A mixture of 1-(4-hydroxy-phenyl)-cyclopentanecarboxylic acid ethyl ester (0.042 g, 0.179 mmol), toluene-4-sulfonic acid 2-[1-(4-methyl-benzyl)-2-oxo-3-propyl-imidazolidin-4-yl]-ethyl ester (0.085 g, 0.197 mmol) and 325 mesh K2CO3 (0.050 g, 0.362 mmol) in ethanol (5 mL) was heated at ref lux for under N2 for 16 h. The reaction was then treated with aqueous 5 N NaOH (0.5 mL) and heated to reflux 1.5 h. The reaction mixture was cooled, the solvent removed in vacuo. The resultant residue was acidified with aqueous 1 N HCl (10 mL) and extracted with Et2O. The organic layer was dried (MgSO4) and the solvent removed in vacuo to afford 0.058 g crude acid that was purified by preparative HPLC to afford 0.033 g (40%) 1-(4-{2-[1-(4-methyl-benzyl)-2-oxo-3-propyl-imidazolidin-4-yl]-ethoxy}-phenyl)-cyclopentanecarboxylic acid. MS (ES+) Calc'd for C28H37N2O4 (M+1) 465. Found m/z 465 (100%). 1H NMR.
