Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates

• Tyler M. M. Stack,
• William H. Johnson Jr. and
• Christian P. Whitman

Beilstein J. Org. Chem. 2017, 13, 1022–1031, doi:10.3762/bjoc.13.101

• described. General methods Mass spectral data were obtained on an LCQ electrospray ion-trap mass spectrometer (Thermo, San Jose, CA) in the ICMB Protein and Metabolite core facility. The samples were prepared as described previously [21]. Kinetic data were obtained at 24 °C on an Agilent 8453 diode-array

• . Pooled fractions were concentrated and exchanged into 20 mM KH2PO4 buffer (pH 7.3) using an Amicon Ultra filter unit (3K membrane). This procedure typically yields ≈8 mg of 4-OT estimated to be ≈95% pure. A sample was analyzed by electrospray ionization mass spectrometry (ESIMS) to verify the molecular

Cyclodextrins tethered with oligolactides – green synthesis and structural assessment

• Cristian Peptu,
• Mihaela Balan-Porcarasu,
• Alena Šišková,
• Ľudovít Škultéty and
• Jaroslav Mosnáček

Beilstein J. Org. Chem. 2017, 13, 779–792, doi:10.3762/bjoc.13.77

• ionization like matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI). Liquid chromatography (LC) separation with evaporative light scattering detection (ELSD) and NMR analysis were employed in order to elucidate the structural profiles of the obtained mixtures. The results

• ) spectroscopy, however, in case of CD-oligolactides no such structural proofs were presented. Later, the LA was polymerized in dimethylformamide (DMF) solution to result in well-defined and homogenous β-CD functionalized with oligolactides as demonstrated by electrospray mass spectrometry (ESI–MS) and NMR

• higher molecular-weight compounds (β-CD-LA) under electrospray conditions. This mass discrimination together with the formation of multiple charged species (example of ESI–MS spectrum of double and triple charged β-CD-LA is provided in Supporting Information File 1, Figure S23) is actually hindering a

Novel β-cyclodextrin–eosin conjugates

• Gábor Benkovics,
• Damien Afonso,
• András Darcsi,
• Szabolcs Béni,
• Sabrina Conoci,
• Éva Fenyvesi,
• Lajos Szente,
• Milo Malanga and
• Salvatore Sortino

Beilstein J. Org. Chem. 2017, 13, 543–551, doi:10.3762/bjoc.13.52

• protons unambiguously confirms the monosubstitution pattern (DS = 1) in both cases and was further proven by electrospray ionization mass spectrometry (ESIMS) analysis of the compounds (see Supporting Information File 1). The signals in the aromatic region are well resolved (see Figures S25 and S33

Characterization of the synthetic cannabinoid MDMB-CHMCZCA

• Carina Weber,
• Stefan Pusch,
• Dieter Schollmeyer,
• Sascha Münster-Müller,
• Michael Pütz and
• Till Opatz

Beilstein J. Org. Chem. 2016, 12, 2808–2815, doi:10.3762/bjoc.12.279

• Ultima 3 instrument (Waters) with a dual electrospray source and an external calibrant. Polarimetry The determination of the optical rotation was carried out at 589 nm and 25 °C in a Perkin-Elmer 241 polarimeter (Perkin Elmer) using a 10 cm path length quartz glass cuvette. Electronic spectroscopy UV and

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

• Ming Liu,
• Jan C. Namyslo,
• Martin Nieger,
• Mika Polamo and
• Andreas Schmidt

Beilstein J. Org. Chem. 2016, 12, 2673–2681, doi:10.3762/bjoc.12.264

• range of 400 to 4000 cm−1. The mass spectra were obtained with a Varian 320 MS Triple Quad GC/MS/MS instrument with a Varian 450-GC. All electrospray ionisation mass spectra (ESIMS) were measured with a Hewlett-Packard/Agilent LCMSD series HP 1100 spectrometer with APIES. The compound samples were

• mass spectrometer with electrospray ionisation. The single-crystal X-ray diffraction studies were carried out on a Bruker D8 Venture diffractometer with Photon100 detector at 123(2) K using Cu Kα (8) and Mo Kα radiation (9, 11, 12) (λ = 1.54178 Å and 0.71073 Å). Dual space methods (8, SHELXT) [53] and

Formose reaction controlled by boronic acid compounds

• Toru Imai,
• Tomohiro Michitaka and
• Akihito Hashidzume

Beilstein J. Org. Chem. 2016, 12, 2668–2672, doi:10.3762/bjoc.12.263

• boronic acid esters. On the other hand, the 1H and 13C NMR spectra for pVPB/NaSS show well-resolved signals, indicating that the formose reaction provides products with a significant selectivity in the presence of pVPB/NaSS. Figure 4 displays typical examples of electrospray ionization mass spectrometry

Facile synthesis of a 3-deazaadenosine phosphoramidite for RNA solid-phase synthesis

• Elisabeth Mairhofer,
• Elisabeth Fuchs and
• Ronald Micura

Beilstein J. Org. Chem. 2016, 12, 2556–2562, doi:10.3762/bjoc.12.250

• : CDCl3 (7.26 ppm) or DMSO-d6 (2.49 ppm) for 1H NMR; CDCl3 (77.0 ppm) or DMSO-d6 (39.5 ppm) for 13C NMR spectra. 1H and 13C assignments are based on COSY and HSQC experiments. MS experiments were performed on a Waters ESI TOF LCT Premier Serie KD172 or Bruker 7T FT-ICR instrument with an electrospray ion

Tunable microwave-assisted method for the solvent-free and catalyst-free peracetylation of natural products

• Manuela Oliverio,
• Paola Costanzo,
• Monica Nardi,
• Carla Calandruccio,
• Raffaele Salerno and
• Antonio Procopio

Beilstein J. Org. Chem. 2016, 12, 2222–2233, doi:10.3762/bjoc.12.214

• , then returning to 5% in 1 minute. At the end it was re-equilibrated for 3 minutes. The total run time, including column wash and equilibration was 15 min. A Thermo Scientific Q-ExactiveTM mass spectrometer was used for HRMS measurements using electrospray as ionization source with both negative and

Artificial Diels–Alderase based on the transmembrane protein FhuA

• Hassan Osseili,
• Daniel F. Sauer,
• Klaus Beckerle,
• Marcus Arlt,
• Tomoki Himiyama,
• Tino Polen,
• Akira Onoda,
• Ulrich Schwaneberg,
• Takashi Hayashi and
• Jun Okuda

Beilstein J. Org. Chem. 2016, 12, 1314–1321, doi:10.3762/bjoc.12.124

• (polyethylene-polyethylene glycol), SDS (sodium dodecyl sulfate), TEV (Tobacco Etch Virus), MALDI–TOF–MS (matrix-assisted laser desorption/ionisation and time-of-flight mass spectrometry), FhuAΔCVFtev (FhuA Δ1-159_C545_V548_F501_tev), CD (circular dichroism), ESI-MS (electrospray ionization-mass spectrometry

Nucleic acids through condensation of nucleosides and phosphorous acid in the presence of sulfur

• Tuomas Lönnberg

Beilstein J. Org. Chem. 2016, 12, 670–673, doi:10.3762/bjoc.12.67

• spectrum, approximately 18% of the phosphite starting material had been converted to diverse phosphorothioate products. The product mixture was fractioned first by ion-exchange (IE) and then by reversed-phase (RP) HPLC (Figure 2, RP chromatograms presented in Supporting Information File 1). Electrospray

New synthetic strategies for xanthene-dye-appended cyclodextrins

• Milo Malanga,
• Andras Darcsi,
• Mihaly Balint,
• Gabor Benkovics,
• Tamas Sohajda and
• Szabolcs Beni

Beilstein J. Org. Chem. 2016, 12, 537–548, doi:10.3762/bjoc.12.53

• theoretical values for a monosubstituted rhodamine-β-CD derivative. This is also confirmed by the found value of the pseudo-molecular ion during the electrospray ionization mass spectrometry (ESIMS) analysis (see Experimental part). The resonance signals in the aromatic region are well resolved (see

Synthesis of cyclic N¹-pentylinosine phosphate, a new structurally reduced cADPR analogue with calcium-mobilizing activity on PC12 cells

• Ahmed Mahal,
• Stefano D’Errico,
• Nicola Borbone,
• Brunella Pinto,
• Agnese Secondo,
• Valeria Costantino,
• Valentina Tedeschi,
• Giorgia Oliviero,
• Vincenzo Piccialli and
• Gennaro Piccialli

Beilstein J. Org. Chem. 2015, 11, 2689–2695, doi:10.3762/bjoc.11.289

• on a Bruker APEX II FT-ICR mass spectrometer using the electrospray ionization (ESI) technique. Column chromatography was carried out on silica gel-60 (Merck, 0.063–0.200 mm) or on C-18 reversed-phase silica gel-60 (Merck, 0.040–0.063 mm). Analytical TLC analyses were performed using F254 silica gel

Two strategies for the synthesis of the biologically important ATP analogue ApppI, at a multi-milligram scale

• Janne Weisell,
• Jouko Vepsäläinen and
• Petri A. Turhanen

Beilstein J. Org. Chem. 2015, 11, 2189–2193, doi:10.3762/bjoc.11.237

• quadrupole time-of-flight mass spectrometer using electrospray ionization (ESI) in the positive ionization mode. The purity of the products was determined from 1H and 31P NMR spectra and was ≥95% unless stated otherwise. Procedure for the preparation of isopentenyl tosylate (7): 3-Methyl-3-buten-1-ol (770 µL

Conformational equilibrium in supramolecular chemistry: Dibutyltriuret case

• Karina Mroczyńska,
• Małgorzata Kaczorowska,
• Erkki Kolehmainen,
• Ireneusz Grubecki,
• Marek Pietrzak and
• Borys Ośmiałowski

Beilstein J. Org. Chem. 2015, 11, 2105–2116, doi:10.3762/bjoc.11.227

• complex. For detailed discussion that supports experimental findings refer to the computations section in Supporting Information File 1. Mass spectrometry To have a more complete view of properties of 1 we applied the combination of soft ionization technique electrospray ionization (ESI) with high

• , m/zmeas = 775.51543) via positive electrospray. The results of performed ESI–HRMS experiments clearly show that dibutyltriuret can easily self-associate in the chloroform/methanol solution, forming singly charged cations of dimers and trimers in positive electrospray and singly charged anions of

• dimers in negative electrospray, respectively. Association processes of dibutyltriuret 1 with anionic guests also occur, however presence of methanol in the analytical solutions and/or mechanism of ESI ionization process (in ESI ions are created by the addition or removal of a proton(s)) [57] have non

Investigation on the reactivity of α-azidochalcones with carboxylic acids: Formation of α-amido-1,3-diketones and highly substituted 2-(trifluoromethyl)oxazoles

• Kandasamy Rajaguru,
• Arumugam Mariappan,
• Rajendran Suresh,
• Periasamy Manivannan and
• Shanmugam Muthusubramanian

Beilstein J. Org. Chem. 2015, 11, 2021–2028, doi:10.3762/bjoc.11.219

• . Electrospray ionization (ESI) mass spectra were obtained on an LCQ Fleet mass spectrometer, Thermo Fisher Instruments Limited, US and an Agilent mass spectrometer. Infrared spectra were recorded on a Shimadzu FTIR instrument (KBr pellet). Elemental analyses were performed on a Perkin Elmer 2400 Series II

Investigation of the role of stereoelectronic effects in the conformation of piperidones by NMR spectroscopy and X-ray diffraction

• Cesar Garcias-Morales,
• David Ortegón-Reyna and
• Armando Ariza-Castolo

Beilstein J. Org. Chem. 2015, 11, 1973–1984, doi:10.3762/bjoc.11.213

• point matrix of 1024 × 256 with a spectral width of 6354 × 6354 Hz, mixture time of 1 s, and a recycle delay of 1.5 s [66][67]. Mass spectra were recorded on an Agilent G1969 LC/MSD TOF spectrometer coupled to HPLC with electrospray ionization. X-ray crystal structure analysis The crystals were mounted

Profluorescent substrates for the screening of olefin metathesis catalysts

• Raphael Reuter and
• Thomas R. Ward

Beilstein J. Org. Chem. 2015, 11, 1886–1892, doi:10.3762/bjoc.11.203

• on Bruker 400 MHz and 500 MHz spectrometers. The chemical shifts are reported in ppm (parts per million). Electrospray ionization mass spectra (ESIMS) were recorded on a Bruker FTMS 4.7T bioAPEX II spectrometer. HRMS was measured on a Bruker maXis 4G QTOF-ESI spectrometer. HPLC was conducted on a

Fe(II)/Et₃N-Relay-catalyzed domino reaction of isoxazoles with imidazolium salts in the synthesis of methyl 4-imidazolylpyrrole-2-carboxylates, its ylide and betaine derivatives

• Ekaterina E. Galenko,
• Olesya A. Tomashenko,
• Alexander F. Khlebnikov,
• Mikhail S. Novikov and
• Taras L. Panikorovskii

Beilstein J. Org. Chem. 2015, 11, 1732–1740, doi:10.3762/bjoc.11.189

• (39.51 ppm). Mass spectra were recorded on a Bruker maXis HRMS–ESI–QTOF, with electrospray ionization in positive mode. IR spectra were recorded on a Bruker FTIR spectrometer Tensor 27 for tablets in KBr, only characteristic absorption is indicated. The single crystal X-ray diffraction experiment was

A hybrid electron donor comprising cyclopentadithiophene and dithiafulvenyl for dye-sensitized solar cells

• Gleb Sorohhov,
• Chenyi Yi,
• Michael Grätzel,
• Silvio Decurtins and
• Shi-Xia Liu

Beilstein J. Org. Chem. 2015, 11, 1052–1059, doi:10.3762/bjoc.11.118

• , multiplet. HRMS data were obtained with electrospray ionization (ESI). Cyclic voltammetry was performed in a three-electrode cell equipped with a platinum-disk working electrode, a glassy carbon counter electrode, and Ag/AgCl was used as the reference electrode. The electrochemical experiments were carried

Synthesis and characterization of the cyanobenzene-ethylenedithio-TTF donor

• Sandrina Oliveira,
• Dulce Belo,
• Isabel C. Santos,
• Sandra Rabaça and
• Manuel Almeida

Beilstein J. Org. Chem. 2015, 11, 951–956, doi:10.3762/bjoc.11.106

• counter electrodes and an Ag/AgNO3 reference electrode. The measurements were performed on fresh solutions with a concentration of 10−3 M, in CH2Cl2, that contained n-Bu4PF6 (10−1 M) as the supporting electrolyte. Mass spectra were obtained with a Bruker HCT electrospray ionization quadrupole ion trap

Discrete multiporphyrin pseudorotaxane assemblies from di- and tetravalent porphyrin building blocks

• Mirko Lohse,
• Larissa K. S. von Krbek,
• Sebastian Radunz,
• Suresh Moorthy,
• Christoph A. Schalley and
• Stefan Hecht

Beilstein J. Org. Chem. 2015, 11, 748–762, doi:10.3762/bjoc.11.85

• more complicated. Therefore, a straightforward and easy analysis of the NMR spectra will likely be impossible. In our earlier studies [37][78][79], however, electrospray ionization (ESI) mass spectrometry (MS) turned out to be a perfectly suited method to characterize the complexes present in solution

• electrospray ionization. These results show that mass spectrometry should be a well suited method for the investigation of the multivalent pseudorotaxanes under study. These usually show much higher binding constants than the monovalent analogue and should therefore very likely survive the ionization process

• conclusion, that this partly bound pseudorotaxane is most probably a product of the electrospray ionization process. In cases of the 1:1 mixture of A4 and C4 and the 1:2 mixture of A4 and C2 the desired pseudorotaxanes [A4@C4]4+ (m/z = 989) and [A4@C22]4+ (m/z = 1200) are the most abundant species and there

3α,5α-Cyclocholestan-6β-yl ethers as donors of the cholesterol moiety for the electrochemical synthesis of cholesterol glycoconjugates

• Aneta M. Tomkiel,
• Adam Biedrzycki,
• Jolanta Płoszyńska,
• Dorota Naróg,
• Andrzej Sobkowiak and
• Jacek W. Morzycki

Beilstein J. Org. Chem. 2015, 11, 162–168, doi:10.3762/bjoc.11.16

• electrospray ionization (ESI) or AutoSpec Premier (Waters) (EI). Merck Silica Gel 60, F 256 TLC aluminum sheets were applied for thin-layer chromatographic analysis. For a visualization of the products, a 5% solution of phosphomolybdic acid in ethanol was used. The reaction products were separated by column

Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer

• Florian Hamon,
• Claire Blaszkiewicz,
• Marie Buchotte,
• Estelle Banaszak-Léonard,
• Hervé Bricout,
• Sébastien Tilloy,
• Eric Monflier,
• Christine Cézard,
• Laurent Bouteiller,
• Christophe Len and
• Florence Djedaini-Pilard

Beilstein J. Org. Chem. 2014, 10, 2874–2885, doi:10.3762/bjoc.10.304

• (λ = 365 nm) for the irradiation of aqueous AZO-CDim 1 solutions (c = 10−4 M). Stepwise control of the reactions was readily achieved by ESIMS in the positive ion mode using a ZQ 4000 quadrupole mass spectrometer (Waters-Micromass, Manchester, UK). High resolution electrospray mass spectra (HRMS–ESI

• mass spectrometer with EBETOF geometry. The compounds were individually dissolved in a 1:1 water/CH3CN mixture at a concentration of 10 μg·cm−3 and then infused into the electrospray ion source at a flow rate of 10 mm3·min−1 at 333 K. The mass spectrometer was operated at 4 kV while scanning the magnet

A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

• Stefanie Wolfram,
• Hendryk Würfel,
• Stefanie H. Habenicht,
• Christine Lembke,
• Phillipp Richter,
• Eckhard Birckner,
• Rainer Beckert and
• Georg Pohnert

Beilstein J. Org. Chem. 2014, 10, 2470–2479, doi:10.3762/bjoc.10.258

• electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC–MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously

• samples. Several probes have been designed for use with liquid chromatography–mass spectrometry (LC–MS). The probes attach covalently to target functional groups like amines, aldehydes/ketones, carboxylic acids and enhance their detection limit in LC–electrospray ionization (ESI) MS. This can be achieved

A new charge-tagged proline-based organocatalyst for mechanistic studies using electrospray mass spectrometry

• J. Alexander Willms,
• Rita Beel,
• Martin L. Schmidt,
• Christian Mundt and
• Marianne Engeser

Beilstein J. Org. Chem. 2014, 10, 2027–2037, doi:10.3762/bjoc.10.211

• temporal evolution has been followed using a microreactor continuous-flow technique. Keywords: charge tag; electrospray; mass spectrometry; organocatalysis; proline; template; Introduction Electrospray ionization (ESI) mass spectrometry [1] has not only developed into a standard characterization method

• mixing event and the electrospray is determined by the flow rates and capillary lengths. Mass spectra of a solution of diethyl ketomalonate, butyraldehyde and unmodified L-proline or 1, respectively, are depicted in Figure 4. The mass spectra shown in Figure 4 do not exhibit abundant signals for the

• . In particular, intermediates [IIa]+ and [IIIa]+ have been detected in high abundances. Again, we unfortunately have not been successful in finding suitable electrospray conditions to detect the fragile intermediates [Ia]+/[Ib]+ and [IVa]+/[IVb]+. More importantly, however, additional species that are