Total synthesis of ent-pavettamine

• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2021, 17, 1440–1446, doi:10.3762/bjoc.17.99

• pavettamine, in order to obtain the enantiomer. The final deprotection step proved particularly efficient, with two protecting groups being removed simultaneously to unveil the desired target. Structure of pavettamine 1 and its enantiomer 2. Crystal structure of compound 9. Single crystal X-ray structure of

Stereoselective synthesis and transformation of pinane-based 2-amino-1,3-diols

• Ákos Bajtel,
• Mounir Raji,
• Matti Haukka,
• Ferenc Fülöp and
• Zsolt Szakonyi

Beilstein J. Org. Chem. 2021, 17, 983–990, doi:10.3762/bjoc.17.80

• enantioselective transformations, while the 2-phenyliminooxazolidines could be interesting in the field of antiproliferative or antioxidants studies based on our former studies on 2-imino-1,3-heterocycles [42][43]. Biologically active 2-amino-1,3-diols. NOESY experiments and X-ray structure elucidation of

• oxazolidin-2-one 9. NOESY experiments and X-ray structure proofment of the structure of oxazolidine 17. Proposed pathway for the ring–ring tautomerism. Stereoselective synthesis of the pinane-fused oxazolidin-2-one 9. Stereoselective synthesis of the pinane spiro-fused oxazolidin-2-one 12. Parallel synthesis

Menthyl esterification allows chiral resolution for the synthesis of artificial glutamate analogs

• Kenji Morokuma,
• Shuntaro Tsukamoto,
• Kyosuke Mori,
• Kei Miyako,
• Ryuichi Sakai,
• Raku Irie and
• Masato Oikawa

Beilstein J. Org. Chem. 2021, 17, 540–550, doi:10.3762/bjoc.17.48

• system towards the TKM-38 enantiomers. Final elaboration towards (2R)- and (2S)-TKM-38. Supporting Information Supporting Information File 12: Synthetic procedures. Supporting Information File 13: NMR spectra of all new compounds. Supporting Information File 14: X-ray structure of the menthyl ester 10

• . Supporting Information File 15: CIF file for the X-ray structure of the menthyl ester 10. Supporting Information File 16: Stereo diagrams for 10, 21*, and 21 as well as superimposed structures of the stable conformers of 10*. Supporting Information File 17: Assignments and intensities of all NOESY crosspeaks

Mesoionic tetrazolium-5-aminides: Synthesis, molecular and crystal structures, UV–vis spectra, and DFT calculations

• Vladislav A. Budevich,
• Sergei V. Voitekhovich,
• Alexander V. Zuraev,
• Vadim E. Matulis,
• Vitaly E. Matulis,
• Alexander S. Lyakhov,
• Ludmila S. Ivashkevich and
• Oleg A. Ivashkevich

Beilstein J. Org. Chem. 2021, 17, 385–395, doi:10.3762/bjoc.17.34

• ) level of theory [42]. X-ray structure determination Single crystal X-ray diffraction data of the mesoionic compounds 8a, 10, 11a, and salt 9 were collected on a SMART Apex II diffractometer using graphite monochromatic Mo Kα radiation (λ = 0.71073 Å) at a temperature of 100 K. The structures were solved

¹⁹F NMR as a tool in chemical biology

• Diana Gimenez,
• Aoife Phelan,
• Cormac D. Murphy and
• Steven L. Cobb

Beilstein J. Org. Chem. 2021, 17, 293–318, doi:10.3762/bjoc.17.28

• agreement to those predicted for modelled MTSL-TFET pairs in adjacent subunits in the X-ray structure, showing only small discrepancies. Overall, the results of this work clearly demonstrated the value of solution 19F NMR for quaternary structure determination and as an alternative approach for generating

Molecular basis for protein–protein interactions

• Brandon Charles Seychell and
• Tobias Beck

Beilstein J. Org. Chem. 2021, 17, 1–10, doi:10.3762/bjoc.17.1

• , whereas the X-ray structure of TMV at 2.45 Å, PDB: 1EI7 [96] is represented by ii, part c) shows the assembly of TMV [95]. The cryo-EM structure was able to elucidate loop regions that were not previously resolved in the X-ray structure. Schematic of the general assembly of charged protein containers to

Chiral anion recognition using calix[4]arene-based ureido receptors in a 1,3-alternate conformation

• Tereza Horáčková,
• Jan Budka,
• Vaclav Eigner,
• Wen-Sheng Chung,
• Petra Cuřínová and
• Pavel Lhoták

Beilstein J. Org. Chem. 2020, 16, 2999–3007, doi:10.3762/bjoc.16.249

• -acetylphenylalaninate. Design of chiral calix[4]arene-based receptors for anions. X-ray structure of 4a: (a) Top view into the cavity. (b) Side view of the same cavity. X-ray structure of 7a: (a) Hydrogen bonding interactions (black) in a dimeric motif, chalcogen interactions are shown in green. (b) π–π interactions in

• the dimeric motif. X-ray structure of 7d, showing hydrogen bonds between the ureido units (green) and hydrogen bonding of acetone molecules (black). One alkyl group in each calixarene was removed for better clarity. 1H NMR titration of 7c with N-acetyl-ᴅ-phenylalaninate and N-acetyl-ʟ-phenylalaninate

Selective and reversible 1,3-dipolar cycloaddition of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with 1,3-diphenylprop-2-en-1-ones under microwave irradiation

• Alexander P. Molchanov,
• Mariia M. Efremova,
• Mariya A. Kryukova and
• Mikhail A. Kuznetsov

Beilstein J. Org. Chem. 2020, 16, 2679–2686, doi:10.3762/bjoc.16.218

• [1,2-a]pyrazoles (Michael-type adducts). For the first time it was shown, that under heating the cycloadducts can undergo cycloreversion with the generation of new azomethine imines, which can be trapped with suitable dipolarophiles. Single-crystal X-ray structure of compound 3e. Single-crystal X-ray

• structure of compound 3g. The two types of azomethine imines (AMI). Reaction of 1,5-diazabicyclo[3.1.0]hexanes 1a–d with diarylpropenones 2a–l. Control experiments. Mechanistic hypothesis for cycloaddition and cycloreversion reactions of diazabicyclohexane 1a with propenone 2f. Experiments on the trapping

Synthesis and characterization of S,N-heterotetracenes

• Astrid Vogt,
• Florian Henne,
• Christoph Wetzel,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2020, 16, 2636–2644, doi:10.3762/bjoc.16.214

• quantitative yield [47]. Single crystals of intermediate thienopyrrole 25 were obtained by slow evaporation of a chloroform solution and an X-ray structure analysis was performed. Structural details and packing motifs of the molecule are described in Supporting Information File 1. Alkylation to N-propyl

Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes

• Thomas Schneider,
• Michael Keim,
• Bianca Seitz and
• Gerhard Maas

Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173

• NOESY NMR experiments and confirmed by an X-ray structure determination (see Figure 3). A mechanistic scheme for the formation of indenes 12 and benzo[a]fluorenes 13 is proposed in Scheme 5. The electrophilic propyn-1-iminium ion 1a adds chemoselectively (by conjugate addition) and regioselectively

• = −46.76 ppm, a value quite different from those of products 12 and 13) could finally be isolated in modest yield and was identified by an X-ray structure analysis as the CF3-substituted fulvene 19 (Scheme 7). A reaction pathway leading to fulvene 19 is proposed in Scheme 8. It begins with the formal [2

Metal-free synthesis of phosphinoylchroman-4-ones via a radical phosphinoylation–cyclization cascade mediated by K₂S₂O₈

• Qiang Liu,
• Weibang Lu,
• Guanqun Xie and
• Xiaoxia Wang

Beilstein J. Org. Chem. 2020, 16, 1974–1982, doi:10.3762/bjoc.16.164

• under metal-free conditions and uses cheap K2S2O8 as oxidant with easy handling and a broad substrate scope. The reaction proceeds through a radical phosphinoylation–cyclization via a tandem C–P and C–C-bond formation. Biologically active compounds featuring the chroman-4-one framework. X-ray structure

Synthesis, docking study and biological evaluation of ᴅ-fructofuranosyl and ᴅ-tagatofuranosyl sulfones as potential inhibitors of the mycobacterial galactan synthesis targeting the galactofuranosyltransferase GlfT2

• Marek Baráth,
• Jana Jakubčinová,
• Zuzana Konyariková,
• Stanislav Kozmon,
• Katarína Mikušová and
• Maroš Bella

Beilstein J. Org. Chem. 2020, 16, 1853–1862, doi:10.3762/bjoc.16.152

• enzymes require an activated sugar donor uridine diphosphate (UDP)-Galf, which is synthesized from UDP-galactopyranose (UDP-Galp) by the enzyme UDP-Galp mutase [9] (Supporting Information File 1, Figure S1). The recently published GlfT2 X-ray structure with a UDP donor part [10] was used in the reaction

• proposed structures nicely follow the probable TS structure of the GlfT2 catalytic reaction as is shown in Supporting Information File 1, Figure S2. The available GlfT2 X-ray structure contains only the UDP part of the native UDP-Galf donor substrate (PDB ID: 4FIY). The structure of the UDP-Galf was docked

• into the GlfT2 structure to obtain the docking score of the native substrate. The observed UDP-Galf docking score serves as a reference for the studied compounds. The obtained UDP-Galf docking pose showed almost the same binding mode of the UDP moiety as UDP present in the X-ray structure (Supporting

Rearrangement of o-(pivaloylaminomethyl)benzaldehydes: an experimental and computational study

• Csilla Hargitai,
• Györgyi Koványi-Lax,
• Tamás Nagy,
• Péter Ábrányi-Balogh,
• András Dancsó,
• Gábor Tóth,
• Judit Halász,
• Angéla Pandur,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2020, 16, 1636–1648, doi:10.3762/bjoc.16.136

• elucidation of compounds 3a [1], 3b, 8a,b, and 23a,b was based on the molecular formula obtained from HRMS, comprehensive 1H and 13C NMR study and on the single-crystal X-ray structure of compounds 3a [1], 3b, 8b, 23a, and 23b (for spectra and detailed interpretation, see Supporting Information File 1

Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

• Natalie Lagesse,
• Luca Pisciottani,
• Maxime Douarre,
• Pascale Godard,
• Brice Kauffmann,
• Vicente Martí-Centelles and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128

• crystal X-ray structure of a doubly ferrocene-decorated [2]rotaxane are further reported. Keywords: ferrocene; macrocycle; rotaxane; single crystal X-ray structure; template; Introduction The development of interlocked molecules with tailored properties allowed the preparation of molecular machines able

• was E1/2 = +0.380 V vs SCE showing that rotaxane 1a retained the redox properties of the parent ferrocene [21][22]. Importantly, the full reversibility of the one electron oxidation–reduction process attested to the stability of the electroactive system. Solid-state X-ray structure The solid-state

• ferrocene units were electronically decoupled and retained the reversible oxidation properties of the parent compound, while the single crystal X-ray structure of a doubly ferrocene-decorated [2]rotaxane indicated four relatively long and seemingly weak NH···CO hydrogen bonds. As the [2]rotaxane could be

One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli–Cushman protocol

• Aleksandar Pashev,
• Nikola Burdzhiev and
• Elena Stanoeva

Beilstein J. Org. Chem. 2020, 16, 1456–1464, doi:10.3762/bjoc.16.121

• –0.200 mm). High-resolution mass spectra (HRMS) were acquired on a Thermo Scientific, model Q-Exactive high resolution LC–MS/MS with a resolution of up to 150000FWHM at m/z 200. X-ray structure determination: Colorless single crystals of compounds 25 and 26 were obtained from DMSO/H2O. Diffraction data

One-pot synthesis of 1,3,5-triazine-2,4-dithione derivatives via three-component reactions

• Gui-Feng Kang and
• Gang Zhang

Beilstein J. Org. Chem. 2020, 16, 1447–1455, doi:10.3762/bjoc.16.120

• . Selected examples of triazinethione-containing bioactive compounds. X-ray structure of 6-(methylthio)-4-phenyl-3,4-dihydro-1,3,5-triazine-2(1H)-thione (6aa) with thermal ellipsoids at 50% probability (CCDC 1991859). Strategies for the synthesis of triazinethiones. Aldehyde substrate scope of three

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

• -fused PAHs in large π-systems. High-resolution MALDI-TOF mass spectrum of 1. Inset: isotopic distribution compared to mass spectrum simulated for C84H50. Single-crystal X-ray structure of 1. (a) Top view and (b) side view of the (P,P) isomer. c) Crystal packing of the enantiomer pairs (P,P and M,M) of 1

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• porphyrin/BODIPY dimers. Moreover, the synthesis of one unsymmetric porphyrin dimer 16 and a porphyrin-linked bistriptycene 18 was also achieved. A single crystal X-ray structure of the former highlighted the evident linearity in the system and arrangement of the porphyrins at a dihedral angle of 66.84

• charge from The Cambridge Crystallographic Data Centre via http://www.ccdc.cam.ac.uk/data_request/cif. Triptycene as a scaffold and selected porphyrin and BODIPY arrays. Single crystal X-ray structure of triptycene 5. (a) Molecular structure of 5 in the crystal with hydrogen atoms and minor disorder

• (iii) of another triptycene molecule. Hydrogen atoms and minor disorder omitted for clarity (thermal displacement 50%). Single crystal X-ray structure of triptycene-linked zinc-nickel porphyrin dimer 16 showing the conformation within the crystal structure; (a) top-view of zinc porphyrin; (b) top-view

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

• Zeguo Fang,
• Nawaf Al-Maharik,
• Peer Kirsch,
• Matthias Bremer,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2020, 16, 674–680, doi:10.3762/bjoc.16.65

• isomer 11b for subsequent analysis. Stereoisomer 11a was a crystalline solid and a suitable crystal was subject to X-ray structure analysis and the structure is shown in Scheme 4. In this way the stereochemistry of 11a and 11b could be confirmed unambiguously. Evaluation of liquid crystal candidates 8

• , and that of the X-ray structure, suggests that the equatorial conformers will dominate in condensed phases, and that the overall molecular dipoles will not be compromised by minor contributions of axial conformers. Conclusion In conclusion, a series of candidate liquid crystals 8–11a with

Direct borylation of terrylene and quaterrylene

• Haruka Kano,
• Keiji Uehara,
• Kyohei Matsuo,
• Hironobu Hayashi,
• Hiroko Yamada and
• Naoki Aratani

Beilstein J. Org. Chem. 2020, 16, 621–627, doi:10.3762/bjoc.16.58

• tetra-borylated quaterrylene despite a low yield. The post modification of rylenes enables us to prepare their borylated products as versatile units after creating the rylene skeletons. Keywords: borylation; π-conjugation; oligorylene; single crystal X-ray structure; solubility; Introduction Compared

• -bridging oligorylenes, d) bay-alkoxy oligorylenes, and e) tetra-tert-butyl oligorylenes. (Top) Single crystal X-ray structure of TB4. The thermal ellipsoids are scaled at 50% probability. (Bottom) Packing diagram of TB4. The solvent molecules are omitted for clarity. UV–vis absorption and fluorescence

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• was also confirmed by its preliminary X-ray structure (Figure S20b, Supporting Information File 1). The 1H NMR spectra of the BODIPY derivatives in CDCl3 reflect the characteristic structural features. The proton signals assignable to the α-pyrrolic CHs appeared in the lowest field region (δ ca. 8.00

Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds

• Vuyisa Mzozoyana,
• Fanie R. van Heerden and
• Craig Grimmer

Beilstein J. Org. Chem. 2020, 16, 190–199, doi:10.3762/bjoc.16.22

• this F···H interaction. The single crystal X-ray structure and the DFT-optimized structure showed that the fluorinated phenyl ring favors the orientation with the fluorine atom closer to H5 than H3. The X-ray structure also showed the existence of the intermolecular C–F···H–C interaction. Keywords

• basis set, as implemented in Gaussian-09W (Rev. C.01) [45]. The superposition of the single-crystal X-ray structure (red) and the optimized structure (green) is shown in Figure 4. The DFT optimized geometric structure is shown in Figure 5 and has a dihedral angle, Φ (C2'–C1'–C4–C4a) of 65.3°. Following

• ) whereas C4 and C4a are not. The 2D HOESY spectrum shows the F···H5 coupling and also F···H3 coupling, seemingly weaker than F···H5 since splitting of the H3 signal is not observed in the 1H and 1H-{19F} 1D spectra. The single crystal X-ray structure showed that the fluorinated phenyl ring is orientated in

The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates

• Narasimhamurthy Rajeev,
• Toreshettahally R. Swaroop,
• Ahmad I. Alrawashdeh,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Seegehalli M. Anil,
• Kuppalli R. Kiran,
• Chandra,
• Paris E. Georghiou,
• Kanchugarakoppal S. Rangappa and
• Maralinganadoddi P. Sadashiva

Beilstein J. Org. Chem. 2020, 16, 159–167, doi:10.3762/bjoc.16.18

• , however, carbamothioates 4a–l were instead obtained in 76–88% yield (Scheme 1). Herein, we report on this intriguing finding and show several examples, including a single crystal X-ray structure of one of the products so obtained. A plausible mechanism to explain the reaction using density functional

• -311++G(d,p) level of theory, with solvent corrections for chloroform, for two rotamers, namely 4cA and 4cB (generically represented as 4A and 4B in Figure 3). These structures were generated based on the X-ray structure of 4c and afforded a computed Gibbs free energy difference of −1.769 kJ mol−1 in

Understanding the role of active site residues in CotB2 catalysis using a cluster model

• Keren Raz,
• Ronja Driller,
• Thomas Brück,
• Bernhard Loll and
• Dan T. Major

Beilstein J. Org. Chem. 2020, 16, 50–59, doi:10.3762/bjoc.16.7

• reaction. The coordinates of the amino acids and the substrate GGPP were taken from the corresponding X-ray structure, with a resolution of 1.8 Å [42]. In this approach, geometry optimizations with the “Modredundant” keyword were performed, and the active site residues, diphosphate moiety, and magnesium

Palladium-catalyzed synthesis and nucleotide pyrophosphatase inhibition of benzo[4,5]furo[3,2-b]indoles

• Hoang Huy Do,
• Saif Ullah,
• Alexander Villinger,
• Joanna Lecka,
• Jean Sévigny,
• Peter Ehlers,
• Jamshed Iqbal and
• Peter Langer

Beilstein J. Org. Chem. 2019, 15, 2830–2839, doi:10.3762/bjoc.15.276

• find docking calculations and scoring functions. Out of 40 conformations for each compound, the conformations with lowest free binding energies and S score were selected for visualization by using Discovery studio visualizer DS [47][48]. X-ray structure determination An X-ray quality crystal of 5d was