Optical and geometric isomers of some fatty acids with vicinal hydroxy groups

1967 ◽  
Vol 45 (11) ◽  
pp. 1259-1265 ◽  
Author(s):  
D. F. Ewing ◽  
C. Y. Hopkins
Keyword(s):  
Chemical Shift ◽  
Seed Oil ◽  
Optically Active ◽  
Geometric Isomers ◽  
Nuclear Magnetic Resonance Spectra ◽  
Significant Difference ◽  
Isopropylidene Derivatives ◽  
Hydroxy Groups ◽  
Derivatives Of ◽  
Long Chain

Racemic threo-9,10-dihydroxypalmitic acid was resolved by means of the brucine salts into the optically active forms. Levorotatory threo-11,12-dihydroxyeicosanoic acid was obtained from the corresponding racemate by crystallization of the ephedrine salts.The conformation of the geometric isomers of certain dihydroxy long-chain acids and their derivatives was studied by means of nuclear magnetic resonance spectra. There was a small but significant difference in the chemical shift of the CH protons in the ( ± )-threo acid as compared with those in the ( ± )-erythro acid. This was observed in 9,10-dihydroxypalmitic, 9,10-dihydroxystearic, and 11,12-dihydroxyeicosanoic acids. A similar but larger difference in the chemical shift (0.49 p.p.m.) was observed for the CH protons in the O-isopropylidene derivatives of the same acids. These differences are discussed and correlated with the stereochemistry of the dihydroxy acids and the corresponding 1,3-dioxolanes.cis-( + )-12,13-Epoxyoleic acid was isolated from the seed oil of Vernonia colorata. ( − )-threo-12,13-Dihydroxyoleic acid was prepared from the oil of V. cinerea.

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.

13C Nuclear Magnetic Resonance Spectra of Organic Sulfur Compounds: Cyclic Sulfides, Sulfoxides, Sulfones, and Thiones

1975 ◽  
Vol 53 (19) ◽  
pp. 2880-2890 ◽  
Author(s):  
M. S. Chauhan ◽  
I. W. J. Still
Keyword(s):  
Chemical Shift ◽  
Chemical Shifts ◽  
Limited Data ◽  
Organic Sulfur Compounds ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Chemical Shift Data ◽  
Derivatives Of ◽  
Shift Data ◽  
Methyl Phenyl

13C Chemical shift data have been obtained for more than 50 thiochromanone and related sulfoxide and sulfone derivatives. The assignments of the various resonances in the most important of these have been made using the limited data already available and also by comparison with certain model compounds, such as thioanisole, diphenyl sulfide, and the corresponding sulfoxides and sulfones.Within each of these three series and in a fourth which comprises derivatives of thiochromone, including three α, β-unsaturated thiones, we have examined the effects on 13C chemical shift of substitution at various positions in the thiochromanone skeleton. Among the substituents examined in this context are methyl, phenyl, methoxyl, bromine, and carbomethoxyl. Attempts to compare the 13C chemical shifts for the thiochromanone series with those in a few oxygen containing analogs and in a small number of structurally similar analogs are also discussed.

Novel optically active organometallic derivatives of fullerenes with non-central types of chirality in addends: synthetic and CD studies

2009 ◽  
Vol 50 (38) ◽  
pp. 5347-5350 ◽  
Author(s):  
Viatcheslav I. Sokolov ◽  
Vasily V. Bashilov ◽  
Fedor M. Dolgushin ◽  
Natalya V. Abramova ◽  
Kyrill K. Babievsky ◽  
...  
Keyword(s):  
Optically Active ◽  
Cd Studies ◽  
Derivatives Of

Chemoenzymatic Preparation of Optically Active Long-Chain 3-Hydroxyalkanoates

Biocatalysis ◽  
1990 ◽  
Vol 3 (1-2) ◽  
pp. 145-158 ◽  
Author(s):  
Clemens Feichter ◽  
Kurt Faber ◽  
Herfried Griengl
Keyword(s):  
Optically Active ◽  
Long Chain
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