Magnetic Resonance in Chemistry

Cover image for Vol. 52 Issue 1-2

January-February 2014

Volume 52, Issue 1-2

Pages 1–59

  1. Editorial

    1. Top of page
    2. Editorial
    3. Research articles
    4. Rapid communication
    5. MRC letters
  2. Research articles

    1. Top of page
    2. Editorial
    3. Research articles
    4. Rapid communication
    5. MRC letters
    1. Diastereotopic splitting in the 13C NMR spectra of sulfur homofullerenes and methanofullerenes with chiral fragments (pages 3–9)

      Arthur R. Tulyabaev, Airat R. Tuktarov and Leonard M. Khalilov

      Article first published online: 31 OCT 2013 | DOI: 10.1002/mrc.4027

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      13C NMR chemical shifts and diastereotopic splittings for a number of sulfur homofullerenes and methanofullerenes with chiral fragments have been predicted. It was shown that an anisochrony of the fullerene core is caused by the chiral moieties attached. The diastereotopic pairs (from 8 to 11) of fullerenyl carbons of homofullerenes were observed. For the methanofullerenes, diastereotopic splittings Δδdias have been estimated corresponding to α, β and γ to the functionalization site.

    2. 13C and 15N CP/MAS, 1H–15N SCT CP/MAS and FTIR spectroscopy as tools for qualitative detection of the presence of zwitterionic and non-ionic forms of ansa-macrolide 3-formylrifamycin SV and its derivatives in solid state (pages 10–21)

      Piotr Przybylski, Krystian Pyta, Katarzyna Klich, Wojciech Schilf and Bohdan Kamieński

      Article first published online: 6 NOV 2013 | DOI: 10.1002/mrc.4028

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      Detailed solid state 13C and 15N CP/MAS NMR and FTIR studies revealed that rifampicin (2), in contrast to 3-formylrifamycin SV (1) and its amino derivatives (3-6), can occur in non-ionic or zwitterionic forms in crystal and in pure these forms or a mixture of them in a powder. FTIR studies indicated that the originally adopted forms of these type antibiotics in crystal or in powder are stable in standard laboratory conditions in time. The results presented point to the fact that because of a possible presence of two forms of rifampicin (compound 2), quantification of the content of this antibiotic in relevant pharmaceuticals needs caution.

    3. Oxidation of quinolones with peracids (an in situ EPR study) (pages 22–26)

      Andrej Staško, Viktor Milata, Zuzana Barbieriková and Vlasta Brezová

      Article first published online: 6 NOV 2013 | DOI: 10.1002/mrc.4029

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      The quinolone derivatives possessing amino hydrogen at the nitrogen of the enaminone system are oxidized with 3-chloroperbenzoic acid to nitroxide radicals in the primary step while maintaining their 4-pyridone ring. Otherwise, N-methyl substituted quinolones also form nitroxide radicals coupled with the opening of the 4-pyridone ring in a gradual oxidation of the methyl group via the nitrone–nitroxide spin-adduct cycle. N-Ethyl quinolones in contrast to its N-methyl analog form only one nitroxide radical without a further degradation.

  3. Rapid communication

    1. Top of page
    2. Editorial
    3. Research articles
    4. Rapid communication
    5. MRC letters
    1. BASHD-J-resolved-HMBC, an efficient method for measuring proton–proton and heteronuclear long-range coupling constants (pages 27–31)

      Kazuo Furihata and Mitsuru Tashiro

      Article first published online: 26 NOV 2013 | DOI: 10.1002/mrc.4032

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      An efficient pulse sequence for measuring nJC-H and nJH-H of multiplet signals has been developed. This method incorporates band selective homo decoupled pulse and J-scaling pulse into HMBC. The key of this method is to selectively decouple methyl groups, which cause broadened multiplets.

  4. MRC letters

    1. Top of page
    2. Editorial
    3. Research articles
    4. Rapid communication
    5. MRC letters
    1. Leptocarposide: a new triterpenoid glycoside from Ludwigia leptocarpa (Onagraceae) (pages 32–36)

      Florence Déclaire Mabou, Perrin Lanversin Foning Tebou, David Ngnokam, Dominique Harakat and Laurence Voutquenne-Nazabadioko

      Article first published online: 30 OCT 2013 | DOI: 10.1002/mrc.4023

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      A new triterpenoid bidesmoside (leptocarposide) possessing an acyl group in their glycosidic moiety (1), together with luteolin-8-C-glucoside and 1-O-β-D-glucopyranosyl-(2S,3R,8E)-2-[(2'R)-2-hydroxypalmitoylamino]-8-octadecen-1,3-diol was isolated from the n-butanol-soluble fraction of whole plant of Ludwigia leptocarpa (Nutt) Hara (Onagraceae). Structure of compound 1 has been assigned on the basis of spectroscopic data (1H and 13C NMR, 1H-1H COSY, HSQC, HMBC and ROESY) and mass spectrometry.

    2. Structure elucidation and NMR assignments of two unusual xanthones from Lomatogonium carinthiacum (Wulf) Reichb (pages 37–39)

      Qinghu Wang, Bagenna Bao and Yulan Chen

      Article first published online: 8 NOV 2013 | DOI: 10.1002/mrc.4024

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      The derivative of two unusual xanthones was identified on the basis of spectroscopic methods including UV, IR, ESI-MS, 1D NMR, and 2D NMR.

    3. 1H, 13C NMR studies of new 3-aminophenol isomers linked to pyridinium salts (pages 40–46)

      Santiago Schiaffino-Ortega, Antonio Espinosa, Miguel A. Gallo, L. Carlota López-Cara and Antonio Entrena

      Article first published online: 30 OCT 2013 | DOI: 10.1002/mrc.4025

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      1H and 13C NMR spectroscopic data of 20 new nonsymmetrical compounds containing a 4-(N,N-dimethylamino)- or 4-(pyrrolidin-1-yl)pyridinium cationic head; a 3-nitro-, 3-amino-, or 3-hydroxyphenyl ring; and a p-xylene, 4,4'-dimethylbiphenyl, 1,2-bis(p-tolyl)ethane or 1,4-bis(p-tolyl)butane linker, assigned by a combination of 1D and 2D NMR experiments (DEPT, HSQC, and HMBC).

    4. 3-Methylflavones characterization revisited: complete assignment of 1H and 13C NMR data (pages 47–50)

      Djenisa H. A. Rocha, Diana C. G. A. Pinto, Raquel S. G. R. Seixas and Artur M. S. Silva

      Article first published online: 8 NOV 2013 | DOI: 10.1002/mrc.4026

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      Ten 3-methylflavone derivatives were studied. Previously reported NMR data of some derivatives were corrected and/or completed, including the complete assignment of the two known natural derivatives. The complete 1H and 13C NMR assignments were achieved by combination of one-dimensional and two-dimensional NMR experiments.

    5. Muurolane-type sesquiterpenes from marine sponge Dysidea cinerea (pages 51–56)

      Phan Van Kiem, Chau Van Minh, Nguyen Xuan Nhiem, Nguyen Thi Cuc, Ngo Van Quang, Hoang Le Tuan Anh, Bui Huu Tai, Pham Hai Yen, Nguyen Thi Hoai, Kim Young Ho, Nanyoung Kim, SeonJu Park and Seung Hyun Kim

      Article first published online: 14 NOV 2013 | DOI: 10.1002/mrc.4030

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      Seven new muurolane-type sesquiterpenes, 1–7 were isolated from the marine sponge Dysidea cinerea. Their structures were determined by the combination of spectroscopic and chemical methods, including 1D-NMR, 2D-NMR, and CD spectra as well as by comparing the NMR data with those reported in the literature.

    6. Structural elucidation and NMR assignments of two new pyrrolosesquiterpenes from Streptomyces sp. Hd7-21 (pages 57–59)

      Dong-Ze Liu and Bo-Wen Liang

      Article first published online: 25 NOV 2013 | DOI: 10.1002/mrc.4031

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      Two new pyrrolosesquiterpenes were isolated from cultures of a Streptomyces sp. The structures of 1 and 2 were elucidated by NMR and MS data analysis. Compounds 1 and 2 showed moderate cytotoxic activity.

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