Formic Acid → Eslicarbazepine acetate

Participants

Reaction Steps

In a 250 ml flask with overhead stirrer, reflux condenser and under nitrogen were combined: 16 g oxcarbazepine (63 mmol, 1 mol eq), 120 ml of ethyl acetate, 35 g IRA-67 tertiary ion exchange resin (SigmaAldrich, cat 476633), 10 ml water and 4.4 g formic acid (96 mmol, 1.5 mol eq). 35 mg RuCl [(S,S)-Ts-DPEN](p-cymene) (SigmaAldrich #703915) was dissolved in 10 ml dimethylformamide and added to the reactor. The reaction was heated in an oil bath to reflux. After 29 hours, without any further formic acid addition, the conversion had reached 98,4%. Product was isolated by filtering off the resin and washing with a 20 ml ethyl acetate. The combined organic phases were then washed with 10 ml water which was separated off. After cooling in the fridge, the product was filtered off and washed twice with 15 ml ethyl acetate. The isolated product had an ee of 98%. After acetylation and crystallisation using a similar method to that described in Example 3, eslicarbazepine acetate was isolated with an ee of 99.8% and product purity of 99.9% (HPLC area %, 210 nm).

Provenance & Evidence