WO2012164516A1

WO2012164516A1 - Process for the preparation of iloperidone

Info

Publication number: WO2012164516A1
Application number: PCT/IB2012/052738
Authority: WO
Inventors: Shahid Akhtar Ansari; Hitin Maganbhai HIRPARA; Ashok Keshavlal YADAV; Jaya Parasram GIANCHANDANI
Original assignee: Lupin Limited
Priority date: 2011-06-03
Filing date: 2012-05-31
Publication date: 2012-12-06

Abstract

The present invention relates to a novel process for the preparation of iloperidone (I) that comprises reaction of 1-[4-(3-halopropoxy)-3-methoxyphenyl] ethanone (IIIa / IIIb) with 6- fluoro-3-(piperidine-4-yl)-1,2-benzisoxazole hydrochloride (II) under pressure in an autoclave.

Description

PROCESS FOR THE PREPARATION OF ILOPERIDONE

Field of the Invention:

The invention relates to a novel process preparation of iloperidone (I). Background of the Invention:

Iloperidone is chemically known as l-[4-[3-[4-(6-fluoro-l,2-benzisoxazol-3-yl)-l-piperidinyl] propoxy]-3-methoxyphenyl]ethanone (I) and it is used for the treatment of schizophrenia.

The method for preparation of iloperidone disclosed in the patent EP 0402644 and the publication Drugs of Future 2000, 25(1 ):29 involves condensation of 6-fluoro-3-(4- piperidinyl)-l,2-benzisoxazole hydrochloride (II) with l-[4-(3-chloropropoxy)-3- methoxyphenyl] ethanone (III a), in the presence of potassium carbonate in dimethylformamide as solvent.

(I I) The patent application IN 1980/MUM/2007 describes the preparation of iloperidone by condensation of 6-fluoro-3-(4-piperidinyl)-l,2-benzisoxazole hydrochloride (II) with l-[4-(3- chloropropoxy)-3-methoxyphenyl] ethanone (Ilia) in the presence of inorganic base using water as solvent.

Summary of the Invention:

The present invention relates to a novel process for the preparation of iloperidone that comprises reaction of 6-fluoro-3-(piperidine-4-yl)-l,2-benzisoxazole hydrochloride (II) with l-[4-(3- chloro / bromopropoxy)-3-methoxyphenyl]ethanone (III) in the presence of base and phase transfer catalyst in an autoclave.

Detailed description of the invention:

The present invention relates to a novel process for the preparation of iloperidone that comprises :

i) reaction of 4-hydroxy-3-methoxy acetophenone (IV) with l-bromo-3- chloropropane (V) in the presence of a base and phase transfer catalyst to obtain l-[4-(3-chloro/bromo propoxy)-3-methoxyphenyl] ethanone (III a / III b); ii) reaction of 6-fluoro-3-(piperidine-4-yl)-l,2-benzisoxazole hydrochloride (II) with l-[4-(3- chloro/ bromopropoxy)-3-methoxyphenyl]ethanone (III a / III b) in the presence of base and phase transfer catalyst in an autoclave;

iii) isolation of iloperidone.

The present invention provides novel process for the preparation of iloperidone (I) as shown below:

lloperidone (I)

The base used is an inorganic base selected from carbonates such as sodium bicarbonate, potassium bicarbonate; bicarbonates such as sodium bicarbonate, potassium bicarbonate; hydroxides such as sodium hydroxide, potassium hydroxide, ammonium hydroxide; alkali amides such as sodium amide, potassium amide etc; the preferred inorganic base is potassium carbonate. Potassium iodide can be optionally used in the steps (i) and (ii).

The solvent used is selected from nitriles such as acetonitrile, alcohols such as methanol, ethanol, isopropanol; ketones such as diethyl ketone, dimethyl ketone, ethyl methyl ketone, methyl isobutyl ketone, esters such as ethyl acetate, methyl acetate; ethers such dioxane, hydrocarbons such as toluene, tetrahydrofuran and polar aprotic solvents such as dimethyl sulfoxide, sulfolanes, 2-pyrrolidinone etc and mixtures thereof. The most preferred solvent for step (i) is acetonitrile and for step (ii) is methanol.

The phase transfer catalyst used is selected from group comprising of benzyltrimethylammonium chloride, hexadecyltributylphosphonium bromide, methyltrioctylammonium chloride, tertiary butyl ammonium bromide (TBAB). The most preferred catalyst is TBAB. 2

The pressure of the autoclave is maintained in the range of 0.1-4 Kg/cm ; preferably 1-2 Kg/cm²

Purification of iloperidone can be carried by crystallization from solvents selected from the group comprising of nitriles such as acetonitrile, alcohols such as methanol, ethanol, isopropanol; ketones such as diethyl ketone, dimethyl ketone, ethyl methyl ketone, methyl isobutyl ketone, esters such as ethyl acetate, methyl acetate; ethers such dioxane, hydrocarbons such as toluene or mixtures thereof. The most preferred solvents for crystallization are methanol or acetone.

The aforementioned process uses less toxic and less hazardous solvents such as dimethyl formamide thereby making ecofriendly process.

The principles, preferred embodiments, and modes of operation of the present invention have been described in the foregoing examples.

Examples

Example 1: Preparation of l-[4-(3-chloro/bromo propoxy)-3-methoxyphenyl] ethanone (III)

Acetonitrile (1L) was charged to 4-hydroxy-3-methoxy acetophenone (IV) (0.5 kg, 3.009 moles). l-Bromo-3-chloropropane (V) (1.89 Kg, 12.036 moles) was added to the reaction mixture and was stirred followed by addition of TBAB (0.030 Kg, 0.0903 moles ). Potassium carbonate (0.78 Kg, 5.657 moles) was added to the reaction mixture and heated to 80°C The mixture was cooled and filtered. The solid obtained was charged to dichloromethane (2 liters) and stirred. The reaction mixture was heated to 40-45 °C and distilled. The reaction mixture was cooled and methanol (0.5 liters ) was added followed by the addition of water (5 liters). The entire reaction mixture was added to chilled water and stirred. The reaction mixture was filtered and washed with water and dried. Yield: 0.779 Kg.

Purity: 99.35%

Example 2: Preparation of iloperidone (I)

6-Fluoro-3-(piperidinyl-4-yl)-l,2-benzisoxazole hydrochloride (II) (0.60 kg, 2.34 moles) and l-[4-(3-chloro/bromo propoxy)-3-methoxyphenyl)ethanone (0.68 kg, 2.81 moles) were added to methanol (6 liters ) in autoclave. To the mixture potassium carbonate (0.39 kg, 2.81 moles) was added followed by the addition of TBAB (0.03 kg). The reaction was maintained in the autoclave at 60-65°C for 15-16 hours. The reaction was then cooled and methanol was distilled out for the mixture. Toluene was charged to the reaction mixture and heated to 50- 55 °C. The reaction mixture was maintained for half an hour. Toluene was distilled out and reaction mixture is cooled. The solid was filtered and washed with chilled toluene and dried. Yield: 0.77kg

Purity: 98.18%

Example 3: Purification of iloperidone

Iloperidone (0.750 kg) was charged to methanol (1.688 liters). The mixture was heated to reflux temperature. The solution was gradually cooled to 0 -5°C. The reaction mixture was maintained for 2 hours and the solid was filtered. The wet solid was washed with chilled methanol at 0-5 °C and dried.

Yield: 0.71 kg

Purity: 99.25%

Example 4: Purification of iloperidone

Iloperidone obtained in example 3 (2.12 kg) was charged to acetone (10.6 liters) and charge charcoal (0.11 Kg) .The mixture was heated to reflux temperature at 55-60°C and maintained for an hour. The solution was filtered through hyflo bed and washed with acetone. The filtrate was heated between 55-60°C to get a clear solution. The reaction was maintained for an hour and cooled to 0-5°C. The solid was filtered and washed with chilled acetone. The solid was dried for 5-6 hours.

Yield: 1.735 kg

Purity: 99.90%

Claims

1) A novel process for the preparation of iloperidone that comprises :

(i) reaction of 4-hydroxy-3-methoxy acetophenone (IV) with l-bromo-3- chloropropane (V) in the presence of a base and phase transfer catalyst to obtain l-[4-(3-chloro/bromo propoxy)-3-methoxyphenyl]ethanone (Ilia / Illb);

(ii) reaction of 6-fluoro-3-(piperidine-4-yl)-l,2-benzisooxazole hydrochloride (II) with l-[4-(3- chloro/ bromopropoxy)-3-methoxyphenyl]ethanone (Ilia / Illb) in the presence of base and phase transfer catalyst in an autoclave;

(iii) isolation of iloperidone.

2) Process according to claim 1 wherein, the base is selected from carbonates such as sodium carbonate, potassium carbonate; bicarbonates such as sodium bicarbonate, potassium bicarbonate; hydroxides such as sodium hydroxide, potassium hydroxide, ammonium hydroxide; alkali amides such as sodium amide, potassium amide.

3) A process of claim 2 wherein, most preferred base is potassium carbonate.

4) Process according to claim 1 wherein, the phase transfer catalyst is selected from benzyltrimethylammonium chloride, hexadecyltributylphosphonium bromide, methyltrioctylammonium chloride, tertiary butyl ammonium bromide.

5) Process according to claim 4 wherein, the most preferred phase transfer catalyst used is tertiary butyl ammonium bromide.

6) Process according to claim 1 wherein, step (i) and step (ii) are optionally carried out in the presence of potassium iodide.

7) A process according to claim 1 wherein, the solvent in step (i) and (ii) is selected from nitriles such as acetonitrile; alcohols such as methanol, ethanol, isopropanol; ketones such as diethyl ketone, dimethyl ketone, ethyl methyl ketone, methyl isobutyl ketone; esters such as ethyl acetate, methyl acetate; ethers such dioxane, tetrahydrofuran; hydrocarbons such as toluene; and polar aprotic solvents such as dimethylformamide, dimethyl sulfoxide, sulfolanes, 2-pyrrolidinone etc and mixtures thereof.

8) Process according to claim 7 wherein, the most preferred solvent for step (i) is acetonitrile.

9) Process according to claim 7 wherein, the most preferred solvent for step (ii) is methanol.

10) Process according to claim 1 wherein the pressure in step (ii) is maintained at 1-2 kg/cm² .

11) The process for the preparation of iloperidone as described by foregoing examples.