# US 8,772,340 B2 · Process for the preparation of fesoterodine or a salt thereof

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- Number: US 8,772,340 B2
- Document ID: US8772340B2
- Status: Granted
- Kind: B2
- Application number: 13/295,224
- Filed: 2011-11-14
- Published: 2012-06-14
- Granted: 2014-07-08
- Earliest claimed: 2010-12-09
- Assignees: Dipharma Francis S.R.L.
- Applicants: Marco Artico; Emanuele Attolino; Pietro Allegrini; Gabriele Razzetti
- Inventors: Marco Artico; Emanuele Attolino; Pietro Allegrini; Gabriele Razzetti
- Web page: https://patentgrep.com/patent/US8772340B2

## CPC

- A61K 31/222: with compounds having aromatic groups, e.g. dipivefrine, ibopamine
- C07C 213/06: from hydroxy amines by reactions involving the etherification or esterification of hydroxy groups
- C07C 217/62: linked by carbon chains having at least three carbon atoms between the amino groups and the six-membered aromatic ring or the condensed ring system containing that ring
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

A process for the preparation of (R)-2-(3-diisopropylamino-1-phenylpropyl)-4-(hydroxymethyl)-phenol isobutyrate (Fesoterodine) or a pharmaceutically acceptable salt thereof having low content in impurities.

## Claims

### Claim 1

A process for the preparation of Fesoterodine of formula (I), or a pharmaceutically acceptable salt thereof
comprising the selective esterification of the phenolic hydroxyl of a compound of formula (II)
wherein the selective esterification comprises the reaction of a compound of formula (II) with an acylating agent, in the presence of an alcoholic solvent and a base, wherein said alcoholic solvent is a C1-C2 alkanol, a mixture of C1-C2 alkanols or a mixture of a C1-C2 alkanol with an inert solvent.

### Claim 2 (depends on 1)

The process according to claim 1 wherein the acylating agent is an isobutyryl halide or isobutyric anhydride.

### Claim 3 (depends on 1)

The process according to claim 1 wherein the inert solvent is selected from the group consisting of a polar aprotic solvent, a C3-C8 ketone, a cyclic or acyclic ether, an ester, a chlorinated solvent, an aromatic hydrocarbon and a mixture thereof.

### Claim 4 (depends on 1)

The process according to claim 1 wherein the alcoholic solvent is an ethanol-toluene, dichloromethane-ethanol, ethanol-methanol or ethanol-tetrahydrofuran mixture.

### Claim 5 (depends on 1)

The process according to claim 1 wherein the base is an organic or inorganic base selected from the group consisting of a tertiary amine, a hydroxide, carbonate, bicarbonate, phosphate, and a monophosphate or dihydrogen phosphate of an alkali metal or alkali earth metal.

### Claim 6 (depends on 1)

The process according to claim 1 wherein the base is potassium carbonate or sodium hydroxide.

### Claim 7 (depends on 1)

The process according to claim 1 wherein the base is triethylamine or N-methyl-morpholine.

### Claim 8 (depends on 1)

The process according to claim 1 wherein the amount of base is at least stoichiometric to the compound of formula (II).

### Claim 9

A process for the preparation of a composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof,
wherein said composition comprises at least one compound with a formula selected from the group consisting of formula (III), formula (IV) and formula (V)
in an amount between about 0.0001% to about 0.1%, wherein said compound of formula (I) is prepared by a process comprising the selective esterification of the phenolic hydroxyl of a compound of formula (II)
wherein the selective esterification comprises the reaction of a compound of formula (II) with an acylating agent, in the presence of an alcoholic solvent and a base, wherein said alcoholic solvent is a C1-C2 alkanol, a mixture of C1-C2 alkanols or a mixture of a C1-C2 alkanol with an inert solvent.

### Claim 10 (depends on 1)

The process according to claim 1, further comprising converting the resulting compound of formula (I) to a pharmaceutically acceptable salt thereof.