Originator
Dexedrine Sulfate,SKF,US,1944
Manufacturing Process
Two mols, for example, 270 grams, of racemic α-methylphenethylamine base
are reacted with one mol (150 grams) of d-tartaric acid, thereby forming dl-αmethylphenethylamine d-tartrate, a neutral salt. The neutral salt thus
obtained is fully dissolved by the addition of sufficient, say about 1 liter, of
absolute ethanol, and heating to about the boiling point. The solution is then
allowed to cool to room temperature with occasional stirring to effect
crystallization. The crystals are filtered off and will be found to contain a
preponderance of the levo enantiomorph.
The residual solid in the mother liquors is repeatedly and systematically
crystallized, yielding a further fraction of 1-α-methylphenethylamine d-tartrate
which may be purified by recrystallization. d-α-Methylphenethylamine may be
readily recovered from the mother liquors by the addition of tartaric acid
thereto for the formation of acid tartrates and separation of d-αmethylphenethylamine d-bitartrate by crystallization.
The free base of either optical isomer may be obtained by addition to the dtartrate in the case of the levo isomer and the d-bitartrate in the case of the
dextro isomer of alkali in excess, as, for example, by the addition of an
aqueous solution of caustic soda, which will cause the base to separate as an oil which may be recovered and purified by any well-known procedure. The
base is exactly neutralized with sulfuric acid to give the sulfate.
