Description:FIELD OF THE INVENTION
The present invention relates to a commercially viable one pot process for the preparation of pure methyl 2-(2-methylphenoxymethyl)-phenylglyoxylate of formula (I).

which is useful intermediate for preparing Kresoxim-methyl and Kresoxim-methyl is useful for the control of scab and other fungal diseases on a wide range of crops.
The process according to the present invention is economically viable and environment friendly involving easier and safer steps for commercial level production.
BACKGROUND OF THE INVENTION
Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate also known as Methyl 2-oxo-2-(2-(o-tolyloxymethyl)phenyl)acetate. The molecular formula for Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate is C17H16O4 and its structural formula is:

Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate is an interesting intermediate in the preparation of Kresoxim-methyl. The Kresoxim-methyl belongs to the strobilurin class of fungicides. Kresoxim-methyl was first disclosed in US4829085.

Horst Wingert et al in US5221762A first discloses a process for the production of Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate and this patent exemplifies the preparation of Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate, which follows the synthetic pathway as given in the Scheme-1:

Scheme - 1: Process as per US5221762A
This process method uses a large amount of excess hydrogen chloride gas, which is highly corrosive to equipment and easily causes environmental pollution; gaseous hydrogen chloride is stored in high-pressure steel cylinders. Improper disposal will have risks and disadvantages of safe production and in this method, use methyl tertiary butyl ether as solvent, add acetic anhydride and a large amount of excess methanol to react, the recovery solvent is to contain methyl acetate, methanol and methyl tertiary butyl ether mixture, the solvent cannot be recycled, and the production cost is high.
Jingxi Huagong Zhongjianti (2003), 33(4), 10-11, discloses the Kresoxim-Methyl was prepared by reacting the intermediate, Methyl 2-(2-methylphenoxymethyl) phenylglyoxylate, with O-methylhydroxylamine hydrochloride. The resulting E/Z isomer mixture was treated with hydrochloride for substantial rearrangement of the Z to the E isomer. The intermediate was synthesized by using O-cresol, phthalide, thionyl chloride, and sodium cyanide as raw materials. The total yield of the five steps reached 57.2%.
Jincheng Ding et al in CN105884651B discloses the synthesis of 2-(2-methylphenoxy)-methylbenzoyl cyanide. According to the synthetic process, O- Cresol is reacted with phthalide to get acid compound, and then substitution are conducted to obtain the product which follows the pathway as given in the Scheme-2.

Scheme - 2: Process as per CN105884651B

Shuaishuai Wang et al in CN110396054B discloses a process for preparing 2-((o-tolyloxy)methyl)benzoyl cyanide, which follows the synthetic pathway as given in the Scheme-3:

Scheme -3: Process as per CN110396054B

The processes disclosed in the prior art commercially not viable since the reaction proceed at high temperature and use of a multiple solvents during the reaction process which makes the process costly on industrial scale.
As a result of much avid research in light of the various literature described above, there still exists the need of more economically viable and amenable to scale up processes for Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate which is useful intermediate for the preparation of Kresoxim-methyl. It is also apparent that need to devoid of by-products.
The present invention relates to a commercially viable one pot process for the preparation of pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I), which is useful intermediate for preparing Kresoxim-methyl. The present invention is a simple, environment friendly, efficient and industry viable one pot process. Additionally, the cost of the process is reduced as solvent consumption is less and loss in isolation and purification of each intermediate is avoided.

SUMMARY OF THE INVENTION
The main aspect of the present invention relates to a one pot process for the preparation of pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I).

Different aspects of the present application are summarized herein below individually.
In one aspect of the present application, the present invention relates to a one pot process for the preparation of compound of formula (I),

comprising the steps of:
a) reacting the acid compound of formula (A) with a suitable reagent and suitable organic solvent at a temperature ranging between 20 to 35°C to get compound of formula (B);

b) reacting in-situ the resulting compound of formula (B) with a metal cyanide in the presence of organic solvent and phase transfer catalyst at suitable temperature to get compound of formula (C);

c) reacting in-situ the resulting compound formula (C) by using dry HCl and in the presence of organic solvent at a suitable temperature ranging between -10 to 25°C to get crude compound of formula (I);

d) purifying the crude compound of formula (I) to get pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I).
Another aspect of the present invention relates to process for the purification of the Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate compound of formula (I); comprising of:
a) dissolving Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate compound of formula-1 in protic solvent,
b) heating the reaction mass, stirring and cooling the reaction mixture,
c) isolating the pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate compound of formula (I) having purity exceeding 90.0 % by HPLC.
Further specific aspects of the invention are detailed in the description part of the specification, wherever appropriate.
DETAILED DESCRIPTION
As set forth herein, embodiments of the present invention relates to a one pot process for the preparation of pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I). The present invention deals with a simple and industrially amenable process for making the compound of formula (I), which exhibits various advantages over other processes known in the state of arts. The advantages are discussed on the relevant places of further description. Individual embodiments of the present invention are detailed herein below separately.
In one embodiment according to the present application, it provides an environment friendly process for the preparation of pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I),

In another embodiment according to the present application, it provides a one pot process for preparation of compound of formula (I),

comprising the steps of:
a) reacting the acid compound of formula (A) with a suitable reagent and suitable organic solvent at a temperature ranging between 20 to 35°C to get compound of formula (B);

b) reacting in-situ the resulting compound of formula (B) with a metal cyanide in the presence of organic solvent and phase transfer catalyst at suitable temperature to get compound of formula (C);

c) reacting in-situ the resulting compound formula (C) by using dry HCl and in the presence of organic solvent at a suitable temperature ranging between -10 to 25°C to get crude compound of formula (I);

d) purifying the crude compound of formula (I) to get pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I).
Individual steps of the process according to the present invention are detailed herein below.
In step a) reaction of 2-((o-tolyloxy)methyl)benzoic acid of formula (A) with a suitable reagent and suitable organic solvent at a temperature ranging between 20 to 35°C to get compound of formula (B).
In a particular embodiment of the present invention, the suitable reagent in step a) is selected from thionyl chloride, oxalyl chloride, phosphorus pentachloride, phosphorus oxychloride or phosphorus trichloride. Most preferably, the reaction is carried out in thionyl chloride.
In step b) in-situ reaction is carried out the resulting compound of formula (B) with metal cyanide in the presence of organic solvent and phase transfer catalyst at suitable temperature to get compound of formula (C).
In a particular embodiment of the present invention, the suitable metal cyanide in step b) is selected from sodium cyanide, copper cyanide or potassium cyanide. Most preferably, the reaction is carried out in sodium cyanide.
In another particular embodiment of the present invention, the suitable phase transfer catalyst used in step (b) is selected from tetrabutylammonium bromide, tetrabutylammonium chloride or tetrabutylammonium iodide, benzyl tetramethylammonium bromide, benzyl tetramethylammonium chloride, benzyl tetraethylammonium bromide or benzyl tetraethylammonium chloride. Most preferably, the reaction is carried out in tetrabutylammonium bromide.
The inventors of the present invention found that the phase transfer catalyst used in step (b) decrease the reaction time.
In step c) reacting in-situ the resulting compound formula (C) by using dry HCl and in the presence of organic solvent at a suitable temperature ranging between -10 to 25°C to get crude compound of formula (I).
In particular embodiment of the present invention, the organic solvent used in step (a), step (b) and step (c) is selected from toluene, ethyl acetate, tetrahydrofuran, acetonitrile, N, N-dimethyl formamide, methanol or mixture thereof.
The inventors of the present invention found that the isolation of the intermediate Formula (B) and Formula (C) affect the yield during the preparation of the compound of Formula (I).
The inventors of the present invention observed that the in-situ intermediate Formula (B) and Formula (C) decrease the reaction time and increase the quality of the compound of Formula (I). In the present invention, there was no use of multiple organic solvents during the reaction process. The organic solvents recovered and reused.
In step d) purifying the crude compound of formula (I) to get pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I).
In another embodiment of the present invention relates to a process for the purification of the Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate compound of formula (I),
comprising of:
a) dissolving Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate compound of formula-1 in protic solvent,
b) heating the reaction mass, stirring and cooling the reaction mixture,
c) isolating the pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I) having purity exceeding 90.0 % by HPLC.
In a particular embodiment of the present invention, the suitable protic solvent used in purification of the Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate compound of formula (I) is selected from (C1-C4) alcohol, anisole or mixture thereof. Most preferably, the reaction is carried out in methanol.
Inventors of the present invention found that the use of protic solvents during the purification of the Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate compound of formula (I) improve the quality and devoid of by-products.
The process of the present invention avoids the formation of by products and process related impurities in the formation of pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate.
In another embodiment according to a present invention, it provides a pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of Formula (I) having purity exceeding 90% (by HPLC).
The process of the present invention avoids tedious and time-consuming steps of work up procedure for the isolation of the intermediate during the preparation of the compound of Formula (I). The reaction step is completed in a significant shorter time compared to the prior art process. The use of different organic solvents as needed in the prior art procedure is disadvantageous in commercial manufacturing and this disadvantage is also overcome by the present invention.
While the present invention has been described in terms of its specific embodiments, certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of the present invention.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further illustrated herein below with the help of the following experiments. The experiments used herein are intended merely to facilitate an understanding of the ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the experiments should not be construed as limiting the scope of embodiments herein. These laboratory scale experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial/commercial scale.

EXAMPLE:
Reference Example: Preparation of 2-((o-tolyloxy)methyl)benzoic acid of formula (A):
Charge 82.3 gm of o-Cresol into 2.0 L 4 neck-round bottom flask at 25oC to 30oC. Raise temperature to 45oC to 50oC. Add 134.3 gm of Sodium methoxide solution (30%w/w in methanol) in 1.0 hr at 45oC to 50oC. Stir the reaction mass for 60 to 90 min.s at 45oC to 50oC. Charge 100 gm of Phthalide into the reaction mass at 45oC to 50oC. Raise temperature of the reaction mass 80oC to 125oC. Distilled out methanol at normal atmospheric pressure till 125oC. After collection of distillate is completely stopped, maintained temperature of reaction mass up to 120oC to 125oC to distil further. Stir the reaction mass for 5 to 7 hrs at 121oC to 125oC. After TLC complies, cool the reaction mass to 80oC to 90oC. Charge water 300 mL in the reaction mass at 80oC to 90oC. Reaction mass gets dissolved quickly in water. Cool the reaction mass to 40oC to 45oC. Charge 100 mL of toluene in the reaction mass at 40oC to 45oC. Stir for 5 to 10 min. at 40oC to 45oC. Settle and separate layers at 40oC to 45oC and preserve the organic layer. Charge aqueous layer in to RBF at 40oC to 45oC. Adjust pH 1.5 to 2.0 by using concentrated HCl solution at 40oC to 45oC. Stir for 30 to 60 min. at 40oC to 45oC. Filter the product at 40oC to 45oC. Wash with 1500 mL of water at 25oC to 30oC. Suck dry the material for 30 min.s at 25oC to 30oC. Washed with 100 mL of toluene and suck dry for 1.0 hr at 25oC to 30oC. Dry in tray dryer. Unload the material.
Output: 140 to 145gm
Yield (w/w): 1.40 to 1.45
Purity by HPLC: >95%
Example 1: Preparation of Methyl 2-(2-methylphenoxymethyl)phenyl glyoxylate of formula (I):
(i) Charge 140 gm of 2-((o-tolyloxy)methyl)benzoic acid into 1.0 L of 4 neck- round bottom flask at 25oC to 30oC. Charge 364 mL of toluene at 25oC to 30oC, Charge 7.6 mL of N, N-Dimethyl formamide at 25oC to 30oC, Add 79.2 gm of thionyl chloride in the reaction mass in 1.0 hr at 25oC to 30oC. Raised the temperature to 45oC to 50oC. Stirred reaction mass for 2.0 to 4.0 hrs at 45oC to 50oC. After TLC complies, distilled out solvent up to 120 mL at 45oC to 50oC. Remaining reaction mass cooled to 25oC to 30oC under nitrogen and preserve under nitrogen which is to be taken in-situ for the next step.
(ii) Charge 36.25gm of Sodium Cyanide into 2.0 L 4 neck round bottom flask at 25oC to 30oC. Charge 252mL of water at 25oC to 30oC and stir for 10 to 15 min. Charge 0.353gm of Tetrabutylammonium Bromide at 25oC to 30oC. Charge 490 mL of toluene at 25oC to 30oC. Cool the reaction mass to 10oC to 15oC. Add reaction mass obtained in step (i) within 1.0 to 2.0 hrs at 10oC to l5oC. Raise temperature to 25oC to 30oC. Stir reaction mass for 2.0 to 3.0 hrs at 25oC to 30oC. After TLC complies, settle and separate the layers at 25oC to 30oC, Preserve aqueous layer. Taken organic layer and washed with 3 x 196 mL of water at 25oC to 30oC. Settle and separate layers at 25oC to 30oC. Preserve the toluene layer under nitrogen which is to be taken in-situ for the next stage.
(iii) The organic layer of reaction mass obtainted in step (ii) was cool (-) 5oC to 0oC. Dry HCI gas purging for 2.0 hrs at (-) 5o to 0oC at the rate of 45 to 50 gm/hr. Add 57 mL of methanol in 20 to 30 min with continue purging of dry HCI gas (-)5oC to 0oC at the rate of 20 to 25 gm/hr. Dry HCI gas purging continue for further 4.0 to 5.0 hrs at (-) 5o to 0oC at the rate of 70 to 75 gm/hr. After TLC complies, raise the temperature to 15oC to 20oC. Add 78 mL of methanol in 20 to 30 min at 15oC to 20oC. Raise the temperature to 40oC to 45oC. Addition of 108 gm of concentrated sulphuric acid in 30 to 40 min at 40oC to 45oC. Stir for 3.0 hrs at 40oC to 45oC. After TLC complies, add 78 mL of methanol in 20 to 30 min. at 40oC to 45oC. Stir for 60 min at 40oC to 45oC. Raise the temperature to 60 to 65oC. Stir for 10 hrs at 60oC to 65oC. Cool the reaction to get temperature 40oC to 45oC. Slowly add 56 mL of water in 10 to 15 min.s at 40oC to 45oC. Settle for 15 to 20 min. at 40oC to 45oC. Separate out layers 40 to 45oC. Keep aside aqueous layer. Charge the clear toluene layer in the RBF. Charge l4 gm of activated carbon and stir for l0 to l5 min. at 40oC to 45oC. Filtered through hyflo bed and wash the bed with 100 mL of preheated toluene of 40oC to 45oC. Distilled out toluene completely under vacuum at 40oC to 45oC. Charge 140 mL of methanol and distilled out completely under vacuum at 40oC to 45oC. Unload the material.
Output: 140gm
Purity by HPLC: > 71%
Example 2: Preparation of Methyl 2-(2-methylphenoxymethyl)phenyl glyoxylate of formula (I):
(i) Charge 100 gm of 2-((o-tolyloxy)methyl)benzoic acid into 1.0 L of 4 neck- round bottom flask at 25oC to 30oC. Charge 262 mL of toluene at 25oC to 30oC, Charge 5.4 mL of N, N-Dimethyl formamide at 25oC to 30oC, Add 57.59 gm of oxalyl chloride in the reaction mass in 1.0 hr at 25oC to 30oC. Raised the temperature to 45oC to 50oC. Stirred reaction mass for 2.0 to 4.0 hrs at 45oC to 50oC. After TLC complies, distilled out solvent up to 85 mL at 45oC to 50oC. Remaining reaction mass cooled to 25oC to 30oC under nitrogen and preserve under nitrogen which is to be taken in-situ for the next step.
(ii) Charge 26gm of Potassium Cyanide into 2.0 L 4 neck round bottom flask at 25oC to 30oC. Charge 181mL of water at 25oC to 30oC and stir for 10 to 15 min. Charge 0.254gm of Tetrabutylammonium chloride at 25oC to 30oC. Charge 352 mL of toluene at 25oC to 30oC. Cool the reaction mass to 10oC to 15oC. Add reaction mass obtained in step (i) within 1.0 to 2.0 hrs at 10oC to l5oC. Raise temperature to 25oC to 30oC. Stir reaction mass for 2.0 to 3.0 hrs at 25oC to 30oC. After TLC complies, settle and separate the layers at 25oC to 30oC, Preserve aqueous layer. Taken organic layer and washed with 3 x 140 mL of water at 25oC to 30oC. Settle and separate layers at 25oC to 30oC. Preserve the toluene layer under nitrogen which is to be taken in-situ for the next stage.
(iii) The organic layer of reaction mass obtainted in step (ii) was cool (-) 5oC to 0oC. Dry HCI gas purging for 2.0 hrs at (-)5oC to 0oC at the rate of 45 to 50 gm/hr. Add 41 mL of methanol in 20 to 30 min with continue purging of dry HCI gas (-)5oC to 0oC at the rate of 20 to 25 gm/hr. Dry HCI gas purging continue for further 4.0 to 5.0 hrs at (-) 5" to 0oC at the rate of 70 to 75 gm/hr. After TLC complies, raise the temperature to 15oC to 20oC. Add 56.15 mL of methanol in 20 to 30 min at 15oC to 20oC. Raise the temperature to 40oC to 45oC. Addition of 80 gm of concentrated sulphuric acid in 30 to 40 min at 40oC to 45oC. Stir for 3.0 hrs at 40oC to 45oC. After TLC complies, add 56 mL of methanol in 20 to 30 min. at 40oC to 45oC. Stir for 60 min at 40oC to 45oC. Raise the temperature to 60 to 65oC. Stir for 10 hrs at 60oC to 65oC. Cool the reaction to get temperature 40oC to 45oC. Slowly add 40 mL of water in 10 to 15 min.s at 40oC to 45oC. Settle for 15 to 20 min. at 40oC to 45oC Separate out layers 40 to 45oC. Keep aside aqueous layer. Charge the clear toluene layer in the RBF. Charge l0 gm of activated carbon and stir for l0 to l5 min. at 40oC to 45oC. Filtered through hyflo bed and wash the bed with 71 mL of preheated toluene of 40oC to 45oC. Distilled out toluene completely under vacuum at 40oC to 45oC. Charge 100 mL of methanol and distilled out completely under vacuum at 40oC to 45oC. Unload the material.
Output: 90-100gm
Purity by HPLC: > 70%
Example 3: Purification of Methyl 2-(2-methylphenoxymethyl)phenyl glyoxylate of formula (I) with methanol:
In one litre four necked round bottom flask 70mL methanol was charged and stirred. While stirring, Charge 35gm of crude Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate and heat to 50-55oC for 15 min. Slowly cool to 25oC to 30oC in 30 to 45 min. Further slowly cool to 0oC to 5oC in 45 to 60 min. Stir for 2 hr at 0oC to 5oC. Filter and wash with 35 mL of pre-chilled methanol of 0oC to 5oC. Suck dry the material for 30 min. at 25oC to 30oC. Dry the material under vacuum for 8.0 to 10.0 hrs at 25oC to 35oC.
Output: 25.195gm
Purity by HPLC: > 95.72%
Example 4: Purification of Methyl 2-(2-methylphenoxymethyl)phenyl glyoxylate of formula (I) with isopropanol:
In one litre four necked round bottom flask 70 mL IPA was charged and stirred. While stirring, Charge 35gm of crude Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate and heat to 55-60oC for 15 min. Slowly cool to 25oC to 30oC in 30 to 45 min. Further slowly cool to 0oC to 5oC in 45 to 60 min. Stir for 2 hr at 0oC to 5oC. Filter and wash with 35 mL of IPA of 0oC to 5oC. Suck dry the material for 30 min. at 25oC to 30oC. Dry the material under vacuum for 8.0 to 10.0 hrs at 25oC to 35oC.
Output: 22gm
Purity by HPLC: > 91.72%
Example 5: Purification of Methyl 2-(2-methylphenoxymethyl)phenyl glyoxylate of formula (I) with n-butanol:
In one litre four necked round bottom flask 70 mL n-butanol was charged and stirred. While stirring, Charge 35gm of crude Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate and heat to 65-70oC for 15 min.. Slowly cool to 25oC to 30oC in 30 to 45 min. Further slowly cool to 0oC to 5oC in 45 to 60 min. Stir for 2 hr at 0oC to 5oC. Filter and wash with 35 mL of n-butanol of 0oC to 5oC. Suck dry the material for 30 min. at 25oC to 30oC. Dry the material under vacuum for 8.0 to 10.0 hrs at 25oC to 35oC.
Output: 23.79gm
Purity by HPLC: > 94.89%

Example 6: Purification of Methyl 2-(2-methylphenoxymethyl)phenyl glyoxylate of formula (I) with anisole:
In one litre four necked round bottom flask 280 mL anisole was charged and stirred. While stirring, Charge 140gm of crude Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate and heat to 50-55oC for 15 min. Slowly cool to 25oC to 30oC in 30 to 45 min. Further slowly cool to 0oC to 5oC in 45 to 60 min. Stir for 2 hr at 0oC to 5oC. Filter and wash with 35 mL of n- anisole of 0oC to 5oC. Suck dry the material for 30 min. at 25oC to 30oC. Dry the material under vacuum for 8.0 to 10.0 hrs at 25oC to 35oC.
Output: 80gm
Purity by HPLC: > 90%

The above mentioned examples, which are provided by way of illustration, should not be construed as limiting the scope of the invention with respect to parameter/s, ingredient/s and quantities use etc.
, Claims:We Claim:
1. A one pot process for the preparation of pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I); comprising the steps of:
a) reacting the acid compound of formula (A) with a suitable reagent and suitable organic solvent at a temperature ranging between 20 to 35°C to get compound of formula (B);

b) reacting in-situ the resulting compound of formula (B) with a metal cyanide in the presence of organic solvent and phase transfer catalyst at suitable temperature to get compound of formula (C);

c) reacting in-situ the resulting compound formula (C) by using dry HCl and in the presence of organic solvent at a suitable temperature ranging between -10 to 25°C to get crude compound of formula (I);

d) purifying the crude compound of formula (I) to get pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I).
2. The process for the preparation of pure compound of formula (I) as claimed in claim 1, wherein the organic solvent used in step (a), step (b) and step (c) is selected from toluene, ethyl acetate, tetrahydrofuran, acetonitrile, N, N-dimethyl formamide, methanol or mixture thereof.
3. The process for the preparation of pure compound of formula (I) as claimed in claim 1, wherein the suitable reagent used in step (a) is selected from thionyl chloride, oxalyl chloride, phosphorus pentachloride, phosphorus oxychloride or phosphorus trichloride.
4. The process for the preparation of pure compound of formula (I) as claimed in claim 1, wherein the metal cyanide used in step (b) is selected from sodium cyanide, copper cyanide or potassium cyanide.
5. The process for the preparation of pure compound of formula (I) as claimed in claim 1, wherein the phase transfer catalyst used in step (b) is selected from tetrabutylammonium bromide, tetrabutylammonium chloride or tetrabutylammonium iodide, benzyl tetramethylammonium bromide, benzyl tetramethylammonium chloride, benzyl tetraethylammonium bromide or benzyl tetraethylammonium chloride.
6. A process for the purification of the Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I), comprising of:
a) dissolving Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate compound of formula-1 in protic solvent,
b) heating the reaction mass, stirring and cooling the reaction mixture,
c) isolating the pure Methyl 2-(2-methylphenoxymethyl)phenylglyoxylate of formula (I) having purity exceeding 90.0 % by HPLC.
7. The process for the purification of Methyl 2-(2-methylphenoxy-methyl)phenylglyoxylate of formula (I) as claimed in claim 6, wherein the protic solvent is selected from (C1-C4) alcohol, anisole or mixture thereof.