Indian Patents. 279995:AN EFFICIENT PROCESS FOR ENHANCING THE OPTICAL PURITY OF 2R-[1-HYDROXY-1-TRIFLUOROMETHYL-3-CYCLOPROPYLPROPYN-2-YL]-4-CHLOROANILINE

Title of Invention	AN EFFICIENT PROCESS FOR ENHANCING THE OPTICAL PURITY OF 2R-[1-HYDROXY-1-TRIFLUOROMETHYL-3-CYCLOPROPYLPROPYN-2-YL]-4-CHLOROANILINE
Abstract	A process for enhancing the chiral purity of 2R-[ 1-hydroxy-1-trifluoromethyl-3- cyclopropylpropyn-2-yl]-4-chloroaniline through the formation of an acid addition salt of amino alcohol in water.

Full Text	Field of the invention: The present invention relates to a process for enhancing the chiral purity of 2R-[l-hydroxy-l- trifluoromethyl-3-cyclopropylpropyn-2-yI]-4-chloroaniline, which is an important intermediate for the synthesis of Efavirenz. Background of the invention: U.S. Pat. No. 5,952,528 discloses a process for enhancing the optical purity of amino alcohols comprising the steps of: • adding slowly an acid solution or gas to a solution of the amino alcohol in an organic solvent to form a slurry of the acid addition salt of the amino alcohol; • concentrating the slurry of the amino alcohol acid addition salt of the amino alcohol; • flushing the concentrated slurry of the amino alcohol acid addition salt with organic solvent to adjust the solvent composition; • aging the slurry of the amino alcohol acid addition salt at ambient temperature for about 2 hours to about 24 hours; • filtering the aged slurry of the amino alcohol acid addition salt to isolate a wet cake of the amino alcohol acid addition salt; • washing the wet cake of the amino alcohol acid addition salt with cold organic solvent; and • drying the wet cake of the amino alcohol acid addition salt to isolate the amino alcohol acid addition salt as a solid with enhanced optical purity. Our co pending application No.l453/CHE/2008 discloses a process to enhance the optical purity of 2R-[1-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline comprising the steps of: • adding slowly a carboxylic acid solution to a solution of 2R-[1-hydroxy-1- trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline in an organic solvent • filtering the slurry of the amino alcohol acid addition salt to isolate a wet cake of the 2R- [l-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salt; • Suspending the 2R- [ 1 -hydroxy-1 -trifluoromethyl-3 -cyclopropylpropyn-2-yl] -4- chloroaniline acid addition salt in water • Adjusting the pH to neutral with aq.ammonia • Filtering the 2R-[l-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline with enhanced optical purity. It has been observed that none of the prior art processes has disclosed the formation of salts in water thereby increasing the chiral purity. The present invention discloses an efficient method for enhancing the optical purity of the amino alcohol regardless of the synthetic route used to make the amino alcohol by making the acid addition salts of amino alcohol in water. Summary of the invention: The main object of the present invention is to provide a process to prepare the acid addition salts of 2R-[1-hydroxy-1-trifluoromethyl-3-eyelopropylpropyn-2-yl]-4-chloroaniline in water. Another object of the present invention is to provide a process to enhance the chiral purity of the 2R-[l-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline by making the acid addition salts. Detailed description of the invention: In accordance with the present invention preparation of 2R-[1-hydroxy-1-trifluoromethyl-3- cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salts comprising the steps of; • Treating 2R- [ 1 -hydroxy-1 -trifluoromethyl-3 -cyclopropylpropyn-2-y 1] -4-chloroaniline with an acid in water • Stirring the slurry of the 2R-[ 1-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]- 4-chloroaniline acid addition salt at ambient temperature • Filtering the slurry of the amino alcohol acid addition salt to isolate 2R-[l-hydroxy-l- trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salt; According to one preferred embodiment 2R-[l-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn- 2-yl]-4-chloroaniline is treated with an acid at a temperature of about 20°C to about 45°C and the acid is selected from the group comprising of oxalic acid, tartaric acid, hydrochloric acid, hydrobromic acid, sulphuric acid and methanesulphonic acid. The reaction mass is maintained at ambient temperature for completion of salt formation and the formed acid addition salt is filtered. The wet cake of the 2R-[1-hydroxy-1-trifluoromethyl-3- cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salt is washed with water and dried at a temperature of 30°C to about 50°C. Another embodiment of the present invention is to provide a process for enhancing the chiral purity of 2R-[1-hydroxy-1 -trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline comprising the steps of: • Suspending the 2R-[ 1-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4- chloroaniline acid addition salt in water and adjusting the pH to neutral • Isolating 2R-[1-hydroxy-1-trifluoromethyl-3-cyclopropyl propyn-2-yl]-4-chloroaniline with enhanced optical purity. The process as described above wherein the optical purity of finally obtained 2R-[ 1-hydroxy-1- trifluoromethy 1-3-cyclopropyl propyn-2-yl]-4-chloroaniline is more than 99.0%. The following examples are meant to be illustrative of the present invention. These examples are presented to exemplify the invention and are not to be construed as limiting the scope of the invention. Example-1: Preparation of hydrochloride salt (S)-5-Chloro-α-(cyclopropylethynyl)-2-amino-α-(trifluoromethyl)benzene methanol (50gm) was suspended in DM Water (250 ml) at RT (25-30°C). Temperature was raised to 35°C and aq. HC1 (48 ml) was added over 10-15 min at 30-35°C. The aqueous layer was cooled to 10°C and maintained for 1 hr. Reaction mass was further cooled to 0-5°C and maintained for 2 hrs at 0- 5°C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 47 gm of the desired product. ExampIe-2: Preparation of hydrobromide salt (S)-5-Chloro- α -(cyclopropylethynyl)-2-amino-α-(trifluoromethyl) benzene methanol (50gm) was suspended in DM Water (250 ml) at RT (25-30°C). Temperature was raised to 35°C and aq.HBr (83gm) was added over 10-15 min at 30-35°C. The aqueous layer was cooled to 10°C and maintained for 1 hr. Reaction mass was further cooled to 0-5°C and maintained for 2 hrs at 0-5 °C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 53 gm of the desired product. Example -3: Preparation of sulphate salt (S)-5-Chloro-α-(cyclopropylethynyl)-2-amino-α-(trifluoromethyl)benzene methanol (50gm) was suspended in DM Water (250 ml) at RT (25-30°C). Temperature was raised to 35°C and sulphuric acid (104 gm) was added over 10-15 min at 30-35°C. Reaction mass was cooled to 10°C and maintained for 1 hr. Reaction mass was further cooled to 0-5 °C and maintained for 2 hrs at 0-5°C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 51 gm of the desired product. Example - 4: Preparation of tartrate salt (S)-5-Chloro- α -(cyclopropylethynyl)-2-amino-α-(trifluoromethyl) benzene methanol (50gm) was suspended in DM Water (250 ml) at RT (25-30°C). Temperature was raised to 35°C and L(+)- tartaric acid solution (155.28 gm dissolved in 120 ml of DM Water) was added over 20-30 min at 30-35°C. Reaction mass was cooled to 20-25°C and maintained for 1 hr. Reaction mass was further cooled to 0-5°C and maintained for 2 hrs at 0-5 °C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 46 gm of the desired product. Example-5: Preparation of methanesulfonate salt (S)-5-Chloro-α-(cyclopropylethynyl)-2-amino-α-(trifluoromethyl)benzene methanol (50gm) was suspended in DM Water (250 ml) at RT (25-30°C). Temperature was raised to 35°C and methanesulphonic acid (163gm) was added over 10-15 min at 30-35°C. The obtained clear solution was washed with Cyclohexane (2 x 50 ml) at RT (25-30°C). The aqueous layer was cooled to 10°C and maintained for 1 hr. Reaction mass was further cooled to 0-5°C and maintained for 2 hrs at 0-5°C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 57 gm of the desired product. Example-6: Preparation of oxalate salt (S)-5-Chloro-α-(cyclopropylethynyl)-2-amino-α-(trifluoromethyl)benzene methanol (50gm) was suspended in DM Water (325 ml) at RT (25-30°C). Temperature was raised to 35°C and Oxalic acid solution (87 gm oxalic acid was dissolved in 250 ml of DM Water at 45°C) was added over 20-25 min at 30-35°C. Reaction mass was cooled to 25-30°C and maintained for 1 hr. Reaction mass was further cooled to 0-5°C and maintained for 2 hrs at 0-5 °C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 68 gm of the desired product. Example-7: Preparation of 2R-[l-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4- chloroaniline 2R- [ 1 -hydroxy-1 -trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline oxalate (100gm) was dissolved in DM Water (400 ml) at 25-35°C. The obtained clear solution was cooled to 20°C and stirred for 15min at 20-25°C. The reaction mass pH was adjusted to 6.5-7.5 with aq.ammonia over a period of 30-45 min at 20-25°C. The reaction mass was stirred for 1 hr at 20- 25°C. The precipitated product was filtered and washed with DM water (200 ml). The wet material was dried at 45-50°C till moisture content comes to below 0.5% Output 65.0 gm Optical purity : 99.6% We claim; 1. An improved process for the preparation of 2R-[1-hydroxy-1-trifluoromethyl-3- cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salts comprising the steps of: • Treating 2R- [1 -hydroxy-1 -trifluoromethyl-3-cyclopropylpropyn-2-yl] -4- chloroaniline with an acid in water • Stirring the slurry of the 2R-[1-hydroxy-1-trifluoromethyl-3-cyclopropylpropyn- 2-yl]-4-chloroaniline acid addition salt at ambient temperature • Isolating the 2R- [ 1 -hydroxy-1 -trifluoromethyl-3 -cyclopropylpropyn-2-yl]-4- chloroaniline acid addition salt; 2. The process as claimed in claim 1, wherein 2R-[1-hydroxy-1-trifluoromethyl-3 - cyclopropylpropyn-2-yl]-4-chloroaniline is treated with an acid at a temperature of about 20°C to about 45°C and 3. The process as claimed in claim 1, wherein the acid is selected from the group comprising of oxalic acid, tartaric acid, hydrochloric acid, hydrobromic acid, sulphuric acid and methanesulphonic acid and mixtures thereof. 4. The process as claimed in claim 1, wherein the wet cake of the 2R-[ 1-hydroxy-1- trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salt is washed with water and dried at a temperature of 30°C to about 50°C. 5. A process for enhancing the chiral purity of 2R-[1 -hydroxy-1 -trifluoromethyl-3 - cyclopropylpropyn-2-yl]-4-chloroaniline comprising the steps of: • Suspending the 2R-[l-hydroxy-1-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4- chloroaniline acid addition salt in water and adjusting the pH to neutral; and • Isolating 2R-[1-hydroxy-1-trifluoromethyl-3-cyclopropyl propyn-2-yl]-4- chloroaniline with enhanced optical purity. 6. The process as claimed in claim 5, wherein the pH adjustment is done using aq.ammonia 7. The process as claimed in claim 5, wherein the wet material is dried at a temperature of 30°C to about 50°C. 8. The process as claimed in claim 5, wherein the optical purity of obtained 2R-[l-hydroxy- l-trifluoromethyl-3-cyclopropyl propyn-2-yl]-4-chloroaniline is more than 99.0%.

Full Text

Field of the invention:

The present invention relates to a process for enhancing the chiral purity of 2R-[l-hydroxy-l- trifluoromethyl-3-cyclopropylpropyn-2-yI]-4-chloroaniline, which is an important intermediate for the synthesis of Efavirenz.

Background of the invention:

U.S. Pat. No. 5,952,528 discloses a process for enhancing the optical purity of amino alcohols comprising the steps of:

• adding slowly an acid solution or gas to a solution of the amino alcohol in an organic solvent to form a slurry of the acid addition salt of the amino alcohol;

• concentrating the slurry of the amino alcohol acid addition salt of the amino alcohol;

• flushing the concentrated slurry of the amino alcohol acid addition salt with organic solvent to adjust the solvent composition;

• aging the slurry of the amino alcohol acid addition salt at ambient temperature for about 2 hours to about 24 hours;

• filtering the aged slurry of the amino alcohol acid addition salt to isolate a wet cake of the amino alcohol acid addition salt;

• washing the wet cake of the amino alcohol acid addition salt with cold organic solvent; and

• drying the wet cake of the amino alcohol acid addition salt to isolate the amino alcohol acid addition salt as a solid with enhanced optical purity.

Our co pending application No.l453/CHE/2008 discloses a process to enhance the optical purity of 2R-[1-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline comprising the steps of:

• adding slowly a carboxylic acid solution to a solution of 2R-[1-hydroxy-1- trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline in an organic solvent

• filtering the slurry of the amino alcohol acid addition salt to isolate a wet cake of the 2R- [l-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salt;

• Suspending the 2R- [ 1 -hydroxy-1 -trifluoromethyl-3 -cyclopropylpropyn-2-yl] -4- chloroaniline acid addition salt in water

• Adjusting the pH to neutral with aq.ammonia

• Filtering the 2R-[l-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline with enhanced optical purity.

It has been observed that none of the prior art processes has disclosed the formation of salts in water thereby increasing the chiral purity.

The present invention discloses an efficient method for enhancing the optical purity of the amino alcohol regardless of the synthetic route used to make the amino alcohol by making the acid addition salts of amino alcohol in water.

Summary of the invention:

The main object of the present invention is to provide a process to prepare the acid addition salts of 2R-[1-hydroxy-1-trifluoromethyl-3-eyelopropylpropyn-2-yl]-4-chloroaniline in water.

Another object of the present invention is to provide a process to enhance the chiral purity of the 2R-[l-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline by making the acid addition salts.

Detailed description of the invention:

In accordance with the present invention preparation of 2R-[1-hydroxy-1-trifluoromethyl-3- cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salts comprising the steps of;

• Treating 2R- [ 1 -hydroxy-1 -trifluoromethyl-3 -cyclopropylpropyn-2-y 1] -4-chloroaniline with an acid in water

• Stirring the slurry of the 2R-[ 1-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]- 4-chloroaniline acid addition salt at ambient temperature
• Filtering the slurry of the amino alcohol acid addition salt to isolate 2R-[l-hydroxy-l- trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salt;

According to one preferred embodiment 2R-[l-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn- 2-yl]-4-chloroaniline is treated with an acid at a temperature of about 20°C to about 45°C and the acid is selected from the group comprising of oxalic acid, tartaric acid, hydrochloric acid, hydrobromic acid, sulphuric acid and methanesulphonic acid.

The reaction mass is maintained at ambient temperature for completion of salt formation and the formed acid addition salt is filtered. The wet cake of the 2R-[1-hydroxy-1-trifluoromethyl-3- cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salt is washed with water and dried at a temperature of 30°C to about 50°C.

Another embodiment of the present invention is to provide a process for enhancing the chiral purity of 2R-[1-hydroxy-1 -trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline comprising the steps of:

• Suspending the 2R-[ 1-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4- chloroaniline acid addition salt in water and adjusting the pH to neutral

• Isolating 2R-[1-hydroxy-1-trifluoromethyl-3-cyclopropyl propyn-2-yl]-4-chloroaniline with enhanced optical purity.

The process as described above wherein the optical purity of finally obtained 2R-[ 1-hydroxy-1- trifluoromethy 1-3-cyclopropyl propyn-2-yl]-4-chloroaniline is more than 99.0%.

The following examples are meant to be illustrative of the present invention. These examples are presented to exemplify the invention and are not to be construed as limiting the scope of the invention.

Example-1: Preparation of hydrochloride salt
(S)-5-Chloro-α-(cyclopropylethynyl)-2-amino-α-(trifluoromethyl)benzene methanol (50gm) was suspended in DM Water (250 ml) at RT (25-30°C). Temperature was raised to 35°C and aq. HC1 (48 ml) was added over 10-15 min at 30-35°C. The aqueous layer was cooled to 10°C and maintained for 1 hr. Reaction mass was further cooled to 0-5°C and maintained for 2 hrs at 0- 5°C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 47 gm of the desired product.

ExampIe-2: Preparation of hydrobromide salt
(S)-5-Chloro- α -(cyclopropylethynyl)-2-amino-α-(trifluoromethyl) benzene methanol (50gm) was suspended in DM Water (250 ml) at RT (25-30°C). Temperature was raised to 35°C and aq.HBr (83gm) was added over 10-15 min at 30-35°C. The aqueous layer was cooled to 10°C and maintained for 1 hr. Reaction mass was further cooled to 0-5°C and maintained for 2 hrs at 0-5 °C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 53 gm of the desired product.

Example -3: Preparation of sulphate salt
(S)-5-Chloro-α-(cyclopropylethynyl)-2-amino-α-(trifluoromethyl)benzene methanol (50gm) was suspended in DM Water (250 ml) at RT (25-30°C). Temperature was raised to 35°C and sulphuric acid (104 gm) was added over 10-15 min at 30-35°C. Reaction mass was cooled to 10°C and maintained for 1 hr. Reaction mass was further cooled to 0-5 °C and maintained for 2 hrs at 0-5°C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 51 gm of the desired product.

Example - 4: Preparation of tartrate salt
(S)-5-Chloro- α -(cyclopropylethynyl)-2-amino-α-(trifluoromethyl) benzene methanol (50gm) was suspended in DM Water (250 ml) at RT (25-30°C). Temperature was raised to 35°C and L(+)- tartaric acid solution (155.28 gm dissolved in 120 ml of DM Water) was added over 20-30 min at 30-35°C. Reaction mass was cooled to 20-25°C and maintained for 1 hr. Reaction mass was further cooled to 0-5°C and maintained for 2 hrs at 0-5 °C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 46 gm of the desired product.

Example-5: Preparation of methanesulfonate salt
(S)-5-Chloro-α-(cyclopropylethynyl)-2-amino-α-(trifluoromethyl)benzene methanol (50gm) was suspended in DM Water (250 ml) at RT (25-30°C). Temperature was raised to 35°C and methanesulphonic acid (163gm) was added over 10-15 min at 30-35°C. The obtained clear solution was washed with Cyclohexane (2 x 50 ml) at RT (25-30°C). The aqueous layer was cooled to 10°C and maintained for 1 hr. Reaction mass was further cooled to 0-5°C and maintained for 2 hrs at 0-5°C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 57 gm of the desired product.

Example-6: Preparation of oxalate salt

(S)-5-Chloro-α-(cyclopropylethynyl)-2-amino-α-(trifluoromethyl)benzene methanol (50gm) was suspended in DM Water (325 ml) at RT (25-30°C). Temperature was raised to 35°C and Oxalic acid solution (87 gm oxalic acid was dissolved in 250 ml of DM Water at 45°C) was added over 20-25 min at 30-35°C. Reaction mass was cooled to 25-30°C and maintained for 1 hr. Reaction mass was further cooled to 0-5°C and maintained for 2 hrs at 0-5 °C. The precipitated material was filtered and washed with chilled water (50 ml). The wet product was dried at 45-50° to get 68 gm of the desired product.

Example-7: Preparation of 2R-[l-hydroxy-l-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4- chloroaniline

2R- [ 1 -hydroxy-1 -trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline oxalate (100gm) was dissolved in DM Water (400 ml) at 25-35°C. The obtained clear solution was cooled to 20°C and stirred for 15min at 20-25°C. The reaction mass pH was adjusted to 6.5-7.5 with aq.ammonia over a period of 30-45 min at 20-25°C. The reaction mass was stirred for 1 hr at 20- 25°C. The precipitated product was filtered and washed with DM water (200 ml). The wet material was dried at 45-50°C till moisture content comes to below 0.5%

Output 65.0 gm

Optical purity : 99.6%

We claim;

1. An improved process for the preparation of 2R-[1-hydroxy-1-trifluoromethyl-3- cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salts comprising the steps of:
• Treating 2R- [1 -hydroxy-1 -trifluoromethyl-3-cyclopropylpropyn-2-yl] -4- chloroaniline with an acid in water

• Stirring the slurry of the 2R-[1-hydroxy-1-trifluoromethyl-3-cyclopropylpropyn- 2-yl]-4-chloroaniline acid addition salt at ambient temperature

• Isolating the 2R- [ 1 -hydroxy-1 -trifluoromethyl-3 -cyclopropylpropyn-2-yl]-4- chloroaniline acid addition salt;

2. The process as claimed in claim 1, wherein 2R-[1-hydroxy-1-trifluoromethyl-3 - cyclopropylpropyn-2-yl]-4-chloroaniline is treated with an acid at a temperature of about 20°C to about 45°C and

3. The process as claimed in claim 1, wherein the acid is selected from the group comprising of oxalic acid, tartaric acid, hydrochloric acid, hydrobromic acid, sulphuric acid and methanesulphonic acid and mixtures thereof.

4. The process as claimed in claim 1, wherein the wet cake of the 2R-[ 1-hydroxy-1- trifluoromethyl-3-cyclopropylpropyn-2-yl]-4-chloroaniline acid addition salt is washed with water and dried at a temperature of 30°C to about 50°C.

5. A process for enhancing the chiral purity of 2R-[1 -hydroxy-1 -trifluoromethyl-3 - cyclopropylpropyn-2-yl]-4-chloroaniline comprising the steps of:

• Suspending the 2R-[l-hydroxy-1-trifluoromethyl-3-cyclopropylpropyn-2-yl]-4- chloroaniline acid addition salt in water and adjusting the pH to neutral; and

• Isolating 2R-[1-hydroxy-1-trifluoromethyl-3-cyclopropyl propyn-2-yl]-4- chloroaniline with enhanced optical purity.

6. The process as claimed in claim 5, wherein the pH adjustment is done using aq.ammonia

7. The process as claimed in claim 5, wherein the wet material is dried at a temperature of 30°C to about 50°C.

8. The process as claimed in claim 5, wherein the optical purity of obtained 2R-[l-hydroxy- l-trifluoromethyl-3-cyclopropyl propyn-2-yl]-4-chloroaniline is more than 99.0%.

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Patent Number

279995

Indian Patent Application Number

2146/CHE/2008

PG Journal Number

06/2017

Publication Date

10-Feb-2017

Grant Date

06-Feb-2017

Date of Filing

02-Sep-2008

Name of Patentee

LAURUS LABS PVT LTD

Applicant Address

2ND FLOOR SERENE CHAMBERS ROAD #7 BANJARA HILLS HYDERABAD 500034

Inventors:

#	Inventor's Name	Inventor's Address
1	MR. KETAVARAPU NARASIMHA RAO	2ND FLOOR , SERENE CHAMBERS ROAD, #7,BANJARA HILLS HYDERABAD-500034
2	DR. GORANTLA SEETA RAMANJANEYULU	2ND FLOOR , SERENE CHAMBERS ROAD, #7,BANJARA HILLS HYDERABAD-500034
3	MR. INDUKURI VENKATA SUNIL KUMAR	2ND FLOOR , SERENE CHAMBERS ROAD, #7,BANJARA HILLS HYDERABAD-500034

PCT International Classification Number

C07C211/46

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA