DESC:TITLE OF THE INVENTION
Process for the preparation of Brivaracetam.

FIELD OF THE INVENTION
The present invention relates to a novel process for the preparation of Brivaracetam having the structural formula (I).

The present invention also relates to novel intermediates which are useful in the preparation of Brivaracetam.

BACK GROUND OF THE INVENTION
Brivaracetam is a chemical analog of Levetiracetam, marketed under the brand name of BRIVIACT for the treatment as adjunctive therapy in the treatment of partial-onset seizures in patients 16 years of age and older with epilepsy.
Brivaracetam is chemically known as (2S)-2-[(4R)-2-oxo-4-propyltetrahydro-lH-pyrrol-l-yl] butanamide and is represented by following general Formula I.
Brivaracetam and process for its preparation is first disclosed in US 6911461 B2. The reported process utilizes preparative HPLC for chiral resolution of isomers which makes it difficult for bulk manufacturing as well as it effects the overall yield making the process uneconomical.
Various synthetic routes for Brivaracetam were disclosed in the prior art like US 7122682, US 7629474, US 8076493, US 8338621 and US 8957226. The reported processes for the preparation of Brivaracetam suffer from many disadvantages which includes difficulty in achieving desired chiral purity, tedious & cumbersome work up procedures, multiple crystallizations or isolation steps, column chromatographic separations and purifications etc. All these disadvantages effect the overall yield as well as the quality of the final product.
In view of all these disadvantages, there is a significant need in the art to develop a novel process for the preparation of highly pure Brivaracetam with good yield.

SUMMARY OF THE INVENTION
The present invention provides a cost effective, novel and an efficient process for the preparation of Brivaracetam with high yields and avoiding chiral resolutions by chromatography.
The first aspect of the present invention provides the following novel intermediates useful in the preparation of Brivaracetam.

The second aspect of the present invention provides a process for the preparation of Brivaracetam compound of formula-I.

which comprises:
a) reaction of compound of formula-II

with glyoxylic acid in the presence of morpholine to give compound of formula-III;

b) condensation of compound of formula-III with amide derivative of formula-IV

to give compound of formula-V;

c) reducing compound of formula-V with a reducing agent to give compound of formula-VI;

d) reaction of compound of formula-VI with methane sulfonyl chloride wherein R2 is C2H5OH in the presence of base to give compound of formula-XVa;

e) reduction of compound of formula-VI or compound of formula-XVa using a catalyst to give compound of formula-VII;

f) optionally deprotecting compound of formula-VII using deprotecting agent to provide Brivaracetam of formula-I.

In another aspect, the present invention provides a process for the preparation of Brivaracetam compound of formula-I

which comprises:
a) reaction of compound of formula-II

with glyoxylic acid in the presence of morpholine to give compound of formula-III;

b) condensation of compound of formula-III with compound of formula-VIII

to provide compound of formula-IX;

c) reduction of compound of formula-IX with a reducing agent to give compound of formula-X;

d) reduction of compound of formula-X using a catalyst to give compound of formula-XI;

e) deprotection of compound of formula-XI using deprotecting agent to give Brivaracetam of compound of formula-I.

In yet another aspect, the present invention provides a process for the preparation of Brivaracetam compound of formula-I.

which comprises:
a) reaction of compound of formula-II

with glyoxylic acid in presence of morpholine to give compound of formula-III;

b) condensation of compound of formula-III with compound of formula-XII

to give compound of formula-XIII;

c) reduction of compound of formula-XIII with a reducing agent to give compound of formula-XIV;

d) reaction of compound of formula-XIV with methane sulfonyl chloride to give compound of formula-XV;

e) reduction of compound of formula-XV using a suitable catalyst to provide Brivaracetam compound of formula-I.

In yet another aspect, the present invention provides a process for the preparation of Brivaracetam compound of formula-I
which comprises:
a) reaction of compound of formula-II

with glyoxylic acid in the presence of morpholine to give compound of formula-III;

b) condensation of compound of formula-III with compound of formula-XVI

to give compound of formula-XVII;

c) reduction of compound of formula-XVII with a reducing agent to give compound of formula-XVIII;

d) reduction of compound of formula-XVIII using a catalyst to give Brivaracetam of compound of formula-I.

DETAILED DESCRIPTION OF THE INVENTION
Accordingly, the present invention provides the novel process for the preparation of Brivaracetam of compound of formula-I.

Scheme-I illustrates the process for the preparation of Brivaracetam of compound of formula-I.

Scheme-I

In step-1, compound of formula-II is reacted with Glyoxylic acid in presence of morpholine in a suitable organic solvent followed by heating the resulting reaction mixture to give compound of formula-III.

The suitable solvent used in the reaction is selected from chloro solvents, alcohol solvents, polar solvents, hydrocarbon solvents, nitrile solvents, ether solvents, ester solvents or polar-aprotic solvents and preferably using n-heptane. The reaction temperature may range from 30-50°C and preferably at a temperature in the range from 40-45°C. The duration of the reaction may range from 18 to 24 hours, preferably for a period of 20 hours.

In step-2, compound of formula-III is reacted with compound of formula-IV in a suitable solvent to give compound of formula-V. Subjecting the obtained compound of formula-V with or without isolating to reduction with a suitable reducing agent in the presence of acetic acid followed by heating the resulting reaction mixture to obtain compound of formula-VI.

The suitable solvent used in this reaction is selected from chloro solvents, alcohol solvents, polar solvents, hydrocarbon solvents, nitrile solvents, ether solvents, ester solvents, polar-aprotic solvents and preferably using isopropanol; more preferably using toluene.
The reaction temperature may range from 40-60°C and preferably at a temperature in the range from 50-55°C. The duration of the reaction may range from 18 to 24 hours, preferably for a period of 20 hours.
The suitable reducing agent is selected from metal borohydrides like sodium borohydride, lithium borohydride, sodium cyanoborohydride and diborane, preferably using sodium borohydride.
The suitable amino protecting group is selected from group consisting of aralkyl, acyl, lower alkoxycarbonyl, aralkyloxycarbonyl, lower alkanesulfonyl, alkoxy benzyl, aryl sulfonyl, tri-(loweralkyl)silyl or triphosgene; preferably methoxy benzyl.

The suitable O-protecting group is selected from the group comprising of acetyl, benzoyl, halobenzoyl, methoxy methyl, pivaloyl, chloroacetyl, benzyl, halobenzyl, trityl, benzyloxy, o,m,p-methoxy benzoyl, alkoxy benzoyl, alkoxy benzyl, trichloroacetyl, trifluoroacetyl, 2,4-dinitrophenyl, methane sulfonyl or para-toluene sulfonyl, preferably methane sulfonyl.

In step-3, the compound obtained in step-2 was reduced by using suitable catalyst in a solvent to provide compound of formula-VII. The suitable solvent is selected from alcohol solvents or ester solvents; preferably using alcohol solvents, more preferably using methanol.

The suitable catalyst is selected from Palladium, Raney nickel, Platinum oxide, Ruthenium or Rhodium; preferably using palladium on charcoal.

In step-4, compound of formula-VII was deprotected in presence of a suitable deprotecting agents to give highly pure Brivaracetam.
The suitable deprotecting agents is preferably using ceric ammonium nitrate.

Scheme-II illustrates the process for the preparation of Brivaracetam compound of formula-I.
Scheme-II

In step-1, compound of formula-II is reacted with glyoxylic acid in presence of morpholine in a suitable solvent, followed by heating to give compound of formula-III. The suitable solvent used in this reaction is n-heptane. The reaction temperature is ranging from 30-50°C and preferably at a temperature in the range from 40-45°C. The duration of the reaction may range from 18 to 24 hours, preferably for a period of 20 hours.

In step-2, compound of formula-III is reacted with compound of formula-VIII in a suitable solvent followed by reduction with a suitable reducing agent in the presence of acetic acid, heating the resulting reaction mixture to obtain compound of formula-X.

The suitable solvent used in this reaction is selected from chloro solvents, alcohol solvents, polar solvents, hydrocarbon solvents, nitrile solvents, ether solvents, ester solvents or polar-aprotic solvents and preferably using isopropanol; more preferably using toluene.
The reaction temperature may range from 40-60°C and preferably at a temperature in the range from 50-55°C. The duration of the reaction may range from 18 to 24 hours, preferably for a period of 20 hours.

The suitable reducing agent is selected from metal borohydrides like sodium borohydride, lithium borohydride, sodium cyanoborohydride and diborane, preferably using sodium borohydride.

In step-3, the compound obtained in step-2 was reduced by using a suitable catalyst in a solvent to provide compound of formula-XI. The suitable solvent is selected from alcohol solvents or ester solvents; preferably using alcohol solvents, more preferably using methanol.

The suitable catalyst is selected from Palladium, Raney nickel, platinum oxide, Ruthenium and rhodium; preferably using palladium on charcoal.

In step-4, compound of formula-XI was deprotected in presence of a suitable deprotecting agents to give highly pure Brivaracetam.

Scheme-III illustrates the process for the preparation of Brivaracetam compound of formula-I.

Scheme-III

In step-1, compound of formula-II is reacted with glyoxylic acid in the presence of morpholine in a suitable solvent, followed by heating to give compound of formula-III. The suitable solvent used in this reaction is n-heptane. The reaction temperature is ranging from 30-50°C and preferably at a temperature in the range from 40-45°C. The duration of the reaction may range from 18 to 24 hours, preferably for a period of 20 hours.

In step-2, compound of formula-III is reacted with compound of formula-XII in a suitable solvent followed by reduction with a suitable reducing agent, acetic acid was added to the resulting reaction mixture and heating the reaction mixture to obtain compound of formula-XIV.

The suitable solvent used in this reaction is selected from chloro solvents, alcohol solvents, polar solvents, hydrocarbon solvents, nitrile solvents, ether solvents, ester solvents or polar-aprotic solvents and preferably using isopropanol; more preferably using toluene.

The reaction temperature may range from 40-60°C and preferably at a temperature in the range from 50-55°C. The duration of the reaction may range from 18 to 24 hours, preferably for a period of 20 hours.

The suitable reducing agent is selected from metal borohydrides like sodium borohydride, lithium borohydride, sodium cyanoborohydride and diborane, preferably using sodium borohydride.
In step-3, the compound obtained in step-2 was reacted with methane sulfonyl chloride in presence of a base in a suitable solvent to provide compound of formula-XV.

The base employed in this reaction can be selected from organic base wherein the organic base is selected from the group comprising of isopropyl amine, diisopropyl amine, diisopropyl ethyl-amine, N-methyl morpholine, N-methyl piperidine, N-methyl piperazine, N-methyl pyridine or triethylamine. Preferably triethylamine.

The suitable solvent used in this reaction is selected from chloro solvents, alcohol solvents, polar solvents, hydrocarbon solvents, nitrile solvents, ether solvents, ester solvents or polar-aprotic solvents and preferably using chlorinated solvent; more preferably using dichloromethane.

In step-4, the compound obtained in step-3 was reduced by using a suitable catalyst in a solvent to provide highly pure Brivaracetam compound of formula-I. The suitable solvent is selected from alcohol solvents or ester solvents; preferably using alcohol solvents, more preferably using methanol.

The suitable catalyst is selected from Palladium, Raney nickel, Platinum oxide, Ruthenium or Rhodium; preferably using palladium on charcoal.

Scheme-IV illustrates the process for the preparation of Brivaracetam compound of formula-I.

Scheme-IV

In step-1, compound of formula-II is reacted with glyoxylic acid in the presence of morpholine in a suitable solvent, followed by heating to give compound of formula-III. The suitable solvent used in this reaction is n-heptane. The reaction temperature is ranging from 30-50°C and preferably at a temperature in the range from 40-45°C. The duration of the reaction may range from 18 to 24 hours, preferably for a period of 20 hours.

In step-2, compound of formula-III is reacted with compound of formula-XVI in a suitable solvent followed by reduction with a suitable reducing agent, acetic acid was added to the resulting reaction mixture and heating the reaction mixture to obtain compound of formula-XVII.

The suitable solvent used in this reaction is selected from chloro solvents, alcohol solvents, polar solvents, hydrocarbon solvents, nitrile solvents, ether solvents, ester solvents or polar-aprotic solvents and preferably using isopropanol; more preferably using toluene.

The reaction temperature may range from 40-60°C and preferably at a temperature in the range from 50-55°C. The duration of the reaction may range from 18 to 24 hours, preferably for a period of 20 hours.

The suitable reducing agent is selected from metal borohydrides like sodium borohydride, lithium borohydride, sodium cyanoborohydride and diborane, preferably using sodium borohydride.

In step-3, the compound obtained in step-2 was reduced by using a suitable catalyst in a solvent to provide highly pure Brivaracetam compound of formula-I. The suitable solvent is selected from alcohol solvents or ester solvents; preferably using alcohol solvents, more preferably using methanol.

The suitable catalyst is selected from Palladium, Raney nickel, Platinum oxide, Ruthenium or Rhodium; preferably using palladium on charcoal.

In another preferred embodiment, the present invention provides a process for the preparation of compound of formula-XIX.

Scheme-V illustrates the process for the preparation of compound of formula-XIX.

Scheme-V

In step-1, L-2-Amino butyric acid is reacted with di tert-butyl dicarbonate in a solvent and maintained at a suitable temperature to provide compound of formula-XX.

The suitable temperature is ranging from 20-40°C. Preferably ranging from 25-30°C.
Solvent used in this reaction is selected from alcoholic solvent or ester solvent; preferably methanol.

In step-2, compound of formula-XX is reacted with ethyl chloroformate in the presence of a base like N-methyl morpholine followed by reacting with para-methoxy benzyl amine and heating the resulted reaction mixture to suitable temperature to give compound of formula-XIX.

Solvent used in this reaction is selected from ether solvent or ester solvent preferably tetrahydrofuran.
The reaction temperature is ranging from 30-70°C and preferably at a temperature in the range from 55-60°C. The duration of the reaction may range from 10 to 18 hours, preferably for a period of 12 hours.

EXPERIMENTAL PORTION
The details of the invention are given in the examples provided below, which are given to illustrate the invention only and therefore should not be construed to limit the scope of the invention.

Example-1: Process for the preparation of (2S)-2-amino-N-(4-methoxybenzyl) butanamide hydrochloride:
Stage-1: Synthesis of 2-[(tert-butoxy carbonyl)amino]butanoic acid
L-2-Aminobutyric acid was suspended in a mixture of 1M sodium hydroxide solution, methanol and di tert-butyl dicarbonate at 0-5°C. The temperature of the resulting reaction mixture was raised to 25-30°C and stirred for 12 hours. Volatiles were removed under reduced pressure and the obtained crude was acidified using 1M hydrochloric acid and extracted with ethyl acetate. Both the aqueous and organic layers were separated, organic layer was washed with brine solution. Volatiles were removed from the organic layer under reduced pressure to get the title compound. (85 % of yield).

Stage-2: Synthesis of tert-butyl {1-[(4-methoxybenzyl)carbamoyl]propyl}carbamate
Compound obtained in stage-1 was suspended in dry tetrahydrofuran at 10-15°C, followed by the addition of N-methyl morpholine and ethyl chloroformate. The resulting reaction mixture was stirred for 2 hours at 10-15°C. Para methoxy benzylamine solution was added dropwise to the resulting reaction mixture over a period of 30 minutes and stirred for 12 hours. Volatiles were removed under reduced pressure, water was added to the obtained residue. Filtered the resulting reaction mixture and washed with water, slurred with isopropyl ether to get the title compound. (75% of yield).

Stage-3: Synthesis of (2S)-2-amino-N-(4-methoxybenzyl) butanamide hydrochloride
Compound obtained in stage-2 was dissolved in methanol, followed by the addition of 15 % methanolic hydrochloric acid solution. The resulting reaction mixture was stirred for 10 hours at 25-30°C. Volatiles were removed under reduced pressure, ethyl acetate was added to the obtained residue. Filtered the precipitated solid and dried to get the title compound. (90 % of yield)

Example-2: Process for the preparation of (2S)-2-aminobut-3-enamide
Stage-1: Synthesis of methyl 2-aminobut-3-enoate
Thionyl chloride was added drop wise to a mixture of vinyl glycine and methanol at 10-15°C and stirred for 1 hour at the same temperature. Raised the temperature of the resulting reaction mixture to 25-30°C and stirred for 18 hours, volatiles were removed under reduced pressure to get the title compound. (90 % of yield)

Stage-2: Synthesis of (2S)-2-aminobut-3-enamide
Compound obtained in stage-1 was suspended in isopropanol and transferred to autoclave. The resulting reaction mixture was purged with ammonia gas. After consumption of starting material, carefully ventilate the ammonia gas, filtered the reaction mixture and volatiles were partially removed from the obtained filtrate under reduced pressure. Isopropanolic hydrochloride solution was added to the obtained crude, stirred for 10 minutes and filtered the precipitated solid. (90 % of Yield).

Example-3: Preparation of (2S)-2-amino-4-hydroxybutanamide
Stage-1: Synthesis of methyl 2-amino-4-hydroxybutanoate
L-homoserine was suspended in methanol, followed by addition of thionyl chloride drop wise at 10-15°C and stirred for 1 hour. Raised the temperature of resulting reaction mixture to 25-30°C and stirred for 18 hours, volatiles were removed under reduced pressure to get the title compound. (90 % of yield)

Stage-2: Synthesis of (2S)-2-amino-4-hydroxybutanamide
Compound obtained in stage-1 was suspended in isopropanol and transferred to autoclave. The resulting reaction mixture was purged with ammonia gas. After consumption of starting material, carefully ventilate the ammonia gas, filtered the reaction mixture and volatiles were partially removed from the obtained filtrate under reduced pressure. Isopropanolic hydrochloride solution was added to the obtained crude, stirred for 10 minutes and filtered the precipitated solid. (90 % of Yield).

Example-4: Process for the preparation of Brivaracetam.
Stage-1: Synthesis of 5-Hydroxy-4-propylfuran-2-one compound of formula-III
Glyoxylic acid was added to the mixture of morpholine and n-heptane, reaction mixture was stirred thoroughly at 0-5°C for 2 hrs and valeraldehyde was added to it. The resulting reaction mixture was heated to 40-50°C for 20 hrs, after consumption of starting material, reaction mixture was cooled to 0-5°C, concentrated hydrochloric acid was added and stirred for 2 hrs. The resulting reaction mixture was washed with n-heptane. Both aqueous and organic layers were separated, aqueous layer was extracted with methyl-tert-butyl ether. Combined the organic layers and volatiles were removed under reduced pressure to get the title compound. (70 % of yield).

Stage-2: Synthesis of compound of formula-X
5-Hydroxy-4-propylfuran-2-one was slowly added to (2S)-2-amino-N-(4-methoxybenzyl)butanamide in isopropanol at 0-5°C. The resulting reaction mixture was stirred for 18 hours at 25-30°C. Volatiles were removed under reduced pressure followed by co-distilled with toluene. Obtained crude was suspended in toluene and aqueous sodium hydroxide solution was added to it at 10-15°C. Aqueous sodium borohydride solution was slowly added to the resulting reaction mixture, stirred for 2 hours at 10-15°C. Acetic acid was added to the reaction mixture, heated to 50-55°C and stirred for 3hours at the same temperature. Cooled the reaction mixture to 25-30°C and aqueous sodium hydroxide solution was slowly added to it. Both the aqueous and organic layers were separated and aqueous layer was extracted with ethyl acetate. Combined the organic layers and volatiles were removed under reduced pressure and the resulting crude was purified by column chromatography [Ethyl acetate: hexane (1:3) to get the title compound (50 % of yield).

Stage-3: Synthesis of compound of formula-XI
The compound obtained in stage-2 was dissolved in methanol followed by addition of palladium on activated charcoal. The resulting reaction mixture was transferred to autoclave vessel. Autoclave was purged with 2 kg/cm3 of hydrogen gas and stirred for 10 hours at 25-30°C. After consumption of starting material, carefully ventilate the hydrogen gas. The resulting reaction mixture was filtered through celite bed to remove the catalyst and washed with methanol. Volatiles were removed from the obtained filtrate to get the title compound (90 % of yield).

Stage-4: Synthesis of Brivaracetam compound of formula-I
Compound of formula-XI was suspended in a mixture of acetonitrile and water. Ceric ammonium nitrate was slowly added lot-wise to the resulting reaction mixture at 0°C and stirred for 30 minutes. After consumption of starting material, ethyl acetate and aqueous sodium bicarbonate solution were added to the reaction mixture, stirred for 30 minutes at 25-30°C. Both the organic and aqueous layers were separated and aqueous layer was washed with ethyl acetate. Combined the organic layers and volatiles were removed under reduced pressure. The obtained crude compound was purified by column chromatography.

Example-5: Process for the preparation of Brivaracetam.
Stage-1: Synthesis of compound of formula-XIV
5-Hydroxy-4-propylfuran-2-one was slowly added to (2S)-2-amino-4-hydroxybutanamide in isopropanol at 0-5°C. The resulting reaction mixture was stirred for 18 hours at 25-30°C. Volatiles were removed under reduced pressure followed by co-distilled with toluene. Obtained crude was suspended in toluene and aqueous sodium hydroxide solution was added to it at 10-15°C. Aqueous sodium borohydride solution was slowly added to the resulting reaction mixture, stirred for 2 hours at 10-15°C. Acetic acid was added to the reaction mixture, heated to 50-55°C and stirred for 3 hours at the same temperature. Cooled the reaction mixture to 25-30°C and aqueous sodium hydroxide solution was slowly added to it. Both the aqueous and organic layers were separated and aqueous layer was extracted with ethyl acetate. Combined the organic layers and volatiles were removed under reduced pressure and the resulting crude was purified by column chromatography [Ethyl acetate: hexane (1:3) to get the title compound (50 % of yield).

Stage-2: Synthesis of compound f formula-XV
Methane sulfonyl chloride was added to the mixture of compound of formula-XIV, triethylamine, dimethyl aminopyridine and dichloromethane at 25-30°C and stirred for 2 hours at the same temperature. After consumption of starting material, water and hydrochloric acid were added to the resulting reaction mixture. Both the organic and aqueous layers were separated. Volatiles were removed from the organic layer under reduced pressure to get the title compound. (80 % of yield).

Stage-3: Synthesis of Brivaracetam compound of formula-I
The compound obtained in stage-2 was dissolved in methanol followed by addition of palladium on activated charcoal. The resulting reaction mixture was transferred to autoclave vessel. Autoclave was purged with 2 kg/cm3 of hydrogen gas and stirred for 10 hours at 25-30°C. After consumption of starting material, carefully ventilate the hydrogen gas. The resulting reaction mixture was filtered through celite bed to remove the catalyst and washed with methanol. Volatiles were removed from the obtained filtrate to get the title compound (90 % of yield).

Example-6: Process for the preparation of Brivaracetam.
Stage-1: Synthesis of compound of formula-XVIII
5-Hydroxy-4-propylfuran-2-one was slowly added to (2S)-2-aminobut-3-enamide in isopropanol at 0-5°C. The resulting reaction mixture was stirred for 18 hours at 25-30°C. Volatiles were removed under reduced pressure followed by co-distilled with toluene. Obtained crude was suspended in toluene and aqueous sodium hydroxide solution was added to it at 10-15°C. Aqueous sodium borohydride solution was slowly added to the resulting reaction mixture, stirred for 2 hours at 10-15°C. Acetic acid was added to the reaction mixture, heated to 50-55°C and stirred for 3 hours at the same temperature. Cooled the reaction mixture to 25-30°C and aqueous sodium hydroxide solution was slowly added to it. Both the aqueous and organic layers were separated and aqueous layer was extracted with ethyl acetate. Combined the organic layers and volatiles were removed under reduced pressure and the resulting crude was purified by column chromatography [Ethyl acetate: hexane (1:3) to get the title compound (50 % of yield).
Stage-2: Synthesis of Brivaracetam compound of formula-I
The compound obtained in stage-2 was dissolved in methanol followed by addition of palladium on activated charcoal. The resulting reaction mixture was transferred to autoclave vessel. Autoclave was purged with 2 kg/cm3 of hydrogen gas and stirred for 10 hours at 25-30°C. After consumption of starting material, carefully ventilate the hydrogen gas. The resulting reaction mixture was filtered through celite bed to remove the catalyst and washed with methanol. Volatiles were removed from the obtained filtrate to get the title compound (90 % of yield).
,CLAIMS:
1. A process for the preparation of Brivaracetam of formula-I.

which comprises:
a) reaction of compound of formula-II

with glyoxylic acid in the presence of morpholine to give compound of formula-III;

b) condensation of compound of formula-III with amide derivative of formula-IV

to give compound of formula-V;

c) reduction of compound of formula-V with a suitable reducing agent to give compound of formula-VI;

d) reaction of compound of formula-VI with methane sulfonyl chloride wherein R2 is C2H5OH in the presence of base to give compound of formula-XVa;

e) reduction of compound of formula-VI or compound of formula-XVa using a suitable catalyst to give compound of formula-VII; and

f) optionally deprotecting compound of formula-VII using deprotecting agent to provide Brivaracetam of formula-I.

2. Intermediate compounds having the following structural formulae: