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

• was discussed previously [29]. The reaction of 4 with malononitrile-derived gem-dithiolate (5b, Scheme 1, route 2) also proceeded under mild conditions in DMF and bicyclic o-quinone 6b was obtained in a good yield. The brown crystals suitable for X-ray analysis were grown from an acetone/diethyl ether

1,2,3-Triazoles as leaving groups in S_NAr–Arbuzov reactions: synthesis of C6-phosphonated purine derivatives

• Kārlis-Ēriks Kriķis,
• Irina Novosjolova,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 193–202, doi:10.3762/bjoc.17.19

• event. The SNAr–Arbuzov reaction of 2,6-bistriazolylpurines follows the general regioselectivity pattern of the C6-position being more reactive towards substitution, which was unambiguously proved by X-ray analysis of diethyl (9-heptyl-2-(4-phenyl-1H-1,2,3-triazol-1-yl)-9H-purin-6-yl)phosphonate

• chromatography. At the preparative level, the excess of P(OEt)3 was evaporated under vacuum (5 mbar) over 4–5 hours at 50 °C before further purification. The regioselectivity of the newly developed SNAr–Arbuzov reaction was unambiguously established by X-ray analysis of the product 4d, which was crystalized from

• : DMSO-d6, 90 °C. Single-crystal X-ray analysis of diethyl (9-heptyl-2-(4-phenyl-1H-1,2,3-triazol-1-yl)-9H-purin-6-yl)phosphonate (4d). CCDC-2044976. Structural diversity and synthetic methods of purinylphosphonates. MWI = microwave irradiation; LG = leaving group. Synthetic routes for the formation of

Au(III) complexes with tetradentate-cyclam-based ligands

• Ann Christin Reiersølmoen,
• Thomas N. Solvi and
• Anne Fiksdahl

Beilstein J. Org. Chem. 2021, 17, 186–192, doi:10.3762/bjoc.17.18

• -equivalent when coordinated to Au(III), as a result of the chiral centers in the ligand. The structure of 5a-Au(III) was not confirmed, due to the lack of a suitable crystal for X-ray analysis, hence, only a proposed structure for 5a-Au(III) is given (Scheme 3). Comparable effects for ligand 6a, Δδ1Hcoord

• , due to sample decomposition. Attempts to obtain crystals for X-ray analysis by slow diffusion of n-pentane into a DCM solution of the complexes were unsuccessful. Catalytic activity For evaluation of the catalytic ability of the new Au(III) complexes, alkyne carboalkoxylation [47][48] and

Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

• Michał M. Więcław and
• Bartłomiej Furman

Beilstein J. Org. Chem. 2021, 17, 115–123, doi:10.3762/bjoc.17.12

• Schwartz’s reagent-mediated reductive amide functionalization followed by a variant of the Ugi–azide multicomponent reaction. The anomeric configurations of two products were unambiguously confirmed by X-ray analysis. This work also describes examples of interesting further transformations of the title

• determine the structure of compounds 3a and 3e unambiguously by means of X-ray analysis, as shown in Figure 2. The configuration of the remaining glucose based products 3 was easily determined by the analysis of 1H-1H coupling constants and NOE effects. Unfortunately, the same approach was not possible in

• , potentially biologically active and organocatalytic compounds. Experimental Experimental procedures and other data are available in Supporting Information File 1. Key concepts behind the goal of this work [34]. ORTEP structures of compounds 3a and 3e obtained by X-ray analysis. Hydrogen atoms and benzyl

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

• in its length from the standard single C(sp2)–C(sp2) bond (ca. 1.48 Å). The X-ray analysis of quinoxaline-fused [6]helicene 10a revealed the presence of the face-to-face π–π interaction between the helicene aggregates. The racemic aggregation was composed by (P)- and (M)-enantiomers on the manner of

Synthesis of tetrafluorinated piperidines from nitrones via a visible-light-promoted annelation reaction

• Vyacheslav I. Supranovich,
• Igor A. Dmitriev and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 3104–3108, doi:10.3762/bjoc.16.260

• a cleaner process. However, the reaction of a nitrone obtained from cyclohexyl carboxaldehyde gave a complex mixture containing unidentified products. The structures of compounds 3f and 3h were established by X-ray analysis (CCDC, 3f: 2032382; 3h: 2032383). The proposed annelation mechanism is shown

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

• for N-acetyl-ʟ-phenylalaninate. The structures of some receptors were confirmed by single crystal X-ray analysis. Keywords: anion recognition; calixarene; chiral receptor; complexation; enantiodiscrimination; Introduction The recognition and complexation of anions has become undoubtedly one of the

• single crystal X-ray analysis. The compound crystallised in a tetragonal system, space group P41212 as a 1:1 complex with methanol used as a solvent for crystallisation. As shown in Figure 2, the calixarene clearly adopts the 1,3-alternate conformation with an almost ideal tetragonal shape of the cavity

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

• molecules of the synthesized α-(arylamino)acetonitrile derivatives in the aggregated crystalline state, single crystals suitable for X-ray analysis were obtained by crystallization from isopropanol. The crystallographic data for the structure 2a reported in this paper have been deposited at the Cambridge

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• sumanene provided the covalent adduct 171 with Cl atoms attached onto the Te atoms, confirmed by an X-ray analysis (Scheme 44). Having the quinone derivatives 166 and 167 in hands, they were next subjected to the condensation reaction with a variety of aryl-1,2-diamines 168 in the presence of AcOH to

Access to highly substituted oxazoles by the reaction of α-azidochalcone with potassium thiocyanate

• Mysore Bhyrappa Harisha,
• Pandi Dhanalakshmi,
• Rajendran Suresh,
• Raju Ranjith Kumar and
• Shanmugam Muthusubramanian

Beilstein J. Org. Chem. 2020, 16, 2108–2118, doi:10.3762/bjoc.16.178

• ). All the synthesized compounds 4a–l were confirmed by 1D and 2D NMR, IR spectroscopy and HRMS techniques. Additional evidence of the structures of these compounds was obtained based on the single-crystal X-ray analysis of 4h [71] (Figure 4). The nitrogen end of the thiocyanate attacks the azirine to

Isolation and structure determination of a tetrameric sulfonyl dilithio methandiide in solution based on crystal structure analysis and ⁶Li/¹³C NMR spectroscopic data

• Jürgen Vollhardt,
• Hans Jörg Lindner and
• Hans-Joachim Gais

Beilstein J. Org. Chem. 2020, 16, 2057–2063, doi:10.3762/bjoc.16.172

• in THF solution in fast equilibrium with a further aggregate, which is stable only at low temperatures. Keywords: crystal structure; dilithio sulfonyl methandiide; NMR; solution structure; X-ray analysis; Introduction Functionalized dilithio methandiides I–III (Figure 1) are a fascinating class of

Synthesis and highly efficient light-induced rearrangements of diphenylmethylene(2-benzo[b]thienyl)fulgides and fulgimides

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Valerii V. Tkachev,
• Andrey N. Utenyshev,
• Olga Yu. Karlutova,
• Alexander D. Dubonosov,
• Vladimir A. Bren,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2020, 16, 1820–1829, doi:10.3762/bjoc.16.149

• shift. Absorption maxima of the isomeric forms of fulgides 3 and 7, and fulgimides 4 and 8 in acetonitrilea. Supporting Information Supporting Information File 130: X-ray analysis data of 3Z, 3E and 9C. Supporting Information File 131: 1H, 13C NMR and IR spectra of all novel compounds. Supporting

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

• should be noted that due to the planar amide fragment the interconversion of the different conformers could be largely suppressed. The X-ray analysis of the above-mentioned (−)-trans-22 [35] and trans-1-ethylbenzo[a]quinolizin-4-ones [40] showed a distortion of the B and C rings, while the substituent at

• ), the 1-ethyl derivative 20 did not react at all with the anhydrides 5–7. The structures of compounds 25 and 26 were confirmed by 2D NMR spectroscopy and singe-crystal X-ray analysis (Figure 3). The piperidine moiety is planar to a significant extent due to the combined influence of the aromatic ring

A simple and easy to perform synthetic route to functionalized thienyl bicyclo[3.2.1]octadienes

• Dragana Vuk,
• Irena Škorić,
• Valentina Milašinović,
• Krešimir Molčanov and
• Željko Marinić

Beilstein J. Org. Chem. 2020, 16, 1092–1099, doi:10.3762/bjoc.16.96

• compounds (trans-3–5, trans-7). The structure of trans-6 was also confirmed by X-ray analysis (Figure 7). The compound crystallized in the space group, with the molecular symmetry Ci. The crystal packing is presented in Figure 8. The next synthesis step involved the preparation of the annulated bicyclo

Efficient synthesis of piperazinyl amides of 18β-glycyrrhetinic acid

• Dong Cai,
• ZhiHua Zhang,
• Yufan Meng,
• KaiLi Zhu,
• LiYi Chen,
• ChangXiang Yu,
• ChangWei Yu,
• ZiYi Fu,
• DianShen Yang and
• YiXia Gong

Beilstein J. Org. Chem. 2020, 16, 798–808, doi:10.3762/bjoc.16.73

• piperazinyl amide was confirmed by X-ray analysis. Experimental Detailed synthetic procedures for all new compounds including copies of their NMR spectra can be found in Supporting Information File 1. Chemical structure of 18β-glycyrrhetinic acid and known derivatives. a) Estimated structure of the

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

• peropyrene 1. Furthermore, the observed isotopic distribution was fully consistent with its simulated spectrum (Figure 1). Characterization of the resultant product by single crystal X-ray analysis unambiguously revealed the selective formation of 1 through twofold [3 + 2] pentannulation and sequent twofold

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

• , this work reports the first example of a linearly connected porphyrin dimer, linked through the bridgehead carbons of triptycene. Symmetric and unsymmetric examples of these complexes are demonstrated and single crystal X-ray analysis of an unsymmetrically substituted porphyrin dimer highlights the

Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates

• Marcin Kaźmierczak and
• Henryk Koroniak

Beilstein J. Org. Chem. 2020, 16, 756–762, doi:10.3762/bjoc.16.69

• Herein, we present an efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates. Each step of the synthesis was optimized to provide excellent yields. Moreover, the absolute configuration of the obtained compounds was determined by X-ray analysis, which proved the stereochemistry

• regioselectivity of the fluorination reaction. The absolute configuration of the obtained compounds was determined and confirmed by X-ray analysis. Furthermore, we present the use of α-fluorinated β-aminophosphonates as building blocks in the synthesis of their dipeptide analogues. In addition, we show the results

• the obtained compounds has been confirmed by X-ray analysis, which is consistent with the stereochemistry proposed based on NMR studies. Dipeptide analogues of α-fluorinated β-aminophosphonates 15 presented in this publication, after deprotection of the amine function appear to be attractive compounds

Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

• Yumi Yakiyama,
• Shota Hishikawa and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2020, 16, 681–690, doi:10.3762/bjoc.16.66

• and optical properties were investigated by single crystal X-ray analysis and UV–vis spectroscopy. In the synthesis of dioxole derivative 5b, the regioisomer 5c was also produced. The yield of 5c was increased by increasing the reaction temperature, indicating that the rearrangement might involve the

• ; anal. calcd for C29H14O2(H2O)0.4: C, 86.73%; H, 3.71%; found: C, 86.58%; H, 3.50%. Single crystal X-ray analysis The diffraction data for 5a and 5c were collected on a Rigaku FR-E Superbright rotating-anode X-ray source with a Mo-target (λ = 0.71073 Å) equipped with a Rigaku RAXIS VII imaging plate as

Cascade trifluoromethylthiolation and cyclization of N-[(3-aryl)propioloyl]indoles

• Ming-Xi Bi,
• Shuai Liu,
• Yangen Huang,
• Xiu-Hua Xu and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2020, 16, 657–662, doi:10.3762/bjoc.16.62

• bearing an alkyl or electron-deficient aryl substituent on the alkynone were not successful. The structure of product 2a was unambiguously identified by single-crystal X-ray analysis. When the N-[(3-aryl)propioloyl]indole substrates (3a–d) with different substituents at the 3-position of the indole ring

Asymmetric synthesis of CF₂-functionalized aziridines by combined strong Brønsted acid catalysis

• Xing-Fa Tan,
• Fa-Guang Zhang and
• Jun-An Ma

Beilstein J. Org. Chem. 2020, 16, 638–644, doi:10.3762/bjoc.16.60

• dr values, including alkyl or halogen-substituted phenyl and 2-naphthyl ketones (Scheme 2). Unfortunately, phenylglyoxal monohydrates bearing strong electron-withdrawing groups were not compatible with the current conditions. X-ray analysis of aziridine 4a confirmed the absolute configuration of the

Synthesis of triphenylene-fused phosphole oxides via C–H functionalizations

• Md. Shafiqur Rahman and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2020, 16, 524–529, doi:10.3762/bjoc.16.48

• cyclization under the same conditions to give the corresponding product 8c albeit in a somewhat lower yield of 40%. The triphenylene-fused phosphole oxide 8a was recrystallized from CH2Cl2, and the molecular structure was unambiguously confirmed by single crystal X-ray analysis (Figure 2) [31]. As can be seen

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

• characteristics in the solid state. The crystal structures of the coupling products were also evaluated by single crystal X-ray analysis and the well-ordered intermolecular stacking arrangements appeared to be responsible for the enhanced CPL. Keywords: BINOL; C–H activation; circularly polarized luminescence

• numerous attempts for obtaining crystals suitable for the X-ray analysis. Based on these observations, it is reasonable to conclude that the tert-butyl substituents effectively restricted the stacking structure to the specific conformations, thereby facilitating the assembly of well-ordered aggregates in

• . Compound 4b: Synthesized similarly to 4b from 3b (254 mg, 0.30 mmol). Purified by silica gel column chromatography (eluent: hexane/EtOAc 4:1) and GPC to give the title compound as pale yellow solid; (S)-4b (45.4 mg, 18% yield), (R)-4b (30.2 mg, 12% yield). Single crystals suitable for the X-ray analysis

Ultrasonic-assisted unusual four-component synthesis of 7-azolylamino-4,5,6,7-tetrahydroazolo[1,5-a]pyrimidines

• Yana I. Sakhno,
• Maryna V. Murlykina,
• Oleksandr I. Zbruyev,
• Anton V. Kozyryev,
• Svetlana V. Shishkina,
• Dmytro Sysoiev,
• Vladimir I. Musatov,
• Sergey M. Desenko and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2020, 16, 281–289, doi:10.3762/bjoc.16.27

• pyrimidine NH group and cross-peaks of the NH group with protons of the aromatic system, thus excluding structure B (Figure 1). Eventually, the structure of tetrahydropyrimidines 4 was proven by X-ray analysis carried out for a single crystal of one diastereomer of compound 4g, which allowed assignment of

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

• be possible to see F–C4a coupling of 1–1.5 Hz, since the F–C5 coupling is observable at a similar magnitude. The model (B3LYP/6-311G) seems to work reasonably well for coupling between F and H3, H5, C3, C4, and C5 but not for C4a. The single crystal X-ray analysis of coumarin 6 was carried out as it