| abstract |
A new process for the optical resolution of racemic mixtures of alpha -naphthyl-propionic acids of formula <IMAGE> I This process comprises reacting a racemic mixture of a compound of formula <IMAGE> II with an optically active substance of formula R4-NH2 (III), said substance being a beta -aminoalcohol, thus forming a pair of diastereoisomeric amides which are resolved into the single diastereoisomers by fractional crystallization. The obtained single diastereoisomeric amide is then hydrolyzed to give the desired optically active alpha -naphthyl-propionic acid of formula <IMAGE> VI In the above compound I->III and VI, R1 is (C1-6)alkyl, R2 stands for hydrogen, halogen, mercapto, (C1-6)alkylthio, phenylthio, benzylthio, (C1-6)alkylsulfonyl, benzenesulfonyl, benzenesulfonyl substituted by halogen or (C1-4)alkyl, R3 is a reactive group and R4 is the residue of a primary or secondary alcohol.n[US4661628A] |