Magnetic Resonance in Chemistry

Cover image for Vol. 51 Issue 9

September 2013

Volume 51, Issue 9

Pages 509–604

  1. Research Articles

    1. Top of page
    2. Research Articles
    3. MRC Letters
    1. On the interference of J(HH) modulation in HSQMBC-IPAP and HMBC-IPAP experiments (pages 509–516)

      Josep Saurí and Teodor Parella

      Version of Record online: 18 JUN 2013 | DOI: 10.1002/mrc.3977

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      The effects of phase signal modulation due to homonuclear proton–proton coupling constants in HSQMBC-IPAP and HMBC-IPAP experiments are experimentally evaluated. An assessment of the reliability of nJCH measurement from distorted cross-peaks obtained in IPAP versions of HMBC and HSQMBC experiments is presented. Finally, it is shown that HMBC-COSY experiments could be an excellent complement to HMBC for the measurement of small nJCH values.

    2. Semi-preparative LC-SPE-cryoflow NMR for impurity identifications: use of mother liquor as a better source of impurities (pages 517–522)

      Frank Rinaldi, Junying Fan, Charles Pathirana and Venkatapurim Palaniswamy

      Version of Record online: 21 JUN 2013 | DOI: 10.1002/mrc.3979

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      We have shown that by using a combination of procedures, the ease of using NMR data for structure elucidation is greatly enhanced. These procedures include the use of: semi-preparative scale chromatography coupled with LC-SPE-NMR for greater analyte concentrations, cryoprobe technology for increased signal-to-noise, and mother liquor as the input to obtain larger amounts of impurities compared with the crystallized product. The result is a facile procedure for obtaining high signal-to-noise NMR data for unambiguous structure elucidation; an example of H-C HMBC spectrum is provided here.

    3. Systematic assignment of NMR spectra of 5-substituted-4-thiopyrimidine nucleosides (pages 523–529)

      Xiaohui Zhang, Jian Wang and Yao-Zhong Xu

      Version of Record online: 23 JUN 2013 | DOI: 10.1002/mrc.3980

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      A series of 5-substituted-4-thio-uridines and their 2'-deoxy analogues have been successfully prepared. Their 1H and 13C NMR have been systemically investigated and discussed together with other base-modified nucleosides. The imino proton in these 4-thionucleosides has an unusually high chemical shift and can serve as an excellent marker in NMR studies of nucleic acids containing these thio-bases.

    4. The structures of two aldazines: [1,1′-(1E,1′E)-hydrazine-1,2-diylidenebis(methan-1-yl-1-ylidene)dinaphthalen-2-ol] (Lumogen) and 2,2′-(1E,1′E)-hydrazine-1,2-diylidenebis(methan-1-yl-1-ylidene)diphenol (salicylaldazine) in the solid state and in solution (pages 530–540)

      Artur M. S. Silva, Vera L. M. Silva, Rosa M. Claramunt, Dolores Santa María, Marta B. Ferraro, Felipe Reviriego, Ibon Alkorta and José Elguero

      Version of Record online: 8 JUL 2013 | DOI: 10.1002/mrc.3983

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      A combination of NMR spectroscopy and theoretical methods (density functional theory and DFT-D) was used to study the structures of Lumogen and salicylaldazine. In the solid state, Lumogen exists as the dihydroxy tautomer. In a deuterated dimethyl sulfoxide solution, another tautomer is observed, its structure corresponding to the hydroxy-oxo tautomer. For the first time, the signals of both tautomers were observed in solution, and the tautomeric equilibrium constant directly measured. In what concerns salicylaldazine, we have observed only the dihydroxy tautomer.

    5. Use of diffusion-ordered NMR spectroscopy and HPLC–UV–SPE–NMR to identify undeclared synthetic drugs in medicines illegally sold as phytotherapies (pages 541–548)

      Lorena M. A. Silva, Elenilson G. A. Filho, Sérgio S. Thomasi, Bianca F. Silva, Antonio G. Ferreira and Tiago Venâncio

      Version of Record online: 2 JUL 2013 | DOI: 10.1002/mrc.3984

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      Phytotherapies are wrongly considered as healthy treatment, and many profiteers have been using the Internet for selling dangerous allopathic formulas as phytotherapies. The cheap and easy acquisition of these formulas, provided without any medical recommendation, is a serious problem that affects mainly the poor countries. Regarding their advantages and limitations, the combined use of DOSY–NMR and LC–UV–SPE–NMR can fully resolve the mixture, detecting undeclared compounds without use of additional analyses.

    6. NMR-based metabolomics coupled with pattern recognition methods in biomarker discovery and disease diagnosis (pages 549–556)

      Ai-hua Zhang, Hui Sun, Shi Qiu and Xi-jun Wang

      Version of Record online: 4 JUL 2013 | DOI: 10.1002/mrc.3985

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      Assessment of fluctuations on the levels of endogenous metabolites by advanced NMR spectroscopy technique combined with multivariate statistics, the so-called metabolomics approach, has proved to be exquisitely valuable in human disease diagnosis. Multivariate statistical methods or pattern-recognition programs have been developed to handle the acquired data and to search for the discriminating features from biosample sets. Furthermore, the combination of NMR with pattern recognition methods has proven highly effective at identifying unknown metabolites that correlate with changes in genotype or phenotype.

    7. One-bond 29Si-1H spin-spin coupling constants in the series of halosilanes: benchmark SOPPA and DFT calculations, relativistic effects, and vibrational corrections (pages 557–561)

      Yury Yu. Rusakov and Leonid B. Krivdin

      Version of Record online: 8 JUL 2013 | DOI: 10.1002/mrc.3986

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      A number of most representative second order polarization propagator approach (SOPPA) based wavefunction methods, SOPPA, SOPPA(CC2) and SOPPA(CCSD), and density functional theory (DFT) based methods, B3LYP, PBE0, KT2, and KT3, have been benchmarked in the calculation of the one-bond 29Si-1H spin-spin coupling constants in the series of halosilanes SiHnX4−n (X = F, Cl, Br, I), both at the non-relativistic and full four-parameter Dirac's relativistic levels taking into account vibrational corrections. At the non-relativistic level, the wavefunction methods showed much better results as compared with those of DFT. At the DFT level, out of four tested functionals, the Perdew, Burke, and Ernzerhof's PBE0 showed best performance. Taking into account, relativistic effects and vibrational corrections noticeably improves wavefunction methods results, but generally worsens DFT results.

    8. 15N NMR spectra and reactivity of 2,4,6-triazidopyridines, 2,4,6-triazidopyrimidine and 2,4,6-triazido-s-triazine (pages 562–568)

      Sergei V. Chapyshev, Evgeny N. Ushakov and Alexander V. Chernyak

      Version of Record online: 22 JUL 2013 | DOI: 10.1002/mrc.3987

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      15N NMR spectra provide important information about reactivity of nonequivalent azido groups in aromatic polyazides.

  2. MRC Letters

    1. Top of page
    2. Research Articles
    3. MRC Letters
    1. 1H, 13C and 15N NMR data for indolo[2,3-b]quinolines, a novel potent anticancer drug family (pages 569–573)

      E. Bednarek, J. Sitkowski, W. Bocian, W. Łuniewski, M. Kobylińska, Ł. Kaczmarek and L. Kozerski

      Version of Record online: 20 JUN 2013 | DOI: 10.1002/mrc.3975

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      1H, 13C and 15N NMR data for indolo[2,3–b]quinolines is presented. The spectra are unambiguously assigned using COSY, HSQC and HMBC techniques.

    2. Structure elucidation of antiproliferative bisbenzylisoquinoline alkaloids from Anisocycla grandidieri from the Madagascar dry forest (pages 574–579)

      Yixi Liu, Liva Harinantenaina, Peggy J. Brodie, Carla Slebodnick, Martin W. Callmander, R. Rakotondrajaona, Etienne Rakotobe, Vincent E. Rasamison, Karen TenDyke, Yongchun Shen and David G. I. Kingston

      Version of Record online: 10 JUN 2013 | DOI: 10.1002/mrc.3976

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      Antiproliferative bioassay-guided fractionation of the ethanol extract of the stems of Anisocycla grandidieri led to the isolation of the known alkaloids stebisimine (1), (+)-1,2-dehydrotelobine (2), (+)-2'-norcocsuline (3) and puetogaline B (4). Herein, we report the full NMR assignments of all compounds and the X-ray crystallography of single crystals of compounds 1 and 3. Compounds 2 and 3 showed moderate antiproliferative activity against the A2780 human ovarian cancer cell line with IC50 values of 4.1 ± 0.3 and 2.7 ± 0.3 μM, respectively, and they also displayed selective activity toward the H460 (large cell lung cancer), MCF-7 (breast ductal carcinoma), and UACC-257 (melanoma) cell lines.

    3. 13C-NMR data of daphnane diterpenoids (pages 580–592)

      Hong-Bing Wang, Li-Ping Liu and Xiao-Yang Wang

      Version of Record online: 27 JUN 2013 | DOI: 10.1002/mrc.3978

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      Daphnane diterpenoids are mainly distributed in Thymelaeaceae and Euphorbiaceae and have various bioactivities. About 100 daphnane diterpenoids have been isolated from natural plants. In this review, we systematically summarize the 13C-NMR data of daphnane diterpenoids isolated from natural plants over the past several decades and briefly discuss their biological activities and basic structural activity relationship.

    4. Complete assignments of 1H and 13C NMR data for 21 naphthalenyl-phenyl-pyrazoline derivatives (pages 593–599)

      Doseok Hwang, Hyuk Yoon, Seunghyun Ahn, Dong-Wook Kim, Dong-Ho Bae, Dongsoo Koh and Yoongho Lim

      Version of Record online: 1 JUL 2013 | DOI: 10.1002/mrc.3981

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      To find potent new chemotherapy drugs, we designed and synthesized a series of naphthochalcones bearing naphthalenyl-phenyl-pyrazoline moieties. The complete 1H and 13C NMR data for these compounds are reported here and can be used to identifying further new naphthochalcones bearing the desired pyrazoline moieties.

    5. Molecular dynamics of (E)-6-acetyl-3-(2-hydroxy-5-methylphenyl)-5-styryl cyclohex-2-en-1-one and (E)-6-ethylcarboxylate-3-(2-hydroxy-5-methylphenyl)-5-styryl cyclohex-2-en-1-one in a solution studied by NMR spectroscopy (pages 600–604)

      I. G. Mamedov, M. R. Bayramov, Y. V. Mamedova and A. M. Maharramov

      Version of Record online: 2 JUL 2013 | DOI: 10.1002/mrc.3982

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      Molecular dynamics of cyclohexenone derivatives of (2E,4E)-1-(2-hydroxy-5-methylphenyl)-5-phenyl-2,4-pentadiene-1-one (chalcone) has been investigated in solutions using NMR. The results confirm the formation of O-H⋯O type intramolecular hydrogen bond and the presence of keto-enol (a, c) tautomeric transitions for the (E)-6-acetyl-3-(2-hydroxy-5-methylphenyl)-5-styryl cyclohex-2-en-1-one in solutions and the possible existence of the keto tautomer (a) in the solid. The free energy of activation for the keto-enol tautomeric transitions has been calculated. The keto-enol tautomerism in the investigated compound has been also confirmed by chemical method.