Abstract: A chemical process is disclosed for the preparation of a pharmaceutically active compound in an enantiomeric form either (R) or (S) of the structure ##STR1## and a suitable pharmaceutical salt, e.g. alkali or earth metal, D-glucamine or D-ribamine, where R.sub.1 represents an optionally substituted aryl group same as phenyl or naphthyl group, optionally including a heterocyclic ring system, which is optionally substituted, or represents a hetero-aromatic ring system optionally containing in addition to carbon atoms one or more atoms selected from the group consisting of nitrogen and oxygen; the enantiomeric R or S-compounds of (I) are obtained from a suitable ketone (II) by reduction with an LiAlH.sub.4.sup.