Novel brominated phospholipid fatty acids from the Caribbean sponge Petrosia sp.

The long-chain fatty acids (5E,9Z)-6-bromo-5,9-heptacosadienoic acid [2a], (5E,9Z)-6-bromo-5,9-octacosadienoic [3a], (Z)-19-heptacosenoic acid [4], and the novel aldehydes 17-pentacosenal [5] and 17-hexacosenal [6] were identified in the phospholipids (mainly phosphatidylethanolamine and phosphatidylcholine) of the sponge Petrosia sp. Structural elucidation was accomplished by means of mass spectrometry and chemical transformations, including deuteration with Wilkinson's catalyst. The dimethyldisulfide derivatization of delta(5.9) fatty acids is also presented.