Two-dimensional POMMIE carbon–proton chemical shift correlated 13C NMR spectrum editing

1990 ◽  
Vol 68 (7) ◽  
pp. 1145-1150 ◽  
Author(s):  
Bruce Coxon
Keyword(s):  
Chemical Shift ◽  
Pulse Sequences ◽  
Coupling Constants ◽  
Data Sets ◽  
Proton Chemical Shift ◽  
Two Dimensional ◽  
Chemical Shift Correlation ◽  
Linear Combinations ◽  
Nmr Spectrum ◽  
C Nmr

Two pulse sequences are described for acquisition of two-dimensional, carbon–proton chemical shift correlated 13C NMR spectra by the "phase oscillations to maximize editing technique". One of these sequences provides two-dimensional, carbon–proton chemical shift correlated spectra in which the 1H–1H coupling constants are present in the 1H chemical shift dimension, whereas the other sequence includes a bilinear rotation decoupling unit that removes the vicinal 1H–1H couplings in this dimension. Extensions of these techniques to generation of two-dimensional, carbon–proton chemical shift correlated CH, CH2, and CH313C NMR subspectra from linear combinations of three two-dimensional data sets are described. Decreased residual signals in the edited 2D subspectra have been achieved by Pascal programs that include six floating point coefficients, and a method for their calibration is discussed. Results are reported for troleandomycin (1). Keywords: 13C nuclear magnetic resonance, carbon–proton chemical shift correlation, DEPT, Pascal programs, POMMIE, two-dimensional NMR spectrum editing, troleandomycin.

Total assignment of the carbon-13 NMR spectrum of the cembranoid diterpene eunicin through the use of two-dimensional proton-carbon chemical shift correlation

1984 ◽  
Vol 106 (6) ◽  
pp. 1823-1826 ◽  
Author(s):  
Robert T. Gampe ◽  
Maktoob Alam ◽  
Alfred J. Weinheimer ◽  
Gary E. Martin ◽  
James A. Matson ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Two Dimensional ◽  
Chemical Shift Correlation ◽  
Nmr Spectrum ◽  
Carbon Chemical Shift

scholarly journals Total assignment of the1H and13C NMR spectra of piperovatine

1998 ◽  
Vol 14 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Willy Rendón ◽  
Galia Chávez ◽  
Myriam Meléndez-Rodríguez ◽  
Pedro Joseph-Nathan
Keyword(s):  
Chemical Shift ◽  
Chemical Shift Correlation ◽  
Nmr Spectrum ◽  
Quaternary Carbon Atom ◽  
H Nmr ◽  
Simulation Based ◽  
Complete Assignment ◽  
Nmr Methods ◽  
Unambiguous Assignment ◽  
C Nmr

Total and unambiguous assignment of the1H NMR spectrum of piperovatine [6‒(4‒methoxyphenyl)‒N‒(2‒methylpropyl)‒2,4‒hexadienamide] was carried out using conventional 1D NMR methods and spectral spin–spin simulation. Based on these data, the complete assignment of the13C NMR chemical shift values was made by a13C/1H chemical shift correlation diagram and conventional considerations for the quaternary carbon atom.

scholarly journals Molecular Determinants for Drug Receptor Interactions, 9 1H and 13C NMR Spectra of the Narcotic Antagonist N-Allyl-N-normetazocine by Two-Dimensional Chemical Shift Correlation Spectroscopy

1987 ◽  
Vol 42 (8) ◽  
pp. 1021-1026 ◽  
Author(s):  
Bruno Perly ◽  
Patricia Le Bail-Richer ◽  
Giuseppe C. Pappalardo ◽  
Antonio Grassi
Keyword(s):  
Chemical Shift ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Exchange Process ◽  
Chair Conformation ◽  
Correlation Spectroscopy ◽  
Coupling Constants ◽  
Chemical Shift Correlation ◽  
Field Frequency ◽  
C Nmr

AbstractThe high frequency 1H and 13C NMR spectra (at 500 and 75.47 MHz, respectively) of N-allyl- N-normetazocine (NAM) hydrochloride in 2H2O solution were run and fully analyzed with the aid of both homonuclear 1H -1H and heteronuclear 13C - 1H chemical shift correlation experiments. Selective broadening of the signals of the protons in 3-, 4-, 8-, 9-, 12-positions was observed at temperatures <350 K. This was found to be consistent with an inversion process occurring between the N-equatorial and N-axial configurational isomers of NAM whose rate of exchange is of the same order of magnitude of the chemical shifts differences at 500 MHz. The increase of temperature at 350 K is thus adequate to make “fast” the process in the NM R time scale and then to resolve the spectral portions. The experimental proton-proton coupling constants were found to be consistent with a slightly distorted chair conformation of the piperidinic ring in NAM hydrochloride. The 13C NMR spectrum showed the distinct spectra of the two conformers, which are present in the ratio of ca. 80 (N-equatorial) : 20 (N -axial). The field frequency employed for the experiment was therefore sufficient to make “slow” the exchange process between the two isomeric forms, whose resonance peaks could be isolated in the non-acidified solution.

21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

1993 ◽  
Vol 58 (1) ◽  
pp. 173-190 ◽  
Author(s):  
Eva Klinotová ◽  
Jiří Klinot ◽  
Václav Křeček ◽  
Miloš Buděšínský ◽  
Bohumil Máca
Keyword(s):  
Spectral Data ◽  
Spin Systems ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
Proton Proton ◽  
H Nmr ◽  
Proton Coupling ◽  
C Nmr

Reaction of 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) and 20β,28-epoxy-21,22-dioxo-19α,19βH-ursan-3β-yl acetate (IIIb) with diazomethane afforded derivatives XII-XIV with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives XV and XVII. Ethylene ketals VIII-X were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the 1H and 13C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the 1H NMR spectrum of bisethylenedioxy derivative Xb led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

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