To a solution of oleyl bromide (1.8 g, 5.4 mmol) in cyclohexanone (20 ml) was added ethyl 3,4-dihydroxybenzoate 7b (0.45 g, 2.5 mmol), potassium carbonate (1.02 g, 7.4 mmol) and potassium iodide (0.05 g, 0.3 mmol). The suspension was stirred at 100° C. for 18 hours under nitrogen. Due to the light sensitivity of the oleyl bromide the flask was covered in aluminum foil. The hot reaction mixture was filtered to remove some of the particulates and the solvent was removed in vacuo. The residue containing ester 8b was dissolved in a solution of ethanol (20 mL) containing potassium hydroxide (0.8 g, 20 mmol) and refluxed for 4 h. The hot reaction mixture was added to water (30 mL) and acidifying with 1M HCl to pH 1 resulted in the precipitation of a white solid. The solid 8c was filtered off and washed several times with water. The crude acid was re-crystallized from ethanol (10 mL) to give the product 8c as a white solid (1.14 g, 70%); 1H NMR (500 MHz, CDCl3) d 7.73 (dd, 1H, phenyl), 7.58 (d, 1H, phenyl), 6.89 (d, 1H, phenyl), 5.35 (t, 4H, olefinic), 4.05 (2×t, 4H, 2×OCH2), 2.01 (m, 8H, CH2C═C), 1.85 (m, 4H, CH2CH2O), 1.48 (quin, 4H, 2×CH2), 1.41-1.19 (m, 40H, 20×CH2), 0.88 (t, 6H, CH3).
