To a solution of (4Z,7Z,10Z,13Z,16Z,19Z)—N-(1-aminopropan-2-yl)docosa-4,7,10,13,16,19-hexaenamide (1.60 g, 4.2 mmol), 2-hydroxybenzoic acid (0.57 g, 4.2 mmol) and imidazole (0.29 g, 4.2 mmol) in EA (40 mL) at 0° C. was added a solution of DCC (0.87 g, 4.2 mmol) in EA (40 mL). The mixture was allowed to warm to RT, stirred (16 h) and filtered. The solvent was removed under reduced pressure and the crude product was purified by chromatography on silica gel, eluting with EA-PE (0-50%) to afford N-(2-(4Z,7Z,10Z,13Z,16Z,19Z)-docosa-4,7,10,13,16,19-hexaenamidopropyl)-2-hydroxybenzamide (1.07 g, 50.5%) as a light yellow oil. Mass calculated for C32H44N2O3=504.70. found: [M+H]+=505.5.
