Patent ID: 8513438

Claim:
A process for the preparation of (6S)-(+5,6,7,8-tetrahydro-6-[propyl-(2-thienyl)ethyl]amino-1-naphthol (I): comprising the following steps: a) hydrolysis of compound (II): wherein R is a linear or branched (C 1 -C 4 )alkyl, in the presence of a coadjuvant selected from the group consisting of: a1) an alkaline or earth-alkaline hydroxide selected from the group consisting of sodium hydroxide, potassium hydroxide and calcium hydroxide; and a2) an aqueous solution containing a mineral acid selected from the group consisting of hydrochloric acid, hydrobromic acid, sulfuric acid and phosphoric acid; in a medium comprising water, an aliphatic alcohol having at most 4 carbon atoms selected from the group consisting of methanol, ethanol, propanol and isopropanol, and their mixtures; and b) optional purification selected from the group consisting of: b1) acylation of final compound (I) with an acylating agent selected from the group consisting of the corresponding acyl chloride of formula RCOCl and the corresponding acid anhydride of formula (RCO) 2 O, wherein R has the same meaning as above, followed by subsequent separation of the ester (II) thus formed and final hydrolysis according to step a); and b2) salification of final compound (I) with a mineral acid selected from the group consisting of hydrochloric acid and hydrobromic acid, followed by subsequent separation of the salt thus formed and its optional crystallization, and final recovery of (I) by treatment of the salt with an inorganic base selected from the group consisting of alkaline or earth-alkaline carbonates and bicarbonates.