to axially chiral biaryls via electrochemically enabled cyclization cascade

• Hong Yan,
• Zhong-Yi Mao,
• Zhong-Wei Hou,
• Jinshuai Song and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2019, 15, 795–800, doi:10.3762/bjoc.15.76

• Me (3j). Pyridyl rings bearing multiple substituents were also tolerated (3k and 3l). The stereochemistry of the biaryl product was determined by obtaining an X-ray crystal structure of 3k. The t-Bu-substituted phenyl ring on the alkyne moiety containing an extra OMe (3m) or Me (3n and 3o) group was

Annulation of 1H-pyrrole-2,3-diones by thioacetamide: an approach to 5-azaisatins

• Aleksandr I. Kobelev,
• Ekaterina E. Stepanova,
• Maksim V. Dmitriev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2019, 15, 364–370, doi:10.3762/bjoc.15.32

• . Supporting Information Supporting Information File 28: Further experimental details, copies of 1H and 13C NMR spectra and X-ray crystal structure details. Acknowledgements The study was performed under the financial support of the Russian Ministry of Education and Science (project no. 4.6774.2017/8.9) and

Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes

• Falco Fox,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2019, 15, 167–186, doi:10.3762/bjoc.15.17

• computationally. Chlorosilanol 8ax, with the axial Si–OH alignment, is the thermodynamically more stable isomer (ΔEr = 2.7 kcal mol−1, Table 3), in accordance with X-ray crystal structure analyses of 8 (Figure 13). The first hydrolysis has a higher activation barrier than the second step, and thus appears to be

• -interactions with dotted lines (M06-2X-D3/6-311++G(d,p)(PCM=THF)//B3LYP-D3BJ/6-31G(d) at 298 K). X-ray crystal structure of BIFOXSiCl2 (7). H atoms on the chiral backbone are omitted for clarity issues and the ellipsoids are shown with 65% probability. X-ray crystal structure of BIFOXSiCl(OH) (8). H atoms on

• the chiral backbone are omitted for clarity issues and the ellipsoids are shown with 65% probability. X-ray crystal structure ofrac-BIFOXSi(OH)2 (9) forming dimers. H atoms on the chiral backbone are omitted for clarity issues and the ellipsoids are shown with 65% probability. For bond lengths and

Green synthesis of new chiral 1-(arylamino)imidazo[2,1-a]isoindole-2,5-diones from the corresponding α-amino acid arylhydrazides in aqueous medium

• Nadia Bouzayani,
• Jamil Kraїem,
• Sylvain Marque,
• Yakdhane Kacem,
• Abel Carlin-Sinclair,
• Jérôme Marrot and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2018, 14, 2923–2930, doi:10.3762/bjoc.14.271

• observed with a total trans-diastereoselectivity controlled by intramolecular hydrogen bonds. Chemical structures of analogues. NOEs correlation showing the stereochemistry of the compound 5a. X-ray crystal structure of 5f shown at the 30% probability level. Strategy for the formation of 1-(arylamino)-1H

Domino ring-opening–ring-closing enyne metathesis vs enyne metathesis of norbornene derivatives with alkynyl side chains. Construction of condensed polycarbocycles

• Ritabrata Datta and
• Subrata Ghosh

Beilstein J. Org. Chem. 2018, 14, 2708–2714, doi:10.3762/bjoc.14.248

• characterization data see Supporting Information File 1). The stereochemical orientation of the secondary hydroxy group was determined through X-ray crystal structure of a compound derived from it in a subsequent step. The primary hydroxy group in the diol 6 was then selectively protected to provide the silyl

• , 41.1, 45.7 and 68.8, one more aliphatic methylene unit than what the structure 12a requires (see Supporting Information File 1). This indicates that the metathesis product is not 9a. The structure of the metathesis product was finally settled by X-ray crystal structure (Figure 2) [48] (see Supporting

Synthesis and post-functionalization of alternate-linked-meta-para-[2ⁿ.1ⁿ]thiacyclophanes

• Wout De Leger,
• Koen Adriaensen,
• Koen Robeyns,
• Luc Van Meervelt,
• Joice Thomas,
• Björn Meijers,
• Mario Smet and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 2190–2197, doi:10.3762/bjoc.14.192

• amide derivative 20 and acid derivative 21 was performed with good overall yields (three steps), 80% and 54%. In the near future, the binding properties of these interesting alternate-linked-meta-para-thiacyclophanes will be investigated. X-ray crystal structure of alternate-linked-meta-para

Cobalt-catalyzed peri-selective alkoxylation of 1-naphthylamine derivatives

• Jiao-Na Han,
• Cong Du,
• Xinju Zhu,
• Zheng-Long Wang,
• Yue Zhu,
• Zhao-Yang Chu,
• Jun-Long Niu and
• Mao-Ping Song

Beilstein J. Org. Chem. 2018, 14, 2090–2097, doi:10.3762/bjoc.14.183

• characterization data of new compounds, and X-ray crystal structure details for 3aa. Supporting Information File 198: Crystallographic information file for compound 3aa. Acknowledgements The work was supported by the National Natural Science Foundation of China (Nos. 21772179, 21502173, 21672192), Outstanding

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

• ligand with three nitrogen donor atoms per metal center. Ligand 16-H2 was found to undergo complex formation with various copper, zinc, palladium and nickel salts. Figure 3 shows the X-ray crystal structure of 16·Ni2(OAc)2, obtained from ligand 16-H2 and two equivalents of nickel(ΙΙ) acetate. The

• nickel, copper and palladium salts. Figure 5 shows the X-ray crystal structure of 30·Pd2Br, obtained from ligand 30-H3 and two equivalents of palladium(ΙΙ) bromide. Each of the two palladium(ΙΙ) centers of the complex 30·Pd2Br is confined in a slightly distorted square planar geometry by three donor

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

• representative X-ray crystal structure of 17d is shown in Figure 3 [38]. Single crystals suitable for X-ray analysis of complexes 17d were obtained by slow evaporation of a mixture of dichloromethane and diethyl ether at about −4 °C. Crystallographic data and structure refinement parameters for 17d are

Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant

• Irina A. Mironova,
• Pavel S. Postnikov,
• Rosa Y. Yusubova,
• Akira Yoshimura,
• Thomas Wirth,
• Viktor V. Zhdankin,
• Victor N. Nemykin and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159

• Figure 2. The X-ray crystal structure 6-K is quite interesting. Each independent unit consists of a tetrameric aggregate, which holds together by relatively strong I=O···I intermolecular interactions formed between molecules of 6 (Figure 2). Two out of three molecules of 6 (those that include I(1) and I

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

• trapping of ketene generated from PQT 1a by benzalaniline (2a)a. Supporting Information Supporting Information File 404: Experimental details, copies of 1H and 13C NMR spectra of pyrimido[1,6-a]quinoxalines 3a–n, STA plots of PQT 1a–h and X-ray crystal structure details of compounds 3g,j

Host–guest complexes of conformationally flexible C-hexyl-2-bromoresorcinarene and aromatic N-oxides: solid-state, solution and computational studies

• Rakesh Puttreddy,
• Ngong Kodiah Beyeh,
• S. Maryamdokht Taimoory,
• Daniel Meister,
• John F. Trant and
• Kari Rissanen

Beilstein J. Org. Chem. 2018, 14, 1723–1733, doi:10.3762/bjoc.14.146

• both exo and endo complexes in acetone. Of note, the X-ray crystal structure of 3@BrC6 (Figure 3e) is obtained from methanol and is presented here only for reference, while its corresponding computational model was optimised using acetone media. To ensure that we were adequately screening the host

• stabilised through C–H···π interactions. Very low shift changes for 11 clearly point to a minimal interaction with the host. This is contrary to the X-ray crystal structure, 11@BrC6, where 11 and BrC6 are locked by several C–H···π interactions, and of more prominently remarkably short C–H···π(centroid

A conformationally adaptive macrocycle: conformational complexity and host–guest chemistry of zorb[4]arene

• Liu-Pan Yang,
• Song-Bo Lu,
• Arto Valkonen,
• Fangfang Pan,
• Kari Rissanen and
• Wei Jiang

Beilstein J. Org. Chem. 2018, 14, 1570–1577, doi:10.3762/bjoc.14.134

• -ray crystal structure of free ZB4 shows it to exist as a self-inclusion conformation in the solid state (Figure 1a). This conformation is different from the ones containing different lower-rim alkyl groups reported earlier [37][38]. Crystals were obtained by slow evaporation of the compounds’ CH3CN

• with TA4 has been 1.7 × 105 M−1. Similar differences were also observed for cations 9+ and 10+, their binding affinities with ZB4 were lower by 1–2 orders of magnitude than those with TA4. However, the small guests, such as 2+ and 6+–8+ share rather similar binding affinities to both ZB4 and TA4. The X

An unusual thionyl chloride-promoted C−C bond formation to obtain 4,4'-bipyrazolones

• Gernot A. Eller,
• Gytė Vilkauskaitė,
• Algirdas Šačkus,
• Vytas Martynaitis,
• Ashenafi Damtew Mamuye,
• Vittorio Pace and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2018, 14, 1287–1292, doi:10.3762/bjoc.14.110

• prepared. Moreover, the structure of a representative 5,5'-dioxo-4,4'-bipyrazole-4,4'-dicarboxylate was confirmed by X-ray crystal structure analysis. Keywords: dimerization; NMR (1H; 13C; 15N); pyrazolones; thionyl chloride; X-ray structure analysis; Introduction Many biologically active substances

• (Figure 1), while the molecular weight obtained by HRMS measurement ([M + Na]+ 485.1432) testified about the possible formation of a dimeric structure. Lastly, by X-ray crystal structure analysis the obtained product could be determined as the dimeric structure 3a (Scheme 2, Figure 2). In addition, HRMS

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

• using 1H and 13C NMR spectral data, HRMS, and IR spectroscopy. In addition, an X-ray crystal structure was obtained for pyrazolo[1,5-a]pyrimidinone 3m and is shown in Figure 2. Conclusion In conclusion, we have developed a new facile method for the one-pot microwave-assisted synthesis of substituted

• 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

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• site in the H4c promoter in treated cells, thereby inhibiting tumor growth in mice. Chenoweth and Dervan showed DNA structural distortion induced by an 8-ring cyclic Py/Im polyamide (conjugate 17) bound to the central 6 bp of the sequence d(5'-CCAGGCCTGG-3')2 by using a high resolution X-ray crystal

• structure as shown in Figure 7a [76]. This allosteric perturbation of the DNA helix by small molecules through binding at distinct locations on promoter DNA provides a clear understanding of how transcription factor activity could be disrupted and gene expressions could also be regulated. In order to target