Ethyl 4-chloro-3-quinolinecarboxylate

26892-90-0

13720-94-0

Synthesis of ethyl 4-chloroquinoline-3-carboxylate (A2): ethyl 4-hydroxyquinoline-3-carboxylate (A1) (1.5 g, 7 mmol) solid was placed in a reaction vial and phosphorus oxychloride (POCl3) (2.2 g, 1.3 mL, 14 mmol) was added. The reaction mixture was heated at 110 °C for 20 min. Upon completion of the reaction, the mixture was slowly poured into a pre-cooled mixture of aqueous ammonia solution (28-30%) and ice and stirred until a granular solid was formed. The reaction mixture was extracted with ether (3 x 40 mL), the organic layers were combined, dried with anhydrous magnesium sulfate (MgSO4), filtered and concentrated under reduced pressure to give an oily product. After standing, the product crystallized (1.44 g, 6 mmol, 87% yield) and could be used for subsequent reactions without further purification.