METHOD FOR CRYSTALLIZING TAPENTADOL INTERMEDIATE, TAPENTADOL INTERMEDIATE OF HIGH PURITY, METHOD OF MAKING TAPENTADOL AND TAPENTADOL OF HIGH PURITY

In one aspect, the present invention relates to a method for crystallizing (2R,3R)-3-(3-methoxyphenyl)-N,N,2-trimethylpentan-1-amine or salts thereof (compound I), the method comprising the following steps: (i) mixing compound I with a solvent comprising 2-propanol; (ii) heating the mixture obtained in step (i); (iii) cooling the mixture of step (ii); and (iv) separating the crystals obtained in step (iii). In further aspects, the invention provides (2R,3R)-3-(3-methoxyphenyl)-N,N,2-trimethylpentan-1-amine or salts thereof in crystal form at high purity level as well as its use in the manufacture of highly pure tapentadol. By consequence, highly pure tapentadol is also provided in yet another aspect of the invention.