WO2018091979A1

WO2018091979A1 - A process for preparation of quinophthalone derivatives

Info

Publication number: WO2018091979A1
Application number: PCT/IB2017/050275
Authority: WO
Inventors: Shripad Sitaram KHER; Sanjay Manganlal NERKAR; Vishwajit Ramchandra NAMJOSHI; Adwait Bhalchandra GOKHALE
Original assignee: Amogh Chemicals Pvt. Ltd
Priority date: 2016-11-15
Filing date: 2017-01-19
Publication date: 2018-05-24

Abstract

The present disclosure relates to a process for the preparation of qumophthalone derivatives. Qumophthalone derivatives are used as intermediates for many commercially important compounds such as pigments, dyes for synthetic fibers, plastic and ink-jet recording dyes. Some of the quinophthalone derivatives are also used in liquid crystal composition and heat transfer dyes. The present disclosure provides a simple and economical process for the preparation of quinophthalone compound of Formula I with high yield and having high purity. (I)

Description

A PROCESS FOR PREPARATION OF QUINOPHTHALONE DERIVATIVES FIELD

The present disclosure relates to a process for the preparation of quinophthalone derivatives. BACKGROUND Quinophthalone derivatives are used as pigments, dyes for synthetic fibers, plastics and ink- jet recording dyes. Some quinophthalone derivatives are also used in heat sensitive transfer dyes and for liquid crystal compositions.

Conventional processes for the preparation of quinophthalone derivatives are associated with drawbacks such as multiple steps and complex reaction procedures thereby making the process un-economical. Further these processes provide the product with low yield and low purity.

However, the purity of the quinophthalone derivatives directly affects the quality of the synthesized compound such as liquid crystal compositions, heat transfer dyes. Thus, it is important to synthesize quinophthalone derivatives with high purity. There is, therefore, felt a need to provide a simple and an economical process for the preparation of quinophthalone derivatives with high yield and having high purity.

OBJECTS

Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows: An object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.

Another object of the present disclosure is to provide a process for the preparation of quinophthalone derivatives with high yield and high purity.

Another object of the present disclosure is to provide a simple and economical process for the preparation of quinophthalone derivatives. Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY

The present disclosure is related to a process for the preparation of a compound of Formula I:

wherein,

R¹ is selected from the group consisting of hydrogen, Ci-Qo linear or branched alkyl group; and ir 2 and R 3" are independently selected from the group consisting of hydrogen, Ci-Cio linear or branched alkyl group, cycloalkyl group and arylalkyl group.

The process for the preparation of the compound of Formula I comprises the following steps:

A mixture of trimellitic anhydride and at least one first fluid medium is heated at a temperature in the range of 150°C to 200°C to obtain a first mixture. A compound of Formula II is slowly added to the first mixture and heated to obtain a first resultant mixture.

Wherein,

R¹ is selected from the group consisting of hydrogen, Q-Cio linear or branched alkyl group. The first resultant mixture so obtained is cooled and at least one second fluid medium is added under continuous stirring to obtain a slurry comprising a first liquid fraction and a first solid fraction. The first solid fraction is separated from the slurry to obtain a compound of Formula III.

wherein,

R¹ is selected from the group consisting of hydrogen, Q-Cio linear or branched alkyl group.

A mixture of the compound of Formula III and at least one third fluid medium is refluxed, while removing the water as an azeotrope with the third fluid medium to obtain a second mixture. At least one catalyst can be added to the second mixture, followed by slowly adding at least one chlorinating agent to obtain a second resultant mixture.

The second resultant mixture so obtained is cooled and the unreacted chlorinating agent can be removed under vacuum with the third fluid medium. At least one amine is slowly added to the third mixture under continuous stirring to obtain a product mixture. The product mixture is diluted with water and the third fluid medium can be removed as an azeotrope with water. At least one base is slowly added under continuous stirring to obtain a suspension comprising a second liquid fraction and a second solid fraction. The second solid fraction is separated from the suspension to obtain the compound of Formula I.

The compound of Formula I is further purified with at least one fourth fluid medium to obtain the compound of Formula I having purity in the range of 98.5% to 99.5%.

DETAILED DESCRIPTION

Quinophthalone derivatives are used as pigments, dyes for synthetic fibers, plastics and ink- jet recording dyes. Some quinophthalone derivatives are also used in heat sensitive transfer dyes and for liquid crystal compositions. The present disclosure envisages a simple and an economical process for the preparation of quinophthalone derivatives with high yield and having high purity. The present disclosure provides a process for the preparation of a compound of a Formula I:

wherein,

R¹ is selected from the group consisting of hydrogen, Ci-Qo linear or branched alkyl group; and

2 3

R and R are independently selected from the group consisting of hydrogen, Ci-Cio linear or branched alkyl group, cycloalkyl group and arylalkyl group.

The process for the preparation of a compound of Formula I, in accordance with the present disclosure, is represented as Scheme I:

Scheme I: Synthesis of quinophthalone derivatives:

The process disclosed by the present application mainly comprises 2 steps.

1. In the first step, a compound of Formula II and trimellitic anhydride are reacted to form a compound of Formula III.

2. In the second step, the compound of Formula III is reacted with a chlorinating agent, followed by reacting with an amine to obtain the compound of Formula I with purity in the range of 98.5% to 99.5%.

The detailed preparation of the compound of Formula I, in accordance with the present disclosure is described herein below: A mixture of trimellitic anhydride and the first fluid medium is heated at a temperature in the range of 150°C to 200°C to obtain a first mixture. A compound of Formula II is added to the first mixture over a time period in the range of 1 hour to 5 hours. The first mixture is further heated for a time period in the range of 1 hour to 10 hours to obtain a first resultant mixture. In accordance with the embodiments of the present disclosure, the first mixture is refluxed for a time period in the range of 1 hour to 10 hours.

The progress of the reaction is monitored by a thin layer chromatography analysis (TLC). After completion of the reaction, the first resultant mixture is cooled to a temperature in the range of 60°C to 70°C. The cooled first resultant mixture is diluted with a second fluid medium. The diluted first resultant mixture is further cooled to a temperature in the range of 25 °C to 35°C and stirred for a time period in the range of 1 hour to 2 hours to obtain a slurry comprising a first liquid fraction and a first solid fraction containing the compound of Formula III.

The first solid fraction is separated from the slurry to obtain the compound of Formula III. Separating the first solid fraction from the slurry further comprises the following steps:

The first solid fraction is separated from the slurry by filtration, followed by washing with the second fluid medium. The washed solid fraction is then dried under vacuum at a temperature in the range of 50°C to 60°C to obtain the compound of Formula III.

In accordance with the embodiments of the present disclosure, the compound of Formula III obtained after washing with the second fluid medium has purity in the range of 98% to 99.9%. No further purification is required and the compound of Formula III is directly taken to the next step.

A mixture of the compound of Formula III and a third fluid medium is refluxed and the water is removed from the mixture as an azeotrope with the third fluid medium to obtain a second mixture.

In accordance with the embodiments of the present disclosure, the water is removed by azeotropic distillation method.

After complete removal of water, the second mixture is cooled to a temperature in the range of 60°C to 75 °C and a chlorinating agent is added over a time period in the range of 1 hour to 5 hours. The resultant mixture is further heated for a time period in the range of 1 hour to 10 hours to obtain a second resultant mixture.

In accordance with the embodiments of the present disclosure, a catalyst such as di- methylformamide can be added to the second mixture before the addition of the chlorinating agent. The catalyst promotes the acid chloride formation, thereby increasing the yield of the reaction.

In accordance with the embodiments of the present disclosure, the chlorinating agent is slowly added to the second mixture so as to maintain the temperature of the reaction mixture in the range of 60°C to 75 °C. High reaction temperature may lead to side product formation, thereby resulting in low yield of the reaction.

After completion of the reaction (monitored by TLC), the unreacted chlorinating agent is removed under vacuum along with the third fluid medium, while maintaining the temperature below 75°C. The second resultant mixture is then cooled to a temperature in the range of 30°C to 40°C and the amine compound is added to the third mixture, followed by stirring for a time period in the range of 1 hour to 5 hours to obtain a product mixture.

In accordance with the embodiments of the present disclosure, the addition of amine to the third mixture is an exothermic reaction. After addition of the amine, the temperature of the third mixture is increased to 60°C to 70°C. Stirring of the reaction is continued at elevated temperature for a time period in the range of 1 hour to 5 hours to obtain the product mixture. The product mixture is diluted with water. The third fluid medium present in the product mixture is distilled out as an azeotrope with water. The resultant product mixture is then cooled to a temperature in the range of 50°C to 60°C. A base is added under continuous stirring to adjust the pH of the product mixture in the range of 10-11. The basic product mixture is further cooled to a temperature in the range of 25°C to 30°C to obtain a suspension comprising a second liquid fraction and a second solid fraction containing the compound of Formula I.

The second solid fraction is separated from the suspension to obtain the compound of Formula I. The second solid fraction is separated from the suspension by filtration, followed by washing with water. The washed second solid fraction is then dried under vacuum at a temperature in the range of 60°C to 80°C to obtain a compound of Formula I. The compound of Formula I is further purified by crystallization with the help of a fourth fluid medium to obtain the compound of Formula I having purity in the range of 98.5% to 99.5%. Crystallization of the compound of Formula I comprises the following sub-steps:

A reactor is charged with the compound of Formula I and the fourth fluid medium and refluxed for a time period in the range of 1 hour to 2 hours. The hot solution of the compound of Formula I in the fourth fluid medium is filtered to obtain a first filtrate. The first filtrate is charged in a reactor along with charcoal. The mixture of the first filtrate and charcoal is refluxed for a time period in the range of 30 minutes to 60 minutes, followed by filtration to obtain a second filtrate. The second filtrate is cooled to a temperature in the range of 20°C to 25 °C and stirred for a time period in the range of 1 hour to 2 hours to obtain a second suspension comprising a third liquid fraction and a third solid fraction consisting of the compound of Formula I. The third solid fraction is separated by filtration. The separated third solid fraction is washed with the fourth fluid medium. The washed third solid fraction is then dried under vacuum at a temperature in the range of 60°C to 80°C to obtain the compound of Formula I having purity in the range of 98.5% to 99.5%.

In accordance with the embodiments of the present disclosure, the first fluid medium is at least one selected from the group consisting of N-methylpyrrolidone, dimethylformamide, dimethylsulfoxide and di-methylacetamide. In an exemplary embodiment of the present disclosure, the first fluid medium is N-methylpyrrolidone. In accordance with the embodiments of the present disclosure, the second fluid medium is at least one selected from the group consisting of methanol, ethanol, and iso-propanol. In an exemplary embodiment of the present disclosure, the second fluid medium is methanol.

In accordance with the embodiments of the present disclosure, the chlorinating agent is at least one selected from the group consisting of thionyl chloride and oxalyl chloride. In an exemplary embodiment of the present disclosure, the chlorinating agent is thionyl chloride.

In accordance with the embodiments of the present disclosure, the third fluid medium is at least one selected from the group consisting of benzene, chlorobenzene, di-chlorobenzene and toluene. In an exemplary embodiment of the present disclosure, the third fluid medium is mono-chlorobenzene. In accordance with the embodiments of the present disclosure, the amine is at least one selected from the group consisting of primary amine, and secondary amine. In accordance with the embodiments of the present disclosure, the amine is at least one selected from the group consisting of propylamine, iso-propylamine, butylamine, di- propylamine, di-iso-propylamine, di-butylamine, di-(2-ethylhexylamine), 3- ethoxypropylamine, 3-methoxypropylamine, N-ethylaniline, N-ethylcyclohexyl amine and di-tertiary-butylamine. In an exemplary embodiment of the present disclosure, the amine is di-butylamine.

In accordance with the embodiments of the present disclosure, the base is at least one selected from the group consisting of sodium hydroxide and potassium hydroxide. In an exemplary embodiment of the present disclosure, the base is sodium hydroxide. In accordance with the embodiments of the present disclosure, the base is added as 25% aqueous solution.

In accordance with the embodiments of the present disclosure, the fourth fluid medium is at least one selected from the group consisting of ethanol, iso-propanol, ethyl acetate and acetonitrile. In an exemplary embodiment of the present disclosure, the fourth fluid medium is iso-propanol. In accordance with the embodiments of the present disclosure, the mole ratio of the compound of Formula II and trimellitic anhydride is in the range of 1 :1 to 1 :3. In an exemplary embodiment of the present disclosure, the mole ratio of the compound of Formula

II and trimellitic anhydride is 1.86.

In accordance with the embodiments of the present disclosure, the mole ratio of the compound of Formula III and the catalyst is in the range of 1 :0.05 to 1 :0.5. In an exemplary embodiment of the present disclosure, the mole ratio of the compound of Formula III and the catalyst is 0.15.

In accordance with the embodiments of the present disclosure, the mole ratio of the compound of Formula III and the chlorinating agent is in the range of 1 : 1 to 1 :3. In an exemplary embodiment of the present disclosure, the mole ratio of the compound of Formula

III and the chlorinating agent is 2.01.

In accordance with the embodiments of the present disclosure, the mole ratio of the compound of Formula III and the amine is in the range of 1 : 1 to 1 :5. In an exemplary embodiment of the present disclosure, the mole ratio of the compound of Formula III and the amine is 2.54. The process of the present disclosure is simple and employs inexpensive and readily available reagents. Thus, the process of the present application is economical. The intermediate compound of Formula III is synthesized with high purity and therefore is directly used in the next step without further purification. High purity of the intermediate compound helps in obtaining high purity of the compound of Formula I.

The present disclosure is further described in light of the following laboratory experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following laboratory scale examples can be scaled up to industrial/commercial scale: EXPERIMENTS

Experiment-I: Preparation of N, N-dibutyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3- dioxo-2,3-dihydro-lH-indene-5-carboxamide using Ν,Ν-dibutyl amine

Step 1: Preparation of 2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH- indene-5-carboxylic acid A mixture of trimellitic anhydride (36 g, 0.1875 moles) and N-methyl pyrrolidone (50 gm) was heated at 180°C to obtain a first mixture. 3-hydroxy-6-isopropyl-2-methylquinoline-4- carboxylic acid (24.7 g, 0.1008 moles) was added to the first mixture over 2 hours and further refluxed for 8 hours to obtain a first resultant mixture. After completion of the reaction (monitored by TLC), the first resultant mixture was cooled to 60°C. Methanol (130 mL) was added to the first resultant mixture, and further cooled to 30°C. The diluted first resultant mixture was stirred for 1 hour to obtain a slurry comprising a first liquid fraction and a first solid fraction containing 2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH- indene-5-carboxylic acid.

The first solid fraction was separated from the slurry by filtration and was washed with methanol (100 mL). The washed solid fraction was then dried under vacuum at 50°C to obtain 2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5- carboxylic acid.

The purity of 2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5- carboxylic acid was analyzed by HPLC and was found to be 99% and the yield was 28.12 gm. Step 2:

Preparation of N,N-dibutyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)- 1 ,3-dioxo-2,3-dihydro- lH-indene-5-carboxamide

A mixture of 2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5- carboxylic acid (50 gm, 0.133 moles) and mono-chlorobenzene (400 mL) was refluxed and water was distilled out as an azeotrope with mono-chlorobenzene to obtain a second mixture. Di-methylformamide (1.55 gm, 0.021 moles) was then added and reaction mass was cooled to 75°C. Thionyl chloride (32 gm, 0.269 moles) was added over 2 hours to the second mixture and further stirred for 4 hours to obtain a second resultant mixture. The second resultant mixture was then cooled to 60°C and unreacted thionyl chloride was distilled out under vacuum with mono-chlorobenzene, while maintaining the temperature below 75°C. The second resultant mixture was then further cooled to 30°C and di-butylamine (43.8 gm, 0.338 moles) was added. The addition of the di-butylamine was exothermic and reaction temperature was increased to 60°C. The resultant mixture was stirred for 1 hour to obtain a product mixture. After completion of the reaction (monitored by TLC), mono- chlorobenzene was distilled out as an azeotrope with water and 25% aqueous sodium hydroxide was added drop wise to adjust pH of the product mixture to 11. The basic product mixture was then cooled to 30°C and stirred for 1 hour to obtain a suspension comprising a second liquid fraction and a second solid fraction containing N,N-dibutyl-2-(3-hydroxy-6- isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5-carboxarnide.

The second solid fraction was separated from the suspension by filtration and the residue obtained was washed with water, followed by drying under vacuum at 80°C to obtain N,N- dibutyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5- carboxamide (54.5 gm). Purification of N,N-dibutyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3- dihydro-lH-indene-5-carboxamide:

N,N-dibutyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5- carboxamide (54.5 gm) so obtained was charged in reactor along with isopropanol (275 mL) and refluxed to get clear solution with very little insoluble. The hot solution was filtered to obtain a first filtrate. The first filtrate was again charged in the reactor along with charcoal (2.56 gm) and further refluxed for 30 min. The solution was filtered to obtain a second filtrate. The second filtrate was then cooled to 80°C and stirred for 1 hour to obtain a second suspension comprising a third liquid fraction and a third solid fraction containing N,N- dibutyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5- carboxamide. The second suspension was filtered and the third solid fraction so obtained was washed with iso-propanol (25 mL) and dried under vacuum at 80°C to obtain N,N- dibutyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5- carboxamide.

The purity of N,N-dibutyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro- lH-indene-5-carboxamide was analyzed by HPLC and was found to be 99.2% and the yield was 44.2 gm. The Melting point was 147°C -148°C.

Experiment II : Preparation of N-butyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo- 2,3-dihydro-lH-indene-5-carboxamide using N-butyl amine

Step 1: Preparation of 2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH- indene-5-carboxylic acid Step 1 was carried out by the procedure disclosed in Experiment 1.

Step 2: Preparation of N-butyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)- 1 ,3-dioxo-2,3- dihydro-lH-indene-5-carboxamide

A mixture of 2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5- carboxylic acid (50 gm, 0.133 moles) and mono-chlorobenzene (400 mL) was refluxed and water was distilled out as an azeotrope with mono-chlorobenzene to obtain a second mixture. Di-methylformamide (1.55 gm, 0.021 moles) was then added and reaction mass was cooled to 75°C. Thionyl chloride (32 gm, 0.269 moles) was added over 2 hours to the second mixture and further stirred for 4 hours to obtain a second resultant mixture.

The second resultant mixture was then cooled to 60°C and unreacted thionyl chloride was distilled out under vacuum with mono-chlorobenzene. The temperature, while removing the unreacted thionyl chloride was maintained below 75 °C. The second resultant mixture was then further cooled to 30°C and n-butylamine (24.8 gm, 0.34 moles) was added. The addition of the n-butylamine was exothermic and reaction temperature was increased to 60°C. The resultant mixture was stirred for 1 hour to obtain a product mixture. After completion of the reaction (monitored by TLC), mono-chlorobenzene was distilled out as an azeotrope with water and 25% aqueous sodium hydroxide was added drop wise to adjust pH of the product mixture to 11. The basic product mixture was then cooled to 30°C and stirred for 1 hour to obtain a suspension comprising a second liquid fraction and a second solid fraction containing N-butyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH- indene-5-carboxamide.

The second solid fraction was separated from the suspension by filtration and the residue obtained was washed with water, followed by drying under vacuum at 80°C to obtain N- butyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5- carboxamide (48 gm). Purification of N-butyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro- lH-indene-5-carboxamide:

N-butyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5- carboxamide (48 gm) so obtained was charged in reactor along with isopropanol (240 mL) and refluxed to get clear solution with very little insoluble. The hot solution was filtered to obtain a first filtrate. The first filtrate was again charged in the reactor along with charcoal (2.5 gm) and further refluxed for 30 min. The solution was filtered to obtain a second filtrate. The second filtrate was then cooled to 80°C and stirred for 1 hour to obtain a second suspension comprising a third liquid fraction and a third solid fraction containing N-butyl-2- (3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5-carboxamide. The second suspension was filtered and the third solid fraction so obtained was washed with isopropanol (25 mL) and dried under vacuum at 80°C to obtain N-butyl-2-(3-hydroxy-6- isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH-indene-5-carboxamide.

The purity of N-butyl-2-(3-hydroxy-6-isopropylquinolin-2-yl)-l,3-dioxo-2,3-dihydro-lH- indene-5-carboxamide was analyzed by HPLC and was found to be 99.3% and the yield was 39 gm. The Melting point was 161 °C - 162°C.

TECHNICAL ADVANCEMENTS

The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a process for the preparation of quinophthalone derivatives, that is: simple; economical; and provides quinophthalone derivatives with high yield and high purity.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.

The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary. While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

Claims

CLAIMS:

1. A process for preparing a compound of Formula I:

wherein,

R is selected from the group consisting of hydrogen, Q-Cio linear or branched alkyl group; and

R 2" and R 3^J are independently selected from the group consisting of hydrogen, Ci- Cio linear or branched alkyl group, cycloalkyl group and arylalkyl group; wherein said process comprises: a. heating a mixture of trimellitic anhydride and at least one first fluid medium at a temperature in the range of 150°C to 200°C to obtain a first mixture, followed by adding a compound of Formula II

II

to said first mixture and heating to obtain a first resultant mixture; b. cooling said first resultant mixture, followed by adding at least one second fluid medium under continuous stirring to obtain a slurry comprising a first liquid fraction and a first solid fraction, and separating said first solid fraction from said slurry to obtain a compound of Formula III;

c. adding at least one third fluid medium to said compound of Formula III and heating at reflux temperature to obtain a second mixture, followed by cooling to a temperature in the range of 60°C to 75 °C and then adding at least one chlorinating agent under continuous stirring to obtain a second resultant mixture; d. cooling said second resultant mixture, followed by adding at least one amine under continuous stirring to obtain a product mixture; e. diluting said product mixture with water and adding at least one base to obtain a suspension comprising a second liquid fraction and a second solid fraction, separating said second solid fraction from said suspension to obtain the compound of Formula I; f. purifying said compound of Formula I with at least one fourth fluid medium to obtain the compound of Formula I having purity in the range of 98.5% to 99.5%.

2. The process as claimed in claim 1, wherein in said step (c), heating at reflux temperature further comprises removing the water as an azeotrope with said third fluid medium prior to cooling and adding said chlorinating agent; in said step (d), cooling said second resultant mixture further comprises removing unreacted chlorinating agent under vacuum with said third fluid medium prior to adding said amine; and in said step (e), diluting said product mixture with water further comprises removing said third fluid medium as an azeotrope with water prior to adding said base.

3. The process as claimed in claim 1, wherein in said step (a) said compound of Formula II is added to said first mixture over a time period in the range of 1 hour to 5 hours; in said step (c) said chlorinating agent is added to said second mixture over a time period in the range of 1 hour to 5 hours; and in said step (d) said amine is added to said third mixture over a time period in the range of 1 hour to 5 hours.

4. The process as claimed in claim 1, wherein said sub-step (c) further comprises adding at least one catalyst to said second mixture prior to adding said chlorinating agent.

5. The process as claimed in claim 1, wherein the mole ratio of compound of Formula II and trimellitic anhydride is in the range of 1: 1 to 1 :3.

6. The process as claimed in claim 1, wherein said amine is at least one selected from the group consisting of primary amine and secondary amine.

7. The process as claimed in claim 1, wherein said amine is at least one selected from the group consisting of propylamine, iso-propylamine, butylamine, di- propylamine, di-iso-propylamine, di-butylamine, di-(2-ethylhexylamine), 3- ethoxypropylamine, 3-methoxypropylamine, N-ethylaniline, N-ethylcyclohexyl amine and di-tertiary-butylamine; and the mole ratio of compound of Formula III and said amine is in the range of 1 :1 to 1 :5.

8. The process as claimed in claim 1, wherein said first fluid medium is at least one selected from the group consisting of N-methyl pyrrolidine, dimethyl formamide and dimethyl sulfoxide.

9. The process as claimed in claim 1, wherein said second fluid medium is at least one selected from the group consisting of methanol, ethanol and iso-propanol.

10. The process as claimed in claim 1, wherein said third fluid medium is at least one selected from the group consisting of benzene, chlorobenzene, di-chlorobenzene, and toluene.

11. The process as claimed in claim 4, wherein said catalyst is dimethylformamide and the mole ratio of the compound of Formula III and said catalyst is in the range of 1 :0.05 to 1 :0.5.

12. The process as claimed in claim 1, wherein said chlorinating agent is at least one selected from the group consisting of thionyl chloride and oxalyl chloride; and wherein the mole ratio of the compound of Formula III and said chlorinating agent is in the range of 1: 1 to 1 :3.

13. The process as claimed in claim 1, wherein said fourth fluid medium is at least one selected from the group consisting of ethanol, iso-propanol, ethyl acetate and acetonitrile.

14. The process as claimed in claim 1, wherein said base is at least one selected from the group consisting of sodium hydroxide and potassium hydroxide.