To a stirred solution of L-methionine (5 mmol, 0.75 g) and triethylamine (15 mmol, 2.1 mL) in 15 mL of water-acetone (1:1), was added succinimidyl nervonate (5 mmol, 2.32 g, prepared according to Example 1A) in portions. The mixture was stirred for 4 hours until no ester remained according to TLC (hexane-diethyl ether-acetic acid, 80:18:2). The solvents were evaporated under reduced pressure. 10 mL of water was then added and the mixture was acidified with concentrated hydrochloric acid to pH 2. The precipitated product was separated by filtration, washed with water and crystallised from ethanol. Hexane was then used to remove traces of non-polar impurities from the title compound.
