Sponge fatty acids. 3. Occurrence of series of n−7 monoenoic and iso ‐5,9 dienoic long‐chain fatty acids in the phospholipids of the marine sponge Cinachyrella aff. schulzei keller

The fatty acid composition of phospholipids from the New Caledonian sponge Cinachyrella aff. schulzei Keller was studied. More than 60 fatty acids were identified as methyl esters and N ‐acyl pyrrolidides by gas chromatography and gas chromatography/mass spectrometry. Two isoprenoid fatty acids also were shown to be present, namely 4,8,12‐trimethyltridecanoic and 5,9,13‐trimethyltetradecanoic acids. The unusual 6‐tetradecenoic, 6‐pentadecenoic, 12‐nonadecenoic and 26‐methylheptacosanoic ( iso ‐28∶0) acids were found for the first time in sponge phospholipids. A series of six n−7 monoenoic long‐chain fatty acids (C 23 to C 28 ) were identified, including the rare 16‐tricosenoic, 18‐pentacosenoic and 21‐octacosenoic acids. Fifteen fatty acids possessing the typical 5,9 dienoic moiety accounted for 30% of the total fatty acid mixture. Two new fatty acids were identified, namely 5( Z )‐octacosenoic and 27‐methyl‐5( Z ),9( Z )‐octacosadienoic ( iso ‐5,9‐29∶2). Based on gas chromatography/Fourier transform infrared experiments, the double bonds were assigned the ( Z ) configuration.