A mixture of methyl 2-[(3,4-dimethoxyphenyl)thio]-3-(3-phenylpropyl-1-yl)-1-cyclopentenecarboxylate (0.5 g, 1.2 mmol) and 10% sodium hydroxide (5 mL) in ethanol (10 mL) is heated under reflux for 4 hours. The mixture is cooled and is poured into aqueous HCl. The mixture is extracted with ether. The organic layer is washed with water and is dried over MgSO4. The solvent is removed in vacuo to provide 2-[(3,4-dimethoxyphenyl)thio]-3-(3-phenylpropyl-1-yl)-1-cyclopentenecarboxylic acid (0.4 g, 85%): m.p. 146-8° C. Anal. (C23H26O4S) C,H,N: 1H-NMR (300 MHz, CDCl3) δ (TMS) 1.10-1.70 (m, 5H), 1.83-2.02 (m, 1H), 2.32-2.41 (t, 2H), 2.60-2.72 (m, 3H), 3.84 (s, 3H), 3.90 (s, 3H), 6.69-6.75 (d, 1H), 6.94-7.00 (m, 2H), 7.00-7.10 (d, 2H), 7.18-7.32 (m, 3H); MS (EI) m/e 398 (M+).
