Synthesis of a derivative of α-D-Glcp(1->2)-D-Galf suitable for further glycosylation and of α-D-Glcp(1->2)-D-Gal, a disaccharide fragment obtained from varianose

• Carla Marino,
• Carlos Lima,
• Karina Mariño and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2012, 8, 2142–2148, doi:10.3762/bjoc.8.241

• incorporation. Synthetic oligosaccharide fragments related to varianose are useful as potential substrates or standards for characterization of the α-galactofuranosyl transferases. In this paper we report a straightforward procedure for the synthesis of α-D-Glcp(1→2)-D-Gal (1) and the use of this compound to

• a good model for studies on the GlfTα. The constitutive oligosaccharides could be used as substrates or as standards for the identification of the products. A pentasaccharide fragment containing both, α and β-galactofuranosyl residues was synthesized by Bay and Lowary [18]. The two possible

New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin

• Adam Mondrzyk,
• Beate Mondrzik,
• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2118–2123, doi:10.3762/bjoc.8.238

• polystyrene standards in a range of 575 to 3,114,000 g/mol. Toluene was used as the internal standard. Dynamic light scattering (DLS) experiments were carried out with a Malvern Zetasizer Nano ZS ZEN 3600 at a temperature of 20 °C. The particle size distribution was derived from a deconvolution of the

Chemical modification allows phallotoxins and amatoxins to be used as tools in cell biology

• Jan Anderl,
• Hartmut Echner and
• Heinz Faulstich

Beilstein J. Org. Chem. 2012, 8, 2072–2084, doi:10.3762/bjoc.8.233

• with the matrix solution and 0.7 µL of this mixture was dried onto the stainless-steel sample holder. Matrix solutions were usually α-cyano-4-hydroxycinnamic acid [dissolved at 10 mg/mL in 50% acetonitrile, 50% 0.1% TFA (all % v/v)]. Spectra were calibrated by using near-external standards consisting

Design and synthesis of quasi-diastereomeric molecules with unchanging central, regenerating axial and switchable helical chirality via cleavage and formation of Ni(II)–O and Ni(II)–N coordination bonds

• Vadim A. Soloshonok,
• José Luis Aceña,
• Hisanori Ueki and
• Jianlin Han

Beilstein J. Org. Chem. 2012, 8, 1920–1928, doi:10.3762/bjoc.8.223

• internal standards. High-resolution mass spectra (HRMS) were recorded on a JEOL HX110A instrument. Optical rotations were measured on a JASCO P-1010 polarimeter. Melting points (mp) are uncorrected and were obtained in open capillaries. All reagents and solvents, unless otherwise stated, are commercially

Synthesis and characterization of low-molecular-weight π-conjugated polymers covered by persilylated β-cyclodextrin

• Aurica Farcas,
• Ana-Maria Resmerita,
• Andreea Stefanache,
• Mihaela Balan and
• Valeria Harabagiu

Beilstein J. Org. Chem. 2012, 8, 1505–1514, doi:10.3762/bjoc.8.170

• determined by gel-permeation chromatography (GPC) analysis, using polystyrenes as standards and CH2Cl2 as eluent. GPC data are listed in Table 1 and shown in Figure S2 and Figure S3 in the Supporting Information File 1. On the basis of the molecular weight, the numbers of repeat units for PDOF-BTc and PDOF

• . The molecular weights of copolymers were determined by gel permeation chromatography (GPC) in CH2Cl2 by using a Water Associates 440 instrument and polystyrene calibrating standards. Differential scanning calorimetry (DSC) was performed with a Mettler Toledo DSC-12E calorimeter with two repeated

Interaction of cyclodextrins with pyrene-modified polyacrylamide in a mixed solvent of water and dimethyl sulfoxide as studied by steady-state fluorescence

• Akihito Hashidzume,
• Yongtai Zheng and
• Akira Harada

Beilstein J. Org. Chem. 2012, 8, 1312–1317, doi:10.3762/bjoc.8.150

• Standards). 1H NMR spectra were measured on a JEOL JNM-ECA500 spectrometer by using a mixed solvent of DMSO-d6 and D2O (1/1, v/v) as a solvent, and chemical shifts were referenced to the solvent value (i.e., 2.49 ppm for DMSO). Steady-state fluorescence spectra for 0.04 g L−1 pAAmPy at varying xDMSO from 0

Partial thioamide scan on the lipopeptaibiotic trichogin GA IV. Effects on folding and bioactivity

• Marta De Zotti,
• Barbara Biondi,
• Cristina Peggion,
• Matteo De Poli,
• Haleh Fathi,
• Simona Oancea,
• Claudio Toniolo and
• Fernando Formaggio

Beilstein J. Org. Chem. 2012, 8, 1161–1171, doi:10.3762/bjoc.8.129

• Peptide antibacterial activity was tested against Gram-positive and Gram-negative bacteria by the standardized disk diffusion Bauer–Kirby method [75] using the Müller–Hinton culture medium at pH 7.2–7.4 as recommended by the National Committee for Clinical Laboratory Standards [76]. The antibacterial

Algicidal lactones from the marine Roseobacter clade bacterium Ruegeria pomeroyi

• Ramona Riclea,
• Julia Gleitzmann,
• Hilke Bruns,
• Corina Junker,
• Barbara Schulz and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2012, 8, 941–950, doi:10.3762/bjoc.8.106

• bacteria of the Roseobacter clade and also from various other species [25], were readily identified according to their mass spectra and by comparison with synthetic standards. However, the volatiles 7–11, including the main compound 8, could not immediately be identified by their mass spectra alone. The

• in the volatile fraction of R. pomeroyi. The structures of these lactones have been unambiguously assigned by comparison to synthetic standards. In agar diffusion assays the synthetic lactones showed specific activity against algae, but not against bacteria or fungi, suggesting that the lactones may

The use of glycoinformatics in glycochemistry

• Thomas Lütteke

Beilstein J. Org. Chem. 2012, 8, 915–929, doi:10.3762/bjoc.8.104

• that structures that have not been observed before or that are missing from the database will not be identified this way. This problem also applies to programs that use experimental MSn data of oligosaccharide standards to assign MSn fragments of larger glycans, such as GLYCH [129] or MSn FragLib [140

Chemo-enzymatic modification of poly-N-acetyllactosamine (LacNAc) oligomers and N,N-diacetyllactosamine (LacDiNAc) based on galactose oxidase treatment

• Christiane E. Kupper,
• Ruben R. Rosencrantz,
• Birgit Henßen,
• Helena Pelantová,
• Stephan Thönes,
• Anna Drozdová,
• Vladimir Křen and
• Lothar Elling

Beilstein J. Org. Chem. 2012, 8, 712–725, doi:10.3762/bjoc.8.80

• analysed by analytical reversed-phase HPLC applying method A and assigned by comparison to defined standards [45]. Concentration was determined by integration of the peak area and calculated against a linear calibration regression of GlcNAc–linker–t-Boc. Synthesis and isolation of LacDiNAc-t-Boc LacDiNAc-t

Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10

• Teresa Weise,
• Marco Kai,
• Anja Gummesson,
• Armin Troeger,
• Stephan von Reuß,
• Silvia Piepenborn,
• Francine Kosterka,
• Martin Sklorz,
• Ralf Zimmermann,
• Wittko Francke and
• Birgit Piechulla

Beilstein J. Org. Chem. 2012, 8, 579–596, doi:10.3762/bjoc.8.65

• (38) (small amounts of which were found to be present among the natural volatiles), retention indices with methylketones as reference standards were calculated. Corresponding data published for methyl-branched hydrocarbons and increment calculations strongly suggested iso-branching for the main

• commercially available or specifically synthesized reference compounds (co-injection). Synthetic 10-methylundecan-2-one and 9-methylundecan-2-one served as standards for the structure assignments of other branched-chain methyl ketones on the basis of their mass spectra and retention indices. Cultivation on

• . Electron ionization (EI) mass spectra were taken at 70 eV. The mass range was m/z = 40–280. Compounds were identified by using available reference compounds and the library of the National Institute of Standards and Technology (NIST147) for the comparison of mass spectra, retention times and Kovats indices

Azobenzene dye-coupled quadruply hydrogen-bonding modules as colorimetric indicators for supramolecular interactions

• Yagang Zhang and
• Steven C. Zimmerman

Beilstein J. Org. Chem. 2012, 8, 486–495, doi:10.3762/bjoc.8.55

• as a control polymer and purified by dissolving in CH2Cl2 and precipitating out with MeOH. PS and PS-DAN were characterized by SEC with THF as eluent, with PS molecular weight standards. The loading of the DAN unit was determined by 1H NMR (Table 1). Poly(butyl acrylate) (PBA) and 2-ureido-4(1H

• )-pyrimidone (UPy) modified poly(butyl acrylate) (PBA-UPy) were prepared and characterized by THF SEC against PS standards according to a known procedure [57]. The loading of the UPy units, determined by 1H NMR, is listed in Table 1. PS and DAN-modified PS were obtained as white powders whereas PBA and UPy

Synthesis of fluorinated maltose derivatives for monitoring protein interaction by ¹⁹F NMR

• Michaela Braitsch,
• Hanspeter Kählig,
• Georg Kontaxis,
• Michael Fischer,
• Toshinari Kawada,
• Robert Konrat and
• Walther Schmid

Beilstein J. Org. Chem. 2012, 8, 448–455, doi:10.3762/bjoc.8.51

• -type 2-F-maltose isomers), which serve as internal standards, to rule out nonspecific binding and interactions, and thus increasing the reliability of this method. The 2-F-maltose reporter system was used to study the ligand binding affinity to MBP. “Fine tuning” by the regioselective fluorination of

Facile synthesis of nitrophenyl 2-acetamido-2-deoxy-α-D-mannopyranosides from ManNAc-oxazoline

• Karel Křenek,
• Petr Šimon,
• Lenka Weignerová,
• Barbora Fliedrová,
• Marek Kuzma and
• Vladimír Křen

Beilstein J. Org. Chem. 2012, 8, 428–432, doi:10.3762/bjoc.8.48

• Avance III 400 MHz spectrometer (400.13 MHz for 1H, 100.55 MHz for 13C at 30 °C) and a Bruker Avance III 600 MHz spectrometer (600.23 MHz for 1H, 150.93 MHz for 13C at 30 °C) in CD3OD or CDCl3 (Sigma-Aldrich). Residual signals of the deuterated solvents were used as internal standards (for CD3OD δH 3.330

Perhydroazulene-based liquid-crystalline materials with smectic phases

• Zakir Hussain,
• Henning Hopf and
• S. Holger Eichhorn

Beilstein J. Org. Chem. 2012, 8, 403–410, doi:10.3762/bjoc.8.44

• using the residual nondeuterated solvent as internal standards (CDCl3: 1H: δ 7.26; 13C: δ 77.00). IR: Nicolet 320 FT-IR and Bruker Tensor 27 spectrometer. Samples were prepared either as KBr pellets or as thin films. UV: In acetonitrile and methanol with a Beckman UV 5230 or a HP 8452A Diode Array

Synthesis of mesomeric betaine compounds with imidazolium-enolate structure

• Nina Gonsior,
• Fabian Mohr and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 390–397, doi:10.3762/bjoc.8.42

• used. The system was calibrated with polystyrene standards with a molecular range from 580 Da to 1186 kDa. Synthesis of 2,3-dibromo-5-(1-butyl-1H-imidazol-3-ium-3-yl)-1,4-benzoquinone-6-olate (3) Tetrabromo-1,4-benzoquinone (p-bromanil, 1) (0.845 g, 2 mmol) was dissolved in 45 mL of acetonitrile at 60

Conserved and species-specific oxylipin pathways in the wound-activated chemical defense of the noninvasive red alga Gracilaria chilensis and the invasive Gracilaria vermiculophylla

• Martin Rempt,
• Florian Weinberger,
• Katharina Grosser and
• Georg Pohnert

Beilstein J. Org. Chem. 2012, 8, 283–289, doi:10.3762/bjoc.8.30

• same procedure was followed in the absence of the labeled fatty acid. Quantitative analysis. The extracted or commercially available compounds were used to create three calibration standards for each analyte, covering the concentration range detected in the extract from wounded algae. A calibration

• comparison of the obtained NMR and MS spectra by co-injection with authentic standards [3]. Stereochemistry of PGE2 was verified with CD spectroscopy in comparison with an authentic standard. Spectroscopic data of 5. 5-((1E,3E,5E,7Z,10Z)-hexadeca-1,3,5,7,10-pentaenyl)dihydrofuran-2(3H)-one (5) was obtained

(How) does 1,3,5-triethylbenzene scaffolding work? Analyzing the abilities of 1,3,5-triethylbenzene- and 1,3,5-trimethylbenzene-based scaffolds to preorganize the binding elements of supramolecular hosts and to improve binding of targets

• Xing Wang and
• Fraser Hof

Beilstein J. Org. Chem. 2012, 8, 1–10, doi:10.3762/bjoc.8.1

• repeating these calculations at the HF/6-31G* level of theory (Table 4). This method, although simple by modern standards, is suitable for conformational analysis and allowed us to calculate the relatively large systems (below) in a short time. Seven conformations including the lowest four conformations

Novel fatty acid methyl esters from the actinomycete Micromonospora aurantiaca

• Jeroen S. Dickschat,
• Hilke Bruns and
• Ramona Riclea

Beilstein J. Org. Chem. 2011, 7, 1697–1712, doi:10.3762/bjoc.7.200

• comparison to library spectra and subsequent GC–MS analysis of synthetic standards. Mass spectra of unbranched FAMEs (for mass spectrum of methyl dodecanoate see Figure 5A) are characterised by fragment ions at m/z = 74 (McLafferty rearrangement, Scheme 2), m/z = 87 (β-cleavage), and [M − 31]+ (loss of OMe

Synthesis and characterization of new diiodocoumarin derivatives with promising antimicrobial activities

• Hany M. Mohamed,
• Ashraf H. F. Abd EL-Wahab,
• Ahmed M. EL-Agrody,
• Ahmed H. Bedair,
• Fathy A. Eid,
• Mostafa M. Khafagy and
• Kamal A. Abd-EL-Rehem

Beilstein J. Org. Chem. 2011, 7, 1688–1696, doi:10.3762/bjoc.7.199

• , compared with the standards ampicillin and calforan. In addition, compounds 2 and 5 in the series were found to be inactive against Escherichia coli (NCTC-10410), while compound 11 was inactive against Serratia marcescens (IMRU-70). An investigation of the structure–activity relationship (SAR) revealed

A practical two-step procedure for the preparation of enantiopure pyridines: Multicomponent reactions of alkoxyallenes, nitriles and carboxylic acids followed by a cyclocondensation reaction

• Christian Eidamshaus,
• Roopender Kumar,
• Mrinal K. Bera and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2011, 7, 962–975, doi:10.3762/bjoc.7.108

• obtained from the solvent purification system MB-SPS-800 (M. Braun). Products were purified by flash chromatography on silica gel (230–400 mesh, Merck). Unless otherwise stated, yields refer to analytically pure samples. Internal standards: for 1H NMR CDCl3 (δ = 7.26 ppm), TMS (δ = 0.00 ppm), CD3OD (δ

Intraannular photoreactions in pseudo-geminally substituted [2.2]paracyclophanes

• Henning Hopf,
• Vitaly Raev and
• Peter G. Jones

Beilstein J. Org. Chem. 2011, 7, 658–667, doi:10.3762/bjoc.7.78

• Kieselgel 60 (70–230 mesh). IR: Perkin–Elmer 1420 or Nicolet 320 FT–IR spectrometer. 1H and 13C NMR: Bruker AC 200 (1H) and 50.3 MHz (13C) in CDCl3, internal standards: TMS, δ = 0 ppm for 1H, CHCl3, δ = 77.05 ppm for 13C spectroscopy. UV–vis: Beckman UV 5230 or Hitachi U 3300. The samples were degassed by

Gold-catalyzed naphthalene functionalization

• Pedro J. Pérez,
• M. Mar Díaz-Requejo and
• Iván Rivilla

Beilstein J. Org. Chem. 2011, 7, 653–657, doi:10.3762/bjoc.7.77

• ), NaBAr'4 and ethyl 2-diazopropionate were prepared by literature procedures [12][13][14][15][16]. 1H and 13C NMR spectra were recorded on a Varian Mercury 400 spectrometer in CDCl3 as solvent, with chemical shifts (δ) referenced to internal standards. General catalytic experiment Complex 1 (0.025 mmol

Novel carbazole–pyridine copolymers by an economical method: synthesis, spectroscopic and thermochemical studies

• Aamer Saeed,
• Madiha Irfan and
• Shahid Ameen Samra

Beilstein J. Org. Chem. 2011, 7, 638–647, doi:10.3762/bjoc.7.75

• was also observed consistent with the in situ formation of the pyridine ring and polymerization. Polymer solutions in THF were subjected to GPC using polystyrene standards for the determination of the molecular weights, however, no elution was observed for any of the polymers. Therefore, molecular

Kinetic evaluation of the solvolysis of isobutyl chloro- and chlorothioformate esters

• Malcolm J. D’Souza,
• Matthew J. McAneny,
• Dennis N. Kevill,
• Jin Burm Kyong and
• Song Hee Choi

Beilstein J. Org. Chem. 2011, 7, 543–552, doi:10.3762/bjoc.7.62

• values of l (0.69) and m (0.95) obtained for the solvolyses of 4, be taken as appropriate standards for the bimolecular addition–elimination and unimolecular ionization (without fragmentation) pathways, respectively. The appreciable sensitivity to solvent nucleophilicity (0.69) seen in the ionization

• (iBuSCOCl, 2) at 25.0 °C in a variety of pure and binary aqueous organic solvents with wide ranging nucleophilicity and ionizing power values. Using Equation 1, we analyze in detail values for l and m obtained for 1 and 2 compared to those of the recommended standards (3 and 4) for such substrates, and also