DESC:Field of the Invention
The present invention relates to an improved process for the preparation of anthranilamide derivatives. More particularly, the present invention relates to an improved process for preparation of Chlorantraniliprole of formula-Ia and Cyantraniliprole of formula-Ib.
Background of the Invention
Anthranilamide derivatives are a kind of novel insecticides with high efficacy and safety. 3-Bromo-N-(4-chloro-2-methyl-6-(methylcarbamoyl)phenyl)-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxamide is highly effective against insects, which is commercialized by DuPont, its generic common name is Chlorantraniliprole of formula-Ia; 3-Bromo-1-(3-chloropyridin-2-yl)-N-(4-cyano-2-methyl-6-(methylcarbamoyl)phenyl)-1H-pyrazole-5-carboxamide in development is highly effective against insects too, whose common name is Cyantraniliprole of formula-Ib.

There are a number of methods reported for preparing anthranilamide derivatives, for example:

The process is as shown in Scheme -I below:
WO03/015519 A1 and Bioorganic & Medicinal Chemistry Letters, 17 (2007), 6274-6279 disclose that 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid reacts with substituted anthranilic acid in the presence of methanesulfonyl chloride and pyridine as acid binding agent to give the benzoxazinone in 86%-92% yield. Then the product reacts with the methylamine to yield the Chlorantraniliprole of formula-Ia. Calculated by 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acids, the total yield of the two-steps is 58%-65%.

The disadvantageous of the above process are involving two step process from the two advanced intermediates. An the process involved usage of excess amount of expensive reagent methanesulfonyl chloride 3.0 to 5.2 mole equivalents and usage of expensive solvent like acetonitrile. Yield of the final step is only 18.7% by theory. Therefore, this process is not suitable for commercial scale.

The process is as shown in Scheme-II below:

WO 2004067528 A1 discloses that 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid reacts with substituted anthranilic acid in the presence of methanesulfonyl chloride and triethylamine as acid binding agent to give Iodobenzoxazinone compound. Then the product under goes cyanation with copper (I) cyanide in the presence of tetra-kis(triphenyphosphine)palladium(0) to obtain cyano benzoxazinone, which further reacts with the methylamine to yield Cyantraniliprole of formula-Ib.

The disadvantageous of the above process are usage of expensive and unstable reagents such as methanesulfonyl chloride, tetrakis(triphenylphosphine)palladium (0), copper (I) iodide and copper (I) cyanide. Purity of the compounds are not given.

The process is as shown in Scheme-III below:
WO2006/062978A1 discloses that 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid reacts with substituted aminobenzamide in the presence of methanesulfonyl chloride and 3-picoline as acid binding agent to give the anthranilamide derivatives (Chlorantraniliprole of formula-Ia or Cyantraniliprole of formula-Ib) and the dehydrated-cyclization by-product, which can be converted into the target anthranilamide derivatives under the reaction with hydrochloric acid. Calculated by 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid, the crude yield under the best reaction conditions is 99.5% without mention of the product purity. The total yield is 88.4% after purified by recrystallization.

The disadvantageous of the above process are usage of expensive reagent methanesulfonyl chloride and purity of compound is not mentioned.

Objective of the Invention
The main objective of the present invention is to provide a simple and cost effective process for the preparation of Chlorantraniliprole of formula-Ia and Cyantraniliprole of formula-Ib with high purity and good yield on a commercial scale.
Summary of the Invention
The present invention relates to an improved process for the preparation of Chlorantraniliprole of formula-Ia and Cyantraniliprole of formula-Ib,

comprising the steps of:
a) reacting 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid,

with a chlorinating agent in a suitable solvent to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride.

b) reacting the 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride in situ with substituted aminobenzamide,

wherein, X = Cl or CN
in presence of a base in a suitable solvent to obtain Chlorantraniliprole of formula-Ia and Cyantraniliprole of formula-Ib.
c) isolating the compounds of formula-1a and formula-1b.
Another embodiment of the present invention relates to an improved process for the preparation of Chlorantraniliprole of formula-Ia,

comprising the steps of:
a) reacting 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid,

with thionyl Chloride (SOCl2) in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride.

b) reacting the 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride compound in situ with 2-amino-5-chloro- 3,N-dimethylbenzamide,

in presence of 3-picoline in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain Chlorantraniliprole of formula-Ia.
c). optionally, purifying the Chlorantraniliprole of formula-Ia with alcohol solvents, acetonitrile or mixture thereof.
Another embodiment of the present invention relates to an improved process for the preparation of Cyantraniliprole of formula-Ib,

comprising the steps of:
a) reacting 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid,

with thionyl chloride (SOCl2) in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride.

b) reacting the 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride compound in situ with 2-amino-5-cyano-3,N-dimethylbenzamide,

in presence of 3-picoline in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain Cyantraniliprole of Formula-Ib.
c) optionally, purifying the Cyantraniliprole of Formula-Ib with acetonitrile, n-heptane solvent or mixture thereof.
Detailed Description of the Invention
In one of the embodiment, the present invention provides an improved process for the preparation of Chlorantraniliprole of formula-Ia and Cyantraniliprole of formula-Ib, comprising the steps of:
a) reacting 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid with a chlorinating agent to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid.
b) reacting the 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride in situ with substituted aminobenzamide in presence of a base in a suitable solvent to obtain Chlorantraniliprole of formula-Ia and Cyantraniliprole of formula-Ib.
c) optionally, isolating the compounds of formula-1a and formula-1b by filtration of the mass and drying at 25-100oC.
The chlorinating agent used in step-a is selected from thionyl Chloride (SOCl2), Oxalyl chloride (C2O2Cl2), Cyanuric Chloride, Phosphorus oxychloride, Phosphorus trichloride, phosphorus pentachloride etc.
The suitable solvent used in step-a is selected from toluene, acetonitrile, methylene chloride chloroform and xylene mixture thereof.
The mole equivalents of chlorinating reagent used in step-a are 1.0 to 1.6, preferably 1.2 to 1.4 mole equivalents and more preferably 1.0 to 1.1 mole equivalents with respective 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid.
In step (a), the reaction may be performed from 25°C to 125oC for 1 hours to 12 hours, preferably 60-90°C for 1 hours to 5 hours. The obtained 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride may be used in the next reaction directly without isolation.

The base used in step-b is organic base comprises diisopropylamine, diisopropylethylamine triethylamine, dimethylamine, trimethyl amine, pyridine, N-methylmorpholine, 3-picoline, 2-picoline, 4-picoline or mixtures thereof, preferably pyridine.
The suitable solvent used in step-b is organic solvents, for example polar aprotic solvent comprises acetonitrile, dimethylformamide, tetrahydrofuran, Ethyl acetate, Acetone, Dimethylsulfoxide or mixture thereof; chlorinating solvent comprises dichloromethane, chloroform, bromodichloromethane, dibromochloromethane, trichlorofluoromethane, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, trichloethylene or mixture thereof. Hydrocarbon solvents such as cyclohexane, hexane, heptane, toluene, xylene, etc or mixture thereof.
The mole equivalents of base used in above condensation step are 1.0 to 2.5, preferably 1.0 to 1.5 mole equivalents with respective 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid.
The reaction may be performed usually from -10 to100oC for 30 min to 48hours and then compound of formula (Ia or Ib) can be obtained by a usual procedure.
In step-c of present invention, purifying the compounds of Formula-Ia and formula-1b with solvents selected from Acetonitrile, alcohol solvents or mixture thereof. wherein, alcohol solvents is selected from methanol, ethanol, propanol, isopropanol.etc or mixture thereof.
In step-c of present invention, isolating the compounds of Formula-Ia and formula-1b by filtration of mass and drying at 25-100oC.
Another embodiment of the present invention relates to an improved process for the preparation of Chlorantraniliprole of formula-Ia, comprising the steps of:
a) reacting 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid with thionyl Chloride (SOCl2) in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride.
b) reacting the 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride compound in situ with 2-amino-5-chloro- 3,N-dimethylbenzamide in presence of 3-picoline in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain Chlorantraniliprole of formula-Ia.
c). optionally, purifying the Chlorantraniliprole of formula-Ia with a alcohol solvents, acetonitrile or mixture thereof.
In step-c of present invention, alcohol solvents is selected from methanol, ethanol, propanol, isopropanol.etc or mixture thereof.

Another embodiment of the present invention relates to an improved process for the preparation of Cyantraniliprole of formula-Ib, comprising the steps of:
a) reacting 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid with thionyl chloride (SOCl2) in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride.
b) reacting the 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride compound in situ with 2-amino-5-cyano-3,N-dimethylbenzamide in presence of 3-picoline in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain Cyantraniliprole of Formula-Ib.
c) optionally, purifying the Cyantraniliprole of Formula-Ib with Acetonitrile, n-heptane solvent or mixture thereof.
Advantageous of the present Invention:
? The present invention process involves less expensive and readily available reagents and solvents.
? Chlorinating reagents employed in present invention process are thionyl chloride, phosphorus oxy chloride, phosphorus trichloride, phosphorus penta chloride which are very less expensive and readily available compared to methanesulfonyl chloride.
? Solvents used in present invention were less expensive and can be recovered and reused.
? Product of present invention is directly isolated from the reaction mass without involving any laborious work-up processes. Therefore, the process of the present invention is suitable for commercial scale.

The following examples are provided to illustrate the invention and are merely for illustrative purpose only and should not be construed to limit the scope of the invention.
Example-1: Preparation of Chlorantraniliprole of formula-1a.
Charged toluene (100 ml) and 3-Bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid (10g, 0.033 moles) into 4N RB flask and the resulting suspension was stirred for 5 min at 25 to 35°C. Thionyl chloride (4.72g, 0.039 moles) was added dropwise to the above suspension. Then the suspension was heated to 75 to 80°C and stirred for 3h. After reaction completion by TLC, solvent was distilled off at 70 to 75°C under reduced pressure to obtain compound of 3-Bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid chloride as cream colored solid.

In another 4N RB flask, 2-Amino-5-chloro-3,N-dimethyl benzamide (6.9g, 0.035 moles), pyridine (6.8g, 0.0859 moles) and toluene (70 ml) were charged and stirred the solution at 25-30°C. Then the solution of compound of 3-Bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid chloride in toluene (50 ml) was added dropwise to the reaction mass. Then the reaction mass was stirred for 3h. After reaction completion by TLC, water (66.0 ml) was added to the reaction mass, stirred for 1h and filtered. Product was washed with toluene (50 ml). The resulting solid was dried under vacuum at 45-50°C to afford Chlorantraniliprole of formula (Ia) as off-white solid. Wt. of the product: 13.4g (83.9% by theory), purity by HPLC > 97.0%.

Example-2: Preparation of Chlorantraniliprole of formula-1a.
Charged acetonitrile (300 ml), 3-bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid (100g, 0.330 moles) into 1L 4N RB flask and reaction mass was stirred for 5-10 min. Thionyl chloride (43.2g, 0.363 moles) was added dropwise to the above reaction mass. The resulting reaction mass was heated to 75-80°C and stirred for 30-3.5h. After completion of reaction by TLC, reaction mas was cooled to 25-35°C and kept aside (Reaction mass-1).

In another 2L 4N RB flask, charged acetonitrile (200 ml), 2-Amino-5-chloro-3,N-dimethyl benzamide (68.8g, 0.346 moles), 3-picoline (36.9g, 0.396 moles) and stirred for 5-10 min at 25-35°C. Reaction mass-1 obtained above was added to the reaction mass during 20-30 min. The resulting reaction mass was stirred for 3.0-3.5h at 25-35°C. After reaction completion, reaction mass was cooled to 5-10°C and stirred for 2.0-2.5h. Solid was filtered from the reaction mass under suction and washed with chilled acetonitrile (100.0 ml). Then the solid was dried in hot air oven at 75-80°C for 6-8h to afford Chlorantraniliprole of formula (1a) as off-white to cream coloured solid. Wt. of the product: 145.5g (91.1%). Purity by HPLC > 98.0%.
Example-3: Preparation of Chlorantraniliprole of formula-1a.
Charged acetonitrile (300 ml), 3-bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid (100g, 0.330 moles) into 1L 4N RB flask and reaction mass was stirred for 5-10 min. Thionyl chloride (43.2g, 0.363 moles) was added dropwise to the above reaction mass. The resulting reaction mass was heated to 75-80°C and stirred for 30-3.5h. After completion of reaction by TLC, reaction mas was cooled to 25-35°C and kept aside (Reaction mass-1).

In another 2L 4N RB flask, charged acetonitrile (300 ml), 2-Amino-5-chloro-3,N-dimethyl benzamide (68.8g, 0.346 moles), 3-picoline (36.9g, 0.396 moles) and stirred for 5-10 min at 25-35°C. Reaction mass-1 obtained above was added to the above reaction mass during 20-30 min. The resulting reaction mass was stirred for 3.0-3.5h at 25-35°C. After reaction completion, solvent was distilled off under reduced pressure at 40-45°C to obtain cream coloured thick suspension. Methanol (100 ml) was added to the above suspension and solvent was distilled off under reduced pressure at 40-45°C to obtain cream coloured thick suspension. Methanol (300 ml) was added to the above suspension, cooled to 5-10°C and stirred for 2h. Solid was filtered from the reaction mass under suction and washed with methanol (100.0 ml). Then the solid was dried in hot air oven at 75-80°C for 6-8h to afford Chlorantraniliprole of formula-1a as off-white to cream coloured solid. Wt. of the product: 145.5g (91.1%). Purity by HPLC > 98.0%.
Example-04: Preparation of Cyantraniliprole of formula-1b.
Charged toluene (300.0 ml) and 3-Bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid (100g, 0.33 moles) into 4N RB flask and the resulting suspension was stirred for 5 min at 25 to 35°C. Thionyl chloride (47.2g, 0.39 moles) was added dropwise to the above suspension. Then the suspension was heated to 75 to 80°C and stirred for 3h. After reaction completion by TLC, reaction mas was cooled to 25-35°C and kept aside (Reaction mass-1).
In another 4N RB flask, 2-Amino-5-cyano-3,N-dimethyl benzamide (65.7g, 0.35 moles), 3-picoline (80.15g, 0.861 moles) and acetonitrile (300.0 ml) were charged and stirred the solution at 25-30°C. The resulting reaction mass was cooled to 0-5°C, and then reaction mass-1 obtained above was added dropwise and then stirred for 3h at 0-5°C. After reaction completion by TLC, water (400.0 ml) was added to the reaction mass, stirred for 30 min. Then conc. hydrochloric acid (39.0g) was added to the reaction mass and stirred for 60-75 min at 0-5°C. Solid was filtered and washed with aq. acetonitrile (100.0 ml obtained from 75.0 ml of acetonitrile and 25.0 ml of water) followed by acetonitrile (200.0 ml). Resulting solid was leached with water (500.0 ml) at 25-30°C and filtered. Then the solid was suspended in acetonitrile (400.0 ml) and heated to reflux temperature and stirred for 90 min. The resulting suspension was cooled 25-30°C, stirred for 90 min and filtered. Solid was washed with acetonitrile (100.0 ml) and suck dried for 30-45 min. The wet solid was suspended in n-heptane (1150.0 ml) and subjected azeotropic distillation. After distilling off about 350.0 ml of solvent, reaction mass was cooled to 40-45°C and solid was filtered off. Solid was washed with n-heptane (100.0 ml) and suck dried for 30-45 min. Then solid was dried in hot air oven at 75-80°C for 6h to afford Cyantraniliprole of formula (1b) as off-white coloured powder. Wt. of the product: 100g (63.86% by theory), purity by HPLC > 97.0%.

Example-05: Preparation of Cyantraniliprole of formula-1b.
Charged acetonitrile (300.0 ml) and 3-Bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid (100g, 0.33 moles) into 4N RB flask and the resulting suspension was stirred for 5 min at 25 to 35°C. Thionyl chloride (43.2g, 0.363 moles) was added dropwise to the above suspension. Then the suspension was heated to 75 to 80°C and stirred for 3h. After reaction completion by TLC, reaction mas was cooled to 25-35°C and kept aside (Reaction mass-1).

In another 4N RB flask, 2-Amino-5-cyano-3,N-dimethyl benzamide (65.7g, 0.35 moles), 3-picoline (36.9g, 0.396 moles) and acetonitrile (300.0 ml) were charged and stirred the solution at 25-30°C. The resulting reaction mass was cooled to 0-5°C, and then reaction mass-1 obtained above was added dropwise and then stirred for 3h at 0-5°C. After reaction completion by TLC, water (400.0 ml) was added to the reaction mass, stirred for 30 min. Then conc. hydrochloric acid (39.0g) was added to the reaction mass and stirred for 60-75 min at 0-5°C. Solid was filtered and washed with aq. acetonitrile (100.0 ml obtained from 75.0 ml of acetonitrile and 25.0 ml of water) followed by acetonitrile (200.0 ml). Resulting solid was leached with water (500.0 ml) at 25-30°C and filtered. Then the solid was suspended in acetonitrile (400.0 ml) and heated to reflux temperature and stirred for 90 min. The resulting suspension was cooled 25-30°C, stirred for 90 min and filtered. Solid was washed with acetonitrile (100.0 ml) and suck dried for 30-45 min. The wet solid was suspended in n-heptane (1150.0 ml) and subjected azeotropic distillation. After distilling off about 350.0 ml of solvent, reaction mass was cooled to 40-45°C and solid was filtered off. Solid was washed with n-heptane (100.0 ml) and suck dried for 30-45 min. Then solid was dried in hot air oven at 75-80°C for 6h to afford Cyantraniliprole of formula (1b) as off-white coloured powder. Wt. of the product: 100g (63.86% by theory), purity by HPLC > 97.0%.
,CLAIMS:We Claim:
1. An improved process for the preparation of Chlorantraniliprole of formula-Ia and Cyantraniliprole of formula-Ib,

comprising the steps of:
a) reacting 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid,

with a chlorinating agent in a suitable solvent to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride,

b) reacting the 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid
chloride compound in situ with substituted aminobenzamide,

wherein, X = Cl or CN
in presence of a base in a suitable solvent to obtain Chlorantraniliprole of formula-Ia and Cyantraniliprole of Formula-Ib,
c) isolating the compounds of formula-Ia and formula-1b.

2. The process as claimed in claim 1, wherein the chlorinating agent used in step-a is selected from thionyl chloride (SOCl2), Oxalyl chloride (C2O2Cl2), cyanuric chloride, phosphorus oxychloride, phosphorus trichloride and phosphorus pentachloride.

3. The process as claimed in claim 1, wherein the suitable solvent used in step-(a) is selected from toluene, acetonitrile, methylene chloride, chloroform and xylene or mixture thereof.

4. The process as claimed in claim 1, wherein the base used in step-(b) is selected from diisopropylamine, diisopropylethylamine triethylamine, dimethylamine, trimethyl amine, pyridine, N-methylmorpholine, 3-picoline, 2-picoline, 4-picoline or mixtures thereof.

5. The process as claimed in claim 1,wherein the suitable solvent used in step-(b) is selected from acetonitrile, dimethylformamide, tetrahydrofuran, ethyl acetate, acetone, dimethylsulfoxide, dichloromethane, chloroform, bromodichloromethane, dibromochloromethane, trichlorofluoromethane, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, trichloethylene, cyclohexane, hexane, heptane, toluene, xylene or mixture thereof.
6. The process as claimed in claim 1, isolating the compounds of formula-Ia and formula-1b in step-(c) by filtration of the mass and drying at 25-100oC.

7. An improved process for the preparation of Chlorantraniliprole of formula-Ia,

comprising the steps of:
a) reacting 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid,

with thionyl chloride (SOCl2) in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride,

b) reacting the 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid
chloride compound in situ with 2-amino-5-chloro-3,N-dimethylbenzamide,
in presence of 3-picoline in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain Chlorantraniliprole of formula-Ia,

c) optionally, purifying the Chlorantraniliprole of formula-Ia with an alcohol
solvents, acetonitrile or mixture thereof.

8. An improved process for the preparation of Cyantraniliprole of formula-Ib,

comprising the steps of:
a) reacting 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid,

with thionyl chloride (SOCl2) in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid chloride,

b) reacting the 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid
chloride compound in situ with 2-amino-5-cyano-3,N-dimethylbenzamide,

in presence of 3-picoline in a solvent selected from acetonitrile, toluene or mixture thereof, to obtain Cyantraniliprole of Formula-Ib,
c) optionally, purifying the Cyantraniliprole of Formula-Ib with acetonitrile, n-
heptane solvent or mixture thereof.