Carboxylic acid synthesis (via ester):


Sodium hydroxide (0.46 g, 11.7 mmol) was added to a solution of the ester compound (2.31 g, 7.77 mmol) in methanol (50 ml) and water (2.8 ml). This mixture was heated to reflux for 16 hours, then cooled and evaporated under reduced pressure. The residue was diluted with water (100 ml) and acidified with an aqueous solution of hydrochloric acid (2M). This aqueous mixture was extracted with ethyl acetate (2 x 200 ml) and the combined organic extracts were washed with brine (400 ml), dried over magnesium sulphate, filtered, and evaporated under reduced pressure to give a yellow solid (2.2 g 100%).


Reference patent: WO2010032200 (Pfizer)