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

Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa

• Tian Cheng,
• Clara Chepkirui,
• Cony Decock,
• Josphat C. Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270

• , solvent A: H2O + 0.1% formic acid, solvent B: acetonitrile + 0.1% formic acid, elution gradient: 5% solvent B for 0.5 min, increasing solvent B to 100% within 19.5 min, 100% solvent B for 5 min, flow rate: 0.6 mL/min, UV–vis detection at λ = 200–600 nm) and ESI–TOF–MS analysis (maXis™ system, Bruker, scan

• range: 100–2500 m/z, capillary voltage: 4500 V, drying temperature: 200 °C). UV–vis spectra were recorded with a Shimadzu UV-2450 UV–vis spectrophotometer. The chromatogram in Figure 1 was recorded on a Bruker Agilent 1260 Infinity Series equipped with DAD and an ESI ion trap mass spectrometer (amaZon

A chiral self-sorting photoresponsive coordination cage based on overcrowded alkenes

• Constantin Stuckhardt,
• Diederik Roke,
• Wojciech Danowski,
• Edwin Otten,
• Sander J. Wezenberg and
• Ben L. Feringa

Beilstein J. Org. Chem. 2019, 15, 2767–2773, doi:10.3762/bjoc.15.268

• by using the Stokes–Einstein equation [54]. By means of ESI high-resolution mass spectrometry, we were able to verify the Pd2L4 constitution of both cages. The HRMS spectrum of Pd2(stable Z-1)4 shows the signals for the cations [Pd2(stable Z-1)4(NO3)3]+, [Pd2(stable Z-1)4(NO3)2]2+, [Pd2(stable Z-1)4

Plasma membrane imaging with a fluorescent benzothiadiazole derivative

• Pedro H. P. R. Carvalho,
• Jose R. Correa,
• Karen L. R. Paiva,
• Daniel F. S. Machado,
• Jackson D. Scholten and
• Brenno A. D. Neto

Beilstein J. Org. Chem. 2019, 15, 2644–2654, doi:10.3762/bjoc.15.257

• ) 156.4, 155.8, 144.1, 130.9, 129.2, 126.4, 123.3, 120.1, 111.9. 71.50, 71.47, 70.2, 69.9, 69.3, 38.9; HRMS (ESI-Q-TOF) calcd. for C18H23N4O3S+, 375.1485; found, 375.1460. Theoretical calculations. All DFT calculations were performed using the Gaussian 09 suite of programs [64]. Geometry optimizations

Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

• Heather J. Lacey,
• Cameron L. M. Gilchrist,
• Andrew Crombie,
• John A. Kalaitzis,
• Daniel Vuong,
• Peter J. Rutledge,
• Peter Turner,
• John I. Pitt,
• Ernest Lacey,
• Yit-Heng Chooi and
• Andrew M. Piggott

Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256

• an Apollo II ESI/MALDI Dual source or a Q Exactive Plus hybrid quadrupole-Orbitrap mass spectrometer (Thermo Fisher Scientific, Bremen, Germany) by direct infusion. NMR data were recorded in DMSO-d6 on either a Bruker Avance III 500 or a Bruker Avance II DRX-600K spectrometer. All NMR spectra were

• −205 (c 0.03, MeOH); UV (MeCN) λmax (log ε) 200 (4.19); 212 (3.71) nm; HRMS–ESI (+, m/z): [M + Na]+ calcd. for C15H22NaO5+, 305.1359; found, 305.1363. Nanangenine B (2): white powder; [α]D20 −226 (c 0.06, MeOH); UV (MeCN) λmax (log ε) 200 (4.08); 208 (3.76) nm; HRMS–ESI (+, m/z): [M + Na]+ calcd. for

• C21H32NaO6+, 403.2091; found, 403.2096. Isonanangenine B (3): white powder; [α]D20 −180 (c 0.04, MeOH); UV (MeCN) λmax (log ε) 200 (4.42); 207 (4.21) nm; HRMS–ESI (+, m/z): [M + Na]+ calcd. for C21H32NaO6+, 403.2091; found, 403.2094. Nanangenine C (4): white powder; [α]D20 −289 (c 0.2, MeOH); UV (MeCN) λmax

AgNTf₂-catalyzed formal [3 + 2] cycloaddition of ynamides with unprotected isoxazol-5-amines: efficient access to functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives

• Ziping Cao,
• Jiekun Zhu,
• Li Liu,
• Yuanling Pang,
• Laijin Tian,
• Xuejun Sun and
• Xin Meng

Beilstein J. Org. Chem. 2019, 15, 2623–2630, doi:10.3762/bjoc.15.255

• ), d (doublet), dd (doublet of doublets), t (triplet), q (quartet), and m (multiplet). All melting points are uncorrected and determined on an X-4 digital microscopic melting point apparatus. HRMS were measured using electrospray ionization (ESI). Ynamide compounds 4a–q were prepared according to the

• –ESI (m/z): [M + H]+ calcd for C20H22N3O3S, 384.1376; found, 384.1375. Selected bioactive molecules containing the 5-amino-1H-pyrrole-3-carboxamide motif. Scope with regard to ynamide 4. All reactions were carried out with ynamide 4 (0.2 mmol), isoxazole 8 (0.22 mmol, 1.1 equiv) with AgNTf2 (5 mol

Anion-driven encapsulation of cationic guests inside pyridine[4]arene dimers

• Anniina Kiesilä,
• Jani O. Moilanen,
• Anneli Kruve,
• Christoph A. Schalley,
• Perdita Barran and
• Elina Kalenius

Beilstein J. Org. Chem. 2019, 15, 2486–2492, doi:10.3762/bjoc.15.241

• and studied by multiple gas-phase techniques, ESI-QTOF-MS, IRMPD, and DT-IMMS experiments, as well as DFT calculations. The comparison of classical resorcinarenes with pyridinearenes by MS and NMR experiments reveals clear differences in their host–guest chemistry and implies that cation encapsulation

• been previously detected by ESI-MS [7]. Very recently, with the help of ion mobility mass spectrometry (IM-MS), we showed that pyridine[4]arenes favor encapsulation of neutral molecules over anionic species and anions are in fact complexed in an exo-position (exclusion complexation) between the lower

• studies with ESI-Q-TOF mass spectrometry. Complex formation was tested with the following series of cationic guests: MeNH3+, Me2NH2+, Me3NH+, Me4N+, EtNH3+, Et2NH2+, Et4N+ and Pr4N+, which were used as the corresponding Cl− or Br− salts. None of the cations MeNH3+, Me2NH2+, Me3NH+, EtNH3+, Et2NH2+ or Pr4N

Indium-mediated C-allylation of melibiose

• Christian Denner,
• Manuel Gintner,
• Hanspeter Kählig and
• Walther Schmid

Beilstein J. Org. Chem. 2019, 15, 2458–2464, doi:10.3762/bjoc.15.238

• (C-4’), 67.28 (C-3’), 66.60 (C-5’), 65.44 (C-1), 61.59 (C-6’), 35.34 (C-7), 20.69, 20.66, 20.63, 20.63, 20.62, 20.61, 20.61, 20.56, 20.50 (9 × O(C=O)CH3) ppm; HRMS (ESI+) m/z: [M + Na]+ calcd for C33H46O20Na+, 785.2475; found, 785.2473. CCDC 1922520 contains the supplementary crystallographic data

• =O)CH3) ppm; HRMS (ESI+) m/z: [M + Na]+ calcd for C33H46O20Na+, 785.2475; found, 785.2479. 2’,3’,4’,6’-Tetra-O-acetyl-α-ᴅ-galactopyranosyl-(1’→8)-1,3,4,6,7-penta-O-acetyl-2-deoxy-α-ᴅ-glycero-ᴅ-ido-octopyranose (5-syn-β): Compound (2-syn) (115 mg, 0.151 mmol) was dissolved in MeOH (15 mL) and treated

• ), 70.36 (C-6), 67.93 (C-2’), 67.79 (C-4’), 67.69 (C-3), 67.37 (C-3’), 66.45 (C-5’), 65.77 (C-4), 65.74 (C-8), 61.35 (C-6’), 29.95 (C-2), 20.97, 20.92, 20.80, 20.74, 20.72, 20.70, 20.66, 20.66, 20.62 (9 × O(C=O)CH3) ppm; HRMS (ESI+) m/z: [M + NH4]+ calcd for C32H48NO21+, 782.2713; found, 782.2719. 2’,3’,4

Combining the Ugi-azide multicomponent reaction and rhodium(III)-catalyzed annulation for the synthesis of tetrazole-isoquinolone/pyridone hybrids

• Gerardo M. Ojeda,
• Prabhat Ranjan,
• Pavel Fedoseev,
• Lisandra Amable,
• Upendra K. Sharma,
• Daniel G. Rivera and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 2447–2457, doi:10.3762/bjoc.15.237

• chromatographic solvents is presented as volume:volume ratios. Isolated compounds were submitted to HRMS using an Agilent 6220A Time of Flight MSD spectrometer equipped with an ESI ionization source. IR spectra were recorded on a Bruker Alpha FTIR spectrometer. Only frequencies (ν, in cm−1) of the most relevant

Excited state dynamics for visible-light sensitization of a photochromic benzil-subsituted phenoxyl-imidazolyl radical complex

• Yoichi Kobayashi,
• Yukie Mamiya,
• Katsuya Mutoh,
• Hikaru Sotome,
• Masafumi Koga,
• Hiroshi Miyasaka and
• Jiro Abe

Beilstein J. Org. Chem. 2019, 15, 2369–2379, doi:10.3762/bjoc.15.229

• solvents. Mass spectra (ESI-TOF-MS) were measured by using a Bruker micrOTOFII-AGA1. All reagents were purchased from TCI, Wako Co. Ltd., Aldrich Chemical Company, Inc. and Kanto Chemical Co., Inc., and were used without further purification. The synthetic procedure of Benzil-PIC is shown in Scheme 2. The

• isomers), 7.33–7.30 (m, 4H, two structural isomers), 7.07–7.04 (m, 4H, two structural isomers), 6.73–6.69 (m, 4H, two structural isomers); ESI-TOF MS m/z: [M + H]+ calcd for C35H24N2O3: 521.1859691; found, 521.1836034. Benzil-PIC A solution of potassium ferricyanide (0.968 g, 2.94 mmol) and KOH (0.741 g

• , 1H), 7.31–7.29 (m, 2H), 7.16 (d, J = 7.7 Hz, 1H), 6.64 (d, J = 10.0 Hz, 2H), 6.36 (d, J = 10.0 Hz, 2H); ESI-TOF MS m/z: [M + H]+ calcd for C35H22N2O3, 519.1703190; found, 519.1696883. Experimental setups Steady-state measurements Steady-state absorption spectra were measured with an UV-3600 Plus

Isolation and biosynthesis of an unsaturated fatty acid with unusual methylation pattern from a coral-associated bacterium Microbulbifer sp.

• Amit Raj Sharma,
• Enjuro Harunari,
• Tao Zhou,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2327–2332, doi:10.3762/bjoc.15.225

• unsaturation on the basis of its NMR and HR-ESI-TOFMS (m/z 181.1230 [M − H]−; calcd for C11H17O2, 181.1229) data. The UV spectrum of 1 in methanol exhibited an absorption maximum at 262 nm. The IR absorption bands at 1678 and 2800–3200 cm−1 suggested the presence of carboxyl group. The 1H and 13C NMR data of 1

• was recorded on a Shimadzu UV-1800 spectrophotometer. The IR spectrum was measured on a Perkin-Elmer Spectrum 100. NMR spectra were obtained on a Bruker AVANCE 500 spectrometer in CDCl3 using the signals of the residual solvent proton (δH 7.26) and carbon (δH 77.0) as internal standards. HR-ESI-TOFMS

• (50:50) to yield (2Z,4E)-3-methyl-2,4-decadienoic acid (1, 8.0 mg, tR 20.5 min). (2Z,4E)-3-Methyl-2,4-decadienoic acid (1): colorless amorphous solid; UV (MeOH) λmax (log ε) 262 (4.16) nm; IR (ATR) νmax 2952, 2923, 2852, 2585, 1678, 1662 cm−1; 1H and 13C NMR data, see Table 1; HR-ESI-TOFMS m/z

Azologization and repurposing of a hetero-stilbene-based kinase inhibitor: towards the design of photoswitchable sirtuin inhibitors

• Christoph W. Grathwol,
• Nathalie Wössner,
• Sören Swyter,
• Adam C. Smith,
• Enrico Tapavicza,
• Robert K. Hofstetter,
• Anja Bodtke,
• Manfred Jung and
• Andreas Link

Beilstein J. Org. Chem. 2019, 15, 2170–2183, doi:10.3762/bjoc.15.214

• apparatus from Büchi and are uncorrected. High accuracy mass spectra were recorded on a Shimadzu LCMS-IT-TOF using ESI ionization. Purity of final compounds was determined by HPLC with DAD (applying the 100% method at 220 nm). Preparative and analytical HPLC were performed using Shimadzu devices CBM-20A, LC

Friedel–Crafts approach to the one-pot synthesis of methoxy-substituted thioxanthylium salts

• Kenta Tanaka,
• Yuta Tanaka,
• Mami Kishimoto,
• Yujiro Hoshino and
• Kiyoshi Honda

Beilstein J. Org. Chem. 2019, 15, 2105–2112, doi:10.3762/bjoc.15.208

• on a JEOL JNM AL-400 (376 MHz) or a JEOL JNM ECA-500 (471 MHz) spectrometer with hexafluorobenzene (C6F6: δ −164.9 ppm) as internal standard. High-resolution mass spectra (HRMS) were obtained with a Hitachi Nanofrontier LD Spectrometer (ESI/TOF). Elemental analyses of carbon, hydrogen, nitrogen, and

• , 6H); 13C NMR (126 MHz, CDCl3) δ 168.3. 165.5. 165.2. 147.8. 142.2. 127.2. 127.0. 125.6. 116.9. 101.8. 101.4. 57.7. 56.7; 19F NMR (376 MHz, CDCl3) δ −81.3; IR (ATR): 1585, 1219, 1143, 1026, 634 cm−1; HRMS (ESI+) m/z: [M]+ calcd for C23H21O4S, 393.1155; found, 393.1171; anal. calcd for C24H21F3O7S2: C

• , 1245, 1148, 1026, 634 cm−1; HRMS (ESI+) m/z: [M]+ calcd for C27H23O4S, 443.1312; found, 443.1316. The generality of diaryl sulfide 1 and benzoyl chloride 2. aThe reaction was carried out with 1a (2.0 mmol), 2a (6.0 mmol), TfOH (3.0 equiv) in chlorobenzene (40.0 mL) at reflux for 1 h under N2. b2 (2.0

Multiple threading of a triple-calix[6]arene host

• Veronica Iuliano,
• Roberta Ciao,
• Emanuele Vignola,
• Carmen Talotta,
• Patrizia Iannece,
• Margherita De Rosa,
• Annunziata Soriente,
• Carmine Gaeta and
• Placido Neri

Beilstein J. Org. Chem. 2019, 15, 2092–2104, doi:10.3762/bjoc.15.207

• dialkylammonium axles. The formation of pseudo[2]rotaxane, pseudo[3]rotaxane, and pseudo[4]rotaxane by threading one, two, and three, respectively, calix-wheels of 6 has been studied by 1D and 2D NMR, DOSY, and ESI-FT-ICR MS/MS experiments. The use of a directional alkylbenzylammonium axle led to the

• -ESI-FT-ICR mass spectrum confirms the formation of 6 thanks to the presence of a molecular ion peak at 3283.1748 m/z (calcd 3283.1319 for C222H288KO18+). 1H and 13C NMR spectra of 6 were consistent with the C3-symmetry of the molecule. In details, three singlets were present in the 1H NMR spectrum of

• axle 7+ was studied by HR-ESI-FT-ICR mass spectrometry and 1D/2D NMR (Figure 3). A 1:1 mixture of 6 and 7+·TFPB− in CHCl3 was stirred at 298 K for 15 min, until the solution was clarified, and then used for mass spectrometry analysis. An ESI-FT-ICR mass spectrum of this solution (Figure 3, bottom

Bipolenins K–N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana

• Chin-Soon Phan,
• Hang Li,
• Simon Kessler,
• Peter S. Solomon,
• Andrew M. Piggott and
• Yit-Heng Chooi

Beilstein J. Org. Chem. 2019, 15, 2020–2028, doi:10.3762/bjoc.15.198

• coupled to an Agilent 6130 Quadrupole MS with an ESI source. The NMR spectra were recorded on Bruker Avance III HD 500 or AV600 spectrometers. The ECD spectra were recorded on a Jasco J-810 spectropolarimeter with MeOH as solvent. Flash cartridge (Reveleris, HP-silica, 12 g, 20 µm), Kinetex C18

Isolation and characterisation of irinans, androstane-type withanolides from Physalis peruviana L.

• Annika Stein,
• Dave Compera,
• Bianka Karge,
• Mark Brönstrup and
• Jakob Franke

Beilstein J. Org. Chem. 2019, 15, 2003–2012, doi:10.3762/bjoc.15.196

• , Waters 2424 ELS detector, and a Waters SQ Detector 2 for mass spectrometry in ESI+ and ESI– modes between m/z 150 and 1000. In analytical mode, a Phenomenex Kinetex column (2.6 µm, C18, 100 Å, 4.6 × 100 mm) was used with a gradient of [solvent A: H2O + 0.05% formic acid; solvent B: acetonitrile + 0.045