N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• stereochemistry of these compounds were assigned based on the single-crystal X-ray diffraction analysis of azaspiroheptane 45 with a 9-fenanthryl substituent at 1-position. The same three-step procedure was applied by Reddy and co-workers to synthesize 1-substituted 2,6-diazaspiro[3.3]heptanes 48, starting in

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• in the efforts to explain the properties and reactivity of this class of compounds. In 1977, S. Ernst et al. proved by X-ray diffraction that biguanide has no hydrogen atom in position 3, an observation that has been later confirmed by quantum chemical geometry optimization studies (Figure 1, 1b) [1

Synthesis, structural characterization, and optical properties of benzo[f]naphtho[2,3-b]phosphoindoles

• Mio Matsumura,
• Takahiro Teramoto,
• Masato Kawakubo,
• Masatoshi Kawahata,
• Yuki Murata,
• Kentaro Yamaguchi,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2021, 17, 671–677, doi:10.3762/bjoc.17.56

• recrystallization. The molecular structure of 2, determined through single-crystal X-ray diffraction analysis, is illustrated in Figure 2, and selected geometrical parameters are shown in Table 1. The results revealed that the naphthalene and fused phosphole rings are almost coplanar (mean deviation = 0.030 Å). The

Synthesis of (Z)-3-[amino(phenyl)methylidene]-1,3-dihydro-2H-indol-2-ones using an Eschenmoser coupling reaction

• Lukáš Marek,
• Lukáš Kolman,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2021, 17, 527–539, doi:10.3762/bjoc.17.47

• solid state by X-ray diffraction. The important role of the intramolecular hydrogen bond fixing the (Z)-configuration has also been observed in the crystal structures of other 3-aminomethylidene derivatives containing a primary or secondary nitrogen [14][49][50][51][52]. The (Z)-configuration of the

A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

• Lucía Rossi-Fernández,
• Viviana Dorn and
• Gabriel Radivoy

Beilstein J. Org. Chem. 2021, 17, 519–526, doi:10.3762/bjoc.17.46

• confirming the heterogeneous nature of the catalytic method. The freshly prepared CoNPs/MgO catalyst was characterized by means of transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD) and

• . X-ray diffraction (XRD) analyses were performed using a Bruker AXS D8 Advance diffractometer, equipped with a Cu-Kα1,2 radiation source. Atomic absorption spectroscopy was carried out on a Perkin Elmer AAnalist200 spectrometer. X-ray photoelectron spectroscopic analyses (XPS) were performed on a PHI

Deoxygenative C2-heteroarylation of quinoline N-oxides: facile access to α-triazolylquinolines

• Geetanjali S. Sontakke,
• Rahul K. Shukla and
• Chandra M. R. Volla

Beilstein J. Org. Chem. 2021, 17, 485–493, doi:10.3762/bjoc.17.42

• ). Electronically rich Me and OMe groups at the 4- or 6-positions of N-oxides were tolerated and delivered the corresponding C2-triazolylquinolines 3z, 3aa and 3ab in 85–90% yield. Further, the structure was unambiguously confirmed by the single-crystal X-ray diffraction analysis of 3z [63]. Halogenated substrates

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

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• analysis of the structures of 56f, 13f, and 21f by X-ray diffraction crystallography revealed similar bond angle distortions [64][65]. A considerable delocalization of the positive charge in the aryl ring was therefore suggested (Scheme 15): in the dominant resonance form 25f’, 48f’, or 14f’, the α

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

• Sergey V. Norkov,
• Anton V. Cherkasov,
• Andrey S. Shavyrin,
• Maxim V. Arsenyev,
• Viacheslav A. Kuropatov and
• Vladimir K. Cherkasov

Beilstein J. Org. Chem. 2021, 17, 273–282, doi:10.3762/bjoc.17.26

• mixture. X-ray diffraction data revealed that the bond lengths distribution in the six-membered ring of 6b is typical of sterically hindered o-quinones. The annulated fragment including the 1,3-dithiole cycle and the malononitrile unit is almost flat. The six-membered o-quinone ring is distorted due to

• . Heating the mixture at 60 °C for 4 h does not result in any change of the color from that characteristic of o-quinone 4. After cooling of the solution red crystals of adduct 8 were isolated (see Figure 2 and Figure S6 in Supporting Information File 1). The X-ray diffraction study reveals that adduct 8 is

• bulky sulfur-containing group. The possible pathway for the following cyclization is the Michael addition of the sulfide atom to the central carbon of the acetylacetonate group [38][39][40][41]. The X-ray diffraction study as well as IR and NMR spectroscopy data reveal that in all synthesized compounds

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

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

• -detection (see Supporting Information File 1, Figures S38–S40). X-ray molecular structures The structures of the title compounds 10a–c were further explored by a single-crystal X-ray diffraction analysis (Figure 1, see also Supporting Information File 1, Figures S35–S37 and Table S1) and compared with that

• steps of the method are electrophile-induced 6-endo-dig cyclizations of ortho-alkynylated biaryls. The overall yields of helicenes in five stages of the synthesis exceed 30%. The single-crystal X-ray diffraction analysis revealed the non-planar crystal structures of the synthesized helicenes responsible

• studies and HRMS measurements (Centre for X-ray Diffraction Studies and Chemical Analysis and Materials Research Centre, Institute of Chemistry, St. Petersburg State University). Funding The authors gratefully acknowledge the Russian Foundation for Basic Research (grant No 18-03-00006) for financial

Construction of pillar[4]arene[1]quinone–1,10-dibromodecane pseudorotaxanes in solution and in the solid state

• Xinru Sheng,
• Errui Li and
• Feihe Huang

Beilstein J. Org. Chem. 2020, 16, 2954–2959, doi:10.3762/bjoc.16.245

• in the solid state. From single crystal X-ray diffraction, the linear guest molecules thread into cyclic pillar[4]arene[1]quinone host molecules in the solid state, stabilized by CH∙∙∙π interactions and hydrogen bonds. The bromine atoms at the periphery of the guest molecule provide convenience for

• maximum. This also indicated that the interactions between H and G were weak. Conclusion In summary, we constructed novel pseudorotaxanes based on a pillar[4]arene[1]quinone and 1,10-dibromodecane. Single crystal X-ray diffraction analysis showed an alkane molecule threaded into the cavities of two pillar

Regioselective synthesis of heterocyclic N-sulfonyl amidines from heteroaromatic thioamides and sulfonyl azides

• Vladimir Ilkin,
• Vera Berseneva,
• Tetyana Beryozkina,
• Tatiana Glukhareva,
• Lidia Dianova,
• Wim Dehaen,
• Eugenia Seliverstova and
• Vasiliy Bakulev

Beilstein J. Org. Chem. 2020, 16, 2937–2947, doi:10.3762/bjoc.16.243

• the heterocycle the N-sulfonyl amidines exist in either E- or Z-isomeric forms. Experimental X-ray diffraction study X-ray analyses were accomplished on an Xcalibur 3 diffractometer using the standard procedure (graphite-monochromated Mo Kα irradiation, ω-scanning with step 1o, T = 295(2) K (see

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

• Emese Gal,
• Luiza Gaina,
• Hermina Petkes,
• Alexandra Pop,
• Castelia Cristea,
• Gabriel Barta,
• Dan Cristian Vodnar and
• Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

• precipitated from the reaction mixture in crystalline form as depicted by scanning electron microscopy (SEM) analysis. The single crystal X-ray diffraction analysis disclosed the arrangement of the α-(arylamino)acetonitrile molecules in the aggregated crystalline state as a racemic mixture. The mutagenic

Synthesis and investigation of quadruplex-DNA-binding, 9-O-substituted berberine derivatives

• Jonas Becher,
• Daria V. Berdnikova,
• Heiko Ihmels and
• Christopher Stremmel

Beilstein J. Org. Chem. 2020, 16, 2795–2806, doi:10.3762/bjoc.16.230

• particular binding mode. However, it was shown by X-ray diffraction analysis of the G4-DNA-bound ligand 1e3 that the berberine unit binds to quadruplex DNA by π-stacking with the 3’-end quartet in a similar mode as the parent berberine; however, in the case of 1e3 the aryl-substituents of the side chain are

Synthesis of purines and adenines containing the hexafluoroisopropyl group

• Viacheslav Petrov,
• Rebecca J. Dooley,
• Alexander A. Marchione,
• Elizabeth L. Diaz,
• Brittany S. Clem and
• William Marshall

Beilstein J. Org. Chem. 2020, 16, 2739–2748, doi:10.3762/bjoc.16.224

• with hexane). Pure 2a was isolated after recrystallization from hexane (see Experimental section), and the structure was established by X-ray diffraction (Figure 1). 4-Azabenzimidazole (3) reacted with tetrakis(trifluoromethyl)-1,3-dithietane (1) under similar conditions, with the formation of the two

• isomeric products 3a and 3b (Scheme 2). The major isomer 3a was isolated in a pure form, and the structure was confirmed by X-ray diffraction. It should be pointed out that the 19F NMR spectra of the two isomers were very different. While the resonance corresponding to the CH(CF3)2 group in the spectrum of

• in the formation of two regioisomers, 4a and 4b (Scheme 3). In this context, the isomers 4a and 4b were separated by column chromatography (see Experimental section), and the structure of both was established by X-ray diffraction. In the 19F NMR spectra of both isomers 4a and 4b, the resonances

A heterobimetallic tetrahedron from a linear platinum(II)-bis(acetylide) metalloligand

• Matthias Hardy,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2020, 16, 2701–2708, doi:10.3762/bjoc.16.220

• succeed to obtain single crystals of our metallosupramolecular assemblies that were suitable for single-crystal X-ray diffraction experiments. Therefore, we generated energy-minimized gas phase structures of 4, employing a force-field approach using the GFN2-xTB approach recently established to model

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

• ). Accordingly, two characteristic signals for carbon atoms of the pyrazolidine ring are present in the 13C NMR spectrum – at 72.2 (2СН) and 68.7 (СН) ppm. The spatial configuration of the adducts 3e and 3g was further determined by single crystal X-ray diffraction analysis (Figure 1 and Figure 2). All products

• Resonance, Center for Chemical analysis and materials research and X-ray Diffraction Center, respectively.

Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate

• Stéphane Menuel,
• Sébastien Saitzek,
• Eric Monflier and
• Frédéric Hapiot

Beilstein J. Org. Chem. 2020, 16, 2598–2606, doi:10.3762/bjoc.16.211

• (Table 1). As expected, an increase in the SSA was observed upon grinding because of the reduction of the β-CD particle size. XRD analysis X-ray diffraction data give additional evidence for the crystallinity variation of the β-CD particles upon grinding. Figure 3 shows a series of X-ray powder

• diffraction X-ray diffraction (XRD) measurements were performed using a Rigaku ULTIMA IV diffractometer equipped with Cu anticathode (λKα = 1.5418 Å), Soller slits to limit the divergence of X-ray beam and a nickel foil filter to attenuate the CuKβ line. XRD patterns were recorded in the range of 3–50° (scan

Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes

• Henrik Hupatz,
• Marius Gaedke,
• Hendrik V. Schröder,
• Julia Beerhues,
• Arto Valkonen,
• Fabian Klautzsch,
• Sebastian Müller,
• Felix Witte,
• Kari Rissanen,
• Biprajit Sarkar and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2020, 16, 2576–2588, doi:10.3762/bjoc.16.209

• Information File 1). Slow diffusion of CH3CN into a concentrated solution of NDIC7 in CH2Cl2 yielded single crystals suitable for X-ray diffraction (Figure 2b). The macrocycle displays a folded conformation in the solid state due to the flexible linker, featuring an intramolecular NDI/naphthalene stacking

Synthesis of novel fluorinated building blocks via halofluorination and related reactions

• Attila Márió Remete,
• Tamás T. Novák,
• Melinda Nonn,
• Matti Haukka,
• Ferenc Fülöp and
• Loránd Kiss

Beilstein J. Org. Chem. 2020, 16, 2562–2575, doi:10.3762/bjoc.16.208

• (rac)-11b was unequivocally established by single-crystal X-ray diffraction (Figure 1). Then, the preparation of another model compound, the trans-annelated bicyclic carbamide derivative (rac)-13, was attempted. This compound was also unknown in the literature. In the reaction of commercially available

• both NOESY measurements and single-crystal X-ray diffraction (Figure 2 and Figure 3). The next rigid bicyclic system studied was the methyl diendo norbornene dicarboxylate 16. The treatment of 16 with NBS/Deoxo-Fluor® yielded the bromolactone (rac)-17a [37]. The reaction, when repeated only with NBS

Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

• Si-Yuan Liu,
• Xin-Rui Wang,
• Man-Ping Li,
• Wen-Rong Xu and
• Dietmar Kuck

Beilstein J. Org. Chem. 2020, 16, 2551–2561, doi:10.3762/bjoc.16.207

• the slight shift of the peaks further indicates the successful complexation of TBTQ-(OG)6 and C60. Simulations of complex TBTQ-(OG)6 C60 in water. In spite of numerous attempts, we failed to obtain good-quality crystals to determine the binding conformation of complex TBTQ-(OG)6 C60 by X-ray

• diffraction. Therefore, the optimized geometry of the 1:1 complex of TBTQ-(OG)6 C60 in water was simulated by density functional theory (DFT) calculations at the B3LYP/6-31G(d) level of theory, which was completed with the aid of Molclus, MOPAC, and ORCA 4.1.0 programs [54][55][56]. As shown in Figure 6, C60

Palladium nanoparticles supported on chitin-based nanomaterials as heterogeneous catalysts for the Heck coupling reaction

• Tony Jin,
• Malickah Hicks,
• Davis Kurdyla,
• Sabahudin Hrapovic,
• Edmond Lam and
• Audrey Moores

Beilstein J. Org. Chem. 2020, 16, 2477–2483, doi:10.3762/bjoc.16.201

• nanomaterials. Specifically, the deacetylation of ChNC into ChsNC led to a decrease in crystallinity in the nanomaterial. Indeed, this can be seen in the FTIR with the broadening of the N–H and O–H stretches from 3000–3500 cm−1. This was more notable in the powder X-ray diffraction (PXRD) spectra of ChNCs and

Design and synthesis of a bis-macrocyclic host and guests as building blocks for small molecular knots

• Elizabeth A. Margolis,
• Rebecca J. Keyes,
• Stephen D. Lockey IV and
• Edward E. Fenlon

Beilstein J. Org. Chem. 2020, 16, 2314–2321, doi:10.3762/bjoc.16.192

• appeared to hinder the formation of crystals suitable for X-ray diffraction to prove the topology of the product. The second-generation TLC approach to trefoil knots is presented here. It involves the binding of an electron-poor guest (2 or 3) in an electron-rich host (1) to promote the threading step, an

Convenient access to pyrrolidin-3-ylphosphonic acids and tetrahydro-2H-pyran-3-ylphosphonates with multiple contiguous stereocenters from nonracemic adducts of a Ni(II)-catalyzed Michael reaction

• Alexander N. Reznikov,
• Dmitry S. Nikerov,
• Anastasiya E. Sibiryakova,
• Victor B. Rybakov,
• Evgeniy V. Golovin and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2020, 16, 2073–2079, doi:10.3762/bjoc.16.174

• (Scheme 2). An X-ray diffraction study [50] of the formyl derivative 10a showed its (2R,3R,4S)-configuration (Figure 3). The absolute configuration of the other phosphonates 10b–d and 11b–d is assumed by analogy. Hydrogenation of phosphonates 6d,f with o-anisyl and bulky adamantan-1-yl substituents at the

• of Henry/acetalyzation reaction with phosphonate 6ea. Supporting Information Supporting Information File 451: Experimental procedures, copies of NMR, FTIR, and mass spectra, HPLC and X-ray diffraction data. Supporting Information File 452: Crystallographic information files (CIF). Funding The