Patent ID: 7777044

Claim:
A process for the preparation of a substantially pure enantiomer of the racemic compound of formula (I), or a salt thereof, wherein R 1 , R 2 and R 3 are radicals, same or different, selected from the group consisting of H; (C 1 -C 3 )-alkyl; (C 1 -C 3 )-alkoxyl optionally substituted by one or more atoms of fluorine; and (C 1 -C 3 )-alkoxy-(C 1 -C 3 )-alkoxyl; and R 4 is a radical selected from the group consisting of H and (C 1 -C 3 )-alkoxyl optionally substituted by one or more atoms of fluorine; comprising the operations of: a) treating the compound of formula (I) in a racemic mixture form with one of the two enantiomers of a substituted [1,1′-binaphthalene]-2,2′-diol, in a mixture of an amine and a solvent, in order to separate an inclusion complex formed by one of the enantiomers of the compound of formula (I) with one of the enantiomers of a substituted [1,1′-binaphthalene]-2,2′-diol; b) treating the resulting inclusion complex with a hydroxide of an alkaline metal in a mixture of water and an organic solvent that is immiscible or minimally miscible in water to give one of the enantiomers of the compound of formula (I) in a free base form, or as a salt thereof; and c) when obtaining an enantiomer of the compound of formula (I) in a free base form, optionally transforming it to a salt.