Patent ID: 7002037

Claim:
A process for the preparation of the (S)-enantiomer of a compound of formula I, wherein R2 is OH or the group OR P , wherein R P is a protecting group, and one or more of the hydrogen atoms of the phenyl group may optionally be substituted by the equivalent number of halogen atoms, comprising reacting a racemic compound according to formula II wherein Q is a protecting group or H, and one or more of the hydrogen atoms of the phenyl group are optionally substituted by the equivalent number of halogen atoms, with a chiral amine, thereby forming a salt according to formula III wherein Q is a protecting group or H, and R1 is a chiral amine, and one or more of the hydrogen atoms of the phenyl group are optionally substituted by the equivalent number of halogen atoms, subsequently separating the diastereomers by crystallization followed by removal of the amine, and thereafter, when Q represents a protecting group, removing the Q group of the resulting compound with a deprotecting agent, and optionally protecting a free carboxylic acid function with the group R P .