Oxcarbazepine (I) was reduced with NaBH4 to afford the racemic alcohol (IIa-b). Esterification with (-)-menthoxyacetic acid chloride (III) in the presence of dimethylaminopyridine provided the diastereomeric mixture of esters (IV) and (V), from which the desired isomer (V) was isolated by fractional crystallization from CH2Cl2/EtOAc. Basic hydrolysis of (V) then provided pure (R)-alcohol (VI). Finally, esterification of (VI) with acetyl chloride led to the title acetate ester.
Reduction of oxcarbazepine (I) using NaBH4 yields the racemic alcohol (II). Resolution of the enantiomers is then achieved by means of fractional crystallization of the diastereomeric esters obtained from alcohol (II) and menthoxyacetyl chloride (III). Alkaline hydrolysis of the desired diastereoisomer (IV) provides the (S)-alcohol (V). This compound is finally converted into the corresponding acetate by esterification with acetyl chloride.
Reaction of 10-methoxy-5H-dibenzo[b,f]azepine (I) with phosgene in toluene produced the dibenzoazepine-5-carbonyl chloride (II). This was converted to urea (III) upon treatment with ethanolic ammonia. Acidic hydrolysis of the enol ether function of (III) afforded ketone (IV). Then, reduction of the ketone (IV) to the target alcohol was accomplished either by catalytic hydrogenation over copper chromite or by means of NaBH4 in aqueous EtOH.