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

• Supporting Information File 48: Experimental procedures and NMR data for new ligands and gold(III) complexes, as well as a method for testing of catalytic activity. Funding This work was partly supported by the Research Council of Nor-way through the Norwegian NMR Platform, NNP (226244/F50).

Facile preparation and conversion of 4,4,4-trifluorobut-2-yn-1-ones to aromatic and heteroaromatic compounds

• Takashi Yamazaki,
• Yoh Nakajima,
• Minato Iida and
• Tomoko Kawasaki-Takasuka

Beilstein J. Org. Chem. 2021, 17, 132–138, doi:10.3762/bjoc.17.14

• to proceed under the action of a catalytic amount of a base, and only 2 mol % of t-BuOK led to the formation of the desired adduct 3aa as a sole stereoisomer in 84% isolated yield under the same reaction conditions (Table 2, entries 6−8). The E-stereochemistry of 3aa was deduced from the NMR data of

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

• others were finally resolved in this work. Subsequently, the Hatakeyama team converted their authentic (+)-82 into the (R)- and (S)-MTPA Mosher esters which provided well-matched NMR data to Hale’s previous synthesis [60]. Upon further purification using flash chromatography, the Hatakeyama team re

Chemical constituents of Chaenomeles sinensis twigs and their biological activity

• Joon Min Cha,
• Dong Hyun Kim,
• Lalita Subedi,
• Zahra Khan,
• Sang Un Choi,
• Sun Yeou Kim and
• Chung Sub Kim

Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257

• together with 11 known phytochemicals through chromatographic methods. The chemical structure of the new isolate 1 was determined by conventional 1D and 2D NMR data analysis, ECD experiment, hydrolysis followed by a modified Mosher’s method, and LC–MS analysis. The characterized compounds’ biological

• sodiated molecular ion peak at m/z 409.1830 (calcd for C19H30O8Na+, 409.1833, error = 0.7 ppm). The 1H and HSQC NMR data of compound 1 suggested the presence of three olefinic protons [δH 5.96 (dt, J = 2.8, 1.5 Hz, 1H), 5.74 (dd, J = 15.3, 5.8 Hz, 1H), and 5.58 (ddd, J = 15.3, 10.1, 1.1 Hz, 1H)], seven

• , 71.5, 68.7, and 62.9), and six methyl/methylene/methine [δC 57.2, 43.4, 26.0, 23.8 (×2), and 16.5] carbons. Further investigation of the NMR data (Table 1) suggested the presence of a glucopyranosyl unit in compound 1 with the characteristic 13C NMR signals (δC 104.9, 78.3, 78.2, 75.7, 71.5, and 62.9

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

• , Supporting Information File 1). A Job plot based on the proton NMR data was made to determine the complexation stoichiometry between H and G. The formation signified a 1:1 binding stoichiometry in chloroform-d at room temperature (Figures S5 and S6, Supporting Information File 1). Combined with the mass

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

• relevant factors that affect the affinity and selectivity of such ligands. Experimental Equipment NMR data were recorded with a Varian VNMR-S600 spectrometer [600 MHz (1H), 150 MHz (13C)] at 35 °C. NMR spectra were processed with the software ACD/NMR Processor Academic Version 12.01 and are referenced to

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

• the compounds 5a and 6a relies solely on NMR data. In both cases, the data were consistent with the structures 5a or 6a, carrying NH2 and CH(CF3)2 groups on the same side of the molecule. Indeed, in the 19F NMR spectra of 5a and 6a, the resonance corresponding to CH(CF3)2 was significantly broadened

• spectroscopy, was at least 99%, unless stated otherwise. Standard NMR experiments The NMR data presented in Table 2 and Table 3 were derived from spectra acquired on a Bruker Neo spectrometer with a 9.4 T magnetic field, equipped with a 5 mm 15N,77Se, 31P {19F,1H} nitrogen cryoprobe. Chemical shifts are

• NMR data are given in Table 1 and Table 3. Reaction of 4-azabenzimidazole (3) and 1 A mixture of 1.2 g (0.01 mol) of 4-azabenzimidazole (3), 2 g (0.06 mol) of 1, and 15 mL of DMSO was agitated at ambient temperature for 24 h. The precipitated sulfur was filtered, washed with hexane, and dried on a

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

• 31P). In order to measure 19F and 31P NMR spectra, the NMR tube was equipped with a coaxial insert containing the external standards. 1H NMR data are reported as follows: chemical shift (δ) in ppm, multiplicity (dt = doublet of triplets, m = multiplet), coupling constant (J) in Hertz (Hz), integral

Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

• Julia N. Artsemyeva,
• Ekaterina A. Remeeva,
• Tatiana N. Buravskaya,
• Irina D. Konstantinova,
• Roman S. Esipov,
• Anatoly I. Miroshnikov,
• Natalia M. Litvinko and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

• kept overnight in a refrigerator. The precipitate formed was filtered off, washed with ethanol, dried in vacuum under CaCl2 at room temperature to give Ara-1Pi (Ba2+) as white powder (244 mg, 96%; TLC: iPrOH/25% NH4OH/water, 11:2:5 (vol), Rf 0.30, development by heating). The NMR data were similar to

• silica gel column (1.5 × 23 cm) prepared in EtOAc. The fractions containing the nucleoside were combined, evaporated and dried to afford the powdered product (25 mg; 66%) of 95.5% purity (HPLC), that was crystallized from MeCN to give nelarabine (19 mg; 53%; 99.0% purity by HPLC). For NMR data, see

• MeCN; 99.0% purity according to HPLC; for NMR data, see Supporting Information File 1, SI-1, SI-2 and SI-4). The capacity of the anion exchange resins to bind PF-1Pi As noted above, when studying Ara-U phosphorolysis catalyzed by E. coli UP in the presence of Dowex-nPi, we found that (1) about 10% of

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

• Information Supporting Information File 400: Characterization and NMR data of the new compounds. Funding We are grateful to the Hungarian Research Foundation (NKFIH No K 119282) for financial support. Fnancial support of the GINOP-2.3.2-15-2016-00038 project is also acknowledged. This research was supported

NMR Spectroscopy of supramolecular chemistry on protein surfaces

• Peter Bayer,
• Anja Matena and
• Christine Beuck

Beilstein J. Org. Chem. 2020, 16, 2505–2522, doi:10.3762/bjoc.16.203

• substituents binding to Cyt c was also studied by 15N-HSQC titrations [59]. Interestingly, large areas of the protein surface showed chemical shift perturbations, even though the binding curves clearly revealed a 1:1 stoichiometry. Crowley et al. concluded from the NMR data in combination with computational

Formation of an exceptionally stable ketene during phototransformations of bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores

• Asitanga Ghosh

Beilstein J. Org. Chem. 2020, 16, 2297–2303, doi:10.3762/bjoc.16.190

• 13C NMR data were found to be much more informative (Table 3). In 1H NMR, a doublet and a triplet in the region of δ 6.6–6.9 ppm confirmed the presence of the OPh group while the bridgehead protons of the ketenes appeared at a slightly up-field position with respect to the parent compounds. Ketenes

Azo-dimethylaminopyridine-functionalized Ni(II)-porphyrin as a photoswitchable nucleophilic catalyst

• Jannis Ludwig,
• Julian Helberg,
• Hendrik Zipse and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2119–2126, doi:10.3762/bjoc.16.179

• ring are strongly dependent on the axial coordination at the central Ni2+ ion (Figure 3, and for details see Tables S1 and S2 in Supporting Information File 1). The analysis of the NMR data revealed that 98.8–99.9% of the cis isomer is coordinated in all solvents, which is expectable because DMAP is a

Muyocopronones A and B: azaphilones from the endophytic fungus Muyocopron laterale

• Ken-ichi Nakashima,
• Junko Tomida,
• Tomoe Tsuboi,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 2100–2107, doi:10.3762/bjoc.16.177

• muyocopronones A (1) and B (2) were isolated from the ethyl acetate layer together with eugenitin (3) [17], and 6-methoxymethyleugenin (4) [18]. The structures of compounds 3 and 4 were identified on the basis of their 1H and 13C NMR data (Figure 1). Muyocopronone A (1) was isolated as yellow amorphous solid

• characterization of the four possible diastereomers of the β-hydroxycarboxylic acid side chain [20]. Based on the obtained NMR data, the relative structure of the side chain of 1 was determined to adopt the (2′R*,3′R*,4′S*) configuration, as determined by the chemical shifts and the coupling constants between H-2

• , 2963, 2934, 2876, 1717, 1674, 1634, 1553, 1456, 1387, 1335, 1314, 1231, 1177, 1121, 1086, 972, 914, 878 cm−1; 1H and 13C NMR data, see Table 1; HRESIMS (m/z): [M + H]+ calcd for C25H31O7, 443.2064; found, 443.2073. Muyocopronone B (2) Yellow amorphous solid; [α]D22 +73 (c 0.1, MeOH); UV (MeOH) λmax

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

• -crystal X-ray crystallographic analysis (Figure 4) [51]. All hydrogen atoms and the hydroxy group occupy an axial position, while the remaining substituents are in equatorial positions. This is consistent with the 1H NMR data for other similar tetrahydropyranols 13b–f, therefore, their configuration was

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• preparative HPLC and treatment with 1 M HCl solution, NDI 5 with three cationic substituents at the imide and bay positions could be obtained in 44% yield. The 1H, 13C NMR data, and high-resolution mass spectra correspond well with the structures of all new compounds synthesised. Spectrophotometric properties

Synthesis of 3(2)-phosphonylated thiazolo[3,2-a]oxopyrimidines

• Ksenia I. Kaskevich,
• Anastasia A. Babushkina,
• Vladislav V. Gurzhiy,
• Dmitrij M. Egorov,
• Nataly I. Svintsitskaya and
• Albina V. Dogadina

Beilstein J. Org. Chem. 2020, 16, 1947–1954, doi:10.3762/bjoc.16.161

• diffraction analysis along with 1H and 13C NMR spectral studies. Unfortunately, the majority of reports on the synthesis of thiazolopyrimidines relied on 1H NMR data to prove the structure of the obtained compounds [18][33][34][35]. There are no systematic data on 13C NMR spectroscopy of thiazolopyrimidines

Selective preparation of tetrasubstituted fluoroalkenes by fluorine-directed oxetane ring-opening reactions

• Clément Q. Fontenelle,
• Thibault Thierry,
• Romain Laporte,
• Emmanuel Pfund and
• Thierry Lequeux

Beilstein J. Org. Chem. 2020, 16, 1936–1946, doi:10.3762/bjoc.16.160

• reaction from acetate derivative 12. Supporting Information The experimental section describing the preparation of all new compounds, the copies of the NMR data (1H NMR, 13C NMR, 19F NMR), HOESY and NOESY experiments and crystallographic data for compounds 1d, 4d and 25. The CIF files of 1d, 4d and 25

Three new O-isocrotonyl-3-hydroxybutyric acid congeners produced by a sea anemone-derived marine bacterium of the genus Vibrio

• Dandan Li,
• Enjuro Harunari,
• Tao Zhou,
• Naoya Oku and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1869–1874, doi:10.3762/bjoc.16.154

• completed the structure of 4 as O-isocrotonyl-3-hydroxybutyric acid (Figure 2). A close similarity of the NMR data for 1–3 (Table 1 and Table 2) allowed the same sequence of structure analysis. The compounds 1 and 2 were found to have extra C1 and C2 extensions on the butyric acid units, while in 3, an

• major conformers of the PGME amide derivatives between the β,β-substituted carboxylic acids (top) and the α,α-substituted carboxylic acids (bottom), showing an orientational inversion of the PGME groups. NMR data for 1 and 2 in CDCl3. NMR data for 3 and 4 in CDCl3. Supporting Information Supporting

Polarity effects in 4-fluoro- and 4-(trifluoromethyl)prolines

• Vladimir Kubyshkin

Beilstein J. Org. Chem. 2020, 16, 1837–1852, doi:10.3762/bjoc.16.151

• direct dipole–dipole interaction between the substituent and the main chain groups could have an effect onto the conformation. Here, the NMR data for the model compounds 1–4 were collected in three solvents with distinct dielectric properties (Table 1). The results were interpreted by comparing the

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• performing the reaction at a temperature below −15 °C yielded the compound β-4Ac-Man-CEP, with no traces of the α-anomer. The configuration was then retained throughout the rest of the synthesis, as indicated by the NMR data of MPC-1 and MPC-2 (Supporting Information File 1). Conclusion We report herein the

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

• 24 h at room temperature led to dimer-like product 23a in 58% yield, obviously via the intermediate cation 22a (Scheme 8). The structure of 23a was supported by NMR data and also by single-crystal X-ray measurement (Figure 3). Nevertheless, HPLC–MS analysis of the crude product mixture showed, in

• possible in case of a RR–SS diastereomer (23b), with only one of the aromatic hydrogen atoms of the isoindoline moiety [H(7)] located in close proximity above the middle of the other aromatic ring. It can be concluded after all that the NMR data also made it possible to assign the RS–SR diastereomeric

• C14H17NO4 (263.29): N, 5.32; H, 6.51; C, 63.87; found: N, 5.38; H, 6.44; C, 63.77%; NMR data are identical with those published earlier [1]. Method B: This compound was prepared according to general procedure II using 1a [2] (1.00 g, 3.80 mmol) and TFA (29 µL, 43 mg, 0.38 mmol). The title compound (592 mg

Synthesis of new dihydroberberine and tetrahydroberberine analogues and evaluation of their antiproliferative activity on NCI-H1975 cells

• Giacomo Mari,
• Lucia De Crescentini,
• Serena Benedetti,
• Francesco Palma,
• Stefania Santeusanio and
• Fabio Mantellini

Beilstein J. Org. Chem. 2020, 16, 1606–1616, doi:10.3762/bjoc.16.133

• of 13a-C, 13-C and 15-C (signals highlighted in green, Figure 3). It is noteworthy that in the reduction process of the DHBER 2 precursors, a single diastereoisomer of the corresponding THBERs 3 is produced according to 1H and 13C NMR data. In particular, the NOE correlation between C13−H and C13a−H

Antibacterial scalarane from Doriprismatica stellata nudibranchs (Gastropoda, Nudibranchia), egg ribbons, and their dietary sponge Spongia cf. agaricina (Demospongiae, Dictyoceratida)

• Cora Hertzer,
• Stefan Kehraus,
• Nils Böhringer,
• Fontje Kaligis,
• Robert Bara,
• Dirk Erpenbeck,
• Gert Wörheide,
• Till F. Schäberle,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2020, 16, 1596–1605, doi:10.3762/bjoc.16.132

• ). Specific optical rotation was measured in chloroform (c = 0.6), giving [α]D +40.5. The molecular formula C29H42O6 was established based on 13C NMR data and HRAPCIMS measurements, yielding m/z 487.3054 [M + H]+ (Supporting Information File 1). The double bond equivalent (DBE) was calculated to be nine and

• together with the 13C NMR data, giving evidence for one C–C and two C–O double bonds, thus suggested a structure with six rings. The presence of a hydroxy group and ester functionalities was deduced from characteristic IR absorptions at 3416, 1732 and 1234 cm−1 (Supporting Information File 1) [39][40][53

• the 2D NMR data and comparison to literature values [53] suggested that the compound belongs to the family of scalarane sesterterpenoids, with similarities to the deoxoscalarin-like molecule 12,24-diacetoxydeoxoscalarin, previously isolated from a Korean sponge of the genus Spongia [53]. The two

4-Hydroxy-3-methyl-2(1H)-quinolone, originally discovered from a Brassicaceae plant, produced by a soil bacterium of the genus Burkholderia sp.: determination of a preferred tautomer and antioxidant activity

• Dandan Li,
• Naoya Oku,
• Yukiko Shinozaki,
• Yoichi Kurokawa and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1489–1494, doi:10.3762/bjoc.16.124

• ; HRESITOFMS (m/z): [M + Na]+ calcd for C10H9NNaO2, 198.0526, found: 198.0525 ; 1H and 13C NMR data are shown in Table 1. Evaluation of Fe3+ binding activity The iron-binding activity was evaluated by the CAS assay developed by Schwyn and Neilands [45]. Compound 1 (2.5 mg) in DMSO (20 μL) was mixed with a blue

• luminol chemiluminescence by 1. 1H (500 MHz) and 13C (125 MHz) NMR data of compound 1 in DMSO-d6 (297 K). Supporting Information Supporting Information File 60: Synthetic procedure of 1, UV, IR, 1H NMR, 13C NMR, COSY, HSQC, HMBC spectra for natural and synthetic 1, and UV, IR, 1H NMR, 13C NMR spectra for