5-{2-[5-Chloro-2-(4-chlorobenzyloxy)-phenyl]-cyclopent-1-enyl}-nicotinic acid ethyl ester (90 mg) was hydrolysed in methanol (3 mL) and 2N sodium hydroxide (2 mL) at 60° C. with stirring for 2 hrs. The reaction mixture was then reduced down to ˜1 mL, diluted with water (10 mL) and treated with a few drops of glacial acetic acid to make the solution ˜pH5. The product was then extracted twice with dichloromethane (10 mL) dried (magnesium sulphate), and evaporated to give the title compound (75 mg).
