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.
