Interpretation of 13C NMR chemical shifts of Hantzsch's pyridines and 1,4-dihydropyridines

1H and 13C NMR spectra of twelve 1,4-dihydropyridines I and twelve corresponding pyridine derivatives II have been measured in hexadeuteriodimethyl sulphoxide and interpreted. Correlation equations are given for the chemical shifts of the atoms in the heterocyclic rings of the two series of compounds.

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The determination of the stereochemistry of epoxides located at the 5,6-positions of decalinic systems: An empirical method based on 13C NMR chemical shifts

Canadian Journal of Chemistry ◽

10.1139/v02-107 ◽

2002 ◽

Vol 80 (7) ◽

pp. 774-778 ◽

Cited By ~ 1

Author(s):

Raquel M Cravero ◽

Guillermo R Labadie ◽

Manuel González Sierra

Keyword(s):

13C Nmr ◽

Nmr Spectra ◽

Chemical Shifts ◽

Empirical Method ◽

Nmr Chemical Shifts ◽

13C Nmr Chemical Shifts ◽

Empirical Rule ◽

C Nmr

The 13C NMR spectra of a series of 5,6-epoxides in decalinic systems were studied. The interpretation of the chemical shifts allowed us to formulate an empirical rule to predict the epoxide stereochemistry. A discussion of the scope and limitations of this method and its extension to larger carbon skeletons is also presented.Key words: epoxide stereochemistry, 13C NMR, NMR, decalinic systems, oxiranes.

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Increments for 1H and 13C NMR chemical shifts in pinacol arylboronates

Canadian Journal of Chemistry ◽

10.1139/v11-099 ◽

2012 ◽

Vol 90 (1) ◽

pp. 71-74

Author(s):

Di Qiu ◽

Zhitong Zheng ◽

Fanyang Mo ◽

Yan Zhang ◽

Jianbo Wang

Keyword(s):

Benzene Ring ◽

13C Nmr ◽

Nmr Spectra ◽

Chemical Shifts ◽

Cross Coupling ◽

Coupling Reactions ◽

1H And 13C Nmr ◽

Nmr Chemical Shifts ◽

Cross Coupling Reactions ◽

C Nmr

Arylboronates are important compounds widely used in cross-coupling reactions. By analyzing the NMR spectra data of a variety of pinacol arylboronates, we have determined the increments for 1H and 13C NMR chemical shifts caused by a pinacol boronate substituent in the benzene ring. These data can be used in the estimation of chemical shifts of aromatic pinacol boronates.

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1H AND 13C NMR SPECTRA OF STRYCHNOS ALKALOIDS: SELECTED NMR UPDATES

Bulletin of the Angarsk State Technical University ◽

10.36629/2686-777x-2020-1-14-77-94 ◽

2020 ◽

Vol 1 (14) ◽

pp. 77-94

Author(s):

Valentin Semenov ◽

Dmitriy Samul'cev ◽

Leonid Krivdin

Keyword(s):

13C Nmr ◽

Nmr Spectra ◽

Mean Absolute Error ◽

Chemical Shifts ◽

Absolute Error ◽

1H And 13C Nmr ◽

Nmr Chemical Shifts ◽

13C Nmr Chemical Shifts ◽

Nmr Data ◽

Distinguished Group

The PBE0/pcSseg-2//pcseg-2 calculations of 1H and 13C NMR chemical shifts were performed for a classical series of 12 Strychnos alkaloids (except for the earlier studied parent strychnine), namely akuammicine, isostrychnine, rosibiline, tsilanine, spermostrychnine, diaboline, cyclostrychnine, henningsamide, strychnosilidine, strychnobrasiline, holstiine, and icajine. It was found that calculated 1H and 13C NMR chemical shifts demonstrated markedly good correlations with available experimental data characterized by a mean absolute error of 0.22 ppm for the range of 8 ppm for protons and 1.97 ppm for the range of 180 ppm for carbons. Complimentary, present results provide essential NMR update and fill a gap in the NMR data of this distinguished group of the vitally important natural products.

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Carbocyclic phenylaminephosphonate stereochemistry as probed via 13C nmr chemical shifts and nuclear spin couplings from 13C to 31P and 15N

Canadian Journal of Chemistry ◽

10.1139/v80-082 ◽

1980 ◽

Vol 58 (5) ◽

pp. 530-536 ◽

Cited By ~ 4

Author(s):

Gerald W. Buchanan ◽

Frederick G. Morin

Keyword(s):

Low Temperature ◽

13C Nmr ◽

Nuclear Spin ◽

Chemical Shifts ◽

Nmr Chemical Shifts ◽

13C Nmr Chemical Shifts ◽

Temperature Spectra ◽

C Nmr

13C nmr chemical shifts and 13C—31P couplings through one, two, and three bonds are reported for eleven carbocyclic phenylaminephosphonates with ring sizes from four to seven. On the basis of these data, inferences regarding preferred conformations are drawn. Low temperature spectra of the 4-methylcyclohexyl derivative show the existence of two conformers, populated in the ratio of approximately 2:1 at 183 K.

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17O and 13C NMR spectra of some geminal diacetates

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19880588 ◽

1988 ◽

Vol 53 (3) ◽

pp. 588-592 ◽

Cited By ~ 10

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.

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

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19902027 ◽

1990 ◽

Vol 55 (8) ◽

pp. 2027-2032 ◽

Cited By ~ 1

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.

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