WO2005051943A1 - Processes for the preparation of highly pure irbesartan - Google Patents

Processes for the preparation of highly pure irbesartan Download PDF

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WO2005051943A1
WO2005051943A1 PCT/IB2004/003777 IB2004003777W WO2005051943A1 WO 2005051943 A1 WO2005051943 A1 WO 2005051943A1 IB 2004003777 W IB2004003777 W IB 2004003777W WO 2005051943 A1 WO2005051943 A1 WO 2005051943A1
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formula
irbesartan
process according
chloride
water miscible
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PCT/IB2004/003777
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French (fr)
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Yatendra Kumar
Mohan Prasad
Asok Nath
Surinder Kumar Arora
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Ranbaxy Laboratories Limited
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    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D403/00Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, not provided for by group C07D401/00
    • C07D403/02Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, not provided for by group C07D401/00 containing two hetero rings
    • C07D403/10Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, not provided for by group C07D401/00 containing two hetero rings linked by a carbon chain containing aromatic rings

Definitions

  • Irbesartan as shown in Formula I, belongs to the class of non-peptide angiotensin - II inhibitors, irbesartan inhibits the action of angiotensin - II which prevents the increase in blood pressure produced by the hormone-receptor interaction. Irbesartan is traditionally used in the treatment of cardiovascular diseases, such as hypertension and heart failure.
  • U.S. Patent No. 5,270,317 describes a process for preparation of irbesartan which involves condensation ofthe spiro compound of Formula II with halomethyl- cyanobiphenyl compound of Formula III. This reaction is carried out in presence of N,N-dimethylformamide as a solvent and sodium hydride as base.
  • U.S. Patent No. 6,162,922 describes a process for preparation of irbesartan which involves treating the spiro intermediate of Formula II with halomethyl- cyanobiphenyl intermediate of Formula III in presence of a water immiscible solvent, a base and a phase transfer catalyst. Summary ofthe Invention In one general aspect there is provided a process for the preparation of irbesartan of Formula I.
  • the process includes condensing a spiro intermediate of Formula II with a halomethyl-cyanobiphenyl compound of Formula III
  • the water miscible organic solvent may include one or more of water miscible lower alkanols, water miscible polar aprotic solvents and mixtures thereof.
  • the lower alkanol may include one or more of methanol, ethanol, isopropanol and n-pr ⁇ panol.
  • the polar aprotic solvent may include one or more of tetrahydrofuran, acetonitrile, 1,4-dioxane, N,N-dimethylacetamide, and dimethylsulphoxide.
  • the base may include one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium methoxide, potassium methoxide, potassium t-butoxide or mixtures thereof.
  • the condensation may be carried out at a temperature of about 0 °C to about 150°C.
  • the condensation may be carried out for about 2 to about 48 hours.
  • the irbesartan of Formula I obtained may have a purity greater than 99.5%.
  • the process includes condensing a spiro intermediate of Formula II with a halomethyl-cyanobiphenyl compound of Formula III
  • FORMULA IV isolating irbesartan of Formula I may include one or more ofthe following features.
  • the process may also include adding a phase transfer catalyst to step (b) or protecting the tetrazolyl intermediate with a suitable protecting group and deprotecting the tetrazolyl protecting group prior to isolating the irbesartan of Formula I.
  • the trialkyltin chloride may include one or more tri Cl-18 alkyltin chlorides.
  • the trialkyltin chloride may include one or more of trimethyltin chloride, triethyltin chloride, tributyltin chloride and trioctyltin chloride.
  • the phase transfer catalyst may include one or more of crown ethers, quaternary ammonium salts, polyethylene glycols, diglyme and phosphoric acid derivatives.
  • the quaternary ammonium salts may include one or more of tetraalkyl ammonium halides or aryl and aralkyl trialkyl ammonium halides.
  • the quaternary ammonium salts may include one or more of tetrabutyl ammonium chloride, tetrabutyl ammonium bromide, tetrabutyl ammonium fluoride, tetrabutyl ammonium iodide, benzalkonium chloride, cetyl trimethyl ammoniiim chloride and benzyl trialkyl ammonium chloride.
  • the protecting group may include trityl, monomethoxytrityl, dimethoxytrityl, benzhydryl and acyl.
  • the irbesartan of Formula I obtained may have a purity greater than about 99.5%.
  • Irbesartan of Formula I with a purity of greater than about 99.5%.
  • the irbesartan of Formula I may be Form A irbesartan.
  • the inventors have now developed processes for the preparation of highly pure irbesartan (Formula I) or pharmaceutically acceptable salts, polymorphs and geometric and optical enantiomers thereof.
  • the process includes condensation ofthe spiro compound of Formula II with the halomethyl-cyanobiphenyl compound of Formula III in presence of a water miscible organic solvent and a base.
  • the product obtained (Formula IV) is treated with trialkyltin chloride and sodium azide, and optionally may include a phase transfer catalyst, to cyclize the aromatic cyano group to a tetrazole group to obtain highly pure irbesartan with or without protecting the tetrazolyl group.
  • Irbesartan of Formula I expressed herein means irbesartan and pharmaceutically acceptable salts, geometric and stereomeric isomers, polymorphic forms including the Form A, B and amorphous form thereof.
  • highly pure irbesartan refers to irbesartan having purity greater than about 99.5%.
  • the condensation of the spiro intermediate with the halomethyl-cyanobiphenyl compound is carried out in the presence of a water miscible organic solvent and a base at temperature of about 0 °C to about 150°C for about 2 to about 48 hours.
  • Suitable water miscible organic solvents include one or more of water miscible lower alkanols, such as methanol, ethanol, isopropanol and n-propanol; water miscible polar aprotic solvents, such as tetrahydrofuran, acetonitrile, 1,4- dioxane, N,N-dimethylacetamide, and dimethylsulphoxide; and mixtures thereof.
  • Suitable bases include one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium methoxide, potassium methoxide, potassium t-butoxide and mixtures thereof
  • a solution of base in water or a suitable organic solvent may also be employed in the reaction.
  • the condensation product (Formula IV) may also be treated with trialkyltin chloride and sodium azide, optionally in the presence of a phase transfer catalyst, to affect the cyclization of aromatic cyano group to tetrazolyl moiety.
  • the cyclization may be efficiently carried out in the presence of an organic solvent at a temperature of about 50 °C to about 250°C for about 10 to about 150 hours.
  • Suitable organic solvents for this cyclization include one or more of aromatic hydrocarbons, non-polar aprotic solvents, high boiling polar aprotic solvents and mixtures thereof.
  • Suitable aromatic hydrocarbons include one or more of benzene, toluene, mono, di or tri-substituted benzenes and xylene.
  • Suitable non-polar aprotic solvents include one or more of diisopropyl ether, methyl isobutyl ketone, diisobutyl ketone and substituted 2-pyrrolidones.
  • Suitable high boiling polar aprotic solvent include one or more of dioxane, dimethylformamide, dimethylacetamide and dimethylsulphoxide.
  • the trialkyltin chloride include tri C 1-18 alkyltin chlorides, such as trimethyltin chloride, triethyltin chloride, tributyltin chloride and trioctyltin chloride.
  • Suitable phase transfer catalysts include one or more of crown ethers, quaternary ammonium salts, polyethylene glycols, diglyme and phosphoric acid derivatives.
  • Suitable quaternary ammonium salts include one or more of tetraalkyl ammonium halides or aryl and aralkyl trialkyl ammonium bromides, such as tetrabutyl ammonium chloride, tetrabutyl ammonium bromide, tetrabutyl ammonium fluoride, tetrabutyl ammonium iodide, benzalkonium chloride, cetyl trimethyl ammonium chloride and benzyl trialkyl ammonium chloride or mixtures thereof.
  • Irbesartan obtained by the above process may also be treated with a conventional protecting agent capable of protecting the tetrazole group.
  • Suitable protecting agents include one or more of trityl, monomethoxytrityl, dimethoxytrityl, benzhydryl and acyl.
  • the protection may be carried out in a conventional manner in an organic solvent.
  • the protected tetrazole derivative of Formula V, wherein P 1 stands for a conventional protecting group, is illustrated below.
  • Suitable organic solvents include one or more of methanol, ethanol, isopropanol, n-butanol, isobutanol, ethyl acetate, tetrahydrofuran, acetone, acetonitrile, N,N-dimethylformamide, dimethylsulphoxide or mixtures thereof.
  • Suitable deprotecting agents include mineral acid or organic acid.
  • Suitable organic acids include one or more of hydrochloric acid, nitric acid, sulphuric acid, phosphoric acid, formic acid, acetic acid, propionic acid and mixtures thereof.
  • the reaction mass is then cooled to an ambient temperature and diluted with water and acetic acid.
  • Irbesartan (Formula I) is isolated by adding a non-solvent and water to the reaction mass sufficient to precipitate the product completely. To enhance the precipitation the reaction mass may be cooled. Seeding with the product crystals may also be used wherever applicable.
  • the purification ofthe irbesartan may be carried out by treating it with a base in the presence of water and converting it to the salt. Next, the salt is washed with an organic solvent to remove the impurities. The aqueous solution ofthe salt is then acidified to liberate irbesartan.
  • the irbesartan may then be crystallized from the organic solvent to get the desired polymorphic form in a high purity.
  • Form A of irbesartan may be prepared by crystallizing the highly pure irbesartan (Formula I) from absolute ethanol or from denatured spirit.
  • EXAMPLE 1 Preparation of 2-n-b ⁇ tyl-3-f r2'(tetrazol-5-vnbiphenyl-4- vnmethyll-l,3-diazaspiro-[4.41non-l-ene-4-one (Irbesartan of Formula I) Step A) 2-n-butyl-3- [2' -cyanobiphenyl-4- yllmethyl] - 1 ,3 -diazaspiro-[4.41non- 1 - ene-4-one ( " Formula TV)
  • Step B 2-n-butyl-3- 2'(tetrazol-5-yl)biphenyl-4-yllmethyl1-l ,3-diazaspiro-[4.4]non- l-ene-4-one (Irbesartan of Formula ⁇ )
  • Step B 2-n-butyl-3- 2'( ' tetrazol-5-yl biphenyl-4-yl]methyll-l ,3-diazaspiro-
  • the resulting layers were separated and the ethyl acetate layer was washed with sodium carbonate solution twice (10%, 50 ml).
  • the ethyl acetate was concentrated under vacuum to get the residue, which was then dissolved in a mixture of water (250 ml) and IN sodium hydroxide solution (100 ml).
  • the aqueous phase was washed with ethyl acetate (2 x 100 ml).
  • To the resulting aqueous phase was added 6N HC1 slowly to adjust the pH ofthe solution to about 4.8 - 5.3.
  • Step B 2-n-butyl-3- 2'(tetrazol-5-vDbiphenyl-4-yl]methyl1- 3-diazaspiro-[4.4]non- l-ene-4-one (Irbesartan of Formula I)
  • step A The product obtained in Example 3, step A) was converted to irbesartan by the process described in Example 1, step B).

Abstract

The present invention relates to processes for synthesis of highly pure irbesartan or pharmaceutically acceptable salts thereof.

Description

PROCESSES FOR THE PREPARATION OF HIGHLY PURE IRBESARTAN Field ofthe Invention The present invention relates to processes for the synthesis of highly pure irbesartan or pharmaceutically acceptable salts thereof. Background ofthe Invention Irbesartan, as shown in Formula I, belongs to the class of non-peptide angiotensin - II inhibitors, irbesartan inhibits the action of angiotensin - II which prevents the increase in blood pressure produced by the hormone-receptor interaction. Irbesartan is traditionally used in the treatment of cardiovascular diseases, such as hypertension and heart failure.
Figure imgf000002_0001
FORMULA I U.S. Patent No. 5,270,317 describes a process for preparation of irbesartan which involves condensation ofthe spiro compound of Formula II with halomethyl- cyanobiphenyl compound of Formula III. This reaction is carried out in presence of N,N-dimethylformamide as a solvent and sodium hydride as base. U.S. Patent No. 6,162,922 describes a process for preparation of irbesartan which involves treating the spiro intermediate of Formula II with halomethyl- cyanobiphenyl intermediate of Formula III in presence of a water immiscible solvent, a base and a phase transfer catalyst. Summary ofthe Invention In one general aspect there is provided a process for the preparation of irbesartan of Formula I.
Figure imgf000003_0001
FORMULA I
The process includes condensing a spiro intermediate of Formula II with a halomethyl-cyanobiphenyl compound of Formula III
Figure imgf000003_0002
FORMULA II FORMULA III in the presence of a water miscible organic solvent and a base. Embodiments ofthe process may include one or more ofthe following features. For example, the water miscible organic solvent may include one or more of water miscible lower alkanols, water miscible polar aprotic solvents and mixtures thereof. The lower alkanol may include one or more of methanol, ethanol, isopropanol and n-prόpanol. The polar aprotic solvent may include one or more of tetrahydrofuran, acetonitrile, 1,4-dioxane, N,N-dimethylacetamide, and dimethylsulphoxide. The base may include one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium methoxide, potassium methoxide, potassium t-butoxide or mixtures thereof. The condensation may be carried out at a temperature of about 0 °C to about 150°C. The condensation may be carried out for about 2 to about 48 hours. The irbesartan of Formula I obtained may have a purity greater than 99.5%. In another general aspect there is provided a process for the preparation of irbesartan of Formula I
Figure imgf000004_0001
FORMULA I
The process includes condensing a spiro intermediate of Formula II with a halomethyl-cyanobiphenyl compound of Formula III
Figure imgf000004_0002
FORMULA II FORMULA III in presence of a water miscible organic solvent and a base; treating the product obtained of Formula TV with trialkyltin chloride and sodium azide; and
Figure imgf000004_0003
FORMULA IV isolating irbesartan of Formula I. Embodiments ofthe process may include one or more ofthe following features. For example, the process may also include adding a phase transfer catalyst to step (b) or protecting the tetrazolyl intermediate with a suitable protecting group and deprotecting the tetrazolyl protecting group prior to isolating the irbesartan of Formula I. The trialkyltin chloride may include one or more tri Cl-18 alkyltin chlorides. The trialkyltin chloride may include one or more of trimethyltin chloride, triethyltin chloride, tributyltin chloride and trioctyltin chloride. The phase transfer catalyst may include one or more of crown ethers, quaternary ammonium salts, polyethylene glycols, diglyme and phosphoric acid derivatives. The quaternary ammonium salts may include one or more of tetraalkyl ammonium halides or aryl and aralkyl trialkyl ammonium halides. The quaternary ammonium salts may include one or more of tetrabutyl ammonium chloride, tetrabutyl ammonium bromide, tetrabutyl ammonium fluoride, tetrabutyl ammonium iodide, benzalkonium chloride, cetyl trimethyl ammoniiim chloride and benzyl trialkyl ammonium chloride. The protecting group may include trityl, monomethoxytrityl, dimethoxytrityl, benzhydryl and acyl. The irbesartan of Formula I obtained may have a purity greater than about 99.5%. In another general aspect there is provided Irbesartan of Formula I with a purity of greater than about 99.5%. The irbesartan of Formula I may be Form A irbesartan. Detailed Description ofthe Invention The inventors have now developed processes for the preparation of highly pure irbesartan (Formula I) or pharmaceutically acceptable salts, polymorphs and geometric and optical enantiomers thereof. The process includes condensation ofthe spiro compound of Formula II with the halomethyl-cyanobiphenyl compound of Formula III in presence of a water miscible organic solvent and a base. The product obtained (Formula IV) is treated with trialkyltin chloride and sodium azide, and optionally may include a phase transfer catalyst, to cyclize the aromatic cyano group to a tetrazole group to obtain highly pure irbesartan with or without protecting the tetrazolyl group. The term Irbesartan of Formula I expressed herein means irbesartan and pharmaceutically acceptable salts, geometric and stereomeric isomers, polymorphic forms including the Form A, B and amorphous form thereof. The term highly pure irbesartan refers to irbesartan having purity greater than about 99.5%. The condensation of the spiro intermediate with the halomethyl-cyanobiphenyl compound is carried out in the presence of a water miscible organic solvent and a base at temperature of about 0 °C to about 150°C for about 2 to about 48 hours. Suitable water miscible organic solvents include one or more of water miscible lower alkanols, such as methanol, ethanol, isopropanol and n-propanol; water miscible polar aprotic solvents, such as tetrahydrofuran, acetonitrile, 1,4- dioxane, N,N-dimethylacetamide, and dimethylsulphoxide; and mixtures thereof. Suitable bases include one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium methoxide, potassium methoxide, potassium t-butoxide and mixtures thereof A solution of base in water or a suitable organic solvent may also be employed in the reaction. The condensation product (Formula IV) may also be treated with trialkyltin chloride and sodium azide, optionally in the presence of a phase transfer catalyst, to affect the cyclization of aromatic cyano group to tetrazolyl moiety. The cyclization may be efficiently carried out in the presence of an organic solvent at a temperature of about 50 °C to about 250°C for about 10 to about 150 hours. For example, the reaction may be carried out at about 90 °C to 130°C for about 20 to about 50 hours. Suitable organic solvents for this cyclization include one or more of aromatic hydrocarbons, non-polar aprotic solvents, high boiling polar aprotic solvents and mixtures thereof. Suitable aromatic hydrocarbons include one or more of benzene, toluene, mono, di or tri-substituted benzenes and xylene. Suitable non-polar aprotic solvents include one or more of diisopropyl ether, methyl isobutyl ketone, diisobutyl ketone and substituted 2-pyrrolidones. Suitable high boiling polar aprotic solvent include one or more of dioxane, dimethylformamide, dimethylacetamide and dimethylsulphoxide. The trialkyltin chloride include tri C1-18 alkyltin chlorides, such as trimethyltin chloride, triethyltin chloride, tributyltin chloride and trioctyltin chloride. Suitable phase transfer catalysts include one or more of crown ethers, quaternary ammonium salts, polyethylene glycols, diglyme and phosphoric acid derivatives. Suitable quaternary ammonium salts include one or more of tetraalkyl ammonium halides or aryl and aralkyl trialkyl ammonium bromides, such as tetrabutyl ammonium chloride, tetrabutyl ammonium bromide, tetrabutyl ammonium fluoride, tetrabutyl ammonium iodide, benzalkonium chloride, cetyl trimethyl ammonium chloride and benzyl trialkyl ammonium chloride or mixtures thereof. Irbesartan obtained by the above process may also be treated with a conventional protecting agent capable of protecting the tetrazole group. Suitable protecting agents include one or more of trityl, monomethoxytrityl, dimethoxytrityl, benzhydryl and acyl. The protection may be carried out in a conventional manner in an organic solvent. The protected tetrazole derivative of Formula V, wherein P1 stands for a conventional protecting group, is illustrated below.
Figure imgf000007_0001
FORMULA V . The protected tetrazole compound is then deprotected in the presence of an organic solvent and deprotecting agent. Suitable organic solvents include one or more of methanol, ethanol, isopropanol, n-butanol, isobutanol, ethyl acetate, tetrahydrofuran, acetone, acetonitrile, N,N-dimethylformamide, dimethylsulphoxide or mixtures thereof. Suitable deprotecting agents include mineral acid or organic acid. Suitable organic acids include one or more of hydrochloric acid, nitric acid, sulphuric acid, phosphoric acid, formic acid, acetic acid, propionic acid and mixtures thereof. After completion ofthe reaction, the reaction mass is then cooled to an ambient temperature and diluted with water and acetic acid. Irbesartan (Formula I) is isolated by adding a non-solvent and water to the reaction mass sufficient to precipitate the product completely. To enhance the precipitation the reaction mass may be cooled. Seeding with the product crystals may also be used wherever applicable. The purification ofthe irbesartan (Formula I) may be carried out by treating it with a base in the presence of water and converting it to the salt. Next, the salt is washed with an organic solvent to remove the impurities. The aqueous solution ofthe salt is then acidified to liberate irbesartan. The irbesartan may then be crystallized from the organic solvent to get the desired polymorphic form in a high purity. Form A of irbesartan may be prepared by crystallizing the highly pure irbesartan (Formula I) from absolute ethanol or from denatured spirit.
EXAMPLE 1: Preparation of 2-n-bιιtyl-3-f r2'(tetrazol-5-vnbiphenyl-4- vnmethyll-l,3-diazaspiro-[4.41non-l-ene-4-one (Irbesartan of Formula I) Step A) 2-n-butyl-3- [2' -cyanobiphenyl-4- yllmethyl] - 1 ,3 -diazaspiro-[4.41non- 1 - ene-4-one ("Formula TV)
Figure imgf000008_0001
FORMULA IV A mixture of 2-n-butyl-l,3-diazaspiro[4.4]non-l-ene-4-one hydrochloride of Formula I (100 g), ethyl acetate (500 ml), water (300 ml) and aqueous ammonia solution (60 ml) was stirred at 25-30°C for 15 min. The layers were separated. After concentration ofthe organic layer, the residue was taken up in acetonitrile (1000 ml) and to the solution was added potassium carbonate (119.7 g) and 4'- bromomethyl[l,l '-biphenyl]-2-carbonitrile of Formula III (118 g). The mixture was refluxed for 10 hrs. After completion ofthe reaction, the reaction mass was concentrated under reduced pressure and the residue was dissolved in a mixture of dichloromethane (500 ml) and water (500 ml). The layers were separated and the organic phase was concentrated under reduced pressure to give an oily residue which was crystallized in methyl-tertiary butyl ether to yield the title compound of Formula rv
Yield: 120 gm
Step B 2-n-butyl-3- 2'(tetrazol-5-yl)biphenyl-4-yllmethyl1-l ,3-diazaspiro-[4.4]non- l-ene-4-one (Irbesartan of Formula ϊ)
Figure imgf000009_0001
FORMULA I A mixture of 2-n-butyl-3 - [ [2 ' -cyanobiphenyl-4-yl]methyl] - 1 ,3 -diazaspiro- [4.4]non-l-ene-4-one of Formula II as obtained in example 1 step A) (25 g), tributyltin chloride (63.4 g), sodium azide (12.7 g) and tetrabutyl ammonium bromide (2.5 g) in toluene (75 ml) was refluxed for 20 hrs. The reaction mixture was cooled to room temperature and to it was added water (100 ml) and acetic acid (12.5 ml). The mixture was stirred at room temperature for 15 min. To it was added methanol (100 ml), water (100 ml) and toluene (100 ml) and the entire mass was filtered. After washing the wet solid with toluene and water, the solids were dissolved in a mixture of water (250 ml) and IN sodium hydroxide solution (100 ml). The aqueous phase was washed with ethyl acetate (2 x 100 ml). To the resulting aqueous phase was added 6N HC1 slowly to adjust the pH ofthe solution to about 4.8 - 5.3. After stirring at room temperature for 30 min, the crystals were filtered, washed with water (200 ml) and dried at 50°C to yield the compound of Formula I in 99.7% purity (24 g) which was purified, although this purification is optional. To this was added ethanol (96%, 250 ml) and the resulting mixture was heated to reflux until the product completely dissolved. The mixture was cooled to 15°C and stireed at 15 - 20°C for 30 min. The separated crystals were filtered and washed with 96% ethanol and dried at 50°C under reduced pressure to yield Irbesartan.
Yield: 23 g (86%) HPLC Purity: 99.95%
EXAMPLE 2: Preparation of 2-n-butyl-3-fr2,(tetrazol-5-yl)biphenyl-4- yllmethyll-l.,3-diazaspiro-|4.41non-l-ene-4-one (Irbesartan of Formula I) Step A 2-n-butyl-3-[ 2'-(N-triphenylmethyltetrazol-5-yl biphenyl-4- yllmethyll-1.3-diazaspiro-[4.41non-l-ene-4-one (Trityl-ιrbesartan of Formula V)
Figure imgf000010_0001
FORMULA V A mixture of 2-n-butyl-3-[[2'-cyanobiphenyl-4-yl]methyl]-l,3-diazaspiro- [4.4]non-l-ene-4-one of Formula II as obtained in example 1 step A) (25 g), tributyltin chloride (63.4 g), sodium azide (12.7 g) and tetrabutyl ammonium bromide (2.5 g) in toluene (75 ml) was refluxed for 20 hrs. The reaction mixture was cooled to room temperature and to it was added water (100 ml) and acetic acid (12.5 ml). The mixture was stirred at room temperature for 15 min. To it was added methanol (100 ml), water (100 ml) and toluene (100 ml) and the entire mass was filtered. The wet solid was dissolved in methylene chloride (150 ml) and to it was added triethylamine (8 gm) followed by triphenylmethyl chloride (18.2 gm). The resultant reaction mass was stirred at 25-30°C for about 2 hours. After the completion ofthe reaction water (125 ml) was added and the biphasic mass was stirred for 30 minutes. Next, the layers were separated and the methylene chloride was layer was concentrated under a vacuum. The crude residue was used as such in the next step.
Step B 2-n-butyl-3- 2'('tetrazol-5-yl biphenyl-4-yl]methyll-l ,3-diazaspiro-|~4.4"|non- l-ene-4-one (irbesartan of Formula D Methanol (65 ml) and formic acid (16 gm) was added to the crude residue I obtained in Example 2 step A). The resultant solution was stirred at 25-30°C for 4 hours. After completion ofthe reaction, ethyl acetate (100 ml) and water (100 ml) were added and stirred for 30 minutes. The resulting layers were separated and the ethyl acetate layer was washed with sodium carbonate solution twice (10%, 50 ml). The ethyl acetate was concentrated under vacuum to get the residue, which was then dissolved in a mixture of water (250 ml) and IN sodium hydroxide solution (100 ml). The aqueous phase was washed with ethyl acetate (2 x 100 ml). To the resulting aqueous phase was added 6N HC1 slowly to adjust the pH ofthe solution to about 4.8 - 5.3. After stirring at room temperature for 30 min, the crystals were filtered, washed with water (200 ml) and dried at 50°C to yield the compound of Formula I in 99.7% purity (24 g) which was purified, although the purification is optional. To this purified compound ethanol (96%, 250 ml) was added and the resulting mixture was heated to reflux until the product completely dissolves. The mixture was cooled to 15°C and stirred at 15 - 20°C for 30 min. The separated crystals were filtered and washed with 96% ethanol and dried at 50°C under reduced pressure to yield irbesartan. Yield: 23 g (86%)
HPLC Purity: 99.95%.
Example 3: Preparation of 2-n-butyl-3-[f2'(tetrazol-5-yl)biphenyl-4-yllmethyl1- l,3-diazaspiro-[4.41non-l-ene-4-one (Irbesartan of Formula I)
Step A 2-n-butyl-3-[ 2'-cyanobiτ)henyl-4-yllmethyl1- 3-diazaspiro- 4.4]non-l-ene- 4-one (Formula TV)
Figure imgf000012_0001
FORMULA IV A mixture of 2-n-butyl-l,3-diazaspiro[4.4]non-l-ene-4-one hydrochloride (25 g), aqueous sodium hydroxide solution (35%, 125 ml), 2-cyano-4'- bromomethylbiphenyl (29.5 g), and tetrabutyl ammonium bromide (2.5 g) in acetonitrile (375 ml) was stirred at room temperature for 3 hrs. After completion of reaction, the two layers were separated and the organic layer was concentrated under reduced pressure. The residue was dissolved in methylene chloride (125 ml) and washed with water (2 x 125 ml). The organic layer was concentrated under reduced pressure. The residue was crystallized in methyl tert-butyl ether to get 2-n-butyl-3- [2 ' -cyanobiphenyl-4-yl] methyl- 1 ,3-diazaspiro [4.4]non- 1 -ene-4-one.
Step B 2-n-butyl-3- 2'(tetrazol-5-vDbiphenyl-4-yl]methyl1- 3-diazaspiro-[4.4]non- l-ene-4-one (Irbesartan of Formula I) The product obtained in Example 3, step A) was converted to irbesartan by the process described in Example 1, step B).
Yield: 35 g
HPLC Purity: 99.85%. While the present invention has been described in terms of its specific embodiments, certain modifications and equivalents will be apparent to those skilled in the art and are included within the scope ofthe present invention.

Claims

We Claim: 1. A process for preparation of irbesartan of Formula I,
Figure imgf000013_0001
FORMULA I the process comprising: condensing a spiro intermediate of Formula II with a halomethyl- cyanobiphenyl compound of Formula III
Figure imgf000013_0002
FORMULA II FORMULA III in the presence of a water miscible organic solvent and a base.
2. The process according to claim 1, wherein the water miscible organic solvent comprises one or more of water miscible lower alkanols, water miscible polar aprotic solvents and mixtures thereof.
3. The process according to claim 2, wherein the lower alkanol comprises one or more of methanol, ethanol, isopropanol and n-propanol. 4. The process according to claim 2, wherein the polar aprotic solvent comprises one or more of tetrahydrofuran, acetonitrile, 1,
4-dioxane, N,N- dimethylacetamide, and dimethylsulphoxide.
5. The process according to claim 1, wherein the base comprises one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium methoxide, potassium methoxide, potassium t-butoxide or mixtures thereof.
6. The process according to claim 1 , wherein the condensation is carried out at a temperature of about 0 °C to about 150°C.
7. The process according to claim 1, wherein the condensation is carried out for about 2 to about 48 hours.
8. The process according to claim 1 , wherein the irbesartan of Formula I obtained has a purity greater than 99.5%.
9. A process for preparation of irbesartan of Formula I
Figure imgf000014_0001
FORMULA I the process comprising: a) condensing a spiro intermediate of Formula II with a halomethyl- cyanobiphenyl compound of Formula III
Figure imgf000014_0002
FORMULA II FORMULA III in presence of a water miscible organic solvent and a base; b) treating the product obtained of Formula IV with trialkyltin chloride and sodium azide; and
Figure imgf000015_0001
FORMULA IV c) isolating irbesartan of Formula I.
10. The process according to claim 9, further comprising adding a phase transfer catalyst to step (b).
11. The process according to claim 9, further comprising the steps of protecting the tetrazolyl intermediate with a suitable protecting group and deprotecting the tetrazolyl protecting group prior to isolating the irbesartan of Formula I.
12. The process according to claim 9, wherein the trialkyltin chloride comprises one or more tri C1-18 alkyltin chlorides.
13. The process according to claim 12, wherein the trialkyltin chloride comprises one or more of trimethyltin chloride, triethyltin chloride, tributyltin chloride and trioctyltin chloride.
14. The process according to claim 10, wherein the phase transfer catalyst comprises one or more of crown ethers, quaternary ammonium salts, polyethylene glycols, diglyme and phosphoric acid derivatives.
15. The process according to claim 14, wherein the quaternary ammonium salts comprise one or more of tetraalkyl ammonium halides or aryl and aralkyl trialkyl ammonium halides.
16. The process according to claim 15, wherein the quaternary ammonium salts comprise one or more of tetrabutyl ammonium chloride, tetrabutyl ammonium bromide, tetrabutyl ammonium fluoride, tetrabutyl ammonium iodide, benzalkonium chloride, cetyl trimethyl ammonium chloride and benzyl trialkyl ammonium chloride.
17. The process according to claim 11, wherein the protecting group comprises trityl, monomethoxytrityl, dimethoxytrityl, benzhydryl and acyl.
18. The process according to claim 9, wherein the irbesartan of Formula I has a purity greater than about 99.5%.
19. Irbesartan of Formula I with a purity of greater than about 99.5%.
20. The irbesartan of Formula I of claim 19, wherein the irbesartan of Formula I is Form A irbesartan.
PCT/IB2004/003777 2003-11-28 2004-11-18 Processes for the preparation of highly pure irbesartan WO2005051943A1 (en)

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CN114478618A (en) * 2020-10-26 2022-05-13 珠海润都制药股份有限公司 Recovery method of tributyl tin halide mother liquor
CN114577971A (en) * 2020-11-30 2022-06-03 珠海润都制药股份有限公司 Method for detecting biphenyl imidazoline isomer in irbesartan
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WO2005122699A2 (en) * 2004-06-16 2005-12-29 Matrix Laboratories Ltd An improved process for the preparation of n-substituted hetero cyclic derivatives
WO2005122699A3 (en) * 2004-06-16 2007-05-31 Matrix Lab Ltd An improved process for the preparation of n-substituted hetero cyclic derivatives
WO2006050923A1 (en) * 2004-11-11 2006-05-18 Lek Pharmaceuticals D.D. Polymorph form of irbesartan
WO2007013101A1 (en) 2005-07-27 2007-02-01 Jubilant Organosys Limited PROCESS FOR PRODUCING 2-(N-BUTYL)-3-[[2'-(TETRAZOL-5-YL)BIPHENYL- 4-YL]METHYL]-l,3-DIAZASPIRO[4.4] NON-1-EN-4-ONE
US7964737B2 (en) 2005-07-27 2011-06-21 Jubilant Organosys Limited Process for producing 2-(n-butyl)-3-[[2′-(tetrazol-5-yl)biphenyl-4-yl]methyl]-1,3-diazaspiro[4.4] non-1-en-4-one
WO2007017469A3 (en) * 2005-08-04 2007-08-02 Farmaprojects S A Process for preparing an angiotensin ii receptor antagonist
EP1749828A1 (en) 2005-08-04 2007-02-07 Farmaprojects S.L. Process for preparing an angiotensin II receptor antagonist
WO2007017469A2 (en) 2005-08-04 2007-02-15 Farmaprojects, S. A. Process for preparing an angiotensin ii receptor antagonist
WO2007020659A2 (en) * 2005-08-16 2007-02-22 Matrix Laboratories Ltd A process for the preparation of irbesartan form a
WO2007020659A3 (en) * 2005-08-16 2008-07-10 Matrix Lab Ltd A process for the preparation of irbesartan form a
WO2007052301A2 (en) * 2005-08-31 2007-05-10 Alembic Limited Process for the preparation of irbesartan
WO2007052301A3 (en) * 2005-08-31 2007-07-12 Alembic Ltd Process for the preparation of irbesartan
US8106216B2 (en) 2006-04-24 2012-01-31 Aurobindo Pharma Ltd. Process for the preparation of Irbesartan
CN100413853C (en) * 2006-09-21 2008-08-27 浙江海正药业股份有限公司 Synthetic intermediate of Irbesartan, preparation method and use thereof
EP1918288A1 (en) 2006-11-02 2008-05-07 Cadila Pharmaceuticals Limited A novel and improved process for the preparation of Irbesartan, an angiotensin-II receptor antagonist for the treatment of hypertension
WO2009149734A1 (en) * 2008-06-13 2009-12-17 Ratiopharm Gmbh Process for the preparation of irbesartan and intermediate products
WO2010133909A2 (en) * 2009-05-20 2010-11-25 Sms Pharmaceuticals Limited Process for preparation of 5-substituted tetrazoles
WO2010133909A3 (en) * 2009-05-20 2012-03-29 Sms Pharmaceuticals Limited Process for preparation of 5-substituted tetrazoles
US8080670B2 (en) 2010-05-04 2011-12-20 Divi's Laboratories, Ltd. Process for the preparation of irbesartan
US11655220B2 (en) 2020-10-22 2023-05-23 Hetero Labs Limited Process for the preparation of angiotensin II receptor blockers
CN114478618A (en) * 2020-10-26 2022-05-13 珠海润都制药股份有限公司 Recovery method of tributyl tin halide mother liquor
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