Ring-closing metathesis of prochiral oxaenediynes to racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans

• Viola Kolaříková,
• Markéta Rybáčková,
• Martin Svoboda and
• Jaroslav Kvíčala

Beilstein J. Org. Chem. 2020, 16, 2757–2768, doi:10.3762/bjoc.16.226

• internal standards. Chemical shifts are given in parts per million and coupling constants in hertz. Mass spectra (ESI, APCI) and HRMS spectra were measured with a hybrid LTQ Obitrap XL instrument (Thermo Fisher Scientific). All reactions were performed in a dry inert atmosphere (Ar) in oven-dried flasks

• ), 129.0 (s, 1C, CH3-C=C), 129.1 (s, 2C, CHAr), 131.9 (s, 1C, CAr), 176.8 (s, 1C, CH-CH-C=O), 178.5 (s, 1C, CH2-CH-C=O); MS (ESI+, m/z) (%): 372.2 [M + Na]+ (100), 350.2 [M + H]+ (20); HRMS (ESI+, m/z): [M + H]+ calcd for C22H24O3N, 350.1751; found, 350.1752; HRMS (ESI+, m/z): [M + Na]+ calcd for

• ), 128.5 (s, 1C, CHAr), 129.1 (s, 2C, CHAr), 131.8 (s, 1C, CAr), 177.0 (s, 1C, CH-CH-C=O), 178.5 (s, 1C, CH2-CH-C=O); MS (ESI+, m/z): 372.2 [M + Na]+ (100), 350.2 [M + H]+ (35); HRMS (ESI+, m/z): [M + H]+ calcd for C22H24O3N, 350.1751; found, 350.1752; HRMS (ESI+, m/z): [M + Na]+ calcd for C22H23O3NNa

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

• diastereomers. The new complexes were characterized by NMR and UV–vis spectroscopy and ESI mass spectrometry. Using GFN2-xTB we generated energy-minimized models of the diastereomers of this cage that further corroborated the results from analytical findings. Keywords: cage compounds; heterobimetallic

• amine functions and thus a higher tendency to undergo one-electron oxidation reactions when stored under ambient conditions. In order to check the composition of heterobimetallic 4 we performed mass spectrometric experiments first. Figure 1 shows the ESI mass spectrum of metallosupramolecular cage 4

• , showing a series of signals with different charge states that could be assigned to 4. The mass spectrum also shows that the cage easily fragments upon ESI, as additional signals a–d were detected. The successful formation of iron(II)-containing metallosupramolecular tetrahedron 4 could also be proven by

Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

• Jannis Ludwig,
• Tobias Moje,
• Fynn Röhricht and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2589–2597, doi:10.3762/bjoc.16.210

• spectra. Acknowledgements We thank Dr. Florian Gutzeit for providing the substance for reference measurements (maximum shift of a fivefold coordinated Ni complex) and Nils Preußke for ESI measurements of compound 1h. Funding This work was funded by the Deutsche Forschungsgemeinschaft (DFG) within the

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

• ppm in the 13C NMR spectrum were attributed to the acetylene protons and carbons, respectively. The electrospray ionization (ESI) mass spectrum showed the most intense peak at m/z 641.1923, which corresponds to the [M + Na]+ molecular adduct ion and matches well with the calculated value (m/z 641.1935

• mass spectrum also shows the characteristic losses of up to at least three tentacle residues from both the [M + Na]+ and [M + K]+ molecular ions [44][45][46]. In contrast to the MALDI mass spectrum, the high-resolution ESI-(+) mass spectrum of TBTQ-(OAcG)6 (see Figure S11 and Table S2) exhibits a sole

• loss of the entire tentacle as an C9H14N3O5· radical (244 u) from the [M + Na]+ ion followed by H atom transfer. Again, accurate mass measurements were not obtained. As another surprise, the high-resolution ESI-(−) mass spectrum of TBTQ-(OG)6 (see Figure S15 and Table S4, Supporting Information File 1

Synthesis of 1,4-benzothiazinones from acylpyruvic acids or furan-2,3-diones and o-aminothiophenol

• Ekaterina E. Stepanova,
• Maksim V. Dmitriev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2020, 16, 2322–2331, doi:10.3762/bjoc.16.193

• approach, we repeated some experiments described previously [27][28] and examined the reaction mixtures by UPLC–UV–MS. We supposed that the peak of the target BTA III would be characterized by appropriate molecular ion signals at ESI+ and ESI− chromatograms and absorbance bands at 400–450 nm

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

• Avance 400 spectrometer. The chemical shifts are reported in ppm and refer to the residual proton signal of the solvent as internal standard. Signal multiplicities are denoted as s (singlet), d (doublet), t (triplet), and m (multiplet). High-resolution ESI-TOF mass spectrometry was carried out on a

• , 18H), 2.14 (m, 4H); 13C NMR (DMSO-d6, 101 MHz) 161.1, 160.7, 137.6, 134.1, 127.0, 126.3, 122.5, 63.2, 52.2, 37.7, 21.4; HRMS-ESI+ (methanol, m/z): [M]2+ calcd for C26H32Cl2N4O4, 267.0900; found, 267.0900; UV–vis (MeOH) λ [nm] (ε [M−1 cm−1]) 397 (10300), 377 (10900), 357 (16000). Synthesis of (S)-N,N

• , 53.7, 53.7, 53.6, 53.5, 43.6, 39.0, 38.4, 23.2, 23.1; HRMS-ESI+ (methanol, m/z): [M]2+ calcd for C29H39ClN6O6, 301.1310; found, 301.1317; UV–vis (cacodylate buffer, pH 5.0) λ [nm] (ε [M−1 cm−1]) 519 (9100), 369 (9400), 351 (7500), 333 (5000); fluorescence (cacodylate buffer, pH 5.0, λex = 470 nm): λmax

Regiodivergent synthesis of functionalized pyrimidines and imidazoles through phenacyl azides in deep eutectic solvents

• Paola Vitale,
• Luciana Cicco,
• Ilaria Cellamare,
• Filippo M. Perna,
• Antonio Salomone and
• Vito Capriati

Beilstein J. Org. Chem. 2020, 16, 1915–1923, doi:10.3762/bjoc.16.158

• mass spectrometer equipped with an electrospray ion source (ESI). NaN3, 2-haloketones, and all other reagents, unless otherwise specified, were purchased from Sigma-Aldrich (Sigma-Aldrich, St. Louis, MO, USA), and used without any further purification. Experimental procedures General procedure for the

One-pot synthesis of oxazolidinones and five-membered cyclic carbonates from epoxides and chlorosulfonyl isocyanate: theoretical evidence for an asynchronous concerted pathway

• Esra Demir,
• Ozlem Sari,
• Yasin Çetinkaya,
• Ufuk Atmaca,
• Safiye Sağ Erdem and
• Murat Çelik

Beilstein J. Org. Chem. 2020, 16, 1805–1819, doi:10.3762/bjoc.16.148

• −1): 3251, 2928, 2863, 1805, 1410, 1358, 1210, 1175, 1034; anal. calcd for: C, 63.88; H, 8.93; N, 8.28; found: 63.56; H, 9.04; N, 8.54; HRMS–ESI (m/z): [M + H]+ calcd for C9H15NO2+, 169,1097; found, 169,1086. 3a,4,9,9a-Tetrahydro-4,9-methanonaphtho[2,3-d][1,3]dioxol-2-one (8i): Colourless solid, Rf

• , cm−1): 2932, 1804, 1460, 1160, 1066, 976; anal. calcd for: C, 71.28; H, 4.98; found: C, 71.43; H, 4.73; HRMS–ESI (m/z): [M + H]+ calcd for C12H10O3+, 202,0624; found, 202,0637. 3a,4,9,9a-Tetrahydro-4,9-methanonaphtho[2,3-d]oxazol-2(3H)-one (9i): Colourless solid, Rf = 0.3 (EtOAc/hexanes, 1:5); mp 133

• (CH2); IR (CHCl3, cm−1): 3340, 2918, 1802, 1647, 1461, 1368, 1166, 1001; anal. calcd for: C, 71.63; H, 5.51; N, 6.96; found: C, 71.48; H, 5.72; N, 6.79; HRMS–ESI (m/z): [M + H]+ calcd for C12H11NO2+, 201,0784; found, 201,0796. 3a-Phenylhexahydrobenzo[d][1,3]dioxol-2-one (8j): Colourless solid, Rf = 0.4

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

• elemental analysis. Mass spectra were recorded in the ESI and EI modes. The nomenclature was generated using ACD/IUPAC Name (version 3.50, 5 Apr. 1998), Advanced Chemistry Development Inc., Toronto, ON (Canada). General procedure for the synthesis of hydrazono-dihydroberberines (DHBERs) 2a–n. To a solution

• ), 108.1 (d), 110.2 (d), 125.2 (d), 126.0 (d), 127.4 (d), 127.8 (s), 128.0 (d), 128.4 (s), 128.7 (s), 129.1 (s), 138.2 (s), 143.8 (s), 145.7 (s), 146.3 (s), 148.9 (s), 150.1 (s), 152.3 (s); IR (nujol): νmax = 3288, 3129, 1742 cm−1; HRMS–ESI (m/z): [M + H]+: calcd. for C33H38N3O6, 572.2761; found, 572.2814

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

• residual solvent signals with resonances at δH/C 7.26/77.00 ppm (CDCl3). Mass spectra were recorded on a micrOTOF-Q mass spectrometer (Bruker) with ESI-source coupled with an HPLC Dionex Ultimate 3000 (Thermo Scientific) using an Agilent Zorbax Eclipse Plus C18 column (2.1 × 50 mm, 1.8 µm) at a temperature

A dynamic combinatorial library for biomimetic recognition of dipeptides in water

• Florian Klepel and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2020, 16, 1588–1595, doi:10.3762/bjoc.16.131

• compounds could not be achieved due to the high complexity of the library and the structural similarity of its members. Hence ESI-TOF mass spectrometry data can be interpreted qualitatively but not quantitatively. A full reference sample is shown in Figure 1. Each chromatogram represents a single

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

• an FD emitter with an emitter voltage of 10 kV. The sample (1–2 µL) was deposited on a 13 μm emitter wire. Electrospray spectra (ESI) were recorded on a Qexactive (Thermo) mass spectrometer. The instrument was equipped with an ESI source and spectra were recorded in the positive mode. The spray

• , 51%). 1H NMR (300 MHz, CDCl3) δ 7.41–7.32 (m, 8H, Ph), 7.32–7.23 (m, 12H, Ph), 4.67 (d, J = 7.6 Hz, 4H, CH), 4.40 (t, J = 7.6 Hz, 2H, OCH2CH), 2.50 (s, 4H, CH2); 13C NMR (75 MHz, CDCl3) δ 172.1, 141.1, 128.6, 128.3, 126.9, 66.9, 49.8, 29.1; HRMS–ESI (m/z): [M + Na]+ calcd for C32H30O4Na, 501.20363

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

• Lívia Dikošová,
• Júlia Laceková,
• Ondrej Záborský and
• Róbert Fischer

Beilstein J. Org. Chem. 2020, 16, 1313–1319, doi:10.3762/bjoc.16.112

• NMR (150 MHz, CDCl3) δ 60.3 (PhCH2), 73.8 (C-5), 79.5 (C-3), 83.5 (C-4), 127.4 (CH-Ph), 127.9 (CH-Ph), 128.2 (CH-Ph), 128.3 (CH-Ph), 2×128.9 (CH-Ph), 137.4 (C-Ph), 138.2 (C-Ph); HRMS (ESI) (m/z): [M + H]+ calcd for C16H18NO2, 256.1333; found 256.1329. Typical procedure for the oxidation of

• (CH-Ph), 129.0 (CH-Ph), 129.2 (CH-Ph), 134.4 (C-Ph), 137.3 (C-Ph); HRMS (ESI) (m/z): [M + H]+ calcd for C16H18NO2, 256.1333; found 256.1329. N-Debenzylation with 2,2,2-trichloroethyl chloroformate (±)-2,2,2-Trichloroethyl 4-(benzoyloxy)-3-isopropylisoxazolidine-2-carboxylate (11): 2,2,2-Trichloroethyl

• ), 129.7 (CH-Ph), 133.7 (CH-Ph), 157.1 (CO2CH2), 165.9 (COPh); HRMS (ESI) (m/z): [M + H]+ calcd for C16H19Cl3NO5, 410.0324; found 410.0329. Hydrolysis of trichloroethyl carbamate (±)-3-Isopropylisoxazolidin-4-ol (12): The NaOH solution (0.6 mL, 3.6 mmol, 6 M) was added to a solution of the N-Troc

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• silica gel (pore size 60 Å, 70–230 mesh, 63–200 μm) was used for gravity column chromatography. C, H, N and S elemental microanalyses were carried out on a Perkin-Elmer 2400-B Series II Analyzer. High-resolution mass spectra-ESI (HRMS-ESI) were recorded using a Bruker MicroToF-Q™ equipped with an API-ESI

• ), 130.1 (d, 4JCF = 3.4 Hz, C, C6H4F), 129.9 (d, 5JCF = 1.6 Hz, =CH, Cvin), 129.3 (s, CH, Cm, C6H5), 128.3 (s, CH, Co, C6H5), 116.3 (d, 2JCF = 22.3 Hz, CH, C6H4F), 113.4 (s, CH, =Cα); 19F NMR (282.40 MHz, CDCl3) δ −106.71 (tt, J = 8.5, 5.6 Hz); HRMS (ESI+) m/z: [M + Na]+: calcd for C18H12FNNaO2, 316.0750

• ', C6H3F). HRMS (ESI+) m/z: [M − COOCF3 + CH3O + Na]+ calcd. for, C38H28F2N2NaO6Pd2 882.9887; found, 882.9908; IR (ν, cm−1): 1791 (νC=O), 1653 (νC=N), 1190 (νCF3). General synthesis of the ortho-palladated cyclobutanes 4a–f, 4h–j The ortho-palladated dimers 3 (amount specified in each case) were suspended

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• system. The IR spectra were obtained (4000–400 cm−1) using a Shimadzu IRAffinity-1S Fourier transform infrared spectrophotometer. The mass spectra were obtained by Bruker microTOFq mass spectrometers to obtain low- and high-resolution spectra using electron ionisation (EI) or electrospray ionisation (ESI

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

• Phil M. Pithan,
• Sören Steup and
• Heiko Ihmels

Beilstein J. Org. Chem. 2020, 16, 904–916, doi:10.3762/bjoc.16.82

• chemical shifts. The final product of the reaction was identified by additional NMR spectroscopic investigations (13C, COSY, HSQC, HMBC) and mass spectrometric analysis (ESI) as the oxazole derivative 4a (Scheme 3). The latter analysis confirmed the loss of one hydrogen atom from the substrate 3a at C2

• collected with a Cary Eclipse spectrophotometer in Hellma quartz cells 114F-QS (10 mm × 4 mm) at 20 °C. Elemental analyses data were determined with a HEKAtech EUROEA combustion analyzer by Mr. Rochus Breuer (Universität Siegen, Organische Chemie I). Mass spectra (ESI) were recorded on a Finnigan LCQ Deca

• ’’), 144.2 (C9a), 146.8 (C2), 149.0 (C7a’), 152.1 (C2’’); MS–ESI+ (m/z): 482 (100, M − BF4); MS–ESI− (m/z): 656 (79, M + BF4), 1225 (100, 2M + BF4), 1794 (22, 3M + BF4); anal. calcd for C33H28BF4N3O·1/3(HBF4): C, 66.21; H, 4.77; N, 7.02; found: C, 66.40; H, 4.49; N, 7.33. All values are given as percentages

Design and synthesis of diazine-based panobinostat analogues for HDAC8 inhibition

• Sivaraman Balasubramaniam,
• Sajith Vijayan,
• Liam V. Goldman,
• Xavier A. May,
• Kyra Dodson,
• Sweta Adhikari,
• Fatima Rivas,
• Davita L. Watkins and
• Shana V. Stoddard

Beilstein J. Org. Chem. 2020, 16, 628–637, doi:10.3762/bjoc.16.59

• an ESI–TOF mass spectrometer (Agilent 6220 Time-of-Flight), gas temperature – 350 °C, drying gas (N2) – 8.0 L/min, mobile phase(s): methanol with 0.1% formic acid, flow rate: 0.2 mL/min, sample preparation: The sample was dissolved in 1 drop of chloroform and diluted with 1 mL methanol. Additional

Formal preparation of regioregular and alternating thiophene–thiophene copolymers bearing different substituents

• Atsunori Mori,
• Keisuke Fujita,
• Chihiro Kubota,
• Toyoko Suzuki,
• Kentaro Okano,
• Takuya Matsumoto,
• Takashi Nishino and
• Masaki Horie

Beilstein J. Org. Chem. 2020, 16, 317–324, doi:10.3762/bjoc.16.31

• spectra were recorded on Bruker Alpha spectrometer with an ATR attachment (Ge). High-resolution mass spectra (HRMS) were measured using a JEOL JMS-T100LP AccuTOF LC-Plus apparatus (ESI) with a JEOL MS-5414DART attachment. For thin-layer chromatography (TLC) analyses throughout this work, Merck precoated

• , 123.5, 124.0, 126.2, 130.6, 131.4, 133.1, 134.2, 139.8; IR (ATR): 2954, 2926, 2856, 1463, 1199, 1042, 830, 705, 617 cm−1; HRMS (DART-ESI+) m/z: calcd for C15H2035ClS2, 299.0695; found, 299.0687. 2-Chloro-3-methyl-5-(3-(4-(1,1,3,3,3-pentamethyldisiloxy)butan-1-yl)thiophen-2-yl)thiophene (4b) [25]: 72

• , 34.5, 124.0, 124.6, 127.6, 128.4, 130.0, 132.7, 134.7, 140.0; IR (ATR): 2955, 2924, 2858, 1567, 1411, 1252, 1194, 1051, 840, 807, 783, 753, 687, 651, 625 cm−1; HRMS (DART-ESI+) m/z: calcd for C18H3035ClS2Si2, 417.0951; found, 417.0979. 2-Chloro-3-methyl-5-(3-(4-(bis(trimethylsiloxy)(methyl)silyl)butan

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

• (d, 4JC,F = 2.9 Hz, C5'), 132.0 (d, 3JC,F = 8.2 Hz, C4'), 150.3 (C4), 155.2 (C8a), 158.6 (d, 1JC,F = 248.6 Hz, C2'), 160.0 (C2), 161.6 (C7); HRMS–ESI+ (m/z): [M + Na]+ calcd for C15H9O3FNa, 279.0433; found, 279.0437, Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin (6): A mixture of 7-hydroxy-4-(2

• , 4JC,F = 3.1 Hz, C5'), 131.5 (d, 3JC,F = 7.9 Hz, C4'), 150.5 (C4), 155.7 (C8a), 159.1 (d, 1JC,F = 250.0 Hz, C2'), 160.9 (C2), 163.0 (C7). HRMS–ESI+ (m/z): [M + Na]+ calcd for C16H11O3FNa, 293.0590; found, 293.0587. 1H NMR spectra for the “aromatic” region of coumarin 6; comparison of 1H spectrum and 1H

Halogen-bonding-induced diverse aggregation of 4,5-diiodo-1,2,3-triazolium salts with different anions

• Xingyu Xu,
• Shiqing Huang,
• Zengyu Zhang,
• Lei Cao and
• Xiaoyu Yan

Beilstein J. Org. Chem. 2020, 16, 78–87, doi:10.3762/bjoc.16.10

• electrospray ionization mode (ESI). Elemental analyses (C, H, N) were performed on Flash EA 1112 Analyzer. Synthesis 2-I: 4,5-Unsubstituted triazolium salt 1 (450 mg, 1 mmol), potassium tert-butoxide (250 mg, 2.2 mmol) and I2 (510 mg, 2 mmol) were added in a Schlenk tube under nitrogen, then THF (20 mL) was

Extension of the 5-alkynyluridine side chain via C–C-bond formation in modified organometallic nucleosides using the Nicholas reaction

• Renata Kaczmarek,
• Dariusz Korczyński,
• James R. Green and
• Roman Dembinski

Beilstein J. Org. Chem. 2020, 16, 1–8, doi:10.3762/bjoc.16.1

• , 78.52, 73.66, 63.53, 52.20, 36.17, 20.76, 20.54, 20.46; IR (cm–1, KBr) 3442 m, 3389 m, 2987 m, 2823 m, 1701 s, 1627 s, 1467 m, 1288 m, 1052 m; TOF–ESI+–MS (m/z): [M + Na]+ calcd for C18H20N2NaO9, 431.1061; found, 431.1064. 2',3',5'-Tri-O-acetyl-5-(3-methoxyprop-1-yn-1-yl)uridine (3). A round-bottom

• , 90.35, 87.46, 80.19, 75.44, 73.20, 70.01, 62.91, 60.30, 57.88, 51.08, 20.83, 20.54, 20.45; IR (cm–1, KBr) 3208 br w, 3082 br w, 2938 br w, 2823 br w, 1743 s, 1692 vs, 1628 m, 1453 m, 1214 vs, 1092 s; TOF–ESI+–MS (m/z): [M + Na]+ calcd for C19H22N2NaO10, 461.1167; found, 461.1171. General procedure for

• NMR (150 MHz, CDCl3) δ 198.71, 170.73, 170.29, 170.26, 160.23, 149.43, 138.26, 113.71, 94.82, 85.91, 82.58, 79.29, 74.03, 65.45, 63.65, 37.93, 20.90, 20.60, 20.54; IR (cm–1, KBr) 3356 br m, 3089 br w, 2960 br w, 2093 m, 2056 s, 2024 br s, 1736 vs, 1638 m, 1561 m, 1406 m, 1228 vs, 1024 s; TOF–ESI+–MS

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

• László Orha,
• József M. Tukacs,
• László Kollár and
• László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

• File 1. Exact mass measurements were performed on a high-resolution Q-Exactive Focus hybrid quadrupole-orbitrap mass spectrometer (Thermo Fisher Scientific, Bremen, Germany) equipped with a heated electrospray ionization (ESI) source. Samples were dissolved in acetonitrile/water 1:1 (v/v) solvent

• mixture containing 0.1% (v/v) formic acid. Solutions were directly introduced into the ion source using a syringe pump. Under the applied conditions, the compounds form protonated molecules, [M + H]+ in positive ionization mode (ESI). Detailed experimental procedures, characterization data are reported in

Facile regiodivergent synthesis of spiro pyrrole-substituted pseudothiohydantoins and thiohydantoins via reaction of [e]-fused 1H-pyrrole-2,3-diones with thiourea

• Aleksandr I. Kobelev,
• Nikita A. Tretyakov,
• Ekaterina E. Stepanova,
• Maksim V. Dmitriev,
• Michael Rubin and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2019, 15, 2864–2871, doi:10.3762/bjoc.15.280

• major products with m/z = 396 ([M + H]+, ESI+) were observed in a ratio of ≈1:1, which corresponded to adducts of thiourea with FPD 1a. The adducts were isolated, and their structures were elucidated as the desired spiro-fused thiohydantoin 2a and pseudothiohydantoin 3a (Scheme 4). It should be pointed

Design, synthesis and investigation of water-soluble hemi-indigo photoswitches for bioapplications

• Daria V. Berdnikova

Beilstein J. Org. Chem. 2019, 15, 2822–2829, doi:10.3762/bjoc.15.275

• ROESY 2D NMR techniques. The carbon NMR signal assignments were performed by means of HSQC and HMBC 2D NMR techniques. Mass spectra (ESI) were recorded on a Finnigan LCQ Deca mass spectrometer. Elemental analysis was performed with a HEKAtech EUROEA combustion analyser by Mr. Rochus Breuer (Universität

Photoreversible stretching of a BAPTA chelator marshalling Ca²⁺-binding in aqueous media

• Aurélien Ducrot,
• Arnaud Tron,
• Robin Bofinger,
• Ingrid Sanz Beguer,
• Jean-Luc Pozzo and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2019, 15, 2801–2811, doi:10.3762/bjoc.15.273

• argon over sodium benzophenone ketyl. CH2Cl2 was distilled over CaH2 under argon. Mass spectrometry was performed at the CESAMO analytical center (University of Bordeaux, France) on a QStar Elite mass spectrometer (Applied Biosystems). The instrument is equipped with an electrospray ion (ESI) source and

• spectra were recorded in the positive mode. High-resolution mass spectrometry (HRMS) measurements were performed with an ESI source on a Q-TOF mass spectrometer with an accuracy tolerance of 2 ppm (Fédération de Recherche CBM/ICOA (FR2708) platform). The electrospray needle was maintained at 5000 V and

• ), 1.16 (t, J = 7.2 Hz, 12H, CH3) ppm; 13C NMR (CDCl3, 75 MHz) δ 170.5, 152.8, 143.9, 139.7, 136.4, 127.6, 126.9, 126.6, 113.8, 106.4, 105.6, 69.6, 67.1, 59.9, 52.6, 13.2 ppm; HRMS–ESI (m/z): [M + Na]+ calculated for C44H52N2O12Na, 823.3429; found, 823.3412. Tetraethyl 2,2',2'',2'''-{1,2-ethanediylbis[oxy