Process for making paroxetine
DCFirst Claim
1. A process for industrial scale preparation of a compound of structure (2) in which R and R′
- are independently selected from an alkyl, aryl, or arylalkyl group, X is fluorine which comprises reacting a compound of structure (4) with an organometallic compound having one or more X-substituted phenyl groups, in a suitable organic solvent, provided that the solvent is not wholly an ether solvent when the organometallic compound is a Grignard reagent.
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Abstract
Compounds of structure (2) are prepared by reaction of an arecoline analogue of structure(4) with an organometallic compound containing an X-substituted phenyl group, such as a compound of structure (3).
Suitably the compound of structure (3) is a Grignard reagent, where M is magnesium and Y is a halogen atom, or M may be a Group II metal and Y is a halogen atom or a second X-substituted phenyl group. When structure (3) is a Grignard reagent, the reaction is carried out either in a suitable non-ether solvent, typically a hydrocarbon or a non-reactive chlorinated hydrocarbon, or in a mixture of such a solvent with diethyl ether. Compounds of structure (2) are important intermediates in the preparation of inter alia paroxetine.
21 Citations
16 Claims
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1. A process for industrial scale preparation of a compound of structure (2)
in which R and R′ - are independently selected from an alkyl, aryl, or arylalkyl group, X is fluorine which comprises reacting a compound of structure (4)
with an organometallic compound having one or more X-substituted phenyl groups, in a suitable organic solvent, provided that the solvent is not wholly an ether solvent when the organometallic compound is a Grignard reagent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
in which X is as defined in claim 1, M is a Group II metal and Y is a halogen or an X-substituted phenyl group. -
3. A process according to claim 2, in which M is Zn and Y is a second X-substituted phenyl group.
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4. A process according to claim 2, in which structure (3) is a Grignard reagent and the organic solvent is a non-ether solvent or a mixture of a non-ether solvent with diethyl ether.
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5. A process according to claim 4, in which M is Mg and Y is Cl or Br.
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6. A process according to claim 1, in which the solvent is a hydrocarbon or a non-reactive chlorinated hydrocarbon.
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7. A process for the preparation of a 4-aryl-3-hydroxymethyl-piperidine of structure (1)
comprising converting a compound of structure (2) obtained by the process of claim 1 into a compound of structure (1). -
8. A process for preparing paroxetine comprising obtaining a compound of structure (1) in which X is 4-fluoro by a process as claimed in claim 7, replacing the 3-hydroxymethyl group by a 3-(3,4-methylenedioxyphenyloxymethyl) group, and replacing the substituent R with a hydrogen atom.
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9. A process according to claim 8, in which paroxetine is obtained as, or converted to, a hydrochloride salt.
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10. A process according to claim 9, in which the paroxetine hydrochloride salt is obtained as the hemihydrate.
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11. Paroxetine when prepared according to the process of claim 8.
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12. Paroxetine hydrochloride when prepared according to the process of claim 9.
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13. Paroxetine hydrochloride hemihydrate when prepared according to the process of claim 10.
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14. A process according to claim 1, in which the solvent contains toluene.
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15. A process according to claim 1, in which the solvent contains dichloromethane.
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16. A process according to claim 7, wherein a reducing agent is used to convert the compound of structure (1) into a compound of structure (2).
- are independently selected from an alkyl, aryl, or arylalkyl group, X is fluorine which comprises reacting a compound of structure (4)
Specification