Novel stereospecific synthesis of (-) (2s, 3s)-1-dimethylamino-3-(3-methoxyphenyl)-2-methyl pentan-3-ol
AssigneeSymed Labs Limited
InventorsDodda Mohan Rao, Pingili Krishnareddy, Pingili Ramachandrareddy, Kirla Haritha, Kolluru Srinivas
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Abstract
The present invention relates to a novel stereospecific synthesis of (−)(2S,3S)-1-dimethylamino-3-(3-methoxyphenyl)-2-methyl pentan-3-ol an intermediate in the synthesis of 3-[(1R,2R)-3-(dimethylamino)-1-ethyl-2-methylpropyl]phenol.
Claims31
1-8. (canceled)
A process for preparing (−)(2S,3S)-1-dimethylamino-3-(3-methoxyphenyl)-2-methyl pentan-3-ol compound of formula III
- by reacting S(+)-1,1-dimethyl amino-2-methyl pentan-3-one of formula (V)
- with a compound of formula (IV)
- wherein X is a halogen (F, Cl, Br, I);
- to produce a compound of formula (III).
Use of an enantiomerically pure compound of the formula III to synthesize enantiomerically pure Tapentadol or a pharmaceutically acceptable acid addition salt thereof.
Use of the enantiomerically pure compound of formula V in the synthesis of enantiomerically pure Tapentadol or a pharmaceutically acceptable acid addition salt thereof.
A process for racemisation of (+) or (−)-1,1-dimethylamino-2-methyl pentan-3-one compound (V) (or) (Va)
- into a racemic compound of the formula (VI)
- comprising:
- a) reacting (+) or (−)-1,1-dimethylamino-2-methyl pentan-3-one compound of formula (V or Va) with a base, optionally in the presence of a solvent or a mixture of solvents;
- and,
- b) recovering a racemic mixture compound (VI) in pure form.
Dependencies are inferred from the claim text.