13C nuclear magnetic resonance spectra of alkyl indoles including derivatives of hexahydroechinulin

1976 ◽  
Vol 54 (18) ◽  
pp. 2915-2918 ◽  
Author(s):  
Robert R. Fraser ◽  
Salvatore Passannanti ◽  
Franco Piozzi
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Original Data ◽  
Single Frequency ◽  
Methyl Groups ◽  
Methyl Substituent ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
A Site ◽  
Derivatives Of ◽  
C Nmr

Revised structures for 4-bromohexahydroechinulin and 6-nitrohexahydroechinulin have been established using 13C nmr spectroscopy. For this purpose the substituent parameter for the nitro group at a site flanked by two methyl groups has been measured. Inconsistencies in previous data on alkyl indoles in comparison with hexahydroechinulin suggested a reassignment of the C4 and C6 signals in 5-methylindole, which we have proven by single frequency spin-decoupling experiments. The original data on methyl indoles has been retabulated to include the above reassignments and others recently reported by Gribble et al. A more consistent and reliable set of methyl substituent parameters is thereby obtained.

Discussion on 13C nuclear magnetic resonance spectra of structurally rigid cyclonucleosides. Violation of Karplus relationship between 3JC,H and dihedral angles

1984 ◽  
Vol 62 (8) ◽  
pp. 1555-1557 ◽  
Author(s):  
Jun Uzawa ◽  
Kentaro Anzai
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Coupling Constants ◽  
Dihedral Angles ◽  
Vicinal Coupling Constants ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Karplus Relationship ◽  
Derivatives Of ◽  
C Nmr

Using structurally rigid cyclonucleoside derivatives of adenosine, the effect of the oxygen functional groups on the vicinal coupling constants between carbon and hydrogen in, 13C nmr was investigated.

13C nuclear magnetic resonance spectra of the spirobenzylisoquinoline alkaloids and related model compounds

1977 ◽  
Vol 55 (18) ◽  
pp. 3304-3311 ◽  
Author(s):  
Donald W. Hughes ◽  
Bala C. Nalliah ◽  
Herbert L. Holland ◽  
David B. MacLean
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Isoquinoline Alkaloids ◽  
Model Compounds ◽  
Related Model ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The natural abundance 13C nuclear magnetic resonance spectra of a number of spirobenzylisoquinoline alkaloids and related model compounds have been recorded. The carbon resonances of the alkaloids were assigned by comparison with the spectra of other isoquinoline alkaloids and with those of the model compounds. It has been shown that 13C nmr spectroscopy may be used to differentiate between diastereomers in this series.

13C Nuclear Magnetic Resonance Studies of Organometallic Compounds. IV. cis-Dimethylplatinum(II) Derivatives

1974 ◽  
Vol 52 (7) ◽  
pp. 1165-1170 ◽  
Author(s):  
Howard Charles Clark ◽  
Leo Ernest Manzer ◽  
John Edward Henry Ward
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Organometallic Compounds ◽  
Methyl Groups ◽  
Magnetic Resonance Studies ◽  
Trans Influence ◽  
13C Nuclear Magnetic Resonance ◽  
Cis And Trans ◽  
Derivatives Of ◽  
Nuclear Magnetic

Data derived from the 13C n.m.r. spectra of seven neutral cis-dimethylplatinum(II) derivatives of the type cis-(CH3)2PtL2 and cis-(CH3)2Pt(L—L) (where L and L—L are neutral donors) are discussed and compared with data derived from the 1H n.m.r. spectra of the complexes. Simultaneous variations in L or L—L reveal that the n.m.r. trans-influence rather than the n.m.r. cis-influence is dominant. The suggestion that the n.m.r. cis- and trans-influences may be additive is discussed. In contrast with data obtained by other workers, it is shown that the 1JCH values of the platinum methyl groups are essentially insensitive to variations in the remaining ligands.

Carbon-13 nuclear magnetic resonance spectra of N-, O-, and S-methylated uracil and thiouracil derivatives

1978 ◽  
Vol 56 (5) ◽  
pp. 725-729 ◽  
Author(s):  
Ian W. J. Still ◽  
Nick Plavac ◽  
David M. McKinnon ◽  
Mohinder S. Chauhan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Chemical Shift ◽  
General Type ◽  
Chemical Shifts ◽  
Pyrimidine Derivatives ◽  
Aromatic Substituent ◽  
Nuclear Magnetic Resonance Spectra ◽  
Derivatives Of ◽  
Thiouracil Derivatives ◽  
C Nmr

13C nmr chemical shifts have been recorded for a number of uracil, thiouracil, and pyrimidine derivatives. These data are discussed in relation to what is known of the lactam–lactim tautomerism in such systems and possible correlations of chemical shifts with normal aromatic substituent chemical shift parameters. The chemical shifts for the CH3 groups in simple methylated derivatives of uracil are very characteristic of the site of methylation and should prove useful as a tool for assigning structures to alkylated derivatives of this general type.

Alkanes with multiple asymmetric centers: synthesis, identification, and 13C nuclear magnetic resonance spectra

1979 ◽  
Vol 57 (4) ◽  
pp. 367-376 ◽  
Author(s):  
Pierre Lachance ◽  
S. Brownstein ◽  
Arthur M. Eastham
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Aliphatic Hydrocarbons ◽  
Capillary Chromatography ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Capillary Glc ◽  
C Nmr ◽  
Magnetic Resonance Spectra

The identification of aliphatic hydrocarbons containing multiple asymmetric centers can be difficult because of the complexity of the nmr spectra and because in capillary chromatography the diastereomers may be resolved to varying degrees. We suggest that the most effective method for identifying such hydrocarbons is through the pattern of retention times developed by the mixture of diastereomers on a suitable capillary glc column.This paper presents the results of some studies of a series of alkanes having the general form C2H5—(CH—CH3)n—R, where n = 1 to 4, and includes the syntheses and 13C nmr spectra of the compounds.

Carbon-13 nuclear magnetic resonance spectra in the identification of N-, O or S-methyl derivatives of some tautomeric hydroxy and mercapto nitrogen heterocycles

1984 ◽  
Vol 37 (11) ◽  
pp. 2391 ◽  
Author(s):  
GB Barlin ◽  
DJ Brown ◽  
MD Fenn
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nitrogen Heterocycles ◽  
Resonance Spectroscopy ◽  
Methyl Groups ◽  
Nuclear Magnetic Resonance Spectra ◽  
Methoxy Groups ◽  
Methyl Derivatives ◽  
Derivatives Of ◽  
Nuclear Magnetic

Carbon-13 nuclear magnetic resonance spectroscopy, in contrast to 1H n.m.r. spectroscopy, has been shown to provide a clear distinction in a variety of nitrogen heterocyclic systems between O-methyl and nuclear N-methyl groups. Methoxy groups were found to occur in the range δ�53.20-61.87, nuclear N-methyl groups at 34.29-49.62, and methylthio groups at 12.35-14.55 for the compounds examined in (D)chloroform. Data for N- and O-methyl derivatives of pyridin-2- and -4-ol,* the corresponding pyrimidines, and some sulfur analogues have been compared with those for the unmethylated parent compounds.

An unlikely coincidence in coupled 13C nuclear magnetic resonance spectra. 2J(C,H) in 2,6-dichlorotoluene and related molecules

1988 ◽  
Vol 66 (1) ◽  
pp. 184-186
Author(s):  
Ted Schaefer ◽  
James Peeling
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Benzyl Bromide ◽  
Correct Choice ◽  
Theoretical Spectrum ◽  
Coupling Constant ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Derivatives Of ◽  
Nuclear Magnetic

Although as many as 13 peaks are observable in each half of the 13C nuclear magnetic resonance spectrum of C-4 in 2,6-dichlorotoluene at 22.6 MHz, the iterative analysis yields an incorrect value of 2J(C,H). Theoretical spectra for two values of this coupling constant are essentially identical under normal linewidth conditions. At 75.5 MHz, the 13C spectrum displays most of the 48 peaks expected for the X part of an AB2XR3 spectrum, yielding the correct choice for 2J(C,H). The theoretical spectrum at 125 MHz is similar to that at 22.6 MHz but only for the correct 2J(C,H). Correct values of 2J(C-4,H) are given for the 2,6-dichloro derivatives of toluene, ethylbenzene, benzyl alcohol, benzyl bromide, and chloride; these were given incorrectly previously.

13C-nuclear magnetic resonance spectra of oxiranes. Configuration of 1,2-epoxypropyl side chains in fungal metabolites

1978 ◽  
Vol 56 (24) ◽  
pp. 3117-3120 ◽  
Author(s):  
Suzanne Lesage ◽  
Arthur S. Perlin
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Side Chain ◽  
Fungal Metabolites ◽  
Trans Isomers ◽  
Model Compounds ◽  
Nmr Data ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Cis And Trans ◽  
C Nmr

13C nmr data indicate that the epoxypropyl side chain of 'asperlin' (1) has a trans configuration. This assignment follows from associated measurements on model compounds, showing that the 13C chemical shift of an epoxypropyl CH3 group is close to either 17 ppm (trans isomers) or 13 ppm (cis isomers). Synthesized as oxirane derivatives related to 1 are diastereomeric pairs of 8-deoxy-6,7-cis- and -trans-epoxy-1,2:3,4-di-O-isopropylidene-α-D-galacto-octopyranoses.

13C nuclear magnetic resonance spectra of some C19-diterpenoid alkaloids and their derivatives

1979 ◽  
Vol 57 (13) ◽  
pp. 1652-1655 ◽  
Author(s):  
S. William Pelletier ◽  
Naresh V. Mody ◽  
Rajinder S. Sawhney
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Conformational Changes ◽  
Nmr Spectra ◽  
Diterpenoid Alkaloids ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The natural abundance carbon-13 nuclear magnetic resonance spectra of some C19-diterpenoid alkaloids and their alkamines (lappaconitine, lappaconine, lapaconidine, ranaconine, 14-dehydrobrowniine, aconine, pseudoaconine, deoxyaconine, and hypaconine) have been determined at 15.03 MHz. With the aid of proton decoupling techniques, additivity relationships, and comparison with spectra of related alkaloids, self-consistent and unambiguous assignments of nearly all carbon resonances for these alkaloids have been made. Some important chemical shift trends have been observed, which are useful for identifying the basic C19-diterpenoid alkaloid skeleton and the hydroxy and methoxy group substitution patterns in these alkaloids. On the basis of 13C nmr spectra of lappaconitine and lappaconine, the anthranoyl ester moiety is assigned to the C-4 position in lappaconitine. The 13C nmr spectra of lapaconidine, aconine, and pseudoaconine taken in pyridine and chloroform have been compared to determine the conformational changes of the ring A hydroxy groups in these alkaloids.

1H and 13C nuclear magnetic resonance assignment of fluorescent olefinic sterol derivatives for use as membrane probes

1987 ◽  
Vol 65 (8) ◽  
pp. 1784-1794 ◽  
Author(s):  
Jacinta Drew ◽  
Jean-Robert Brisson ◽  
Peter Morand ◽  
Arthur G. Szabo
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Chemical Shifts ◽  
Methyl Groups ◽  
Coupling Constant ◽  
13C Nuclear Magnetic Resonance ◽  
High Degree ◽  
Degree Of Similarity ◽  
C Nmr ◽  
Membrane Probes

A number of fluorescent steroids with unsaturated sidechains have been analyzed by high resolution 1H and 13C nmr spectroscopy. The geometry of the olefinic systems was assigned on the basis of 1H–1H shift-correlated spectra (COSY) and selected nOe difference experiments. For one of these compounds, a 13C–1H shift-correlated spectrum, a COSY spectrum, a 1H J-resolved spectrum as well as nOe experiments on the angular methyl groups permitted complete ring proton assignment and coupling constant analysis. The high degree of similarity of the ring carbon 13C chemical shifts of these steroids and cholesterol would indicate that the former have the potential for use as fluorescent probes of cholesterol domains in membranes.

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