NOVEL FATTY-ACID ESTERS OF (7E, 12E, 18R, 20Z)-VARIABILIN FROM THE MARINE SPONGE IRCINIA FELIX

The methanolic extract of the marine sponge Ircinia felix has yielded nine novel fatty acid esters, (7E, 12E, 18R, 20Z)-variabilin (5Z, 9Z)- 22-methyltricosadienoate, (7E, 12E, 18R, 20Z)-variabilin (5Z, 9Z)-tetr acosadienoate, (7E, 12E, 18R, 20Z)-variabilin hexadecanoate, (7E, 12E, 18R, 20Z)-variabilin 10-methylhexadecanoate, (7E, 12E, 18R, 20Z)-vari abilin 15-methylhexadecanoate, (7E, 12E, 18R, 20Z)-variabilin 14-methy lhexadecanoate, (7E, 12E, 18R, 20Z)-variabilin 9-octadecenoate, (7E, 1 2E, 18R, 20Z)-variabilin octadecanoate, and (7E, 12E, 18R, 20Z)-variab ilin 2,11-dimethyloctadecanoate, along with the recently described (7E , 12E, 18R, 20Z)-variabilin 11-methyloctadecanoate. The characterizati on of the new fatty acids (5Z, 9Z)-22-methyltricosadienoic and 2,11-di methyloctadecanoic acids is also described. The chemical structures we re determined by extensive spectroscopic, chromatographic, and chemica l analyses.