To a solution of docosahexaenoic acid (0.986 g, 3.0 mmol) in CH3CN (6.0 mL) was added carbonyldiimidazole (0.535 g, 3.3 mmol) in one portion at 0° C. The mixture was allowed to warm to room temperature and stirred at room temperature for 30 min. TLC showed a complete reaction (1:1 EtOAc/hexane). N,N-dimethylaminoethanol (0.89 g, 10.0 mmol) was added dropwise followed by addition of 4-dimethylaminopyridine (0.073 g, 0.60 mmol) The mixture was stirred at room temperature overnight. The solvent was removed by rotary evaporation and the residue was purified on silica gel using 72% EtOAc/hexane, 80% EtOAC/hexane and 100% EtOAc with 0.5% MeOH each to provide the product, 2-dimethylaminoethyl docosahexaenoate (1.098 g, 92%), as a light yellow oil. The product was stored at -20° C. with small amount of β-carotene.
