Absolute configuration of 2,6 dimetylheptyl sulphate and its distribution in Ascidiacea

2,6-Dimethylheptyl sulfate (1) was isolated for the first time from a marine ascidian from Policitor adriaticus Drasche (class Ascidiacea, order Aplousobranchiata, family Polycitoridae). In this work, the absolute stereochemistry at C-2 of 1 was determined by 1H-NMR analysis of its (+)- and (-)-methoxy(trifluoromethyl)phenylacetic acid (MTPA) esters (Mosher's method). The distribution of 1 was investigated among the three orders (Aplousobranchiata, Phlebobranchiata, and Stolidobranchiata) of the class Ascidiacea. Compound 1 showed cytotoxicity (LC50 ) 17.8 íg/mL) in the Artemia salina bioassay and was not toxic (not toxicity at 100 íg/ mL) in a fish (Gambusia affinis) lethality assay