Acknowledgements

Claridge, Tim D. W.

doi:10.1016/s1460-1567(99)80003-8

Cited by 82 publications

(115 citation statements)

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“…Data processing was performed with 1K ð 256w blocks, using backward linear prediction in F 1 to generate the final data matrix. The NOESY and TOCSY experiments 9 were obtained with a 5 kHz spectral width for both F 2 and F 1 . For processing, 1K ð 1K data blocks, with phase adjustment for both F 2 and F 1 , followed by final data matrix symmetrization, were used.…”

Section: Nmr Spectramentioning

confidence: 99%

Characterization of two minor saponins fromCordia piauhiensis by1H and13C NMR spectroscopy

et al. 2005

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A careful NMR analysis with full assignment of the 1H and 13C spectral data for two minor saponins isolated from stems of Cordia piauhiensis is reported. These saponins were isolated by high-performance liquid chromatography and characterized as 3beta-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]pomolic acid 28-O-[beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl] ester (1) and 3beta-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]oleanolic acid 28-O-[beta-D-xylopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl] ester (2). Their structures were established using a combination of 1D and 2D (1H, 1H-COSY, TOCSY, NOESY, gs-HMQC and gs-HMBC) NMR techniques, electrospray ionization mass spectrometry and chemical evidence.

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Section: Nmr Spectramentioning

confidence: 99%

Characterization of two minor saponins fromCordia piauhiensis by1H and13C NMR spectroscopy

et al. 2005

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“…Comparative analysis of the 13 C NMR spectra (f 1 Hg and DEPT135) 5 of each of the four chalcone dimers (1-4) was used to identify signals corresponding to quaternary [1, (C) 4,5 were also used to establish unequivocally the complete 1 H and 13 C resonance assignments of these two chalcone dimers, as summarized in Tables 1 and 2.…”

Section: Resultsmentioning

confidence: 99%

“…The results of the extensive application of 1D ( 1 H NMR, 13 C NMR) and 2D (COSY, HMQC, HMBC) spectral techniques 4,5 were used to characterize the structures of 1-4 and to establish the complete 1 H and 13 C resonance assignments of these four chalcone dimers.…”

Section: Introductionmentioning

confidence: 99%

Structural elucidation and total assignment of the ¹H and ¹³C NMR spectra of new chalcone dimers

Bandeira¹,

Matos²,

Braz-Filho³

2003

Magnetic Reson in Chemistry

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“…2). Signal separation in the first dimension of 2D spectra requires, however, an increased number of t 1 increments, which results in exceedingly long experimental times [2]. The digital resolution is small when the resolution of the signals is high.…”

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confidence: 99%

“…In this report, we describe computer-assisted aliasing as a practical method to produce routine 2D NMR spectra with excellent signal-to-noise ratios as well as excellent digital resolution without the need for excessive acquisition time. This method, communicated previously by means of the less-demanding methoxybenzyl analog of {323}-p-octiphenyl 2 as an initial example [3] and discussed in detail elsewhere [4 ± 6], is based on a violation of the Nyquist condition [2]. In routine 2D NMR spectra, data acquisition covers the full spectral width with all signals.…”

mentioning

confidence: 99%

NMR Characterization of Complex p‐Oligophenyl Scaffolds by Means of Aliasing Techniques to Obtain Resolution‐Enhanced Two‐Dimensional Spectra

Jeannerat

Ronan

Baudry

et al. 2004

Helvetica Chimica Acta

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Dedicated to Professor Ulrich Burger on the occasion of his 65th birthdayThe usefulness of computer-assisted aliasing to secure maximal resolution of signal clusters in 1 H-and 13 C-NMR spectra (which is essential for structure determination by HMBC 2D NMR spectroscopy) in minimal acquisition time is exemplified by the complete characterization of the two complementary p-octiphenyls 1 and 2 with complex substitution patterns. The need for digital resolution near 1 Hz/pt to dissect the extensive signal clusters in the NMR spectra of these refined oligomers excluded structure determination under routine conditions. High resolution was secured by exploiting the low signal density in the 13 C dimension of HMBC spectra by using computer-assisted aliasing to maximize signal density. Based on the observed shifts in DEPT and 1 H-decoupled 13 C-NMR spectra of 1 and 2, computer-assisted aliasing allowed to reduce the number of required time increments by a factor of 20 to 30 compared to full-width spectra with identical resolution. Without signal-to-noise constraints, this computer-assisted aliasing reduced the acquisition time for highresolution NMR spectra needed for complete characterization of refined oligomers 1 and 2 by the same factor (e.g., from over a day to about an hour). With resolved signal clusters in fully aliased HSQC and HMBC spectra, unproblematic structure determination of 1 and 2 is demonstrated by unambiguous assignment of all C-and Hatoms. These findings demonstrate that computer-assisted aliasing of the underexploited 13 C dimension makes extensive molecular complexity accessible by conventional multidimensional heteronuclear NMR experiments without extraordinary efforts.

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Acknowledgements

Cited by 82 publications

References 0 publications

Characterization of two minor saponins fromCordia piauhiensis by1H and13C NMR spectroscopy

Characterization of two minor saponins fromCordia piauhiensis by1H and13C NMR spectroscopy

Structural elucidation and total assignment of the ¹H and ¹³C NMR spectra of new chalcone dimers

NMR Characterization of Complex p‐Oligophenyl Scaffolds by Means of Aliasing Techniques to Obtain Resolution‐Enhanced Two‐Dimensional Spectra

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Acknowledgements

Cited by 82 publications

References 0 publications

Characterization of two minor saponins fromCordia piauhiensis by1H and13C NMR spectroscopy

Characterization of two minor saponins fromCordia piauhiensis by1H and13C NMR spectroscopy

Structural elucidation and total assignment of the 1H and 13C NMR spectra of new chalcone dimers

NMR Characterization of Complex p‐Oligophenyl Scaffolds by Means of Aliasing Techniques to Obtain Resolution‐Enhanced Two‐Dimensional Spectra

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Structural elucidation and total assignment of the ¹H and ¹³C NMR spectra of new chalcone dimers