NMR Studies of Selected Cholesteric Compounds

Cameron, Louis M.; Callender, R. E.; Kramer, A. J.

doi:10.1080/15421407208083581

Cited by 9 publications

(3 citation statements)

References 5 publications

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“…Cholesteryl octanoate and cholesteryl 9-oxononanoate were synthesized via esterification with the respective acid, and cholesteryl 9-hydroxynonanoate was obtained by reduction of cholesteryl 9-oxononanoate with sodium borohydride as described in a previous publication for the corresponding sitosteryl esters . The NMR spectra of cholesteryl octanoate and cholesteryl 9-oxononanoate corresponded to previously published data. , The identity of cholesteryl 9-hydroxynonanoate was confirmed by two-dimensional NMR of the fatty acid part ( 13 C/ 1 H): δ 173.29 (FA-1), 63.06/3.66 (FA-9, 2H, t), 34.70/2.29 (FA-2, 2H, t), 32.71/1.58 (FA-8, 2H, m), 29.22/1.35 (FA-4/5/6, 2H, m), 29.22/1.35 (FA-4/5/6, 2H, m), 29.03/1.35 (FA-4/5/6, 2H, m), 25.66/1.64 (FA-7, 2H, m), 25.02/1.65 (FA-3, 2H, m). No impurities were observed for cholesteryl octanoate (GC-FID and 1 H NMR); cholesteryl 9-oxononanoate and cholesteryl 9-hydroxynonanoate had purities of ≥92%.…”

Section: Methodssupporting

confidence: 69%

“…10 The NMR spectra of cholesteryl octanoate and cholesteryl 9-oxononanoate corresponded to previously published data. 12,13 The identity of cholesteryl 9hydroxynonanoate was confirmed by two-dimensional NMR of the fatty acid part ( Thermal Treatment of Phytosteryl/-stanyl Oleates and Linoleates. Each ester mixture (11 ± 0.2 mg) was weighed into a 2 mL brown glass vial without a lid and oxidized in a heating block (VLM Metal, Bielefeld, Germany) at 180 °C for 40 min.…”

Section: ■ Materials and Methodsmentioning

confidence: 93%

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Quantitation of Acyl Chain Oxidation Products Formed upon Thermo-oxidation of Phytosteryl/-stanyl Oleates and Linoleates

Wocheslander

Groß

Scholz

et al. 2017

J. Agric. Food Chem.

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A GC-based approach involving preseparation via solid-phase extraction was established for the quantitation of acyl chain oxidation products (ACOPs) formed upon thermo-oxidation (180 °C, 40 min) of oleates and linoleates of phytostanols and phytosterols. The concentrations of ACOPs resulting from initially formed 9-hydroperoxides (octanoates, 8-hydroxyoctanoates, 9-oxononanoates) were higher than those from 8-hydroperoxides (heptanoates, 7-hydroxy- and 7-oxoheptanoates, 8-oxooctanoates) in both oleates and linoleates. Significantly higher amounts of ACOPs were found in heat-treated linoleates compared to oleates. However, despite lower thermally induced losses of stanyl oleates and linoleates compared to the respective steryl esters, higher concentrations of ACOPs (approximately 9 and 10% of the ester losses, respectively) were observed in the heat-treated stanyl esters. In contrast, in the heated steryl oleates and linoleates the contribution of the ACOPs to the ester losses was lower (approximately 3 and 5%, respectively), and there was a more pronounced formation of oxidation products of the sterol moieties (approximately 26 and 18% of the ester losses, respectively).

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Section: Methodssupporting

confidence: 69%

Section: ■ Materials and Methodsmentioning

confidence: 93%

Quantitation of Acyl Chain Oxidation Products Formed upon Thermo-oxidation of Phytosteryl/-stanyl Oleates and Linoleates

Wocheslander

Groß

Scholz

et al. 2017

J. Agric. Food Chem.

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show abstract

“…NMR studies of poly-7 -benzyl-L -glutamate in static electric fields (600), various cholesteric compounds (601), proton resonance lineshapes in lamellar liquid crystals (602) and sodium-23 in macroscopically aligned lamellar mesophases (603) have been reported. Investigations of variable frequency pulsed NMR (604), nitrogen-15 labeled formamide (605), p-dithin (606), ethylene carbonate and monothiocarbonate (607), D20 (608), paraffinic chain motions (609), furan and thiophene (610), methyl halides (611), amphiphiles (612), and sodium-23 ions (613) have been reported for lyotropic liquid crystal systems.…”

Section: Liquid Crystalsmentioning

confidence: 99%