Hydrochloric Acid → Eslicarbazepine

Participants

Reaction Steps

A solution of phenyl boronic acid (19.4 gm), D-(−)-tartaric acid (23.8 gm), calcium hydride (13.3 gm) in acetonitrile (300 mL) was heated to about 80-85° C. for about 1 hr. The reaction mass was cooled to 25-30° C. (‘Solution X’). A solution of oxcarbazepine (20 gm) in acetonitrile (100 mL) was prepared separately. ‘Solution X’ obtained above was added to the solution of oxcarbazepine followed by stirring the reaction mass for about 2 hrs. To the resulting solution sodium borohydride (4.5 gm) was added at about 30-35° C. The reaction mass was stirred at the same temperature for about 8 hrs. The pH of the resulting solution was adjusted to 1-2 by adding HCl (3N, 200 mL) followed by stirring for about 30 minutes. To the resulting solution, NaOH (20% w/v) solution was added to adjust the pH at about 12-13. Dichloromethane was added to the resulting solution followed by stirring. The organic layer was separated and distilled to obtain the title compound (Yield: 91%; HPLC purity: 98.6%; Chiral purity: 92.5%).

Provenance & Evidence