Bacterial fatty acid biosynthesis initiation

Two rather interesting racemic syntheses for allylic methylated fatty acids have been recently accomplished [15]. One of these corresponds to the intriguing (12 )-11-methyl-12-octadecenoic acid (6), a marine bacterial fatty acid that in most reported identifications from natural sources has been shown to have the E double bond stereochemistry, but both Z,E isomers have been synthesized [15]. This mainly bacterial fatty acid was initially isolated from Byrsocarpus coccineus seed oil [16], but later it was reported in a bacterium associated with cat scratch disease [17], in Mycobacterium fallax [18], and most recently in a Pseudomonas sp. (.Alteromonas) associated with both the toxic dinoflagellate Ostreopsis lenticularis and several Caribbean Palythoa species [15]. More recently, acid 6 has been identified as an intermediate in the biosynthesis of the bacterial acid 10,13-epoxy-l l-methyloctadeca-10,12-dienoic acid, a furan fatty acid identified in several marine bacteria such as Shewanella putrefaciens [19-20]. 

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