11,14-Eicosadienoic acid

The enzymes catalyse desaturation in sequence for example, the A desaturase converts stearate to oleic acid, which is converted, by the A desaturase, to the di-unsaturated fatty acid (18 2n-9), which is elongated to form eicosadienoic acid, which can be converted by the A -desaturase to the tri-unsaturated fatty acid (20 3n-9) which is known as Mead acid (see below). 

Carballeira NM, Reyes M (1995) Identification of a New 6-Bromo-5,9-eicosadienoic Acid from the Anemone Condylactis gigantea and the Zoanthid Palythoa caribaeorum. J Nat Prod 58 1689... 

Mutant Mut48 is characterized by a high oleic acid (18 lco9) level and the absence of co6 PUFAs in its mycelia. In contrast to the wild type, this mutant produces three 9 PUFAs, i.e., 6,9-cis-octadecadienoic acid (18 2 9), 8,11-cis-eicosadienoic acid (20 2 9), and 20 3 9 [159]. The formation of 20 3 9 would occur through the desaturation of 18 loo9 at A6 position into 18 2(09 followed by elongation and A5 desaturation to 20 3 9 (Fig. 15). 

In the family of non-methylene interrupted fatty acids, the total syntheses of the unusual marine acids (11Z, 15Z)-11,15-eicosadienoic acid (20) and (10Z, 15Z)-10, 15-eicosadienoic acid (21), have been reported [55-56]. The (11Z, 15Z)-11,15-eicosadienoic acid (20) was identified for the first... 

The stereochemical control in the synthesis of (10Z, 15Z)-10,15-eicosadienoic acid (21) was achieved by selective hydrogenation of a double acetylide as shown in Fig. (23). This synthesis started with the conversion of 4-nonyn-l-ol to l-bromo-4-nonyne with PPh3Br2 that was coupled with 10-undecynoic acid, resulting in the 10,15-eicosadiynoic acid. This double acetylide was further hydrogenated to the (10Z, 15Z)-10,15-eicosadienoic acid (21), as shown in Fig. (23). 

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