Hydrochloric Acid → (RS)-Naproxen methyl ester

Participants

Reaction Steps

16.1 Grams of the methyl ester of the 2-(5-bromo-6-methoxy-2-naphthyl)propionic acid are dissolved in 65 ml of methylene chloride and then 10.4 ml of mesitylene and 12 ml of anhydrous titanium tetrachloride are added while keeping the temperature at about 20° C. The reaction mixture is kept under stirring at room temperature for 80 hours and then is poured into a mixture made of 68 g of crushed ice and of 15 ml of a 35% (w/v) aqueous solution of hydrochloric acid. The layers are separated after 15 minutes of stirring, the aqueous layer is extracted with 30 ml of methylene chloride and then is discarded. The organic layers are collected, first washed with 50 ml of a 1N aqueous solution of hydrochloric acid, then with 50 ml of water and lastly with 50 ml of a 8% (w/v) aqueous solution of sodium bicarbonate. The organic solution is dried over anhydrous sodium sulfate and then is evaporated under vacuum. The residue is crystallized first with n-hexane and then with methyl alcohol obtaining 4 g of product with a yield equal to 32.7%.

Provenance & Evidence