Acetyl chloride → 1-(3-(Benzyloxy)phenyl)-3-(dimethylamino)-2-methylpropan-1-one

Participants

Reaction Steps

WO2008/012046 describes another method for the preparation of tapentadol, wherein 1-(3-(benzyloxy)phenyl)propan-1-one is reacted with N-Methyl-N-methylene-methaneaminium chloride in presence of acetyl chloride and solvent acetonitrile to obtain compound 1-(3-(benzyloxy)phenyl)-3-(dimethylamino)-2-methylpropan-1-one. The compound is resolved with L-(−)-dibenzoyltartaric acid to get (S)-1-(3-(benzyloxy)phenyl)-3-(dimethylamino)-2-methylpropan-1-one. The isolated compound is then reacted with ethyl magnesium bromide undergoing Grignard reaction to isolate (2S,3R)-3-(3-(benzyloxy)phenyl)-1-(dimethylamino)-2-methylpentan-3-ol, which on reaction with trifluoroacetic anhydride in acetic acid results in acetylated compound. The acetylated compound on hydrogenolysis results in the compound 3-[(2R,3R)-1-(dimethylamino)-2-methylpentan-3-yl]phenol of Formula-I.

Provenance & Evidence