1H and 13C nmr study of exchange and isomerism in dimethylsulphoxide solutions of neutral methylmercury–xanthosine complexes

1985 ◽  
Vol 63 (7) ◽  
pp. 2054-2058 ◽  
Author(s):  
François Allaire ◽  
Michel Simard ◽  
André L. Beauchamp
Keyword(s):  
13C Nmr ◽  
Room Temperature ◽  
Free Ligand ◽  
1H And 13C Nmr ◽  
Slow Exchange ◽  
Linkage Isomers ◽  
Nmr Study ◽  
C Nmr

The xanthosine (H2Xan) complexes (CH3Hg)(HXan) and (CH3Hg)2(Xan) have been studied in (CD3)2SO solution at room temperature by 1H (90 MHz) and 13C nmr (20.1 MHz) spectroscopy. For (CH3Hg)2(Xan), where the N1-H and N3-H protons have been substituted by CH3Hg+ groups, individual 1H and 13C resonances from the unequivalent CH3Hg+ groups indicate that these cations do not exchange rapidly between the two sites. For solutions of (CH3Hg)(HXan), in which only one of the N—H protons has been substituted, both types of spectra show two sets of resonances for the purine unit as well as for the CH3Hg+ groups. This indicates that the 1:1 complex exists as two linkage isomers (N3—H, N1—Hg) and (N3—Hg, N1—H) in slow exchange. These two isomers are formed in equal amounts. When free xanthosine is added, the N3-mercurated complex exchanges rapidly with the free ligand, whereas the N1-mercurated complex does not exchange.

scholarly journals Evidence of the Existence of 2:1 Guest–Host Complexes between Diclofenac and Cyclodextrins in D2O Solutions. A 1H and 13C NMR Study on Diclofenac/β-Cyclodextrin and Diclofenac/2-Hydroxypropyl-β-cyclodextrin Systems

1999 ◽  
Vol 23 (7) ◽  
pp. 414-415
Author(s):  
Adele Mucci ◽  
Luisa Schenetti ◽  
Maria A. Vandelli ◽  
Barbara Ruozi ◽  
Flavio Forni
Keyword(s):  
13C Nmr ◽  
Sodium Salt ◽  
Multiple Equilibria ◽  
Diclofenac Sodium ◽  
1H And 13C Nmr ◽  
Nmr Study ◽  
Nmr Techniques ◽  
Nmr Titrations ◽  
C Nmr

The interaction of diclofenac sodium salt (DCFNa) and two cyclodextrins, β-cyclodextrin (βCD) and 2-hydroxypropyl-β-cyclodextrin (HPβCD), studied in D2O solution with different NMR techniques (1H, 13C NMR, ROESY experiments, NMR titrations), shows the existence of multiple equilibria involving 1:1 and 2:1 guest–host complexes.

1H and 13C NMR study of (X-phenyl)-5-nitro-2-furylvinyl ethers

1980 ◽  
Vol 45 (12) ◽  
pp. 3557-3563 ◽  
Author(s):  
Miloslava Dandárová ◽  
Jaroslav Kováč ◽  
Daniel Végh
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Furan Ring ◽  
Chemical Shifts ◽  
1H And 13C Nmr ◽  
H Nmr ◽  
Nmr Study ◽  
Hammett Σ Constants ◽  
C Nmr

Reaction of 5-nitro-2-furylvinyltrimethylammonium bromide with substituted phenolates gave (E)- and (Z)-(X-phenyl)-5-nitro-2-furylvinyl ethers. The preffered s-cis and s-trans orientations of the furan ring in Z and E isomers, respectively, were determined by 1H NMR spectroscopy. To study the extent of p-π conjugation, 13C NMR spectra of compounds under investigation have also been measured and interpreted. Chemical shifts for ethylenic carbons and protons were correlated with Hammett σ constants.

8-Acyl-7-phenylbicyclo[2.2.2]-2,6-diones by rearrangement of 3-acyloxy-5-(2-phenylethenyl)-2-cyclohexen-1-ones. 1H and 13C NMR spectral evidence of their structure

1990 ◽  
Vol 55 (5) ◽  
pp. 1208-1215 ◽  
Author(s):  
Pavel Hrnčiar ◽  
Tibor Liptay ◽  
Ján Šraga
Keyword(s):  
Double Bond ◽  
Spectral Data ◽  
13C Nmr ◽  
1H And 13C Nmr ◽  
Spectral Evidence ◽  
C Nmr

3-Acyloxy-5-(2-phenylethenyl)-2-cyclohexen-1-ones II were prepared by O-acylation of 5-(2-phenylethenyl)-1,3-cycloxanedione (I). Treatment of II with AlCl3 resulted in rearrangement of the acyl group to the double bond of the phenylethenyl grouping followed by cyclization to 8-acyl-7-phenylbicyclo[2.2.2]octane-2,6-diones III. Their structure was evidenced by analysis of the 1H and 13C NMR spectral data.

ChemInform Abstract: 1H and 13C NMR Study of the Pyrazolo(1,5-a)pyrimidine System.

ChemInform ◽  
2010 ◽  
Vol 23 (49) ◽  
pp. no-no
Author(s):  
S. CHIMICHI ◽  
B. COSIMELLI ◽  
F. BRUNI ◽  
S. SELLERI
Keyword(s):  
13C Nmr ◽  
1H And 13C Nmr ◽  
Nmr Study

Preparation, 1H and 13C NMR, and ab initio/IGLO study of mono-O-protonated deltic acid and theoretical investigation of di-, tri-, and tetra-O-protonated deltic acids

1999 ◽  
Vol 77 (5-6) ◽  
pp. 525-529 ◽  
Author(s):  
GK Surya Prakash ◽  
Golam Rasul ◽  
George A Olah ◽  
Ronghua Liu ◽  
Thomas T Tidwell
Keyword(s):  
Nmr Spectroscopy ◽  
Ab Initio ◽  
Theoretical Investigation ◽  
13C Nmr ◽  
Chemical Shifts ◽  
1H And 13C Nmr ◽  
Nmr Chemical Shifts ◽  
Molar Solution ◽  
Protonated Species ◽  
C Nmr

The hitherto elusive mono-O-protonated deltic acid C3O3H3+ was prepared by protolysis of di-tert-butoxy deltate in FSO3H-SO2ClF and in FSO3H:SbF5 (Magic Acid; 1:1 molar solution) in SO2ClF as solvent at -78°C and was characterized by 1H and 13C NMR spectroscopy. The structure and NMR chemical shifts were also calculated by the ab initio/IGLO method. No NMR evidence was found for persistent di-O-protonated deltic acid under these conditions, although a limited equilibrium with the mono-O-protonated species can be involved. Di-, tri-, and tetra-O-protonated deltic acids were also studied by ab initio/IGLO method.Key words: protonated deltic acid, aromaticity, superacids, NMR spectroscopy, ab initio and IGLO calculations.

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.

1H and 13C NMR Study of Proton Transfer in Azoles. Mechanism of Proton Transfer in Pyrazole in Solutions Containing bis-(Acetylacetonato) Nickel (II)

1976 ◽  
Vol 31 (7-8) ◽  
pp. 353-360 ◽  
Author(s):  
V. N. Babin ◽  
E. B. Zavelovidi ◽  
E. I. Fedin
Keyword(s):  
Proton Transfer ◽  
Ligand Exchange ◽  
Hyperfine Coupling ◽  
Outer Sphere ◽  
Coupling Constants ◽  
1H And 13C Nmr ◽  
Nmr Study ◽  
Nmr Techniques ◽  
Kinetics Of ◽  
C Nmr

Abstract Proton Transfer, Pyrazole, Outer-Sphere Coordination Proton transfer in pyrazole systems involving interaction with a paramagnetic transition metal complex has been studied with 1H and 13C NMR techniques. Kinetics of the ligand exchange in the pyrazole complex of bis-(acetylacetonato) nickel (II) has been investigated, and hyperfine coupling constants for the interaction of the nickel unpaired electron with the ligand nuclei in the complex have been determined. Catalytic admixtures of bis-(acetylacetonato) nickel (II) are shown to modify the mechanism of the proton transfer in pyrazole. The spectral data are discussed in terms of outer-sphere coordination and cooperative proton transfer effects.

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

A Domino Reaction for the Synthesis of Novel 1,3-Dihydrofuro[3,4-c]pyridines from Pyridoxal and Ketones

Synthesis ◽  
2020 ◽  
Vol 53 (02) ◽  
pp. 365-370
Author(s):  
Lucas Pizzuti ◽  
Izamara Casadia ◽  
Thalita O. Daher ◽  
Sidnei Moura ◽  
Davi F. Back ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Room Temperature ◽  
13C Nmr Spectroscopy ◽  
Domino Reaction ◽  
Alkyl Aryl ◽  
1H And 13C Nmr ◽  
X Ray ◽  
Pyridine Series

A convenient domino route for the synthesis of novel 1,3-dihydrofuro[3,4-c]pyridines from pyridoxal and alkyl, aryl or heteroaryl ketones under basic conditions is reported. A series of nine derivatives is obtained in 53–90% yields after stirring reactants for 48 hours at room temperature. Most products are easily isolated by filtration followed by recrystallization from ethanol. All products were fully characterized by FTIR, HRMS, and 1H and 13C NMR spectroscopy. The X-ray crystal structure of a representative example of the 1,3-dihydrofuro[3,4-c]pyridine series is also presented.

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