Water → Tapentadol

Participants

Reaction Conditions

Reaction Steps

18.9 kg of methanesulfonic acid and 2458 g D,L methionine were placed in methyl cyclohexane and then 3192 g (2R,3R)-[3-(3-methoxy-phenyl)-2-methyl-pentyl]-dimethylamine were added and the mixture was stirred at 82° C. for 18 hours. Subsequently, dilution was carried out with 10.3 l water at a maximum of 80° C. and 9 l methyl cyclohexane were added. At a maximum of 42° C., 17.3 l ammoniac were added until the pH was 8.8. A phase separation took place at 45° C. and 3.2 g (1R,2R)-3-(3-dimethylamino-1-ethyl-2-methyl-propyl)-phenol were added to the organic phase at 40° C. and stirred for 1 hour at 36° C. Subsequently, after cooling slowly to 5° C. and a further hour of stirring, the precipitate which formed was extracted by suction, washed with 12 l methyl cyclohexane and dried in a drying chamber. 2685 g (89.5%) (1R,2R)-3-(3-dimethylamino-1-ethyl-2-methyl-propyl)-phenol were obtained in modification B.

Provenance & Evidence