title: Short synthesis of labeled and unlabeled 6Z,9Z,12Z,15-hexadecatetraenoic acid as metabolic probes for biosynthetic studies on diatoms.
abstract: We describe a short synthesis of the unusual polyunsaturated 6Z,9Z,12Z,15-hexadecatetraenoic acid found in marine and fresh water diatoms. Using a one pot reductive bis-Wittig-olefination, the homoconjugated tetraene backbone of the fatty acid can be generated from easy available precursors. Reductive olefination allows the non-statistical dissymmetrisation of a symmetrical bis-Wittig salt as key synthon. This short sequence was also applied to the generation of the corresponding 9,10-[(2)H(2)] labeled fatty acid. If administered to cell fragments of Thalassiosira rotula 9,10-[(2)H(2)]-6Z,9Z,12Z,15-hexadecatetraenoic acid is transformed oxidatively to the aldehyde 1,2-[(2)H(2)]-2E,4E/Z,7-octatrienal which is involved in the chemical defense of this alga. Using the synthetic standard it could be shown that the C16:4 omega1 fatty acid is released upon wounding of T. rotula cells. The synthesis with the labeled bis-Wittig salt is of general use and can also be applied for the fast generation of other internally labeled functionalized and non-functionalized polyunsaturated fatty acids. To our knowledge this represents the first synthesis of 6Z,9Z,12Z,15-hexadecatetraenoic acid.
authors.affiliation: Max-Planck-Institute for Chemical Ecology, Hans-Knöll-Str. 8, D-07745 Jena, Germany. pohnert@ice.mpg.de
authors.forename: Georg
authors.initials: G
authors.lastname: Pohnert
authors.forename: Sven
authors.initials: S
authors.lastname: Adolph
authors.forename: Thomas
authors.initials: T
authors.lastname: Wichard
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D017377:Diatoms / Q000737:chemistry*; D005227:Fatty Acids / Q000737:chemistry*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D019787:Linoleic Acid / Q000737:chemistry; D015394:Molecular Structure
chemical_list: D000447:Aldehydes; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; C114465:hexadecatetraenoic acid; D019787:Linoleic Acid