title: Total synthesis of 2-methoxy-14-methylpentadecanoic acid and the novel 2-methoxy-14-methylhexadecanoic acid identified in the sponge Agelas dispar.
abstract: The phospholipid FA composition of the Caribbean sponge Agelas dispar was revisited and 40 different FA were identified. Among these a novel 2-methoxylated FA, namely, the anteiso methyl-branched 2-methoxy-14-methylhexadecanoic acid, was identified together with the recently discovered iso methyl-branched 2-methoxy-14-methylpentadecanoic acid and the normal-chain 2-methoxytetradecanoic acid. The structures of the iso and anteiso methyl-branched 2-methoxylated FA were confirmed by total syntheses, which were accomplished in seven steps and in 45-48% overall yields. Other phospholipid FA identified in A. dispar include the unusual methyl-branched 10,13-dimethyltetradecanoic acid, 3,7,11,15-tetramethylhexadecanoic (phytanic) acid, and the 11-methyloctadecanoic acid. In addition, the delta5,9 FA (5Z,9Z)-15-methyl-5,9-hexadecadienoic acid and (5Z,9Z)-5,9-octadecadienoic acid were characterized. These findings establish alternative FA biosynthetic possibilities for these marine organisms.
authors.affiliation: Department of Chemistry, University of Puerto Rico, San Juan, Puerto Rico 00931-3346, USA. ncarball@upracd.upr.clu.edu
authors.forename: Néstor M
authors.initials: NM
authors.lastname: Carballeira
authors.forename: Heidyleen
authors.initials: H
authors.lastname: Cruz
authors.forename: Norma L
authors.initials: NL
authors.lastname: Ayala
mesh_terms: D000818:Animals; D005227:Fatty Acids / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification*; D008401:Gas Chromatography-Mass Spectrometry; D015394:Molecular Structure; D010169:Palmitic Acids / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification*; D011161:Porifera / Q000737:chemistry*
chemical_list: C480286:2-methoxy-14-methylhexadecanoic acid; C422846:2-methoxy-14-methylpentadecanoic acid; D005227:Fatty Acids; D010169:Palmitic Acids