Assignment of 1H and 13C NMR spectra by a combination of homo- and heteronuclear shift correlated two-dimensional NMR. Application to oligosaccharides related to arabinoxylane

1984 ◽  
Vol 49 (7) ◽  
pp. 1605-1616 ◽  
Author(s):  
Jan Schraml ◽  
Ján Hirsch ◽  
Eva Petráková ◽  
Eduard Krahé ◽  
Claus Bliefert
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Suitable Model ◽  
13C Nmr Spectra ◽  
Molecular Fragments ◽  
Model Compounds ◽  
1H And 13C Nmr ◽  
Complete Assignment ◽  
Other Information ◽  
C Nmr

It is shown that a combination of homo- and heteronuclear shift correlated 2 D NMR yields correct and complete assignment of 1H and 13C NMR spectra. The amount of the work necessary can be considerably reduced if some of the lines can be unambiguously assigned on the basis of other information or if suitable model compounds are available.The pattern of homonuclear cross-peaks is characteristic for molecular fragments and can be used with advantage to trace out the lines in the spectral regions with heavy overlap. The exactly assigned 13C chemical shifts of disaccharide and trisaccharide related to arabinoxylan agree satisfactorily with the shifts predicted according to the shifts found in the spectra of model mono- and disaccharides measured under the same conditions.

Preparation of β-D-Glucopyranosyl Derivatives of 1,6:2,3- and 1,6:3,4-Dianhydro-β-D-hexopyranoses and Their 1H and 13C NMR Spectra

1995 ◽  
Vol 60 (2) ◽  
pp. 311-323 ◽  
Author(s):  
Miloš Buděšínský ◽  
Miloslav Černý ◽  
Ivan Černý ◽  
Stanislav Sámek ◽  
Tomáš Trnka
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Derivatives Of ◽  
C Nmr

The corresponding acetylated and free 2-O- and 4-O-glucosyl derivatives of dianhydrohexoses Ib - VIIb and Ic - VIIc have been obtained by the reactions of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (IX) with 1,6:3,4- and 1,6:2,3-dianhydro-β-D-hexopyranoses (Ia - VIIa). Structure of the products and the effects of glycosylation upon chemical shifts and conformations of the disaccharides prepared have been studied using 1H and 13C NMR spectra.

1H and 13C NMR Spectra of Technically Important Sodium 1- and 2-Aminonaphthalenesulfonates

1993 ◽  
Vol 58 (6) ◽  
pp. 1378-1387 ◽  
Author(s):  
Josef Jirman
Keyword(s):  
13C Nmr ◽  
Sulfonic Acid ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Deuterium Oxide ◽  
Acid Group ◽  
Sulfonic Acid Group ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
C Nmr

The 1H and 13C NMR spectra of twenty-one technically important sulfonated 1- and 2-naphthylamines have been measured in deuterium oxide. The substituent chemical shifts (SCS) of a sulfonic acid group on naphthylamine skeleton have been calculated from the chemical shifts assigned.

Some Considerations Regarding the 1H and 13C Spectra of 4-(1-azulenyl)-2,6-bis(2-heteroaryl-vinyl)- pyrylium and Pyridinium and their Corresponding Pyridines

2018 ◽  
Vol 69 (1) ◽  
pp. 64-69
Author(s):  
Liviu Birzan ◽  
Mihaela Cristea ◽  
Constantin C. Draghici ◽  
Alexandru C. Razus
Keyword(s):  
Double Bond ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Pyridinium Salts ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Pyrylium Salts

The 1H and 13C NMR spectra of several 2,6-diheteroarylvinyl heterocycles containing 4-azulenyl moiety were recorded and their proton and carbon chemical shifts were compared with those of the compounds without double bond between the heterocycles. The influence of the nature of central and side heterocycles, molecule polarization and anisotropic effects were revealed. The highest chemical shifts were recorded for the pyrylium salts and the lowest at pyridines, but in the case of the pyridinium salts, the protons chemical shifts at the central heterocycle are more shielded due to a peculiar anisotropy of the attached vinyl groups.

17O and 13C NMR spectra of some geminal diacetates

1988 ◽  
Vol 53 (3) ◽  
pp. 588-592 ◽  
Author(s):  
Antonín Lyčka ◽  
Josef Jirman ◽  
Jaroslav Holeček
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
The Other ◽  
13C Nmr Spectra ◽  
Other Hand ◽  
Carboxylic Esters ◽  
C Nmr ◽  
Oxygen Atoms

The 17O and 13C NMR spectra of eight geminal diacetates RCH(O(CO)CH3)2 derived from simple aldehydes have been measured. In contrast to the dicarboxylates R1R2E(O(CO)R3)2, where E = Si, Ge, or Sn, whose 17O NMR spectra only contain a single signal, and, on the other hand, in accordance with organic carboxylic esters, the 17O NMR spectra of the compound group studied always exhibit two well-resolved signals with the chemical shifts δ(17O) in the regions of 183-219 ppm and 369-381 ppm for the oxygen atoms in the groups C-O and C=O, respectively.

Proximity and conformation effects in 29Si and 13C NMR spectra of di-ortho substituted trimethylsiloxybenzenes

1990 ◽  
Vol 55 (8) ◽  
pp. 2027-2032 ◽  
Author(s):  
Jan Schraml ◽  
Robert Brežný ◽  
Jan Čermák
Keyword(s):  
Benzene Ring ◽  
13C Nmr ◽  
Proximity Effect ◽  
Nmr Spectra ◽  
Methoxy Group ◽  
Chemical Shifts ◽  
Proximity Effects ◽  
13C Nmr Spectra ◽  
Methoxy Groups ◽  
C Nmr

29Si and 13C NMR spectra of five 4-substituted 2,6-dimethoxytrimethylsiloxybenzenes were studied with the aim to elucidate the nature of the deshielding proximity effects observed in the spectra of ortho substituted trimethylsiloxybenzenes. The sensitivity of 29Si chemical shifts to para substitution is in the studied compounds essentially the same as in mono ortho methoxytrimethylsiloxybenzenes. The deshielding proximity effect of the ìsecondî methoxy group is somewhat smaller than that of the ìfirstî group. The present results indicate that the two methoxy groups assume coplanar conformations with the benzene ring and are turned away from the trimethylsiloxy group which is not in the benzene plane. It is argued that in mono ortho methoxytrimethylsiloxybenzenes the two substituent groups adopt the same conformations as in the compounds studied here.

scholarly journals The NMR Spin Systems of Scutellaria 8β,13-Epoxy-neo-clerod-3-en-15,16-olides and Revision of 1H and 13C NMR Spectra Reported Data

2020 ◽  
Vol 15 (10) ◽  
pp. 1934578X2093378
Author(s):  
Josep Coll Toledano
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Spin Systems ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Nmr Data ◽  
Reported Data ◽  
New Compounds ◽  
C Nmr ◽  
Shielding Effects

The present review of NMR spectroscopic structural elucidation data of new compounds isolated from Scutellaria species is focused on the title compounds, displaying a peculiar 13-spiro feature. It contains a compilation of 1H and 13C NMR data of these diterpenoids grouped by similar substitution patterns. Comparing shielding effects pointed out not only the identity of some compounds (already reported) but also potential misassignments and convenient revisions to get unambiguous structural proposals.

scholarly journals 1H- und C-NMR-Spektren von Methoxy-substituierten Äthylenen / 1H and 13C NMR Spectra of Methoxy-substituted Ethylenes

1976 ◽  
Vol 31 (1) ◽  
pp. 35-38 ◽  
Author(s):  
M. Herberhold ◽  
G. O. Wiedersatz ◽  
C. G. Kreiter
Keyword(s):  
Charge Distribution ◽  
Vinyl Ether ◽  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Methyl Vinyl ◽  
Methyl Vinyl Ether ◽  
Cis And Trans ◽  
C Nmr

The charge distribution in the methoxy -substituted olefins of the series ethylene, methyl vinyl ether, 1,1-dimethoxyethylene, cis- and trans-dimethoxyethylene, tetramethoxyethylene, is discussed on the basis of the 1H and 13C NMR spectra

Synthetic, Infrared, 1H and 13C NMR Spectral Studies on N-(2/3/4-Substituted Phenyl)-2,4-Disubstituted Benzenesulphonamides, 2,4-(CH3)2/2-CH3-4-Cl/2,4-Cl2C6H3SO2NH(i-XC6H4) (i-X = H, 2-CH3, 3-CH3, 4-CH3, 2-Cl, 3-Cl, 4-Cl, 4-F, 4-Br)

2006 ◽  
Vol 61 (10-11) ◽  
pp. 600-606
Author(s):  
Savitha M. Basappa ◽  
Basavalinganadoddy Thimme Gowda
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Spectral Studies ◽  
1H And 13C Nmr ◽  
Nmr Chemical Shifts ◽  
Benzene Rings ◽  
Stretching Vibrations ◽  
Absorption Frequencies ◽  
C Nmr

Twenty six N-(2/3/4-substituted phenyl)-2,4-disubstituted benzenesulphonamides of the general formulae 2,4-(CH3)2C6H3SO2NH(i-XC6H4), 2-CH3-4-ClC6H3SO2NH(i-XC6H4) and 2,4- Cl2C6H3SO2NH(i-XC6H4), where i-X = H, 2-CH3, 3-CH3, 4-CH3, 2-Cl, 3-Cl, 4-Cl, 4-F or 4-Br, have been prepared, characterized and their infrared spectra in the solid state and 1H and 13C NMR spectra in solution studied. The infrared N-H stretching vibrational frequencies vary in the range 3298 - 3233 cm−1. Asymmetric and symmetric SO stretching vibrations appear in the ranges 1373 - 1311 cm−1 and 1177 - 1140 cm−1, respectively, while C-S, S-N and C-N stretching absorptions vary in the ranges 840 - 812 cm−1, 972 - 908 cm−1 and 1295 - 1209 cm−1, respectively. The various 1H and 13C NMR chemical shifts are assigned to the protons and carbon atoms of the two benzene rings in line with those for similar compounds. The incremental shifts due to the groups in the parent compounds have been computed by comparing the chemical shifts of the protons or carbon atoms in these compounds with those of benzene or aniline, respectively. The computed incremental shifts and other data were used to calculate the 1H and 13C NMR chemical shifts of the substituted compounds in three different ways. The calculated chemical shifts by the three methods compared well with each other and with the observed chemical shifts. It is observed that there are no particular trends in the variation of either the infrared absorption frequencies or the chemical shifts with the nature or site of substitution.

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