(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• concentrations of 1a. Photocatalytic CO2 reduction tests with different concentrations of HFIP.a Supporting Information Additional information regarding the instrumentation, structural analyses, and X-ray structures is provided. Crystal structures were deposited in the Cambridge Crystallographic Data Centre

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• : (i) FAIR open data from X-ray structures and Mercury® 2020.1 Software (Cambridge Crystallographic Data Center) to create Figures 1b (CCDC number 1943103), 3b (CCDC number 2018646) and 4 (CCDC numbers 2090727 and 2090729); (ii) chemical structures employing ChemBioDraw® Ultra 12.0 (CambridgeSoft

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• the extent of π-conjugation and the efficiency of particular donor–acceptor conjugation path in these new compounds. X-ray structures and absorption spectra of doubly protonated tetrafluoroborate salts of the oligomers are also discussed. Keywords: 1,8-bis(dimethylamino)naphthalene; cross-conjugated

• were obtained in good yields regardless of the substituent R in the benzene ring. Treatment of the latter with fluoroboric acid in dichloromethane gave double salts 11a–e. X-ray structures Slow evaporation of solutions of butadiynes 5 in the CHCl3/EtOAc system made it possible to grow single crystals

Synthesis, α-mannosidase inhibition studies and molecular modeling of 1,4-imino-ᴅ-lyxitols and their C-5-altered N-arylalkyl derivatives

• Martin Kalník,
• Sergej Šesták,
• Juraj Kóňa,
• Maroš Bella and
• Monika Poláková

Beilstein J. Org. Chem. 2023, 19, 282–293, doi:10.3762/bjoc.19.24

• active site almost identical to those of human GMII [22]. In addition, analysis of the available X-ray structures of GH38 enzymes such as dGMII [23], bovine lysosomal α-mannosidase II (bLMan) [17] and JBMan [24] showed that the active sites of Golgi and acidic α-mannosidases are structurally very similar

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• estimates obtained consequently correlated with the results from the 1H NMR analyses to varying degrees from very good to fair. PXRD patterns generated from the final single crystal X-ray structures were in good agreement with the respective PXRD patterns of the CD complexes formed via co-precipitation

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• /methanol, this H-bond is broken and two new H-bonds are formed resulting in a less strained structure with a normal pyramidal geometry of the N-4 nitrogen atom. The calculated structural metrics of complexes modeled by DFT are close to those observed in the X-ray structures. The formation of inclusion

• -tetraazaadamantane motif in X-ray structures of the obtained N-TAAD derivatives (representation of non-hydrogen atoms as thermal ellipsoids at 50% probability level). Anions and crystal-solvate molecules are omitted for clarity. (a) 4a·HCl·H2O·MeOH. (b) 4c·HCl·3.5MeOH. (c) Bn-4c·3CD3OD (bromide salt). (d) 8a. (e

Mechanochemical halogenation of unsymmetrically substituted azobenzenes

• Dajana Barišić,
• Mario Pajić,
• Ivan Halasz,
• Darko Babić and
• Manda Ćurić

Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69

• Information Supporting Information File 167: Detailed experimental procedures, complete characterization data for new compounds, X-ray structures of compounds, and the results of in situ Raman monitoring. Supporting Information File 168: X-ray crystallographic data. Funding Financial support was provided by

Flow synthesis of oxadiazoles coupled with sequential in-line extraction and chromatography

• Kian Donnelly and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 232–239, doi:10.3762/bjoc.18.27

• solving all X-ray structures reported in this article. Funding M.B. thanks the Royal Society of Chemistry for a Research Enablement Grant (E20-2998) as well as Science Foundation Ireland for generous support of our research program through grants 19/IFA/7420, 18/RI/5702 and 12/RC2275_P2. Support from the

Structural effects of meso-halogenation on porphyrins

• Keith J. Flanagan,
• Maximilian Paradiz Dominguez,
• Zoi Melissari,
• Hans-Georg Eckhardt,
• René M. Williams,
• Dáire Gibbons,
• Caroline Prior,
• Gemma M. Locke,
• Alina Meindl,
• Aoife A. Ryan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

• . Additionally, we have used density functional theory calculations to determine the structure of several halogenated porphyrins. This contrasts conformational analysis with existing X-ray structures and gives a method to characterize samples that are difficult to crystallize. By using the methods outlined above

Biochemistry of fluoroprolines: the prospect of making fluorine a bioelement

• Vladimir Kubyshkin,
• Rebecca Davis and
• Nediljko Budisa

Beilstein J. Org. Chem. 2021, 17, 439–460, doi:10.3762/bjoc.17.40

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

• -containing alkylation reagents [27]. Very recently, this aminide was found to be a suitable ligand for manganese complexes [28] and used as the agent for the preparation of salts with high energy density [29]. Also, it is worth noting that today only a few examples of mesoionic tetrazole aminide X-ray

• structures are known [17][28]. Thus, the information on tetrazole-5-aminides is very limited and fragmentary. In the present work, we try to fill this gap by carrying out experimental (synthesis, X-ray, UV–vis) and theoretical density functional theory (DFT) studies of some selected 1,3-dialkyltetrazolium-5

Synthesis, crystal structures and properties of carbazole-based [6]helicenes fused with an azine ring

• Daria I. Tonkoglazova,
• Anna V. Gulevskaya,
• Konstantin A. Chistyakov and
• Olga I. Askalepova

Beilstein J. Org. Chem. 2021, 17, 11–21, doi:10.3762/bjoc.17.2

• were used as starting materials. To discern the effect of merging an azine moiety within a helical skeleton, the X-ray structures, UV–vis absorption and fluorescence spectra of the helicenes were investigated and compared to that of the parent carbazole-based [6]helicene (7H-phenanthro[3,4-c]carbazole

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

• shown by the X-ray structures of these compounds (Figure 1 and Figure 3), and also reflected by their low 3J(H,H) coupling constants (ca. 1 Hz) detected in CDCl3 solution. In the 1H NMR spectra of compounds 3b, 8a,b, and 23a, the δΝΗ chemical shifts appeared in a narrow range between 9.39–9.06 ppm

• (182 mg, 18%) was isolated as white solid. Analytical data are identical with those described in Method A. X-ray structures of compounds 3b (left) and 8b (right). Gibbs free energy diagram for the 1→2 rearrangement. X-ray structures of compounds 23a (left) and 23b (right). Structures of the minimal

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

• rotaxane 1a (top) and thread 4a (bottom) in CDCl3 (a designation of the signals is described in Figure 2). 1H,1H-ROESY NMR spectrum (600 MHz) of the rotaxane 1a in CDCl3. Cyclic voltammogram of ferrocene rotaxane 1a (0.67 mM) in CH2Cl2/CH3CN 1:5 (TBAPF6 0.10 M, scan rate = 10 mV/s). Single crystal X-ray

• structures of (a) rotaxane 1a and (b) Leigh’s rotaxane I [4]. Selected H···O distances from the solid-state structures. Supporting Information Supporting Information File 71: Further experimental details and NMR spectra of new compounds. Supporting Information File 72: X-ray data of rotaxane 1a

Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

• Carlos H. Escalante,
• Eder I. Martínez-Mora,
• Carlos Espinoza-Hicks,
• Alejandro A. Camacho-Dávila,
• Fernando R. Ramos-Morales,
• Francisco Delgado and
• Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

• 8b/7c and 8c/7c (Figure 4a,b and Supporting Information File 1, Appendix 6). All the observable π···π interactions were parallel-displaced (offset) π-stacking, and the distance values were within the range of the known values, whether determined from X-ray structures or calculated values (3.2–4.0 Å

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

• geometry of ortho-halogenated Z-arylazopyrazoles. Description of the lowest-lying n–π* excitation for the Z-isomers of halogenated 4pzH-F2 and 4pzH-Cl2 photoswitches. Description of the lowest-lying n–π* excitation for the E-isomers of halogenated 4pzH-F2 and 4pzH-Cl2 photoswitches. X-ray structures of

Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis

• Zhen Cao,
• Aline Lacoudre,
• Cybille Rossy and
• Brigitte Bibal

Beilstein J. Org. Chem. 2019, 15, 2465–2472, doi:10.3762/bjoc.15.239

• . These silver(I) complexes adopted similar structures in solution and in the solid state. As each sulfur atom in the ligand is prochiral, macrocycles L2M2 were obtained as mixtures of diastereoisomers, depending on the configurations of the sulfur atoms coordinated to silver cations. The X-ray structures

• acetate 70:1) to obtain pyrrole 5. X-ray structures of complex 1a, as two diastereoisomeric macrocycles (R,S-1)2·(AgOTf)2 with ligands assembled in: (a) a head-to-head fashion and, (b) a head-to-tail mode. Hydrogen atoms are omitted for clarity. X-ray structure of complex 1c, as a (R,S-1)4·(AgNO3)6 cage

• -atropisomer. Addition/cycloisomerization of alkyne 2.a Condensation/cycloisomerization of alkyne 3.a Supporting Information Supporting Information File 385: Synthesis and characterization data of ligand and silver complexes, details of X-ray structures. Supporting Information File 386: Crystallographic

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

• level optimized and experimental geometry of THTAA and its derivatives show considerable loss of aromaticity within the quinoxaline moiety. Keywords: aromaticity; density functional calculations; heterocycles; hydrogen bonds; X-ray structures; Introduction Quinoxaline derivatives 1 – also called

• the synthesis and purification of THTAA (3), and report on the results of our investigation based on the quantum mechanical calculations, X-ray structures and electronic absorption spectra of 3 and a number of its derivatives. Results and Discussion Synthesis, purification and chemical modification of

• , 6a and 7a obtained by calculations are in good agreement with the X-ray structural data (Table 1). The geometry optimized structures confirm that the bond lengths equalization and the aromaticity loss observed in the X-ray structures stem from the intramolecular charge transfer from the electron

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

• useful catalysts that control the regiospecificity in an environmentally friendly manner. The information from their X-ray structures will contribute to future engineering of PTases. Furthermore, the structure of AmbP1 can serve as a model to alter the reaction through creating a metal binding site

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

• reasons why it is able to accommodate quite a disparity of encapsulated guests [45][46][47][48][49]. In Figure 3 is a collection of different [2]rotaxane X-ray structures with tetralactam A as the surrounding macrocycle. The collection has been divided into four groups according to the macrocyclic

• excellent guests [24]. Shown in Figure 5b are X-ray structures of AuBr4− inside organic-soluble versions of tetralactam B and C with 9,10-anthrylene or 2,3,5,6-tetramethyl-1,4-phenylene sidewalls, respectively. Solution-state binding studies in organic solvents showed that tetralactam C exhibited higher

• are omitted for clarity. Selected X-ray structures of [2]rotaxanes with tetralactam A as the surrounding macrocycle reported by groups led by Leigh, Smith, Cooke, and Berná [37][39][50][52][53][54][55][56]. (a) Chemical structures of squaraine, thiosquaraine, croconaine, and acene guests that can bind

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

• , Finland Oakland University, Department of Chemistry, 146 Library Drive, Rochester, Michigan, 48309-4479, USA 10.3762/bjoc.15.91 Abstract Single crystal X-ray structures of halogen-bonded assemblies formed between host N-hexylammonium resorcinarene bromide (1) or N-cyclohexylammonium resorcinarene

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• solvent-assisted grinding using ethanol (Figure 25). The single crystal X-ray structures of the obtained co-crystals 44–46 were reported to match with the solution-phase co-crystals. They have also studied energy levels, thermal properties and the stability of these structures through DFT calculations

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

• hydrogen bonds [74]. X-ray structures of BIFOXSi(OH)2 (9, Figure 16) and BIFOXSiCl(OH) (8, Figure 17) with co-crystallized acetone indicate the bonding behavior of the silanediols to carbonyl acceptors. Chlorosilanol 8 binds one acetone with a bonding length of 2.16(0) Å (H3···O4) and 2.89(4) Å (O3–H···O4

Computational characterization of enzyme-bound thiamin diphosphate reveals a surprisingly stable tricyclic state: implications for catalysis

• Ferran Planas,
• Michael J. McLeish and
• Fahmi Himo

Beilstein J. Org. Chem. 2019, 15, 145–159, doi:10.3762/bjoc.15.15

• to identify tricyclic intermediates on ThDP-dependent enzymes. Critically, even though they were treated dismissively, there are two X-ray structures which, at a minimum, provide unambiguous evidence for the formation of stable tricyclic intermediates on an enzyme [46][47]. Additional evidence

• evidence for the slow first step, i.e., formation of the mandelylThDP adduct [29]. In addition to BFDC, the X-ray structures of tricyclic intermediates suggest that an even greater stabilization is present on phosphoketolase and acetolactate synthase. It could well be argued that TC stabilization may prove