CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority from International application No.
PCT/IN2011/000504 filed on 01 August 2011, the contents of which are incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to processes for the preparation of 4-{4-[5(S)-(aminomethyl)-2-oxo-l,3-oxazolidin-3-yl]phenyl}morpholin-3-one of formula (II) a key intermediate in the synthesis of rivaroxaban (I).

The intermediate compound of formula II is represented by

BACKGROUND OF THE INVENTION

Rivaroxaban is a novel anticoagulant used for the prevention of venous thromboembolism in adult patients undergoing elective hip or knee replacement surgery and is approved in US and Europe. Rivaroxaban is structurally related to the antibacterial compound Linezolid (Zyvox) is enantiomerically pure. Rivaroxaban is available in the market under the brand name Xarelto® as 10 mg tablets in Europe. Rivaroxaban is chemically described as 5-chloro-N-( {(5 S)-2-oxo-3 - [4-(3 -oxo-4-morpholiny l)phenyl]-1,3 -oxazolidin-5 -yl} methyl)-2-thiophene-carboxamide (herein after referred as rivaroxaban) and is represented by the structural formula I shown below:

U.S. Patent No. US 7,585,860 describes morpholinyl oxazolidinone thiophene carboxamides including rivaroxaban or pharmaceutically acceptable acid addition salts thereof, a pharmaceutical composition and a method of treatment.

The US'860 patent also discloses a process for the preparation of rivaroxaban which is illustrated by scheme below:

U.S. Publication application US2007/0149522A1 and Drugs of the future 2006, 31(6), 484-493 discloses a process for the preparation of rivaroxaban which is illustrated by scheme below:

U.S. Patent No. US 7,816,355 Bl describes a process for the preparation of rivaroxaban which is illustrated by below scheme:

The process disclosed in the patent US'860 patent exhibits various disadvantages in the reaction management which has particularly unfavourable effects for preparation of the compound of the formula (I) on the industrial scale.

The alternate process disclosed in the U.S. Publication application US '522A1 involves the usage of toxic solvents and reagents. This is disadvantageous per se, and in addition these toxic substances must be removed from the final product (I) until below the maximum limit permissible in each case and may require additional process steps which make the process expensive.

The reported processes aforementioned involves hazardous and expensive reagents like haloformates and bromine derivatives, has more scope for the formation of impurities, intricate to handle on commercial scale, requires additional purification steps thus ending up with low yields and purities of the final product thus rendering the process not amenable on commercial scale.

Keeping the importance of the compound rivaroxaban , there is a need to provide an improved process for the preparation of rivaroxaban, which avoids the use of potentially
hazardous, expensive chemicals, the formation of isomeric and other process related impurities, while affording the desired product rivaroxaban in high yield and purity.

The reaction steps of the present invention involving the conversion of compound of formula V to the compound of formula IV followed by conversion of thus obtained compound of formula IV to the compound of formula III of the present invention have not been reported in the literature.

The processes of the present invention are simple, eco-friendly, cost-effective, reproducible, robust and are well amenable on industrial scale.

SUMMARY OF THE INVENTION

The present invention relates to processes for the preparation of 4-{4-[5(S)-(aminomethyl)-2-oxo-l,3-oxazolidin-3-yl]phenyl}morpholin-3-one of formula (II) a key intermediate in the synthesis of rivaroxaban (I).

In one aspect, the present invention relates to a process for the preparation of compound 4-{4-[5(S)-(aminomethyl)-2-oxo-l ,3-oxazolidin-3-yl]phenyl}morpholin-3-one of formula (II) a key intermediate in the synthesis of rivaroxaban (I), comprising:

a) reacting a compound 4-(4-morpholin-3-onyl)aniline of formula (VII) or a salt thereof
with a compound R-epichlorohydrin of formula (VI) to give the compound 4-[4-(3-chloro-2(R)-hydroxy-propyl amino)-phenyl]-morpholin-3-one of formula (V),

b) cyclization of the compound of formula (V) or a salt thereof using a suitable reagent to give the compound 4-[4-(5(R)- chloromethyl-2-oxo-oxazolidin-3-yl)-phenyl]-morpholin-3-one of formula (IV)

c) reacting the compound of formula (IV) with a suitable reagent to give the
compound 2- { 2-Oxo-3 - [4-(3 -oxo-morpholin-4-y 1) phenyl] -oxazolidin-5 (S)-
ylmethyl}-isoindole-l,3-dione of formula (III)

d) reacting the compound of formula (III) with a suitable reagent to give the compound of formula (II).
In another aspect, the present invention relates to a process for the preparation of 2-{2-oxo-3-[4-(3-oxo-morpholin-4-yl)-phenyl]-oxazolidin-5(S)-ylmethyl}-isoindole-l,3-dione compound of formula (III) comprising:

a) reacting the compound 4-[4-(3-Chloro-2(R)-hydroxy-propyl amino)-phenyl]-morpholin-3-one of formula (V) or a salt thereof, with a suitable phthalimide derivative to give the 2-((2R)-2-hydroxy)-3-{[4-(3-oxo-4-morpholinyl)-phenyl]amino}-propyl)-lH-isoindole-l,3-(2H)-dione of formula (VIII)

b) cyclization of compound of formula (VIII) or a salt thereof using suitable reagent gives the compound of formula (III).

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1: is a schematic representation of the processes of present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to processes for the preparation of 4-{4-[5(S)-(aminomethyl)-2-oxo-l,3-oxazolidin-3-yl]phenyl}morpholin-3-one of formula (II) a key intermediate in the synthesis of rivaroxaban (I).

In one embodiment, the present invention provides a process for the preparation of
compound 4- {4- [5 (S)-(aminomethyl)-2-oxo-1,3 -oxazolidin-3 -y l]pheny 1} morpholin-3 -one of formula (II) a key intermediate in the synthesis of rivaroxaban (I), comprising:

a) reacting a compound 4-(4-morpholin-3-onyl)aniline of formula (VII) or a salt thereof
with a compound R-epichlorohydrin of formula (VI) (VI) to give the compound 4-[4-(3-chloro-2(R)-hydroxy-propyl amino)-phenyl]-morpholin-3-one of formula (V),

b) cyclization of the compound of formula (V) or a salt thereof by using a suitable reagent to give the compound 4-[4-(5(R)- chloromethyl-2-oxo-oxazolidin-3-yl)-phenyl]-morpholin-3-one of formula (IV)

c) reacting the compound of formula (IV) with a suitable reagent to give the
compound 2-{2-Oxo-3-[4-(3-oxo-morpholin-4-yl)phenyl]-oxazolidin-5(R)-
ylmethyl}-isoindole-l,3-dione of formula (III)

d) reacting the compound of formula (III) with a suitable reagent to gives the compound of formula (II).

The reaction of step (a) may optionally be carried out in absence of organic solvents. Preferably, the reaction step a) is performed in the presence of organic solvents.

Any solvent, which is neutral towards the reactants are suitable.

The organic solvents that can be used include alcohols such as methanol, ethanol, t-amyl alcohol, t-butyl alcohol and Isopropyl alcohol and the like or aqueous mixtures; cyclic ethers such as tetrahydrofuran and the like; aprotic polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, acetonitrile and the like; or mixture thereof. Preferably methanol.

The molar equivalents of compound of formula VI being used can be from about 0.5 to 7.5moles to the compound of formula VII taken, preferably one mole is being used.

The reaction can be carried out at a temperature range from about 30°C to about 100°C or the boiling point of the solvent(s) used, preferably at boiling point of the solvent (s) used.

The time required for the reaction to complete may also vary widely, depending on various factors, notably the reaction temperature, the nature of the reagent and the solvents employed. However, the reaction is effected under the preferred conditions discussed above, a period of from about 1 hour to about 24 hours, preferably from about 5 hour to 16 hours.

The reaction of step (b) is performed using any carbonylating reagent commonly known for such purposes. The carbonylating reagent that can be used include but not limited to carbonyldiimidazole, phosgene, Triphosgene, methyl chloroformate, benzyl chloroformate and phenylchloroformate and the like; carbonyldiimidazole is being preferred.

The molar equivalents of carbonylating reagents being used can be from about 1 to 5 moles to the compound of formula V taken, preferably one mole is being used.

The organic solvents that can be used include but are not limited to halogenated solvents such as dichloromethane, ethylene dichloride, chloroform and the like; esters such as ethyl acetate, isopropyl acetate and the like; hydrocarbon solvents such as n-hexane, cyclohexane, toluene, xylene and the like; ether such as tetrahydrofuran (THF), 1,4-dioxane and the like; aprotic polar solvents such as N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N,N-dimethylacetamide (DMA), N-methyl pyrrolidone (NMP) and the like; or mixture thereof in various proportions. Preferably dichloromethane.

The reaction is performed at a temperature range from about 25°C to about 100°C or the boiling point of the solvent(s) used, preferably from about 25°C to about 50 °C.

The time required for the reaction to complete may also vary widely, depending on several factors, notably the reaction temperature, the nature of the reagent and solvents employed. The reaction is effected under the preferred conditions at time period from about 1 hour to about 24 hours, preferably from about 10 hours to 20 hours.

The reaction step (c) is a reaction of compound of formula (IV) with a suitable reagent which includes but are not limited to derivatives of phthalimide such as sodium phthalimide, potassium phthalimide and the like; potassium phthalimide is being most preferred.

The molar equivalents of the reagent being used can be from about 1 to 5 moles on the compound of formula IV taken, preferably one mole is being used.

Choosing of solvent is not critical, but preferably the organic solvents must dissolve both the compound of formula VI and reagent making the reaction mixture homogenous and should be neutral, the organic solvents that can be used is selected from the group consisting of halogenated solvents such as dichloromethane, ethylene dichloride , chloroform and the like; esters such as ethyl acetate, isopropyl acetate and the like; aprotic polar solvents such as N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N,N-dimethylacetamide (DMA), N-methyl pyrrolidone (NMP) and the like; or mixtures thereof in various proportions. Preferably, N,N-dimethylformamide (DMF) is being used.

The reaction is performed at a temperature range that can be from about 25°C to about 150°C or the boiling point of the solvent(s) used, preferably boiling point of the solvent(s) used.

The time required for the reaction to complete may also vary widely, depending on several factors, for example the reaction temperature, the nature of the reagent and solvents employed. However, the reaction is effected at a time period from about 1 hour to about 20 hours, preferably from about 2 hours to about 10 hours.

The reaction step (d) is reaction of the intermediate compound of formula III with suitable reagent in the presence of solvent(s) include but are not limited to hydrazine hydrate or aqueous methyl amine and the like; preferably hydrazine hydrate or aqueous methyl amine.

The organic solvents that can be used is selected from the group consisting of alcohols such as methanol, ethanol, t-amyl alcohol, t-butyl alcohol and Isopropyl alcohol and the like or their aqueous mixtures; cyclic ethers such as tetrahydrofuran and the like; aprotic polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl pyrrolidone (NMP), acetonitrile and the like; or mixture thereof. Preferably methanol.

The reaction temperature can be in the range of about 25°C to about 150°C or the boiling point of the solvent(s) used, preferably boiling point of the solvent(s) used.

The time period required for the reaction to complete can be range from about 30 minutes to about 5 hours, preferably 1 hour.

In another embodiment, the present invention provides a process for the preparation of 2-{2-oxo-3-[4-(3-oxo-morpholin-4-yl)-phenyl]-oxazolidin-5(S)-ylmethyl}-isoindole-l,3-dione compound of formula (III) comprising:

a) reacting the compound 4-[4-(3-Chloro-2(R)-hydroxy-propyl amino)-phenyl]-morpholin-3-one of formula (V) or a salt thereof, with a suitable phthalimide derivative to give the 2-((2R)-2-hydroxy)-3-[4-(3-oxo-morpholin-4yl)-phenylamino]-propyl} -isoindole-1,3-dione of formula (VIII)

b) cyclization of compound of formula (VIII) or a salt thereof using suitable reagent gives the compound of formula (III).

The reaction step (a) is a reaction of compound of formula (V) with a suitable pthalimide derivative which include but are not limited to potassium phthalimide, sodium phthalimide and the like; Potassium phthalimide is being most preferred.

The molar equivalents of reagent being used can be from about 1 to 5 moles on the compound of formula V taken, preferably one mole is being used.

The organic solvents that can be used is selected from the group consisting of halogenated solvents such as dichloromethane, ethylene dichloride , chloroform and the like; esters such as ethyl acetate, isopropyl acetate and the like; aprotic polar solvents such as N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N,N-dimethylacetamide (DMA), N-methyl pyrrolidone (NMP) and the like; or mixtures thereof in various proportions. Preferably, N,N-dimethylformamide (DMF) is being used.

Suitably the reaction temperature can be in the range from about 25°C to about 150°C or the boiling point of the solvent(s) used, preferably boiling point of the solvent(s) used.

Typically the time required for the reaction to complete may vary depending on factors, like reaction temperature and the nature of the reagent and solvents used. However, the reaction period can be from about 1 hour to about 24 hours, preferably from about 10 hours to 20 hours.

The reaction of step (b) is cyclization of the compound of formula (VIII) can be performed by using any carbonylating reagent commonly known for such purpose. The carbonylating reagent that can be used is selected from the group consisting of carbonyldiimidazole, phosgene, Triphosgene, methyl chloroformate, benzyl chloroformate and phenylchloroformate and the like; carbonyldiimidazole is being more preferred. The molar equivalents of carbonylating reagents being used can be from about 1 to 5 moles on the compound of formula VIII taken, preferably one mole is being used.

The organic solvents that can be employed in step (b) is selected from the group consisting of halogenated solvents such as dichloromethane, ethylene dichloride, chloroform and the like; esters such as ethyl acetate, isopropyl acetate and the like; hydrocarbon solvents such as n-hexane, cyclohexane, toluene, xylene and the like; ether such as tetrahydrofuran (THF), 1,4-dioxane and the like; aprotic polar solvents such as N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N,N-dimethylacetamide (DMA), N-methyl pyrrolidone (NMP) and the like; or mixtures thereof. Preferably dichloromethane.

The reaction is performed at a temperature range from about 25°C to about 100°C or the boiling point of the solvent(s) used, preferably from about 25°C to about 50 °C.

The time period for the reaction to complete may vary depending on factors like the temperature, the nature of the reagent and solvent employed. However, the time period is from about 1 hour to about 20 hours, preferably from about 5 hour to 10 hours.

The stereoisomers, for example, can be synthesized by using optically resolved raw material compounds or using a conventional optical resolution or separation method.

It is apparent to one skilled in the art that one could easily perform the identical process steps with the opposite enantiomeric form or racemic form to obtain the corresponding stereoisomers. Therefore, using the chemistry of the claimed process with any of the enantiomeric forms is considered equivalent to the claimed processes.

Optionally the processes for the preparation of intermediates of present invention can be carried out in one pot.

Compound of formula II is a key intermediate in the synthesis of rivaroxaban which are obtained usually in high yields and purity. These compounds may optionally further purified by recrystallization or making slurry in suitable aprotic polar solvent for example acetone, acetonitrile, ethers and or mixtures thereof or by formation of salts for ex. methansulfonate salt. The Examples included in this document illustrate the results obtained regarding purity and yield of these intermediates.

In one embodiment, the intermediates or their salts used here in the processes of the present invention may exist in either crystalline or amorphous or mixtures thereof.

The processes reported for the preparation of intermediates of rivaroxaban results in various process related impurities and bye products thus leading to include additional several purification steps thus resulting in very poor yields and purities of the final product.

The starting intermediate compounds of (VII) and (VI) are commercially available or known per se to the person skilled in the art or can be prepared by processes reported in the literature. For ex. US 7,585,860 which is herein incorporated for reference.

After completion of the reaction, the desired compounds can be obtained from the reaction mixture by conventional means known in the art.

For example, the working-up of reaction mixtures, especially in order to isolate desired compounds, follows customary procedures, known to the organic chemists skilled in the norms of the art and steps, e.g. selected from the group comprising but not limited to extraction, neutralization, crystallization, chromatography, evaporation, drying, filtration, centrifugation and the like.

Optionally the process steps of present invention can be carried out by one pot synthesis independently.

The reported processes aforementioned involves hazardous and expensive reagents like haloformates and bromine derivatives has more scope for the formation of impurities, difficult to handle on commercial scale and also requires additional purification steps thus ending up with low yields and purities of the final product thus rendering the process not amenable on commercial scale.

The processes of present invention are especially valuable for the following reasons: it makes it possible to obtain the intermediate compounds on an industrial scale in excellent yields, starting from a simple, low-cost starting materials, involve simple process steps and reagents thus making processes more cost effective than reported processes.

Advantageously, the processes of present invention do not involve purification steps thus provides the intermediates of rivaroxaban with higher yields and purities.

Having described the invention with reference to certain preferred embodiments, other
embodiments will become apparent to one skilled in the art from consideration of the
specification. The invention is further defined by reference to the following examples
describing in detail the preparation of the composition and methods of use of the invention. It will be apparent to those skilled in the art that many modifications, both to materials and methods, may be practiced without departing from the scope of the invention.

EXAMPLES

Example 1: Preparation of 4-[4-(3-chloro-2(R)-hydroxypropyl amino)-phenyl]-
morphoIin-3-one (V)

4-(4-Morpholin-3-onyl) aniline (39 g), R-epichlorohydrin (18.5 g) and methanol (200 ml) were charged into a clean and dry 4 neck R.B.flask followed by heating to about reflux for about 16 hours. After completion of the reaction, the solvent was distilled completely to give 57 gms of the title compound.

Example 2: Preparation of 4-[4-(5(R)-chIoromethyI-2-oxo-oxazolidin-3-yl)-phenyl]-morpholin-3-one (IV)

57 gms of 4 -[4-(3-chloro-2-hydroxy-propyl amino)-phenyl]-morpholin-3-one and methylene chloride (600 ml) were charged into a clean and dry 4neck R.B.flask. 32 gms of carbonyl diimidazole was added at about 30 °C and the resultant reaction mixture was stirred for about 20 hours. After completion of the reaction, reaction mixture was washed with water and methylene chloride was distilled completely to give 48 gms of the title compound. Example 3: Preparation of 2-5 (S){2-oxo-3-[4-(3-oxo-morpholin-4-yl)-phenyl]-oxazolidin-5-ylmethyl}-isoindole-l,3-dione(III) 60 gms of 4-[4-(5-chloromethyl-2-oxo-oxazolidin-3-yl)-phenyl]-morpholin-3-one, potassium phthalimide (40 g) and N,N-dimethyl formamide (400 ml) were charged into a clean and dry 4 neck R.B.flask. The resultant reaction mixture was heated to reflux for about 5 hours. After completion of the reaction, the reaction mixture was cooled to about 30°C, poured into 2 L of water and the solid separated was filtered to give 50 gms of the title compound.

Purification of intermediate compound of formula III using DMF and acetone 50g of crude compound of formula III and 125 ml DMF were charged into a clean and
dry 4 neck R.B.flask and heated to about 90°C, the clear solution obtained, carbon (5g) was charged. The reaction suspension was stirred for 5 mins and filtered under hot conditions. The filtrate was cooled to about 30°C, 150 ml of acetone was added and the solid separated was filtered after 30-45 min and washed with acetone(50ml) to afford 42.5g of pure product as half white colored solid. Purification of intermediate compound of formula HI using DMF and Methanol

Dissolve 50g of crude compound in 235 ml DMF at 90-95°C, to the clear solution add carbon (5g), filter after 5 min under hot conditions. Cool the filterate to 25-30°C,add 125 ml of methanol and filter the solid after 30-45 min and wash with methanol (50ml) to yield 40g of pure product of off white colored solid.

Example 4: Preparation of 4-{4-[5(S)-(amino methyI)-2-oxo-l,3-oxazoIidin-3-yl]phenyI}morpholin-3-one (II)

Methanol (240 ml) and Hydrazine hydrate (26 g) were added to a flask containing the (2-{2-Oxo-3-[4-(3-oxo-morpholin-4-yl)-phenyl]-oxazolidin-5-ylmethyl}-isoindole-l,3-dione (40 g), heated for 1 hour at reflux temperature and cooled to room temperature. After completion of the reaction, 500ml of water was added to the reaction mass and was extracted with methylene dichloride (300 ml). The combined extractions were washed with water (100 ml) and the solvent was distilled completely to give 20 gms of the title compound. Example - 5: Preparation of 2-{2(R)-Hydroxy-3-[4-(3-oxo-morphoiin-4-yl)phenyl amino]-propyl}-isoindole-l,3-dione(VIII)

(50 g) 4-[4-(3-Chloro-2-hydroxy-propylamino)-phenyl]-morpholin-3-one, (45 g) of potassium phthalimide and ( 100 ml) N,N-dimethyl formamide (DMF) were charged into a clean and dry 4 neck R.B.flask. The resultan reaction mixture was heated to reflux for about 5 hours After completion of the reaction, the reaction mixture was cooled to about 30 °C and quenched with 2L water and the solid separated was filtered to give 60gms of title compound. Example-6: Preparation of2-5(S)-{2-Oxo-3-[4-(3-oxo-morpholin-4-yl) phenyl]-oxazolidin-5-ylmethyl}-isoindole-l,3-dione(IH) 60 gms of 2-{2-Hydroxy-3-[4-(3-oxo-morpholin-4-yl)phenylamino]-propyl}-isoindole-1,3-dione and 180 ml of methylene chloride were charged into a clean and dry 4 neck R.B.flask. 29 gms of carbonyl diimidazole was added at about 30°C and the resultant reaction mixture was stirred at about 30°C for about 20 hours. After completion of the reaction, the reaction mixture was washed with water and the solvent was distilled completely to give
55gms of the title compound.

Example -7: Preparation of 2-5(S)-{2-Oxo-3-[4-(3-oxo-morpholin-4-yl) phenyl]-oxazolidin-5-ylmethyl}-isoindole-l,3-dione (HI) by one pot process

A mixture of (50 g) 4-[4-(3-Chloro-2-hydroxy-propylamino)-phenyl]-morpholin-3-one and (45 g) isoindole-l,3-dione and (100 ml) N,N-dimethyl formamide (DMF) was heated to reflux temperature for about 5 hours. After completion of the reaction, the reaction mixture was cooled to about 30 °C and quenched with 2L water and the solid separated was filtered to give 60gms of -{2-Hydroxy-3-[4-(3-oxo-morpholin-4-yl)phenylamino]-propyl} -isoindole-1,3-dione crude. To this 180 ml) of methylene dichloride and 29 gms of carbonyl diimidazole was added at about 30°C and the reaction mixture was stirred for about 20 hours. After completion of the reaction, the reaction mixture was washed with water and the solvent was distilled completely to give 55gms of the title compound.
Example -8: Preparation of 4-[4-(5(R)-chloromethyl-2-oxo-oxazolidin-3-yl)-phenyl]-morpholin-3-one (IV) using triphosgene

4 -[4-(3-chloro-2-hydroxy-propyl amino)-phenyl]-morpholin-3-one (57 g) and chloroform (600 ml) were charged into a clean and dry 4 neck R.B.flask. triphosgene(32 g) was added at about 30 °C and the resultant reaction mixture was stirred at about 30°C for about 20 hours. After completion of the reaction, reaction mixture was washed with water and chloroform was distilled completely to give 48 gms of the title compound.

We Claim:

1. A process for the preparation of 4-[4-[5(S)-(aminomethyl)-2-oxo-l ,3-oxazolidin-3-yl]phenyl]morpholin-3-one of formula II:

comprising:

a) reacting 4-(4-morphol in-3 -onyl)aniline of formula VII:

or a salt thereof with R-epichlorohydrin of formula VI:

to produce 4-[4-(3-chloro-2(R)-hydroxy-propylamino)-phenyl]-morpholin-3-one of formula V:

or a salt thereof;

b) cyclization of the compound of formula V or a salt thereof using a suitable reagent to produce 4-[4-(5(R)-chloromethyl-2-oxo-oxazolidin-3-yl)-phenyl]-morpholin-3-one of formula IV:

c) reacting the compound of formula IV with a suitable reagent to produce 2-[2-oxo-3-[4-(3-oxo-morpholin-4-yl)phenyl]-oxazolidin-5(S)-ylmethyl]-isoindole-1,3-dione of
formula HI:

d) reacting the compound of formula III with a suitable reagent to produce the compound of formula II.

2. The process of claim 1, wherein the reaction in step-(a) is carried out in the presence of an organic solvent selected from the group consisting of an alcohol, an ether, a polar aprotic solvent, and mixtures thereof; wherein the reaction in step-(b) is carried out in the presence of an organic solvent selected from the group consisting of a halogenated solvent, an ester, a hydrocarbon, an ether, a polar aprotic solvent, and mixtures thereof; wherein the reaction in step-(c) is carried out in the presence of an organic solvent selected from the group consisting of a halogenated solvent, an ester, a polar aprotic solvent, and mixtures thereof; and wherein the reaction in step-(d) is carried out in the presence of an organic solvent selected from the group consisting of an alcohol, a cyclic ether, a polar aprotic solvent, and mixtures or aqueous mixtures thereof.

3. The process of claim 2, wherein the organic solvent used in step-(a) is selected from the group consisting of methanol, ethanol, t-amyl alcohol, t-butyl alcohol, isopropyl alcohol, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, and mixtures thereof; wherein the organic solvent used in step-(b) is selected from the group consisting of dichloromethane, ethylene dichloride, chloroform, ethyl acetate, isopropyl acetate, toluene, xylene, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, dimethylsulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, and mixtures thereof; wherein the organic solvent used in step-(c) is selected from the group consisting of dichloromethane, ethylene dichloride, chloroform, ethyl acetate, isopropyl acetate, N,N-dimethylformamide, dimethylsulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, and mixtures thereof; and wherein the organic solvent used in step-(d) is selected from the group consisting of methanol, ethanol, t-amyl alcohol, t-butyl alcohol, isopropyl alcohol, tetrahydrofuran, N,N-dimethylformamide, dimethylsulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, and mixtures thereof.

4. The process of claim 1, wherein the suitable reagent used in step-(b) is selected from the group consisting ofcarbonyldiimidazole, phosgene, triphosgene, methyl chloroformate, benzyl chloroformate and phenylchloroformate; wherein the suitable reagent used in step-(c) is a phthalimide derivative; and wherein the suitable reagent used in step-(d) is selected from hydrazine hydrate and aqueous methyl amine.

5. The process of claim 4, wherein the reagent used in step-(b) is carbonyldiimidazole; and wherein the phthalimide derivative used in step-(c) is potassium phthalimide.

6. A process for the preparation of 4-[4-(5(R)-chloromethyl-2-oxo-oxazolidin-3-yl) phenyl]-morpholin-3-one of formula IV:

comprising:

cyclization of 4- [4-(3 -chloro-2(R)-hydroxy-propy lamino)-phenyl] -morpholin-3-one of formula V:

or a salt thereof in the presence of triphosgene in an organic solvent.

7. A process for the preparation of 2-[2-oxo-3-[4-(3-oxo-morpholin-4-yl) phenyl]-oxazolidin-5(S)-ylmethyl]-isoindole-l ,3-dione of formula III:

comprising reacting 4-[4-(5(R)-chloromethyl-2-oxo-oxazolidin-3-yl)-phenyl]-morpholin-3-one of formula IV:

with a phthalimide derivative in the presence of an organic solvent.

8. A process for the preparation of 4-[4-[5(S)-(aminomethyl)-2-oxo-1,3-
oxazolidin-3-yl]phenyl]morpholin-3-one of formula II:

comprising:

reacting 2-[2-oxo-3-[4-(3-oxo-morpholin-4-yl)phenyl]-oxazolidin-5(S)-ylmethyl]-
isoindole-l,3-dione of formula III:

with a suitable reagent in an organic solvent, wherein the reagent is hydrazine hydrate or aqueous methyl amine.

9. A process for the preparation of 2-[2-oxo-3-[4-(3-oxo-morpholin-4-yl)-phenyl]-oxazolidin-5(S)-ylmethyl]-isoindole-l,3-dione of formula III:

comprising:

a) reacting 4-[4-(3-chloro-2(R)-hydroxy-propylamino)-phenyl]-morpholin-3-one of formula V:

or a salt thereof with a phthalimide derivative in the presence of an organic solvent to produce 2-[2(R)-hydroxy-3-[4-(3-oxo-morpholin-4-yl)-phenylamino]-propyl]-isoindole-l,3-dione of formula VIII:

or a salt thereof; and b) cyclization of the compound of formula VIII or a salt thereof using a suitable reagent in the presence of an organic solvent to produce the compound of formula III.

10. The process of claim 9, wherein the phthalimide derivative used in step (a) is potassium phthalimide or sodium phthalimide; wherein the reagent used in step-(b) is selected from the group consisting of carbonyldiimidazole, phosgene, triphosgene, methyl chloroformate, benzyl chloroformate, phenyl chloroformate, and mixtures thereof; and wherein the reaction steps are optionally performed in one pot.

11. The process of claim 9, wherein the organic solvent employed in step-(a) is selected from the group consisting of a halogenated solvent, an ester, a polar aprotic solvent, and mixtures thereof; and wherein the organic solvent employed in step-(b) is selected from the group consisting of a halogenated solvent, an ester, a hydrocarbon, an ether, a polar aprotic solvent, and mixtures thereof.

12. The process of claim 11, wherein the organic solvent employed in step-(a) is selected from the group consisting of dichloromethane, ethylene dichloride, chloroform, ethyl acetate, isopropyl acetate, N,N-dimethylformamide dimethylsulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, and mixtures thereof; and wherein the organic solvent employed in step-(b) is selected from the group consisting of dichloromethane, ethylene dichloride, chloroform, ethyl acetate, isopropyl acetate, toluene, xylene, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide dimethylsulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, and mixturesthereof.