Patent ID: RE43984

Claim:
A process for making optically pure (R) salbutamol or pharmaceutically acceptable salts thereof having a value of 95% enantiomeric excess or more, which process comprises obtaining the (R) isomer of either salbutamol or a salbutamol precursor, wherein the salbutamol precursor is 4-benzyl albuterol or methyl-5-[2-[(1,1-dimethylethyl)amino]-1-hydroxyethyl]-2-(phenylmethoxy)-benzoate in optically pure form by: a) dissolving a mixture of salbutamol, 4-benzyl albuterol or methyl-5-[2-[(1,1-dimethylethyl)amino]-1-hydroxyethyl]-2-(phenylmethoxy)-benzoate enantiomers and a molar excess (with respect to said salbutamol or said precursors) of (L) tartaric acid in a solvent; b) allowing the solution to cool to crystalize a salt of one enantiomer; c) separating the salt from the solution; d) liberating the enantiomer from the salt; e) when the enantiomer is 4-benzyl albuterol or methyl-5-[2-[(1,1-dimethylethyl)amino]-1-hydroxyethyl]-2-(phenylmethoxy)-benzoate, reducing the enantiomer; and f) except when salbutamol is used in step a), debenzylating the enantiomer and recoVering the (R) enantiomer of salbuamol; then optionally converting said optically pure (R) salbutamol into a pharmeucedically acceptable salt.