A process for the preparation of enantiomerically pure norepinephrine

A process for the preparation of a single enantiomer of norepinephrine or of an addition salt thereof, the process comprising the following steps:

• a) reacting a compound of formula (IV)
• wherein X is halogen (F, Cl, Br, I), with benzylamine in a suitable solvent, using an auxiliary base, under the atmosphere of an inert gas, and isolating the resulting condensation product as an acid addition salt with a carboxylic acid, to give a compound of formula (III)
• wherein R is hydrogen, or the residue of an aliphatic, cycloaliphatic or aromatic monocarboxylic or dicarboxylic acid;
• b) enantioselective reduction of the benzylamino ketone acid addition salt of Formula III to give a single enantiomer of the benzylamino alcohol of Formula V
• wherein the carbon atom bearing the waxy bond can be in the (R) or (S) configuration;
• c) debenzylation of the single enantiomer of the compound of Formula V to give a single enantiomer of norepinephrine, and
• d) isolating the single enantiomer of norepinephrine as a free base or acid addition salt thereof.