US Patent 7495028 R-bambuterol, its preparation and therapeutic uses

R-enantiomer of Bambuterol, its preparation and therapeutic uses are disclosed. A composition includes R-Bambuterol or its therapeutically acceptable salt. A composition of R-Bambuterol includes at least 80% by weight of the R-enantiomer and not more than 20% by weight of the S-enantiomer based on a total weight of the Bmbuterol. A process includes: (a) asymmetrically reducing a suitably substituted and suitably protected bromoacetophenone compound to a chiral phenyl-bromoethanol comprising a primary bromo group and a secondary hydroxyl group; (b) displacing the bromo group by a suitably substituted and optionally protected primary amine to produce a protected chiral phenylethanolamine, and (c) removing the protecting groups to convert the protected chiral phenylethanolamine to a chiral phenylethanolamine.