Chiral resolution method of N-[4-(1-aminoethyl)-phenyl]-sulfonamide derivatives

A method for chiral resolution of a mixture of stereoisomers of a compound of formula (I),

• wherein each of R1, R2, R3, R4, R5, R6 and R7 is independently any one selected from a group consisting of H, —NH2, a C1-6 alkyl group, a C2-6 alkenyl group, a C2-6 alkynyl group and a halogen, and R1 and R2 are different from each other,
• comprising mixing said mixture of stereoisomers of the compound of formula (I) with
• (i) a chiral auxiliary;
• and
• (ii) an auxiliary salt-forming compound
• in the presence of a solvent, thereby precipitating a diastereomeric salt of said chiral auxiliary (i) with the compound of formula (I) in enantiomeric excess,
• wherein the chiral auxiliary is one or more selected from a group consisting of 2,3-dibenzoyltartaric acid, O,O′-di-p-toluoyltartaric acid, a stereoisomer thereof, and a combination thereof, and the auxiliary sal-forming compound is one or more selected from a group consisting of mandelic acid, camphorsulfonic acid, a stereoisomer thereof, and a combination thereof.