Process for the Preparation of Optically Active Derivatives of 2-(2-Pyridylmethylsulfinyl)-Benzimidazole Via Inclusion Complex with 1,1'-Binaphthalene-2, 2'Diol

A process for the preparation of a substantially pure enantiomer of the racemic compound of formula (I), or a salt thereof, or one or more of its solvates including hydrates,

• wherein R1, R2 and R3 are radicals, same or different, selected from the group consisting of H;
• (C1-C3)-alkyl;
• (C1-C3)-alkoxyl optionally substituted by one or more atoms of fluorine;
• and (C1-C3)-alkoxy-(C1-C3)-alkoxyl;
• and R4 is a radical selected from the group consisting of H and (C1-C3)-alkoxyl optionally substituted by one or more atoms of fluorine;
• comprising the operation 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.