Chemical shifts of ethylenic carbons in polyunsaturated fatty acids and related compounds

✍ Scribed by Jacqueline Sandri; Thierry Soto; Jean-Louis Gras; Jacques Viala

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 397 KB
• Volume: 35
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199711)35:11<785::aid-omr178>3.0.co;2-f

✦ Synopsis

The 13C NMR of ethylenic carbon atoms in the methylene-interrupted cis double bonds as found in polyunsaturated fatty acids (PUFAs), their precursors and analogs was studied. The chemical shifts of unsaturated carbon atoms are strongly dependent on a combination of electric Ðeld e †ects from the head group, steric hindrance and the presence of other double bonds. A full set of shift parameters were determined based on a reference value given by a long aliphatic alkene (cis-6-dodecene at 129.99 ppm) and various functionalities (double bond, ester, aldehyde, acetal, hydroxyl methyl, etc.) with one, two and three double bonds. Application of shift parameters to polyfunctionalized polyenes, high PUFAs and new analogs of arachidonic acids shows that the method is a convenient way to predict the chemical shift of all ethylenic carbon atoms. 1997