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

2002 ◽  
Vol 80 (7) ◽  
pp. 774-778 ◽  
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.

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

1984 ◽  
Vol 49 (10) ◽  
pp. 2393-2399 ◽  
Author(s):  
Antonín Kurfürst ◽  
Petr Trška ◽  
Igor Goljer
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Correlation Equations ◽  
Pyridine Derivatives ◽  
Nmr Chemical Shifts ◽  
13C Nmr Chemical Shifts ◽  
C Nmr

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.

Determination of second-order association constants by global analysis of 1H and 13C NMR chemical shifts.

Steroids ◽  
2003 ◽  
Vol 68 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Wajih Al-Soufi ◽  
Pedro Ramos Cabrer ◽  
Aida Jover ◽  
Rosane M. Budal ◽  
José Vázquez Tato
Keyword(s):  
13C Nmr ◽  
Chemical Shifts ◽  
Global Analysis ◽  
Association Constants ◽  
Second Order ◽  
1H And 13C Nmr ◽  
Nmr Chemical Shifts ◽  
13C Nmr Chemical Shifts

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

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.

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

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.

13C NMR study of tetrosides and their derivatives

1980 ◽  
Vol 45 (10) ◽  
pp. 2779-2783 ◽  
Author(s):  
Jiří Urban ◽  
Miroslav Marek ◽  
Jiří Jarý ◽  
Petr Sedmera
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Direct Coupling ◽  
Coupling Constants ◽  
Anomeric Configuration ◽  
Nmr Study ◽  
C Nmr

13C NMR spectra of 23 tetrose derivatives were assigned. The C(1) resonates below 103 ppm with compounds having cis-arranged substituents at C(1) and C(2) and above 106 ppm with compounds having trans-arrangement. The carbon-13 chemical shifts are mainly influenced by the 1,2-interaction. The magnitudes of direct coupling constants 1J(C(1), H) cannot be used for the determination of the anomeric configuration.

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