A method for the synthesis of substituted anthranilic amide compounds, intermediates and salts thereof

Abstract

The present invention discloses a method for the synthesis of compounds of formula (I) or a salt thereof, wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; R4 is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2- C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-C1-C10 alkyl; and n represents an integer selected from 0-4. The process further comprises the synthesis of an anthranilic diamide compound of formula (A).

Description

A METHOD FOR THE SYNTHESIS OF SUBSTITUTED ANTHRANILIC AMIDE COMPOUNDS, INTERMEDIATES AND SALTS THEREOFFIELD OF THE INVENTION:

[0001] The present invention is related to a method for the synthesis of substituted anthranilic amide compounds, intermediates used for their preparation, and salts thereof. Particularly, the present invention relates to a method for the synthesis of di-substituted 2-amino-A-alkyl-benzamide compounds of formula (I), intermediates used for their preparation, and salts thereof.BACKGROUND OF THE INVENTION:

[0002] Anthranilic amide compounds are important intermediates for various pharmaceutically and agrochemically active ingredients.

[0003] WO2012103436 and WO2013117601 describe the preparation of anthranilic amides from 2-halo aniline derivatives using hazardous carbon monoxide gas and an appropriate palladium catalyst, which as such is a disadvantage from safety and economical point of view.

[0004] The method described in the Journal of Heterocyclic Chemistry 2016, 53(4), 1036-1045 involves five steps in order to achieve the synthesis of an anthranilic amide compound. Another method described in WO2012161313 involves the usage of n-butyl lithium, which is pyrophoric and can be difficult to handle on a larger scale.

[0005] W02020170092 describes a process for preparing substituted anthranilic diamides and intermediates thereof, particularly, disclosing the process for the synthesis of substituted anthranilic amides of formula (VII) from substituted isatin derivatives of formula II via the formation of substituted isatoic anhydride intermediates of formula (V), as shown in Scheme-A:

[0006] Similarly, WO2021086957 describes the synthesis of substituted anthranilic amides from substituted isatin derivatives via the formation of substituted isatoic anhydride intermediates, as shown in Scheme 1:Scheme 1.

[0007] The reaction sequence described in the above cited prior art involves more than two steps to prepare the substituted anthranilic amide compounds from the respective substituted isatin intermediates, causing additional operation cost and an increased consumption of solvents to isolate the respective substituted intermediates, and thereby making the process environmentally not friendly.

[0008] WO2022058916 describes the synthesis of substituted anthranilic amides of formula (Z) by reacting substituted anilines of formula (II) with the trihaloacetonitriles (IX), followed by reacting the substituted trihaloacetyl intermediates (Z), wherein R10is (CX3), with suitably substituted amines of formula (VIII), to obtain the substituted anthranilic amides of formula (Z) as shown in the scheme below:

[0009] The substituted trihaloacetyl intermediates (Z), wherein R10is CX3, were prepared by using a combination of the Lewis acid reagents, e.g., BCI3-AICI3 which is uneconomical as well and difficult to handle at a large scale.

[0010] Further to that, WO2022064454A1 reports the synthesis of isatin derivatives (V) and amides (VII). In this document, the amine (II) is reacted with a carbonyl compound (III) to obtain an amide (IV), which is further cyclized by treatment with an acid to obtain an isatin of formula (V). After that, the isatin of formula (V) is treated with an oxidizing agent and a catalyst to obtain isatoic anhydride of formula (VI). Finally, the isatoic anhydride of formula (VI) is reacted with a substituted amine of formula HN(R4a)(R4b) (VIII) to obtain the amide (VII).

[0011] According to WO2022064454A1, the conversion of isatin of formula (V) to the amide of formula (VII) occurs in two steps - (a) isatin (V) to isatoic anhydride (VI), and (b) isatoic anhydride (VI) to amide (VII). The conversion of isatin into isatoic anhydride is carried out using A-methylpyrrolidone as a solvent, and selenous acid, tungstic acid, and hydrogen peroxide as catalysts resp. reagents. Thereafter, the isatoic anhydride is isolated and reacted with a primary amine in presence of a solvent and pyridine to obtain the amide (VII).

[0012] From the above discussion it is noted that the conversion of isatin of formula (V) to the amide of formula (VII) proceeds through the isatoic anhydride intermediate of formula (VI). This route for the synthesis of the amide suffers from low yields, utilizes numerous solvents and catalysts and involves additional purification and isolation steps, which makes this prior art process unfit for commercial production on a large scale. Accordingly, there is a need for a process for the conversion of isatin to an amide that does not involve the use of expensive solvents and catalysts, and isolation and purification steps.

[0013] It is also noted that as per WO2022064454A1, the conversion of the ester (IVf) via the diamide (IVh) to the isatin (V) involves three steps, i.e., (a) conversion of ester (IVf) to the diamide (IVh) using the solvents methanol and n- hexane and ammonia gas, (b) conversion of the diamide (IVh) to the carbamoyl cyanide (IVi) using POCI3 and dichloroethane as the solvent, and (c) conversion of the carbamoyl cyanide (IVi) into the isatin in m-chlorobenzene as a solvent using AICI3 as a catalyst. This route to the isatin (V) starting from the ester amide (IVf), that comprises three steps, also suffers from low yields, utilizes numerous solvents and catalysts and involves purification and isolation at every step, which makes this prior art process unfit for commercial production on a large scale. Accordingly, there is a need for a process for the conversion of an ester amide (IVf) to an amide (VII) that does not involve the use of expensive solvents and catalysts, and isolation and purification steps after every reaction step.

[0014] N-substituted anthranilic amides with desired substitution patterns being suitable as advanced intermediates for the preparation of anthranilic acid diamides of formula (A), are not easily available, and the processes mentioned in the literatures to synthesize them lack from selectivity as well as from scalability. Therefore, there is a need to find a simple, efficient and industrially economical process for the preparation of anthranilic acid diamides from N-substituted anthranilic amides as well as for N-substituted anthranilic amides themselves. This need is addressed by the present invention.

[0015] The above literature methods are tedious as well as have disadvantages that are mentioned herein. There is a need to find a simple, efficient,and industrially economical method for the preparation of substituted anthranilic amide compounds. Accordingly, the present invention provides a facile, environment-friendly, and cost-efficient method for the preparation of substituted anthranilic amides and respective intermediates thereof, based on readily available starting materials.OBJECTIVE OF THE INVENTION:

[0016] The objective of the present invention is to provide a method for the synthesis of N-substituted anthranilic amides of formula (I) or its salts thereof.

[0017] Another objective of the present invention is to provide a method for the synthesis of the-compounds of formula (VI) and compounds of formula (V).

[0018] Yet another objective of the present invention is to provide a simple, environmental-friendly and cost-effective method for the synthesis of anthranilic diamides of formula (A), based on readily available starting materials.SUMMARY OF THE INVENTION:

[0019] The main objective of the present invention is to provide an industrially amenable and convenient method for the preparation of anthranilic amides of formula (I).

[0020] Surprisingly, the present invention provides a solution to this objective by providing a novel process that allows for the preparation of anthranilic amides, overcoming at least one of the shortcomings of the processes described in the prior art.

[0021] Accordingly, in the first aspect, the present invention provides a novel process for the preparation of a compound of formula (I),formula (I) wherein,R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, Ci- C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and n represents integer selected from 0-4; comprising the steps of:A. preparing an isatin of formula (VI),formula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and n represents an integer selected from 0- 4; by reacting a mixture comprising of, i. an amide of formula (IV)Hu(rfYp-(IV) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, Cl, Br and C1-C4 alkoxy; and n represents an integer selected from 0-4; ii. an amine of formula (XA)NR5aR5b(XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids, iv. optionally in the presence of a solvent; andB . obtaining a compound of formula (I) by reacting a mixture comprising of, i. an isatin of formula (VI) obtained in step A; ii. a base; iii. optionally in the presence of a solvent; iv. an amine of formula (IX) or salt thereof;H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; v. an oxidizing agent;wherein said method optionally comprising the step of; halogenating the isatin of formula (VI), wherein at least one R is hydrogen, with a suitable halogenation reagent, optionally in the presence of a suitable solvent to obtain halogenated isatins of formula (VI).

[0022] In a second aspect, the present invention relates to a method for the preparation of a compound of formula (A) or of salts thereof;Formula (A) wherein,R is selected from the group comprising of halogen, cyano, C1-C4 alkyl, Ci- C4 haloalkyl and C3-C4-cycloalkyl;R4is selected from the group consisting of hydrogen, Ci-Ce alkyl, C3-C6 cycloalkyl, C3-C6 cycloalkyl-Ci-C4 alkyl;R5is selected from the group comprising of halogen, C1-C4 alkyl, C1-C4 haloalkyl, CHF2, CF3, C1-C4 alkoxy, OCHF2, OCH2CF3,heterocyclyl; wherein -A- is selected from the group comprising of a direct bond, CHR6, -O- or -S-; and said heterocyclyl may optionally be substituted with one or more group selected from hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl;R6is selected from the group comprising of hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl; X represents halogen;and n represents an integer selected from 0-4; comprising the step of reacting a substituted anthranilic amide compound of formula (I),wherein,R is selected from the group comprising of halogen, cyano, C1-C4 alkyl, Ci- C4 haloalkyl and C3-C4-cycloalkyl;R4is selected from the group consisting of hydrogen, Ci-Ce alkyl, C3-C6 cycloalkyl, C3-C6 cycloalkyl-Ci-C4 alkyl;andnrepresents an integer selected from 0-4; with a pyrazole compound of formula (B),wherein W is OH, Cl, O-C1-C4 alkyl, O-C(O)Ci-C4 alkyl or imidazolyl;R5is selected from the group comprising of halogen, C1-C4 alkyl, C1-C4 haloalkyl, CHF2, CF3, C1-C4 alkoxy, OCF2H, OCH2CF3,heterocyclyl; wherein -A- is selected from the group comprising of direct bond, CHR6, - O- or -S-; and said heterocyclyl may optionally be substituted with one or more group selected from hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl;R6is selected from the group comprising of hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl andX represents halogen; in the presence of a coupling reagent, a suitable solvent, and optionally in the presence of a base, according to the following reaction scheme as depicted below,wherein, the compound of formula (I) is prepared comprising the steps of:A. preparing an isatin of formula (VI)formula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, Ci- C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and n represents an integer selected from 0-4; by reacting a mixture of, i. an amide of formula (IV)wherein Rn is selected from hydrogen, halogen, C1-C12 alkyl, Ci- C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl,R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy, ii. an amine of formula (XA)HN(R5aR5b) (XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring, iii. cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids, iv. optionally in the presence of a solvent, andB . obtaining a compound of formula (I) by reacting a mixture of, i. an isatin of formula (VI) obtained in step A; ii. a base; iii. optionally in the presence of a solvent; iv. an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; v. an oxidizing agent; wherein said method optionally comprising the step of; halogenating the isatin of formula (VI) wherein at least one R is hydrogen with a suitable halogenation reagent, optionally in the presence of a suitable solvent to obtain halogenated isatins of formula (VI).

[0023] In a third aspect, the present invention, provides a method for preparing an isatin of formula (VI)formula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and n represents an integer selected from 0-4; comprising the steps of:(A-a). reacting the amide of formula (IV) with a suitable amine of formula HN(R5aR5b) (XA) to obtain a compound of formula (V), and(A-b). cyclising the compound of formula (V) with a cyclising reagent to obtain the isatin of formula (VI), wherein the cyclization of the amide of formula (V) is carried out without isolation from the reaction mixture;wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3- Cs cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy;R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N- atom to which they are attached form a heterocyclic ring; and wherein the cyclising reagent is a mixture of two or more acids;DETAILED DESCRIPTION OF THE INVENTIONGENERAL DEFINITIONS

[0024] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps, features, compositions, and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features. Definitions

[0025] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

[0026] The definitions provided herein for the terminologies used in the present disclosure are for illustrative purpose only and in no manner limit the scope of the present invention disclosed in the present disclosure.

[0027] As used herein, the terms “comprises”, “comprising”, “includes”, “including”, “has”, “having”, “contains”, “containing”, “characterized by” or any other variation thereof, are intended to cover a non-exclusive inclusion, subject to any limitation explicitly indicated. For example, a composition, mixture, process or method that comprises a list of elements is not necessarily limited to only thoseelements but may include other elements not expressly listed or inherent to such composition, mixture, process or method.

[0028] The transitional phrase “consisting of ’14xcludees any element, step or ingredient not specified. If in the claim, such would close the claim to the inclusion of materials other than those recited except for impurities ordinarily associated therewith. When the phrase “consisting of’ appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

[0029] The transitional phrase “consisting essentially of’ is used to define a composition or method that includes materials, steps, features, components or elements, in addition to those literally disclosed, provided that these additional materials, steps, features, components or elements do not materially affect the basic and novel character! stic(s) of the claimed invention. The term “consisting essentially of’ occupies a middle ground between “comprising” and “consisting of’.

[0030] Further, unless expressly stated to the contrary, “or” refers to an inclusive “or” and not to an exclusive “or”. For example, a condition A “or” B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0031] Also, the indefinite articles “a” and “an” preceding an element or component of the present invention are intended to be non-restrictive regarding the number of instances (i.e. occurrences) of the element or component. Therefore “a” or “an” should be read to include one or at least one, and the singular word form of the element or component also includes the plural unless the number is obviously meant to be singular.

[0032] Carbon-based radical refers to a monovalent molecular component comprising a carbon atom that connects the radical to the remainder of the chemical structure through a single bond. Carbon-based radicals can optionally comprise saturated, unsaturated and aromatic groups, chains, rings and ring systems, andheteroatoms. Although carbon-based radicals are not subject to any particular limit in size, in the context of the present invention they typically comprise 1 to 16 carbon atoms and o to 3 heteroatoms. Of note are carbon-based radicals selected from Ci- Ce alkyl, Ci-C6haloalkyl and phenyl optionally substituted with 1-3 substituents selected from C1-C3 alkyl, halogen and nitro.

[0033] The meaning of various terms used in the description shall now be illustrated.

[0034] The term “alkyl”, used either alone or in compound words such as“alkylthio” or “haloalkyl” or -N(alkyl) or alkylcarbonylalkyl or alkylsuphonylamino includes straight-chain or branched Ci to Ci, alkyl. Representative examples of alkyl include methyl, ethyl, propyl, 1 -methylethyl, butyl, 1 -methylpropyl, 2 -methylpropyl, 1,1 -dimethylethyl, pentyl, 1 -methylbutyl, 2-methylbutyl, 3 -methylbutyl, 2,2-dimethylpropyl, 1 -ethylpropyl, hexyl, 1,1- dimethylpropyl, 1,2-dimethylpropyl, 1 -methylpentyl, 2-methylpentyl, 3- methylpentyl, 4-methylpentyl, 1,1 -dimethylbutyl, 1,2-dimethylbutyl, 1,3- dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3, 3 -dimethylbutyl, 1- ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1 -ethyl- 1- methylpropyl and l-ethyl-2-methylpropyl or the different isomers. If the alkyl is at the end of a composite substituent, as, for example, in alkylcycloalkyl, the part of the composite substituent at the start, for example the cycloalkyl, may be mono- or polysubstituted identically or differently and independently by alkyl. The same also applies to composite substituents in which other radicals, for example alkenyl, alkynyl, hydroxyl, halogen, carbonyl, carbonyloxy and the like, are at the end.

[0035] The term “cycloalkyl” means alkyl closed to form a ring. Representative examples include but are not limited to cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. This definition also applies to cycloalkyl as a part of a composite substituent, for example cycloalkylalkyl etc., unless specifically defined elsewhere.

[0036] The term “alkoxy” used either alone or in compound words included Ci to Ge alkoxy. Non limiting examplesof alkoxy include methoxy, ethoxy, propoxy, 1 -methylethoxy, butoxy, 1 -methylpropoxy, 2-methylpropoxy, 1,1-dimethylethoxy, pentoxy, 1 -methylbutoxy, 2 -methylbutoxy, 3-methylbutoxy, 2,2- dimethylpropoxy, 1 -ethylpropoxy, hexoxy, 1,1 -dimethylpropoxy, 1,2- dimethylpropoxy, 1 -methylpentoxy, 2 -methylpentoxy, 3-methylpentoxy, 4- methylpentoxy, 1,1 -dimethylbutoxy, 1,2 -dimethylbutoxy, 1,3-dimethylbutoxy, 2,2-dimethylbutoxy, 2,3 -dimethylbutoxy, 3, 3 -dimethylbutoxy, 1 -ethylbutoxy, 2- ethylbutoxy, 1,1,2-trimethylpropoxy, 1,2,2-trimethylpropoxy, 1 -ethyl- 1- methylpropoxy and l-ethyl-2-methylpropoxy and the different isomers. This definition also applies to alkoxy as a part of a composite substituent, for example haloalkoxy, alkynylalkoxy, etc., unless specifically defined elsewhere.

[0037] The term ’’hydroxy” means -OH.

[0038] The term “halogen”, either alone or in compound words such as “haloalkyl”, includes fluorine, chlorine, bromine or iodine. Further, when used in compound words such as “haloalkyl”, said alkyl may be partially or fully substituted with halogen atoms which may be the same or different.

[0039] The term “halogen”, either alone or in compound words such as “haloalkyl”, includes fluorine, chlorine, bromine or iodine. Further, when used in compound words such as “haloalkyl”, said alkyl may be partially or fully substituted with halogen atoms which may be the same or different. Non-limiting examples of “haloalkyl” include chloromethyl, bromomethyl, dichloromethyl, trichloromethyl, fluoromethyl, difluoromethyl, trifluoromethyl, chlorofluoromethyl, dichlorofluoromethyl, chlorodifluoromethyl, 1 -chloroethyl, 1- bromoethyl, 1-fluoroethyl, 2-fluoroethyl, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, 2- chloro-2-fluoroethyl, 2-chloro-2,2-difluoroethyl, 2,2-dichloro-2-fluoroethyl, 2,2,2- trichloroethyl, pentafluoroethyl, l,l-dichloro-2,2,2-trifluoroethyl, and 1,1,1- trifluoroprop-2-yl. This definition also applies to haloalkyl as a part of a composite substituent, unless specifically defined elsewhere.

[0040] The term "hetero" in connection with rings refers to a ring in which at least one ring atom is not carbon and which can contain 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, oxygen and sulfur, provided that each ring contains no more than 4 nitrogen, no more than 2 oxygen and no more than 2 sulfur.

[0041] The term “aromatic” indicates that the Huckel rule is satisfied and the term “non-aromatic” indicates that the Huckel rule is not satisfied.

[0042] The term “heterocycle” or “heterocyclic” or “heterocyclyl” includes “aromatic heterocycle” or “heteroaryl bicyclic ring system” and “nonaromatic heterocycle “ or polycyclic or bicyclic (spiro, fused, bridged, non-fused) ring compounds in which ring may be aromatic or non-aromatic, wherein the heterocycle ring contains at least one heteroatom selected from N, O, S(0)o-2, and / or C ring member of the heterocycle may be replaced by C(=O) and C(=S).

[0043] The term "non-aromatic heterocycle” or “non-aromatic heterocyclic” means three- to ten-membered, preferably three- to six-membered, saturated or partially unsaturated heterocycle containing one to four heteroatoms, selected from the group of oxygen, nitrogen and sulphur; mono, bi- or tricyclic heterocycles which contain, in addition to carbon ring members, one to three nitrogen atoms and / or one oxygen or sulphur atom or one or two oxygen and / or sulphur atoms; if the ring contains more than one oxygen atom, they are not directly adjacent; for example (but not limited to) oxetanyl, thietanyl, oxiranyl, aziridinyl, azetidinyl, tetrahydrofuranyl, tetrahydrothienyl, pyrrolidinyl, isoxazolidinyl, isothiazolidinyl, pyrazolidinyl, oxazolidinyl, thiazolidinyl, imidazolidinyl, oxadiazolidinyl, thiadiazolidinyl, triazolidinyl, dihydrofuryl, dihydrothienyl, pyrrolinyl, isoxazolinyl, isothiazolinyl, dihydropyrazolyl, dihydrooxazolyl, dihydro thiazolyl, piperidinyl, pyrazynyl, morpholinyl, thiomorphlinyl, 1,3-dioxany, tetrahydropyranyl, tetrahydro thienyl; wherein these rings are attached to the skeleton via one of the carbon or nitrogen of said rings. This definition also applies to heterocyclyl as a part of a composite substituent, for example heterocyclylalkyl etc., unless specifically defined elsewhere.

[0044] The term "heteroaryl" or "aromatic heterocyclic" means 5 - membered, fully unsaturated monocyclic ring system containing one to four heteroatoms selected from the group of oxygen, nitrogen and sulphur; if the ring contains more than one oxygen atom, they are not directly adjacent; 5 -membered heteroaryl containing one to four nitrogen atoms or one to three nitrogen atoms and one sulphur or oxygen atom; 5-membered heteroaryl groups which, in addition tocarbon atoms, may contain one to four nitrogen atoms or one to three nitrogen atoms and one sulphur or oxygen atom as ring members, for example (but not limited thereto) furyl, thienyl, pyrrolyl, isoxazolyl, isothiazolyl, pyrazolyl, oxazolyl, thiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl; wherein these rings are attached to the skeleton via one of the carbon or nitrogen of said rings,

[0045] To achieve at least one of the above defined objectives, the present invention is described in the following embodiments.Embodiment-001: The present invention provides a method for the synthesis of compounds of formula (I) from substituted amides of formula (IV),formula (I) wherein,R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, Ci- C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and n represents an integer selected from 0-4; comprising the steps of:A. Preparing an isatin of formula (VI),formula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and n represents an integer selected from 0-4; by reacting a mixture of, i. an amide of formula (IV)wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl, n represents an integer selected from 0-4; and R10is selected from the group consisting of OH, Cl, Br and C1-C4 alkoxy; ii. amine of formula (XA)HN(R5aR5b) (XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids; optionally in the presence of a solvent; andB . preparing a compound of formula (I) by reacting a mixture of, i. an isatin of formula (VI) obtained from step A; ii. a base; iii. optionally in the presence of a solvent; iv. an amine of formula (IX) or salt thereof;H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and v. an oxidizing agent.Embodiment-001 A: The present invention provides a method for the synthesis of compounds of formula (IA) from substituted amides of formula (IVA),formula (IA) wherein,R1, R2, R3are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl; and R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; comprising the steps of:A. preparing an isatin of formula (VIA),formula (VIA) wherein R1, R2and R3is selected from hydrogen, halogen, C1-C12 alkyl, Ci- C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;by reacting a mixture of, i. an amide of formula (IVA)wherein,R1, R2, R3are independently selected from hydrogen, halogen, Ci- Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3- Cs cycloalkyl; and wherein R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy; ii. an amine of formula (XA)HN(R5aR5b) (XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids; optionally in the presence of a solvent; andB. preparing a compound of formula (IA) by reacting a mixture of; i. an isatin compound of formula (VIA) obtained in step A; ii. a base, iii. optionally in the presence of a solvent; iv. an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; v. an oxidizing agent.Embodiment-00 IB: The present invention provides a method for the synthesis of compounds of formula (IB) from substituted amides of formula (IVB),formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I; comprising the steps of:A. preparing an isatin of formula (VIB),formula (VIB)wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; wherein X = Cl, Br, or I; by reacting a mixture of, i. an amide of formula (IVB)wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and Ci- C4 alkoxy, and wherein X = Cl, Br or I; ii. an amine of formula (XA)HN(R5aR5b)(XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids; and iv. optionally in the presence of a solvent;B. preparing a compound of formula (IB), by reacting a mixture of, i. an isatin compound of formula (VIB) obtained in step-A;ii. a base; iii. optionally in the presence of a solvent; iv. an amine compound of formula (IX) or salt thereof,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and v. an oxidizing agent.Embodiment-001C: The present invention provides a method for the synthesis of compounds of formula (IB) from substituted amides of formula (IVC),formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I, comprising the steps of:A. preparing an isatin of formula (VIB)formula (VIB) wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; wherein X = Cl, Br, or I; by reacting a mixture of, i. an amide of formula (IVC)wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl; andR10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy; ii. an amine of formula (XA)HN(R5aR5b) (XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids, andiv. optionally in the presence of a solvent; and vi. halogenating the isatin of formula (VIC), formed after (iv) above, with a halogenation reagent to obtain an isatin of formula VIB;wherein R1and R2are independently selected from hydrogen, halogen, Ci- Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl; and X = Cl, Br, or I;B. preparing a compound of formula (IB), by reacting a mixture of, i. an isatin compound of formula (VIB) obtained in step-A; ii. a base; iii. optionally in the presence of a solvent; iv. an amine compound of formula (IX) or salt thereof,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; v. an oxidizing agent.Embodiment-00 ID: The present invention provides a method for the synthesis of compounds of formula (IB) from substituted amides of formula (IVC),formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I, comprising the steps of:A. preparing an isatin of formula (VIC)formula (VIC) wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; by reacting a mixture of, i. an amide of formula (IVC) 1wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl; andR10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy; ii. an amine of formula (XA)HN(R5aR5b) (XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids, optionally in the presence of a solvent to obtain compound of formula (VIC)B. preparing a compound of formula (IC),formula (IC) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; by reacting a mixture of, i. an isatin compound of formula (VIC) obtained in step-A; ii. a base; iii. optionally in the presence of a solvent; iv. an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; v. an oxidizing agent; to obtain a compound of formula (IC),C. preparing a compound of formula (IB) from a compound of formula (IC) obtained from step-B, by halogenating the compound of formula (IC) using a suitable halogenating reagents to obtain a compound of formula (IB).Embodiment-002: According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (I) from substituted amides of formula (IV),formula (I) wherein,R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and n represents integer selected from 0-4; comprising the steps of:A. preparing an isatin of formula (VI)formula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; by,(A-a). reacting the amide of formula (IV) with a suitable amine of formula HN(R5aR5b) (XA) optionally in the presence of a suitable solvent to obtain a compound of formula (V), and(A-b). cyclising the compound of formula (V) with a cyclising reagent to obtain isatin of formula (VI), wherein the cyclization of the amide of formula (V) is carried out without isolation from the reaction mixture;wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy;R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; and wherein the cyclising reagent is a mixture of two or more acids;B. preparing the amide of formula (I) by,(B-a). forming a mixture comprising of i. an isatin of formula (VI) obtained in step-A;, ii. a base; and iii. optionally in the presence of a solvent;(B-b). introducing an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR1is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl, into the mixture; and(B-c) introducing an oxidation agent into the mixture.Embodiment-002 A: According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (IA) from substituted amide of formula (IVA),formula (IA)wherein,R1, R2, R3are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl; and R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; comprising the steps of:A. preparing an isatin of formula (VIA)formula (VIA) wherein R1, R2and R3is selected from hydrogen, halogen, C1-C12 alkyl, Ci- C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;(A-a). reacting the amide of formula (IVA) with a suitable amine of formula HN(R5aR5b) (XA) and optionally in the presence of a suitable solvent to obtain a compound of formula (VA), and(A-b). cyclising the compound of formula (VA) with a cyclising reagent to obtain isatin of formula (VIA), wherein the cyclization of the amide of formula (VA) is carried out without isolation from the reaction mixture;wherein R1, R2, R3are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl,R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy, R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring, and wherein the cyclising reagent is a mixture of two or more acids;B. preparing the amide of formula (IA) by,(B-a). forming a mixture comprising of i. an isatin of formula (VIA) obtained in step-A, ii. a base; and iii. optionally in the presence of a solvent;(B-b). introducing an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR4is selected from hydrogen, C2-C12 alkyl, C2-C12 alkenyl, C1-C12 alkynyl, C2-C12 haloalkyl, C2-C12 haloalkenyl, C1-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; into the mixture,(B-c) introducing an oxidation agent into the mixture.Embodiment-002B : According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (IB) from substituted amides of formula (IVB),formula (IB)wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I, comprising the steps of:A. preparing an isatin of formula (VIB),formula (VIB) wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and wherein X = Cl, Br, or I;(A-a). reacting the amide of formula (IVB) with a suitable amine of formula HN(R5aR5b) (XA) and optionally in the presence of a suitable solvent to obtain a compound of formula (VB), and(A-b). cyclising the compound of formula (VB) with a cyclising reagent to obtain an isatin of formula (VIB), wherein the cyclization of the amide of formula (VB) is carried out without isolation from the reaction mixture;wherein R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl, R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy, R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring,X = Cl, Br, or I, and wherein the cyclising reagent is a mixture of two or more acids;B. preparing the amide of formula IB by,(B-a). forming a mixture comprising of i. an isatin of formula (VIB) or salt thereof, obtained in step- A; ii. a base; and iii. optionally in the presence of a solvent;(B-b). introducing an amine compound of formula (IX) or salt thereof , H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C1-C12 haloalkenyl, Ci-C 12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; into the mixture,(B-c) introducing an oxidation agent into the mixture.Embodiment-002C: According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (IB) from substituted amides of formula (IVC),formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I; comprising the steps of:A. preparing an isatin of formula (VIB),formula (VIB) wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;(A-a). reacting the amide of formula (IVC) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (VC), and(A-b). cyclising the compound of formula (VC) with a cyclising reagent to obtain an isatin of formula (VIC), wherein the cyclization of theamide of formula (VC) is carried out without isolation from the reaction mixture;wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl,R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy, R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring, wherein the cyclising reagent is a mixture of two or more acids; and(A-c). halogenating the isatin of formula VIC to obtain an isatin of formula VIB;B. preparing the amide of formula IB by,(B-a). forming a mixture comprising of i. an isatin of formula (VIB) or salt thereof, obtained in step-A ii. a base; iii. optionally in the presence of a solvent;(B-b) introducing an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX)whereinR1and R2are independently selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; into the mixture, (B-c) introducing an oxidation agent into the mixture.Embodiment-002D: According to another embodiment the present invention provides a method for the synthesis of compounds of formula (IB) from substituted amides of formula (IVC),formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I, comprising the steps of:A. preparing an isatin of formula (VIC)formula (VIC) wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; by reacting a mixture of,(A-a). reacting the amide of formula (IVC) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (VC), and(A-b). cyclising the compound of formula (VC) with a cyclising reagent to obtain the isatin of formula (VIC), wherein the cyclization of the amide of formula (VC) is carried out without isolation from the reaction mixture;wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl,R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy, R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring, wherein the cyclising reagent is a mixture of two or more acids;B. preparing a compound of formula (IC),formula (IC) wherein,R1and R2are independently selected from hydrogen, halogen, Ci- Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl;(B-a). forming a mixture comprising of i. an isatin of formula (VIC) or salt thereof, obtained in step-A ii. a base; iii. optionally in the presence of a solvent;(B-b) introducing an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; into the mixture,(B-c) introducing an oxidation agent into the mixture.C. preparing a compound of formula (IB) from a compound of formula (IC) obtained from step-B, by halogenating the compound of formula (IC) using a suitable halogenating reagents to obtain a compound of formula (IB).Embodiment-003: According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (I) from substituted amide of formula (IV),formula (I) wherein,R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and n represents integer selected from 0-4; comprising the steps of:A. preparing an isatin of formula (VI)formula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and n represent an integer selected from 0-4;(A-a). reacting the amide of formula (IV) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (V), and(A-b). cyclising the compound of formula (V) with a cyclising reagent to obtain the isatin of formula (VI), wherein the cyclization of the amide of formula (V) is carried out by optionally isolating the compound of formula (V) from the reaction mixture;wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy;R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; and n represents an integer selected from 0-4; wherein the cyclising reagent is a mixture of two or more acids;B. preparing the amide of formula (I) by,(B-a). forming a mixture comprising of i. the isatin of formula (VI) or salt thereof, obtained in step-A ii. a base and optionally in the presence of a solvent; to obtain a compound of formula (XI),formula (XI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; M+represent metal ion; and n represents an integer selected from 0-4;wherein the compound of formula (XI) or salt thereof, was optionally isolated;(B-b) introducing an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; into the mixture, reacting the mixture, to obtain a compound of formula (XII) or salt thereof,formula (XII) wherein,R is selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and n represents an integer selected from 0-4; wherein the compound of formula (XII) or salt thereof, was optionally isolated;(B-c) introducing an oxidation agent to the mixture; and reacting the mixture to obtain a compound of formula (I).Embodiment-003 A: According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (IA) from substituted amides of formula (IVA),formula (IA) wherein,R1, R2, R3are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl; and R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; comprising the steps of:A. preparing an isatin of formula (VIA)formula (VIA) wherein R1, R2, and R3are selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;(A-a). reacting the amide of formula (IVA) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (VA), and(A-b). cyclising the compound of formula (VA) with a cyclising reagent to obtain the isatin of formula (VIA), wherein the cyclization of the amide of formula (VA) is carried out by optionally isolating the compound of formula (VA) from the reaction mixture;wherein R1, R2, R3are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl, R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy, R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring, and wherein the cyclising reagent is a mixture of two or more acids;B. preparing the amide of formula (IA) by,(B-a). forming a mixture comprising of i. the isatin of formula (VIA) or salt thereof, obtained in step- A ii. a base and optionally in the presence of a solvent; to obtain a compound of formula (XIA),formula (XIA) wherein R1, R2and R3are selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; M+represent metal ion; wherein the compound of formula (XIA) or salt thereof, was optionally isolated;(B-b) introducing an amine compound of formula (IX) or salt thereof,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; into the mixture, reacting the mixture, to obtain a compound of formula (XIIA) or a salt thereof,wherein,R1, R2and R3are selected from hydrogen, halogen, C1-C12 alkyl, Ci- C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl,C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and wherein the compound of formula (XIIA) or salt thereof, was optionally isolated;(B-c) introducing an oxidation agent to the mixture; and reacting the mixture to obtain a compound of formula (IA).Embodiment-003 B: According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (IB) from substituted amides of formula (IVB),formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I; comprising the steps of:A. preparing an isatin of formula (VIB),formula (VIB) wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and X = Cl, Br, or I,(A-a). reacting the amide of formula (IVB) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (VB), and(A-b). cyclising the compound of formula (VB) with a cyclising reagent to obtain the isatin of formula (VIB), wherein the cyclization of the amide of formula (VB) is carried out by optionally isolating the compound of formula (VB) from the reaction mixture;wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and Ci- C4 alkoxy;R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring;X = Cl, Br or I, andwherein the cyclising reagent is a mixture of two or more acids;B. preparing the amide of formula IB by,(B-a). forming a mixture comprising of i. the isatin of formula (VIB) or salt thereof obtained in step A, ii. a base and optionally in the presence of a solvent; to obtain a compound of formula (XIB),formula (XIB) wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; M+represent metal ion, X = Cl, Br, or I; and wherein the compound of formula (XIB) or salt thereof, was optionally isolated;(B-b) introducing an amine compound of formula (IX) or a salt thereof,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; into the mixture, reacting the mixture, to obtain a compound of formula (XIIB) or a salt thereof,wherein,R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; X = Cl, Br, or I; and wherein the compound of formula (XIIB) or salt thereof, was optionally isolated;(B-c) introducing an oxidation agent to the mixture; and reacting the mixture to obtain a compound of formula (IB).Embodiment-003 C: According to another embodiment the present invention provides a method for the synthesis of compounds of formula (IB) from substituted amides of formula (IVC),formula (IB)wherein,R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I; comprising the steps of:A. preparing an isatin of formula (VIC)formula (VIB) wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3- Cs cycloalkyl; and X = Cl, Br, or I,(A-a). reacting the amide of formula (IVC) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (VC),(A-b). cyclising the compound of formula (VC) with a cyclising reagent to obtain the isatin of formula (VIC), wherein the cyclization of the amide of formula (VC) is carried out after optionally isolating the compound of formula (VC) from the reaction mixture;wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and Ci- C4 alkoxy,R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; and wherein the cyclising reagent is a mixture of two or more acids; and(A-c). halogenating the isatin of formula (VIC) to obtain isatin of formula (VIB);wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl, and wherein X = Cl, Br, or I.B. preparing the amide of formula (IB) by;(B-a). forming a mixture comprising of i. the isatin of formula (VIB) or salt thereof, obtained from step A; ii. a base and optionally in the presence of a solvent; to obtain a compound of formula (XIB),formula (XIB) wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; X = Cl, Br, or I; and wherein the compound of formula (XIB) or salt thereof, was optionally isolated;(B-b) introducing an amine compound of formula (IX) or a salt thereof,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; into the mixture, reacting the mixture, to obtain a compound of formula (XIIB) or a salt thereof,R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I; and wherein the compound of formula (XIIA) or a salt thereof, was optionally isolated;(B-c) introducing an oxidation agent to the mixture; and reacting the mixture to obtain a compound of formula (IB).

[0046] Embodiment-003 D: According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (IB) from substituted amides of formula (IVC),formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2C12 haloalkynyl, C1-C12 alkoxy, Ci- C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I; comprising the steps of:A. preparing an isatin of formula (VIC)formula (VIC) wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and X = Cl, Br, or I,(A-a). reacting the amide of formula (IVC) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (VC),(A-b). cyclising the compound of formula (VC) with a cyclising reagent to obtain the isatin of formula (VIC), wherein the cyclization of the amide of formula (VC) is carried out after optionally isolating the compound of formula (VC) from the reaction mixture;wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and Ci- C4 alkoxy,R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; andB . preparing the amide of formula (IC)formula (IC) wherein,R1and R2are independently selected from hydrogen, halogen, Ci- Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl;(B-a). forming a mixture comprising of iii. the isatin of formula (VIC) or a salt thereof, obtained from step A; iv. a base and optionally in the presence of solvent; to obtain a compound of formula (XIC),formula (XIC) wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; X = Cl, Br, or I; and wherein the compound of formula (XIC) or a salt thereof, was optionally isolated;(B-b) introducing an amine compound of formula (IX) or a salt thereof,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; into the mixture, reacting the mixture, to obtain a compound of formula (XIIB) or a salt thereof,formula (XIIC) wherein,R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I; and wherein the compound of formula (XIIC) or a salt thereof, was optionally isolated;(B-c) introducing an oxidation agent to the mixture; and reacting the mixture to obtain compound of formula (IC);C. preparing a compound of formula (IB) from a compound of formula (IC) obtained from step-B, by halogenating the compound of formula (IC) using a suitable halogenating reagents to obtain a compound of formula (IB).D.

[0047] The embodiments 001, 001 (A, B, C, D), 002, 002 (A, B, C, D), 003, and 003 (A, B, C, D) provide a method for the synthesis of compounds of formula (I) in two steps, i.e., step A and step B. Step A further comprises the sub-steps of (A-a), (A-b), and (A-c) and step B further comprises the sub-steps of (B-a), (B-b), and (B-c). Step A can be performed by carrying out the sub-steps (A-a) and (A-b) separately, or by combining sub-steps (A-a) and (A-b) in a single step, or by performing sub-step (A-b) without isolating the product of step (A-a). Likewise, Step B can be performed by carrying out the sub-steps (B-a), (B-b), and (B-c) separately, or by combining sub-steps (B-a), (B-b) and (B-c) in a single step.Embodiment-004: According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (ID) from substituted amides of formula (IB),formula (ID) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or Cs-Cs cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl;comprising the step of reacting a compound of formula IB with a source of CN“ ions and optionally in the presence of a ligand;formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I; wherein the compounds of formula (IB) are prepared from substituted amides of formula (IVB) according to the Embodiment-00 IB; comprising the steps of:A. preparing an isatin of formula (VIB) by reacting a mixture of, i. an amide of formula (IVB)wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and Ci- C4 alkoxy, and wherein X = Cl, Br or I; ii. an amine of formula (XA)HN(R5aR5b)(XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids; and iv. optionally in the presence of a solvent;B. preparing a compound of formula (IB)formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I; by reacting a mixture of, i. an isatin compound of formula (VIB) obtained in step-Aformula (VIB) wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and X = Cl, Br, or I. ii. a base; iii. optionally in the presence of a solvent; iv. an amine compound of formula (IX) or a salt thereof,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C1-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and v. an oxidizing agent.Embodiment-004 A: According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (ID) from substituted amides of formula (IB),formula (ID)wherein,R1, R2and R4are same as defined above; comprising the step of reacting a compound of formula (IB) obtained according to any of above embodiments with a source of CN’ ions and in the presence of a suitable ligand;Formula (IB) wherein,R1, R2and R4are same as defined above; and X = Cl, Br, or I.Embodiment-004B : According to another embodiment, the present invention provides a method for the synthesis of compounds of formula (ID) from substituted amides of formula (IB),formula (ID) wherein,R1and R4= methyl; comprising the step of reacting a compound of formula (IB) obtained according to any of above embodiments with a source of CN’ ions and in the presence of a suitable ligand;Formula (IB) wherein,R1and R4= methyl; and X = Cl, Br, or I.Embodiment-005: In another embodiment, the compound of formula (VI), according to any of above embodiments, is prepared in a single step comprising the step of:formula (VI) by reacting a mixture of, i. An amide of formula (IV)wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, Ci- C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, Cl, Br, I and C1-C4 alkoxy; and n represents an integer selected from 0-4; ii. an amine of formula (XA),HN(R5aR5b) formula(XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids, optionally in the presence of a solvent.Embodiment-006: In another embodiment, the present invention relates to a method for the preparation of a compound of formula (A) or of salts thereof;Formula (A) wherein,R is selected from the group comprising of halogen, C1-C4 alkyl, C1-C4 haloalkyl and C3-C4-cycloalkyl;R4is selected from the group consisting of hydrogen, Ci-Ce alkyl, C3-C6 cycloalkyl, C3-C6 cycloalkyl-Ci-C4 alkyl;R5is selected from the group comprising of halogen, C1-C4 alkyl, C1-C4 haloalkyl, CHF2, CF3, C1-C4 alkoxy, OCHF2, OCH2CF3,heterocyclyl;wherein -A- is selected from the group comprising of a direct bond, CHR6, -O- or -S-; and said heterocyclyl may optionally be substituted with one or more group selected from hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl;R6is selected from the group comprising of hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl; X represents Cl, Br, or I; and n represents an integer selected from 0-4; comprising the step of reacting a substituted anthranilic amide of formula (I),wherein,R is selected from the group comprising of halogen, cyano, C1-C4 alkyl, Ci- C4 haloalkyl and C3-C4-cycloalkyl;R4is selected from the group consisting of hydrogen, Ci-Ce alkyl, C3-C6 cycloalkyl, C3-C6 cycloalkyl-Ci-C4 alkyl; and n represents an integer selected from 0-4; with a compound of formula (B)wherein W is OH, Cl, O-C1-C4 alkyl, O-C(O)Ci-C4 alkyl or imidazolyl;R5is selected from the group comprising of halogen, C1-C4 alkyl, C1-C4 haloalkyl, CHF2, CF3, C1-C4 alkoxy, OCF2H, OCH2CF3, or -A-C1-C5 heterocyclyl;Wherein -A- is selected from the group comprising of a direct bond, CHR6, - O- or -S-; and said heterocyclyl may optionally be substituted with one or more group selected from hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl;R6is selected from the group comprising of hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl andX represents Cl, F, Br, or I; in the presence of a coupling reagent, a suitable solvent, and optionally in the presence of a base, according to the following reaction scheme as depicted below,wherein, the compound of formula (I) is prepared comprising the steps of:A. preparing an isatin of formula (VI)formula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, Ci- C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and n represents an integer selected from 0-4; by reacting a mixture of, i. an amide of formula (IV)wherein R is selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl, wherein R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy, ii. an amine of formula (XA)HN(R5aR5b) (XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring, iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids, iv. optionally in the presence of a solvent, andB . obtaining a compound of formula (I) by reacting a mixture of, i. the isatin of formula (VI) obtained in step-Aformula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, Ci- C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; ii. a base; iii. optionally in the presence of a solvent; iv. an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; v. an oxidizing agent; wherein the said method optionally comprising the step of; halogenating the isatin of formula (VI) wherein at least one R is hydrogen with a suitable halogenation reagent, optionally in the presence of a suitable solvent to obtain halogenated isatins of formula (VI).The compounds of formula (B) can be obtained by either of the processes disclosed in W02003015518, W020030155519, WO2011157664 and W02013030100.Embodiment-007: In another embodiment, the present invention relates to a method for the synthesis of a compound of formula (I), wherein said method further comprises the step of preparation of a compound of formula (Aa) or of salts thereof;Formula (Aa) wherein,R1, R2, R3are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from the group consisting of hydrogen, Ci-Ce alkyl, C3-C6 cycloalkyl, C3-C6 cycloalkyl-Ci-C4 alkyl;R5is selected from the group comprising of halogen, C1-C4 alkyl, C1-C4 haloalkyl, CHF2, CF3, C1-C4 alkoxy, OCHF2, OCH2CF3,heterocyclyl; wherein -A- is selected from the group comprising of a direct bond, CHR6, -O- or -S-; and said heterocyclyl may optionally be substituted with one or more group selected from hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl;R6is selected from the group comprising of hydrogen, halogen, cyano, Ci- C4 alkyl or C1-C4 haloalkyl; X represents halogen; comprising the step of: reacting the substituted anthranil amide compound of formula (I), wherein the anthranil amide compound of formula (I) is a compound of (IA),formula (IA) wherein,R1, R2, R3are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl; and R4is selected from the group consisting of hydrogen, Ci-Ce alkyl, C3-Ce cycloalkyl, C3-C6 cycloalkyl-Ci-C4 alkyl; with a pyrazole compound of formula (B),wherein W is OH, Cl, O-C1-C4 alkyl, O-C(O)Ci-C4 alkyl or imidazolyl;R5is selected from the group comprising of halogen, C1-C4 alkyl, C1-C4 haloalkyl, CHF2, CF3, C1-C4 alkoxy, OCF2H, OCH2CF3,heterocyclyl; wherein -A- is selected from the group comprising of direct bond, CHR6, - O- or -S-; and said heterocyclyl may optionally be substituted with one or more group selected from hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl;R6is selected from the group comprising of hydrogen, halogen, cyano, Ci- C4 alkyl or C1-C4 haloalkyl andX represents halogen; in the presence of a coupling reagent, a suitable solvent, and optionally in the presence of a base.Embodiment-008: According to an embodiment, the compound of formula (IV) is prepared by reacting the compound of formula (II) with the compound of formula (III) to afford a compound of formula (IV), optionally in the presence of a suitable base and a solvent;wherein, R10is selected from the group consisting of OH, Cl, Br, I and C1-C4 alkoxy; and wherein R1, R2and R3are as defined herein above.Embodiment-009: In an embodiment, the compound of formula (IVA) is prepared by reacting the compound of formula (II) with the compound of formula (III A) to afford a compound of formula (IVA), optionally in the presence of a suitable base and a solvent;wherein, R1, R2and R3are as defined herein above.Embodiment-010: In an embodiment, the compound of formula (IVA) is prepared by reacting the compound of formula (II) with the compound of formula (IIIB) to afford a compound of formula (IVA), optionally in the presence of a suitable base and a solvent;(II) (Illb) (IVa) wherein, R1, R2and R3are as defined herein above.Embodiment-011: In one embodiment, compounds of formula (VIC) can be converted to compounds of formula (VICC) by reacting them with anappropriate halogenating agent such chlorine or bromine gas; as for instance chlorine gas; as shown in the following Scheme:Embodiment-012: In one embodiment, compounds of formula (IC) can be converted to compounds of formula (IB) by reacting them with an appropriate halogenating agent such as chlorine or bromine gas; H2O2 and HC1 or H2O2 and HBr; as shown in the following Scheme:Embodiment-013: In another embodiment, compounds of formula (IVC) can be converted to compounds of formula (IVB) by reacting them with halogenating agents such as for instance chlorine gas; or hydrochloric acid / hydrobromic acid and hydrogen peroxide; as shown in the following Scheme:wherein R1, R10and X have the same meaning as defined above.Embodiment-014: The method according to any of the above embodiments comprising optionally halogenating the isatins of formula (VI), (VIA), and (VIC) wherein at least one R is hydrogen with a suitable halogenation reagent, optionally in the presence of a suitable solvent to obtain halogenated isatins of formula (VI), (VIA), and (VIB).Embodiment-015: According to any of the above embodiments, halogenations as described in the present invention are carried out in the presence of suitable halogenating reagents which include, but are not limited to, HX, NaX, KX, CuX2, MgX2, CsX, ZnX2, SOC12, SO2C12, COC12, X2, C(=O)(OC13)2, Z-BuOCl, NaOCl, HX+H2O2, A-halosuccinamides, methane sulfonyl chloride, POX3, PX3, PX5, metal halides or mixture thereof; wherein X is Cl, Br, I or F.Embodiment-016: According to any of the above embodiments, halogenations as described in step-C, and (A-c) mentioned in the present invention are carried out in the presence of suitable halogenating reagents which are selected from X2, particularly chlorine or bromine gas; SOC12, SO2C12, or HX+H2O2wherein X represents Cl or Br.Embodiment-017: According to any of the above embodiments, the amine of formula (XA) HN(R5aR5b), as used in the instant invention is selected from, but not limited to, various mono- and dialkylated amines and cyclic amines, methylamine, dimethylamine, diethylamine, diisopropylamine, di-tert butylamine, dicyclohexylamine, ethyl methylamine, pyrrolidine, 2,5- dimethyl pyrrolidine, morpholine, 3,5-dimethyl-morpholine, piperidine, 2,6-dimethyl-piperidine, piperazin and 2,5-dimethyl-pyrrole.Embodiment-018: According to any of the above embodiments, the amine of formula (XA) HN(R5aR5b), is selected from secondary amines, cyclic secondary amines, dimethyl amine, diethyl amine, ethyl methylamine, morpholine, diisopropylamine, diisopropyl ethyl amine, diisopropyl amine and di-tert butyl amine.Embodiment-019: According to any of the above embodiments the isatins of formula (VI), (VIA), (VIB), and (VIC) in step A, and the anthranilic amidesof formula (I), (IA), and (IB), in step B are prepared without isolating any of the intermediates obtained of steps A and B.Embodiment-020: According to any of the above embodiments the isatin of formula (VI) in step A, and the anthranilic amide of formula (I) in step B are prepared by optionally isolating one or more intermediates formed during the reaction.Embodiment-021: According to any of the above embodiments, the reagents for cyclising compounds of formula (V) useful in the present invention are a mixture of two or more acids selected from the group consisting of hydrochloric acid, hydrobromic acid, sulfuric acid, formic acid, acetic acid, trifluoroacetic acid, propionic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, acidic ion-exchange resin, AIX3, BX3, FcX4. ZnX2, GaX3, InX3, TiX4, BiX3, SbX3, SnX2, SnX4, SiX4, POX3, and hypovalent Lewis acids, wherein X = F, Cl, Br and I.Embodiment-022: According to any of the above embodiments, the reagents for cyclising compounds of formula (V) useful in the present invention are a mixture of two or more acids selected from the group consisting of sulfuric acid, formic acid, trifluoroacetic acid, methanesulfonic acid, and POX3, wherein X = Cl, or Br.Embodiment-023: According to any of the above embodiments, the reagents for cyclising compounds of formula (V) useful in the present invention are a mixture of two or more acids selected in the ratio of 1 :20 to 20: 1 ; preferably 1:10 to 10:1; more preferably 1:5 to 5: 1.Embodiment-024: The source of CN“ ions in carrying out the cyanation reactions mentioned in the present invention of embodiment-4 , 4A, 4B and 4C are selected from metal cyanaide particularly, sodium cyanide (NaCN), potassium cyanide (KCN), copper(I)cyanide (CuCN), zinc(II) cyanide(Zn(CN)2), sodium ferrocyanide (Na4Fe(CN)6 Potassium hexacyanoferrate (II) (K4[Fe(CN)6]) .Embodiment-025: The ligands used in carrying out the cyanation reactions mentioned in the present invention of embodiment-4, 4A, 4B and 4C are selected from 1,1 -dimethylethylenediamine (DEMDA), ethylenediamine, 1-butyl- IH-imidazole, 2-picoline, 3-picoline, 2,6-lutidine, 2- hydroxypyridine or 1 -methyl pyrolidine.Embodiment-026: The catalysts used in carrying out the cyanation reactions mentioned in the present invention of embodiment-4, 4A, 4B and 4C are selected from copper salts such as copper (I) iodide (Cui), copper (I) chloride, copper (I) bromide, copper acetate or potassium salts such as potassium iodide (KI).Embodiment-027 : According to any of the above embodiments, a base is a inorganic base and selected from alkali metal and alkaline earth metal hydroxides, alkali metal and alkaline earth metal carbonates, alkali metal and alkaline earth metal oxides, alkali metal and alkaline earth metal phosphates and any combination thereof, each alkali metal being independently selected from lithium, sodium and potassium and each alkaline earth metal being independently selected from calcium, magnesium and barium.Embodiment-028: According to any of the above embodiments the said inorganic base is selected from sodium carbonate (Na2COs), calcium carbonate (CaCCE), cesium carbonate (CS2CO3), lithium carbonate (Li2CO3), potassium carbonate (K2CO3), lithium hydroxide (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), cesium hydroxide (CsOH), calcium hydroxide (Ca(0H)2), sodium diphosphate (Na2HPO4),sodium phosphate (NasPCU), potassium diphosphate (K2HPO4), and potassium phosphate (K3PO4).Embodiment-029: According to any of the above embodiments an oxidizing agent is selected from oxygen, chlorine, sodium hypochlorite, chromium trioxide, 3-chloroperoxybenzoic acid, hydrogen peroxide, tert-butyl hydroperoxide, peroxyacetic acid, potassium peroxymonosulfate, potassium permanganate, and combinations thereof.Embodiment-030: According to any of the above embodiments there is a method provided wherein, the said base is selected from sodium hydroxide and the said oxidizing agent is selected from hydrogen peroxide.Embodiment-031: According to any of the above embodiments, the amidation of the compounds of formula (IV), (IVA), (IVB), (IVC), (1 molar equivalent) in sub-step [A-a] is conducted using from 1 to 10, 1 to 5, 1 to 4, 1 to 3, 1 to 1.1 molar equivalents of the amine of formula (XA) HN(R5aR5b). The amidation reaction in sub-step [A-a], is conducted at a temperature in the range of 25 to 200 °C, 35 to 175 °C, 80 to 160 °C, 100 to 155 °C or 125 to 150 °C.Embodiment-032: According to any of the above embodiments, the cyclization of the compounds of formula (V), (VA), (VB), or (VC), (made from 1 molar equivalent of compounds of formula (IV), (IVA), (IVB), or (IVC)) in substep [A-b] is conducted using from 1 to 20, 1 to 15, 1 to 10, 1 to 7, 1 to 5 molar equivalents of the mixture of acids. If one of the acid is referred to as acid A and the other acid is referred to as acid B, then the two acids (Acid A: Acid B) can be mixed in a molar ratio in the range of 1:100 to 100:1, 1:50 to 50:1, 1:25 to 25:1, 1:10 to 10:1 or 1:5 to 5:1. The cyclization reaction in sub-step [A-b], is conducted at varying temperatures in the range of 0 to 200 °C, 10 to 180 °C, 25 to 160 °C, 25 to 140 °C or 25 to 130 °C.Embodiment-033: According to any of the above embodiments, the sub-step (B-a) for the conversion of the compounds of formula (VI), (VIA), (VIB) or (VIC) (1 molar equivalent) to compounds of formula (XI), (XIA) (XIB), or (XIC), is conducted using from 1 to 20, 1 to 15, 1 to 10, 1 to 7, 1 to 5, 1 to 2 or 1 molar equivalents of a suitable base, at temperatures in the range of from 0 to 100 °C.Embodiment-034: According to any of the above embodiments, the sub-step (B-b) for the conversion of the compounds of formula (XI), (XIA) (XIB), or (XIC), (obtained from 1 molar equivalent of the compounds of formula (VI), (VIA) (VIB) or (VIC) to the compounds of formula (XII), (XIIA), (XIIB), or (XIIC), is conducted using from 1 to 5, 1 to 4, 1 to 3, 1 to 2, or 1 molar equivalents of a suitable amine H2N-R4(IX).Embodiment-035: According to any of the above embodiments, the sub-step (B-c) for the conversion of compounds of formula (XII) (XIIA) (XIIB), or (XIIC), (obtained from 1 molar equivalent of compounds of forula (VI), (VIA), (VIB), or (VIC) to compounds of formula (I, IA, IB or IC) is conducted using from 1 to 20, 1 to 15, 1 to 10, 1 to 7, 1 to 5, 1 to 2 or 1 molar equivalents of a suitable oxidizing agent, at temperatures in the range of -40 to 50 °C. In any of the above embodiments, the reaction in step B, is conducted at various temperatures in the range of -40 to 50, -20 to 50, -10 to 30, 0 to 30 or 5 to 25 °C.Embodiment-036: According to any of the above embodiments, the halogenation of isatins of formula (VIC) (1 molar equivalent) is conducted using from 1 to 20, 1 to 15, 1 to 10, 1 to 8, 1 to 5, 1 to 4, 1 to 3, 1 to 2, or 1 molar equivalents of the halogenation reagent. This halogenation reaction isconducted at temperatures in the range from 0 to 150, 10 to 100, 10 to 100, 10 to 75, 10 to 65, or 10 to 55, °C.Embodiment-037 : The optional solvents useful in carrying out the reaction steps mentioned in the present invention are selected from aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, dodecane, decaline and the like; alicyclic hydrocarbons such as cycloalkanes: cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and the like; aromatic hydrocarbons such as toluene, xylene, mesitylene, benzene and the like; halogenated aromatic hydrocarbons as chlorobenzene, 1,2- dichlorobenzene, 1,3 -dichlorobenzene and the like; ethers such as diisopropyl ether, t-butyl methyl ether, tetrahydrofuran, 2-methyl tetrahydrofuran, dioxane, monoglyme, diglyme, methoxy-methane, methoxy-ethane, ethoxy-ethane, di-methoxyethane, di-ethoxyethane and the like; alcohols such as methanol, ethanol, n- or i-propanol, n-, i-, sec- or tert-butanol, ethanediol, propane- 1,2-diol, ethoxy ethanol, methoxy ethanol, ketones such as acetone, ethyl methyl ketone, esters such as ethyl acetate and methyl acetate; halogenated hydrocarbons such as dichloromethane, chloroform, dichloroethane and the like; nitriles, such as acetonitrile, propionitrile; polar aprotic solvents such as A imcthy formamide, dimethyl sulfoxide, A ncthyl-2-pyrrolidonc, 1, 3-dimethyl-3, 4,5,6- tetrahydro-2(lH)-pyrimidinone, hexamethylphosphortriamide, 1,3- dimethyl-2-imidazolidinone and the like; water or mixtures thereof.Embodiment-038: The solvent useful in carrying out the acylation reaction in embodiment 006, 007, and 008 mentioned in the present invention is selected from aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, dodecane and the like; alicyclic hydrocarbons such as cycloalkanes: cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and the like; aromatic hydrocarbons such as toluene, xylene,mesitylene, benzene and the like; halogenated aromatic hydrocarbons as chlorobenzene, 1,2-dichlorobenzene, 1,3 -dichlorobenzene and the like; ethers such as diisopropyl ether, t-butyl methyl ether, tetrahydrofuran, 2- methyl tetrahydrofuran, halogenated hydrocarbons such as dichloromethane, chloroform, dichloroethane and the like; polar aprotic solvents such as AAli methyl formamide, dimethyl sulfoxide, A / -mcthyl-2- pyrrolidone. Preferably halogenated hydrocarbons such as dichloromethane, dichloroethane and the like; aromatic hydrocarbons such as toluene and xylene.Embodiment-039: The solvents useful in carrying out the amidation reaction, sub-step (A-a), mentioned in the present invention are selected from polar aprotic solvents such as dichloromethane, A,A-dimethylformamide, dimethylsulfoxide and hydrocarbons such as hexane, heptane, octane, nonane, decane, dodecane and the like; alicyclic hydrocarbons such as cycloalkanes: cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, and the like; aromatic hydrocarbons such as toluene, xylene, mesitylene, benzene and the like.Embodiment-040: The solvents useful in carrying out the cyclising reaction, sub-step (A-b), mentioned in the present invention are selected from halogenated hydrocarbons such as dichloromethane, chloroform, dichloroethane and the like.Embodiment-041: The solvents useful in carrying out the reactions in sub-steps (B-a), and (B-b) mentioned in the present invention are selected from acetonitrile, ethers such as diisopropyl ether, t-butyl methyl ether, tetrahydrofuran, 2-methyl tetrahydrofuran, dioxane, monoglyme, diglyme, methoxy-methane, methoxy-ethane, ethoxy-ethane, di-methoxyethane, diethoxyethane and the like; water, and esters such as ethyl acetate and methyl acetate.Embodiment-042: The solvents useful in carrying out the reactions in step-C, and (A-c) mentioned in the present invention are selected from acetic acid, hydrochloric acid or hydrobromic acid.Embodiment-043: The solvents useful in carrying out the cyanation reaction mentioned in the present invention of embodiment-4, 4A, 4B and 4C are selected from A,A-di methyl formamide, A-methyl-2-pyrrolidone n-butanol, i-butanol, sec-butanol or tert-butanol.Embodiment-044: The reaction steps mentioned in the present invention can also be carried out in the absence of solvents.Embodiment-045: The compounds of formula (A) are obtained from the compounds of formula (I) and compounds of formula (B) wherein W is OH using a suitable reagent such as SOCh, SO2Ch, COC12, X2, C(=O)(OC13)2, chloramine-T, methane sulfonyl chloride, POX3, PX3, PX5 or metal halides; wherein X is Cl, Br.Embodiment-046: The compound of formula (Aa) is obtained from the compound of formula (IA) and a compound of formula (B) wherein W is Cl, O-C1-C4 alkyl using suitable reagents such as triethylamine, diisopropylamine, diisopropyl ethyl amine, pyridine, alkylated and dialkylated pyridines, dimethylamino pyridine, and the like, or of mixtures thereof.Embodiment-047 : In an embodiment there are provided compounds of formula (I, IB), wherein, R4is selected from hydrogen, methyl, ethyl, isopropyl, t- butyl, methyl cyclopropyl or ethyl cyclopropyl.Embodiment-048: In an embodiment the amine R4-NH2, useful in the present invention include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, sec-butyamine, isobutylamine, pentylamine and its primary amine isomers, hexylamine and its primary amine isomers, benzylamine, and cyclohexylamine.Embodiment-049: Yet another embodiment provides the compounds of formula (B), wherein, R5is selected from the group comprising of bromo, chloro,Embodiment-050: According to any of the above embodiments, the present invention provides a method for the synthesis of compounds of formula (I), wherein the compounds of formula (I) are selected from:Embodiment-051 : In another embodiment the compound of formula (A) comprises of chlorantraniliprole, cyantraniliprole, cyclaniliprole, tetraniliprole, tetra-chlorantraniliprole, bromantraniliprole or fluchlordiniliprole .

[0048] Any person skilled in the art knows the best work-up of the reaction mixtures after the end of the respective reactions. In one embodiment, the work-up is usually carried out by isolation of the product by filtration, and optionally washing with solvent, further optionally drying of the product if required.

[0049] The process steps according to the invention are generally carried out under atmospheric pressure. Alternatively, however, it is also possible to work under increased or reduced pressure.

[0050] Without further elaboration, it is reasonable to believe that any person skilled in the art who is using the preceding description can utilize the present invention to its fullest extent. The following examples are therefore to be interpreted as merely illustrative and not limiting of the disclosure in any way whatever.EXAMPLES

[0051] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices, and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may apply.Example-l-a: Synthesis of 7-methylindoline-2, 3-dione (compound of formula (IV)).Step-1: Synthesis of ethyl 2-oxo-2-(o-tolylamino)acetate:

[0052] To preheated diethyl oxalate (III, 937 g, 6306 mmol, 3.5 equivalents), o-toluidine (II, 200 g, 1802 mmol, 1.00 equivalents) was added at 150 °C under stirring. The reaction was maintained at 150 °C for 8 h. After completion of the reaction, excess diethyl oxalate was distilled off to obtain ethyl 2-oxo-2-(o- tolylamino)acetate (IV, 337.4 g, Yield: 88%).

[0053] ’ H-NMR (400 MHz, DMSO-6) 6 10.27 (s, 1H), 7.33 (dd, Ji = 7.6 Hz, J2= 1.6 Hz, 1H), 7.27 (dd, Ji = 6.8 Hz, , J2= 1.6 Hz, 1H), 7.23-7.14 (m, 2H), 4.12 (q, J = 6.8 Hz, 2H), 2.18 (s, 3H), 1.31 (t, J = 7.2 Hz, 3H); LCMS m / z = 208.00 [M+H],

[0054] Step-2: Synthesis of 7-methylindoline-2, 3-dione (compound of formula (VI)) from ethyl 2-oxo-2-(o-tolylamino)acetate (IV), without isolating the intermediate 2-morpholino-2-oxo-N-(o-tolyl)acetamide (V)

[0055] Ethyl 2-oxo-2-(o-tolylamino)acetate (IV, 100 g, 476 mmol, 1.00 equivalent) was added to morpholine (XA, 43.6 g, 500 mmol, 1.05 equivalents), and the reaction mixture was heated to 125-130 °C under stirring for 6 h. After completion of the reaction, the reaction mixture was cooled to 45 to 50 °C, and phosphorus oxychloride (POCI3) (240 g, 1568 mmol, 3.3 equivalents) was added dropwise under stirring over a period of 10 to 15 min. After that, sulphuric acid was added to the reaction mixture at a temperature of 40 to 45 °C, over a period of 10 to 15 minutes. Alternatively, a premix of the same quantities of POCI3 and H2SO4 (cyclising reagent) as described above can also be used. The reaction mixture was heated to 60 °C, and stirring was continued for 5h. After completion of the reaction, the reaction mixture was poured into ice cold water (1.5 L) and extracted with ethyl acetate (3 x 125 ml). The combined organic layers were washed with 10% aq. NaHCCh, dried over anhydrous sodium sulphate and concentrated under reduced pressure to obtain 7-methylindoline-2, 3-dione. Yield 78%; Purity: 94%.

[0056] 1H-NMR (400 MHz, DMSO-6) 6 11.07 (s, 1H), 7.32 (d, J = 7.6 Hz,1H), 7.24 (d, J = 7.6 Hz, 1H), 6.90 (t, J = 8 Hz, 1H), 2.17 (s, 3H). MS: m / z = 162.05 [M+H],Example-l-b: Synthesis of 7-methylindoline-2, 3-dione (compound of formula (IV)).

[0057] A mixture of o-toluidine (1) (108 g, 1.0 mole) and dimethyl oxalate (354 g, 3.0 moles) was heated at a between 75 to 80°C and stirred for 8-10 h. After completion of the reaction, methanol and dimethyl oxalate were removed under reduced pressure. To residue obtained to 40±5°C and morpholine (87.1 g, 1 mole) was added. The reaction mixture was heated to 100±5°C under stirring for 4-5 h. After completion of the reaction, the reaction mixture was cooled to 50°C, followed by dropwise addition of a premix solution of sulfuric acid (70.3 g) and phosphorus oxychloride (382.5 g) maintaining the temperature between 55±5°C and maintained for 5h. After completion of the reaction, the reaction mixture was poured into water (2000 g) and stirred for 2 h. The solid obtained was filtered, washed with water (300 g) and dried to afford 7-methylindoline-2,3-dione (4) (Yield: 68%) as brownish color solid. MS: m / z = 162.05 [M+H],Example 2Comparative example: Synthesis of 7-methylindoline-2, 3-dione (formulaVI)Step-l:Synthesis of 2-morpholino-2-oxo-N-(o-tolyl)acetamide (formula V):

[0058] Ethyl 2 -oxo-2-(o-tolylamino)acetate (IV, 10 g, 48.3 mmol) was added to morpholine (XA, 21.02 mL, 241 mmol), and the reaction mixture was heated to 125-130 °C under stirring for 6 h. After completion of the reaction, excess morpholine was distilled off, and the residue was treated with n-hexane (50 g). The product was isolated by filtration, dried under reduced pressure to obtain 2- morpholino-2-oxo-N-(o-tolyl)acetamide (V, 11.50 g, 46.3 mmol,);

[0059] XH-NMR (400 MHz, DMSO-6): 6 10.21 (s, 1H), 7.39 (dd, Ji = 8 Hz, J2= 1.2 Hz, 1H), 7.28-7.11 (m, 3H), 3.64 (t, J = 4.8 Hz, 4H), 3.55 (t, J = 4.4 Hz, 4H), 2.04 (s, 3H); LCMS m / z = 247.03 [M-H],Step-2: Synthesis of 7-methylindoline-2, 3-dione (formula VI):

[0060] Phosphorus oxychloride (POCI3) (cyclising reagent, 1.877 mL, 20.14 mmol) was added dropwise and under stirring to 2-morpholino-2-oxo-N-(o- tolyl) acetamide (V, 0.5 g, 2.014 mmol). The reaction mixture was heated to 60 °C, and stirring was continued for 16 h. After completion of the reaction, the reaction mixture was poured into ice cold water (50 g) and extracted with ethyl acetate (3 x 20 ml). The combined organic layers were washed with 10% aq. NaHCCh (20 g), dried over anhydrous sodium sulphate and concentrated under reduced pressure to obtain 7-methylindoline-2, 3-dione (VI, Yield 30%). The yield was found to be poor due to the usage of POCI3 alone as the cyclising reagent, instead of employing a mixture of two or more acids as the cyclising reagent.

[0061] 1H-NMR (400 MHz, DMSO-6) 6 11.07 (s, 1H), 7.32 (d, J = 7.6 Hz,1H), 7.24 (d, J = 7.6 Hz, 1H), 6.90 (t, J = 8 Hz, 1H), 2.17 (s, 3H). MS: m / z = 162.05 [M+H],Example-2Synthesis of 5-chloro-7-methylindoline-2, 3-dione (compound of formula(VIB)) from 7-methylindoline-2, 3-dione (VI).

[0062] To a stirred solution of 7 -methylindoline-2, 3 -dione (VI, 100 g) in acetic acid (840 g), chlorine gas (halogenating reagent, 62 g) was purged at 45 ±5 °C. The reaction mixture was cooled to 25-30 °C, after completion of reaction, nitrogen gas was purged to remove dissolved chlorine. The obtained solid product was isolated by filtration, and dried under reduced pressure to obtain 5-chloro-7- methylindoline-2, 3-dione (VIB, 100 g

[0063] ’ H-NMR (400 MHz, DMSO-6) 6 11.18 (s, 1H), 7.48(d, J = 2 Hz, 1H), 7.35 (d, J = 2 Hz, 1H), 2.16 (s, 3H). MS: m / z = 193.90 [M-H],

[0064] Process-4: To a solution of 7 -methylindoline-2, 3 -dione (VI, 50 g, 279 mmol) in 35% hydrochloric acid (246 ml), hydrogen peroxide (35.4 ml, 614 mmol) was added as halogenating reagent, at 15-20 °C over a period of 1-2 h. The reaction mixture was stirred further at room temp for 4 h. After completion of the reaction, water (250 ml) was added to the reaction mixture. The reaction mass was stirred further for 20-30 mins at room temperature. The solid obtained was filtered and dried to obtain 5-chloro-7-methylindoline-2, 3-dione (VIB, 55 g, 81% yield)Example-3: Synthesis of 2-amino-N-(methyl)-5-chloro-3-methylbenzamide (compound of formula (IB)).

[0065] To a stirred suspension of 5-chloro-7-methylindoline-2, 3-dione (VIB, 49.0 g, 250 mmol, 1.0 eq) in water (245.0 g), sodium hydroxide (base, 50.0 g, 1250 mmol, 5 eq) was added, and stirring was continued further for 3 to 4 h at 80 °C. Thereafter, the reaction mixture was cooled to 0 °C. Methylamine gas (IX, 7.8 g, 2500 mmol, 1.0 eq.) was purged into the reaction mixture for about 30 minutes at 0 °C, and the temperature of the reaction mixture was raised to 25 °C, and maintained at 25 °C under stirring for 5 to 6 h. After that, the reaction mixture was again cooled to 0 °C, and H2O2 (oxidizing agent, 1250 moles, 5 eq, of 48% aq) was added dropwise into the reaction mixture. The temperature of the reaction mixture was slowly raised to 25 °C, and the reaction mixture was further stirred for4 to 5 hours at 25 °C. On completion of the reaction, the obtained solid product was filtered, washed with water and dried under reduced pressure to obtain 35.0 g of 2- amino-5-chloro-N,3-dimethylbenzamide (formula IB) in a yield of 83%.Example-4: Synthesis of 2-amino-5-bromo-2V-3-dimethylbenzamide (formula IB):

[0066] To a suspention ofof 2-amino-A,3-dimethylbenzamide (25 g, 147 mmol) in 47% aq HBr (370 gm, 2.14 mol) hydrogen peroxide (12.25 gm, 176 mmol) was added at 15-20 °C over a period of 30-60 min. The reaction mass was stirred for 2-3h.. After completion of the reaction, the reaction mass was filtered and dried to obtain 2-amino-5-bromo-N,3-dimethylbenzamide salt. The obtained 2- amino-5-bromo-N,3-dimethylbenzamide salt was neutralized with aq sodium hydroxide solution to obtain 2-amino-5-bromo-N,3-dimethylbenzamide (34 g)Example-5: Synthesis of 2-amino-5-cyano-N,3-dimethylbenzamide (compound of formula (I)).

[0067] To a stirred solution of 2-amino-5-chloro-A,3-dimethylbenzamide (5.0 g, 25.2 mmol) in NMP (45.0 mL), potassium iodide (2.09 g, 12.58 mmol), copper iodide (Cui) (0.48 g, 2.52 mmol) A7,A2-dimethylethane-l,2-diamine (1.55 g, 17.62 mmol) was added, followed by CuCN (2.71 g, 30.2 mmol) at 25-30 °C. After complete addition, the reaction mixture was heated at 160 °C for 30 h. Aftercompletion of reaction, the reaction mixture was cooled to 30 °C and filtered.The filtrate was distilled under reduced pressure. The residue obtained was cooled below 30 °C and treated with a mixture of water (50 mL) and 25% ammonia (15 mL). The reaction mixture was filtered and the solid obtained was dried under reduced pressure to obtain 2-ainino-5-cyano-A%3-dimcthylbcnzamidc (3.6 g, 19.02 mmol, Yield: 76%).Example-6: In-situ synthesis of 5-chloro-7-methylindoline-2, 3-dione from o- Toluidine (compound of formula (VI)).

[0068] o-Toluidine (formula II, 110.0 g, 1.007 moles) and diethyl oxalate (formula III, 515.0 g, 3.523 moles) was charged into reactor at 25+5 °C. The reaction mixture was heated between 95 to 100°C and stirred for 10-12 h. After completion of reaction, the reaction mixture was gradually cooled to 25+5 °C followed by sequentially distiling ethanol at temperature (25.6-35°C) and excess diethyl oxalate at temperature 90-130°C under reduced pressure to afford ethyl 2- oxo-2-(o-tolylamino)acetate (formula IV, 204.0 g, 0.923 moles). Morpholine (formula XA, 85.0 g, 0.969 moles) was added to the reaction vessel and the resulting reaction mixture was heated to 100+5°C under stirring for 4-5 h. After completion of the reaction, the reaction mixture was cooled to 50°C., A premix solution of sulfuric acid (cyclising reagent, 69.3 g) and phosphorus oxychloride (cyclising reagent, 377.0 g) was added in dropwise manner over a period of 45 mins at 55+5°C. The reaction mixture was heated to 60°C, and stirring was continued for 5h. After completion of the reaction, the reaction mixture was cooled to 50 °C and diluted with ethylene dichloride (EDC) (750 g) and cooled to 25 °C. The reaction mass further diluted with sulfuric acid (183.0 g) and stirred for 10 min. Chlorine gas (halogenating reagent) was then purged through the reaction mass at 25 °C. After completion of the reaction, the reaction mixture was poured into water maintaining the temp below 60+5 °C. After complete addition, the reaction mass was stirred for 2 h at 60°C. The reaction mass was filtered, the wet cake obtained was washed with water and dried to afford 5-chloro-7-methylindoline-2, 3-dione (formula VIB, 108.5 g, Yield-55.2%).Example-7: Synthesis of 2-amino-5-chloro-N,3-dimethylbenzamide from o- Toluidine (compound of formula (I)).

[0069] A mixture of o-toluidine (formula II, 108 g, 1.0 moles) and diethyl oxalate (formula III, 736.5.0 g, 5.0 moles) was heated between 95 to 100°C and stirred for 10-12 h. After completion of reaction, ethanol and and diethyl oxalate were sequentially distlled under reduced pressure. The concentrated reaction material was cooled to 40±5°C followed by the addition of morpholine (87.4 g, 0.983 moles). The reaction mixture was heated to 100±5°C under stirring for 4-5 h. After completion of the reaction, the reaction mixture was cooled to 50°C followed by dropwise addition of a premix solution of sulfuric acid (cyclising reagent, 70.3 g) and phosphorus oxychloride (cyclising reagent, 382.5 g) maintaining a temperature of 55±2°C and stirred further at the same temperature for 5h. After completion of the reaction, the reaction mixture was cooled to 50 °C, diluted with ethylene dichloride (750 g) and further cooled to 25°C. Chlorine gas (halogenating reagent) was purged through the reaction mass at 25°C. After completion of reaction, the reaction mixture was poured into water (2000 g) and stirred for 2 h. The solid obtained was filtered, washed with water (300 g) to afford 5-chloro-7- methylindoline-2, 3-dione (formula VIB, wet cake: 161 g). To the wet cake (138.0 g, 0.463 moles), caustic lye (45.5 g, 48.9% aq. solution., 0.556 moles) and water (80 g) was added at 25+5 °C. The reaction mixture was heated to 40±5°C under stirring for 2-3 h. After completion of the reaction, methylamine (215.3 g, 40% aq. solution, 2.778 moles) was added. The reaction mixture was further stirred at the same temperature for 5-6 h. After completion of the reaction, the reaction mixture was cooled to 25+5 °C, toluene (40.1 g) was added followed by the addition of hydrogen peroxide solution (213.23 g; 48% aq. solution, 3.010 moles) at 25+5 °C, and stirred for 2-3 h. After completion of the reaction, reaction mass was filtered, washed water (184.9 g), and dried to afford 2-amino-5-chloro-A,3- dimethylbenzamide (79.3 g, Yield:47% ) as an off-white color solid.

[0070] 'H-NMR: (400 MHz, DMSO- e) 6 8.307 (br d, J= 4, 1H), 7.384 (d, J= 2.4, 1H), 7.116 (d, J= 2, 1H), 6.339 (s, 2H), 2.711 (d, J= 4.4, 3H), 2.09 (s, 3H).Example-8: Preparation of the compound of Fomula (Aa)

[0071] The compound of Formula (I) prepared by the process as explained in above examples, was then used for preparation of a compound of formula (Aa). The preparation was carried out according to the protocol / procedure mentioned in prior art WO2019224678 and WO2024194896.

[0072] 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. 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.

Claims

WE CLAIM:

1. A method for the synthesis of a compound of formula (I),formula (I) wherein,R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and n represents an integer selected from 0-4; comprising the steps of:A. preparing an isatin of formula (VI),formula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and n represents an integer selected from 0-4; by reacting a mixture comprising of, i. an amide of formula (IV)wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, Cl, Br and C1-C4 alkoxy; and n represents an integer selected from 0-4; ii. an amine of formula (XA),HNR5aR5b(XA), wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; and iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids, optionally in the presence of a solvent; andB . obtaining a compound of formula (I) by reacting a mixture comprising of, i. isatin of formula (VI) obtained in step A; ii. a base; iii. optionally in the presence of a solvent; iv. an amine of formula (IX) or salt thereof;H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, and C3-C8 cycloalkyl-Ci-Cio alkyl; v. an oxidizing agent; wherein said method optionally comprising the step of;halogenating the isatin of formula (VI), wherein at least one R is hydrogen, with a suitable halogenation reagent, optionally in the presence of a suitable solvent to obtain halogenated isatins of formula (VI).

2. The method as claimed in claim 1, wherein said method for preparation of compound of formula (I) comprises the steps of: step A: for preparing an isatin of formula (VI)formula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and n represent an integer selected from 0-4;(A-a). reacting the amide of formula (IV) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (V), and(A-b). cyclising the compound of formula (V) with a cyclising reagent to obtain the isatin of formula (VI), wherein the cyclization of the amide of formula (V) is carried out by optionally isolating the compound of formula (V) from the reaction mixture;wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy;R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; and n represents an integer selected from 0-4; wherein the cyclising reagent is a mixture of two or more acids; and step B: for preparing the compound of formula (I),(B-a). forming a mixture comprising of iii. the isatin of formula (VI) or salt thereof, obtained in step-A iv. a base and optionally in the presence of a solvent; to obtain a compound of formula (XI),formula (XI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; M+represent metal ion; and n represents an integer selected from 0-4; wherein the compound of formula (XI) or salt thereof, was optionally isolated;(B-b) introducing an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl;into the mixture, reacting the mixture, to obtain a compound of formula (XII) or salt thereof,formula (XII) wherein,R is selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and n represents an integer selected from 0-4; wherein the compound of formula (XII) or salt thereof, was optionally isolated; and(B-c) introducing an oxidation agent to the mixture; and reacting the mixture to obtain a compound of formula (I).

3. The method as claimed in claim 1, wherein the compound of formula I isformula (IA)wherein,R1, R2, R3are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl; and R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl.

4. The method as claimed in claim 1, wherein the compound of formula I is,formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I.

5. The method as claimed in claim 4, wherein the preparation of a compound of formula (IB) comprises the steps of:A. preparing an isatin of formula (VIB),formula (VIB)wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and wherein X = Cl, Br, or I;(A-a). reacting the amide of formula (IVB) with a suitable amine of formula HN(R5aR5b) (XA) and optionally in the presence of a suitable solvent to obtain a compound of formula (VB), and(A-b). cyclising the compound of formula (VB) with a cyclising reagent to obtain an isatin of formula (VIB), wherein the cyclization of the amide of formula (VB) is carried out without isolation from the reaction mixture;wherein R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy;R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring;X = Cl, Br, or I; and wherein the cyclising reagent is a mixture of two or more acids;B. preparing the amide of formula IB by,(B-a). forming a mixture comprising of i. an isatin of formula (VIB) or salt thereof, obtained in step- A; ii. a base; and iii. optionally in the presence of a solvent;(B-b). introducing an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl into the mixture; and(B-c) introducing an oxidation agent into the mixture.

6. The method as claimed in claim 4, wherein the preparation of a compound of formula (IB)formula (IB) wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; and X = Cl, Br, or I; the method comprising the steps of:A. preparing an isatin of formula (VIB),formula (VIB) wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and X is selected from Cl, Br, or I;(A-a). reacting the amide of formula (IVC) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (VC), and(A-b). cyclising the compound of formula (VC) with a cyclising reagent to obtain an isatin of formula (VIC), wherein the cyclization of the amide of formula (VC) is carried out without isolation from the reaction mixture;wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy;R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring, wherein the cyclising reagent is a mixture of two or more acids; and(A-c). halogenating the isatin of formula (VIC) to obtain an isatin of formula (VIB);B. preparing the amide of formula IB by,(B-a). forming a mixture comprising of i. an isatin of formula (VIB) or salt thereof, obtained in step-A ii. a base; and iii. optionally in the presence of a solvent;(B-b) introducing an amine compound of formula (IX) or salt thereof into the mixture,H2N - R4formula (IX) whereinR1and R2are independently selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl, into the mixture; and(C-c) introducing an oxidation agent into the mixture.

7. The method as claimed in claim 4, wherein the preparation of a compound of formula (IB) comprises the steps of:A. preparing an isatin of formula (VIC)formula (VIC) wherein R1and R2are independently selected from hydrogen, halogen, Ci- C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; by reacting a mixture of,(A-a). reacting the amide of formula (IVC) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (VC), and(A-b). cyclising the compound of formula (VC) with a cyclising reagent to obtain the isatin of formula (VIC), wherein the cyclization of the amide of formula (VC) is carried out without isolation from the reaction mixture;wherein R1and R2are independently selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl,R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy,R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring, wherein the cyclising reagent is a mixture of two or more acids;B. preparing a compound of formula (IC),formula (IC)wherein,R1and R2are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-C6haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl;(B-a). forming a mixture comprising of iv. an isatin of formula (VIB) or salt thereof, obtained in step-A v. a base; vi. optionally in the presence of a solvent;(B-b) introducing an amine compound of formula (IX) or salt thereof ,H2N - R4formula (IX) whereinR4is selected from hydrogen, C1-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C1-C12 haloalkyl, C2-C12 haloalkenyl, C2-C12 haloalkynyl, C1-C12 alkoxy, C1-C12 haloalkoxy, C3-C8 cycloalkyl, or C3-C8 cycloalkyl-Ci-Cio alkyl; into the mixture,(B-c) introducing an oxidation agent into the mixture.C. preparing a compound of formula (IB) from a compound of formula (IC) obtained from step-B, by halogenating the compound of formula (IC) using a suitable halogenating reagent to obtain a compound of formula (IB).

8. A method for preparing an isatin of formula (VI),formula (VI)wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and n represents an integer selected from 0-4; by reacting a mixture comprising of, i. an amide of formula (IV)wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, Cl, Br and C1-C4 alkoxy; and n represents an integer selected from 0-4; ii. an amine of formula (XA)NR5aR5b(XA) wherein R5aand R5bare independently selected from substituted or unsubstituted C1-C12 alkyl or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; iii. a cyclising reagent, wherein the cyclising reagent is a mixture of two or more acids, iv. optionally in the presence of a solvent; wherein said method optionally comprising the step of; halogenating the isatin of formula (VI), wherein at least one R is hydrogen, with a suitable halogenation reagent, optionally in the presence of a suitable solvent to obtain halogenated isatins of formula (VI).

9. The method as claimed in claim 1, wherein step A for preparing an isatin of formula (VI) comprises the step of,formula (VI) wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; and n represent an integer selected from 0-4;(A-a). reacting the amide of formula (IV) with a suitable amine of formula (XA) HN(R5aR5b) and optionally in the presence of a suitable solvent to obtain a compound of formula (V), and(A-b). cyclising the compound of formula (V) with a cyclising reagent to obtain the isatin of formula (VI), wherein the cyclization of the amide of formula (V) is carried out by optionally isolating the compound of formula (V) from the reaction mixture;wherein R is selected from hydrogen, halogen, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl;R10is selected from the group consisting of OH, F, Cl, Br, I and C1-C4 alkoxy;R5aand R5bare independently selected from substituted or unsubstituted Ci- C12 alkyl, or R5aand R5btogether with the N-atom to which they are attached form a heterocyclic ring; and n represents an integer selected from 0-4; wherein the cyclising reagent is a mixture of two or more acids.

10. The method as claimed in claim 8, wherein the compound of formula (VI) isformula (VIA) wherein R1, R2and R3are selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl.

11. The method as claimed in claim 8, wherein the compound of formula (VI) isformula (VIB) wherein R1and R2are selected from hydrogen, halogen, C1-C12 alkyl, Ci- C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl.

12. The method as claimed in any one of the claims 1 to 11, wherein the reaction is carried out in a single step without purifying or isolating the intermediates.

13. The method as claimed in any one of the claims 4 to 7, further comprising the step of preparing compounds of formula (ID) from substituted amides of formula (IB),formula (ID) wherein,R1, R2and R4are same as defined above;comprising the step of reacting a compound of formula (IB) with a source of CN“ ions and in the presence of a suitable ligand.

14. The method according to claim 1, wherein said method further comprises the step of preparation of a compound of formula (Aa) or of salts thereof;Formula (Aa) wherein,R1, R2, R3are independently selected from hydrogen, halogen, Ci-Ce alkyl,Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl;R4is selected from the group consisting of hydrogen, Ci-Ce alkyl, C3-C6 cycloalkyl, C3-C6 cycloalkyl-Ci-C4 alkyl;R5is selected from the group comprising of halogen, C1-C4 alkyl, C1-C4 haloalkyl, CHF2, CF3, C1-C4 alkoxy, OCHF2, OCH2CF3,heterocyclyl; wherein -A- is selected from the group comprising of a direct bond, CHR6,-O- or -S-; and said heterocyclyl may optionally be substituted with one or more group selected from hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl;R6is selected from the group comprising of hydrogen, halogen, cyano, Ci-C4 alkyl or C1-C4 haloalkyl; X represents halogen; comprising the step of: reacting the substituted anthranil amide compound of formula (I), wherein the anthranil amide compound of formula (I) is a compound of (IA),formula (IA) wherein,R1, R2, R3are independently selected from hydrogen, halogen, Ci-Ce alkyl, Ci-Ce haloalkyl, Ci-Ce alkoxy, Ci-Ce haloalkoxy, or C3-C8 cycloalkyl; and R4is selected from the group consisting of hydrogen, Ci-Ce alkyl, C3-Ce cycloalkyl, C3-C6 cycloalkyl-Ci-C4 alkyl; with a pyrazole compound of formula (B),wherein W is OH, Cl, O-C1-C4 alkyl, O-C(O)Ci-C4 alkyl or imidazolyl;R5is selected from the group comprising of halogen, C1-C4 alkyl, C1-C4 haloalkyl, CHF2, CF3, C1-C4 alkoxy, OCF2H, OCH2CF3,heterocyclyl; wherein -A- is selected from the group comprising of direct bond, CHR6, - O- or -S-; and said heterocyclyl may optionally be substituted with one or more group selected from hydrogen, halogen, cyano, C1-C4 alkyl or C1-C4 haloalkyl;R6is selected from the group comprising of hydrogen, halogen, cyano, Ci- C4 alkyl or C1-C4 haloalkyl; andX represents halogen; in the presence of a coupling reagent, a suitable solvent, and optionally in the presence of a base.

15. The method as claimed in claim 1, wherein the amide of formula (IV) is prepared by the step,(ii) (in) (IV) wherein, R is selected from hydrogen, halogen, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 haloalkoxy, or C3-C8 cycloalkyl; R10is selected from the group consisting of OH, Cl, Br, I and C1-C4 alkoxy; and n represents an integer selected from 0-4.

16. The method as claimed in any one of the claims 1, 6, 7 or 8, wherein halogenating is carried out in the presence of a suitable halogenating reagent which is selected from X2, particularly chlorine or bromine gas; SOCI2, SO2CI2, or HX+H2O2 wherein X represents Cl or Br.

17. The method as claimed in claim 1, 2, 5, 6, 7, or 8, wherein the amine of formula (XA) HN(R5aR5b), is selected from the group consisting of mono- and dialkylated amines and cyclic amines, comprising methylamine, dimethylamine, diethylamine, diisopropylamine, di-tert butylamine, dicyclohexylamine, ethyl methylamine, pyrrolidine, 2,5-dimethyl pyrrolidine, morpholine, 3,5-dimethyl- morpholine, piperidine, 2,6-dimethyl-piperidine, piperazin and 2,5-dimethyl- pyrrole.

18. The method as claimed in claim 1, 2, 5, 6, 7, 8, or 9, wherein the cyclising reagent is a mixture of two or more acids selected from the group consisting ofhydrochloric acid, hydrobromic acid, sulfuric acid, formic acid, acetic acid, trifluoroacetic acid, propionic acid, methanesulfonic acid, benzenesulfonic acid, p- toluenesulfonic acid, acidic ion-exchange resin, AIX3, BX3, FcXs. ZnX2, GaXs, InXs, TiX4, BiXs, SbXs, SnX2, SnX4, SiX4, POX3, and hypovalent Lewis acids, wherein X = F, Cl, Br and I.

19. The method as claimed in claim 1, 3, or 18, wherein the cyclising reagent is a mixture of two or more acids selected from the group consisting of sulfuric acid, formic acid, trifluoroacetic acid, methanesulfonic acid, and POX3, wherein X = Cl, or Br.

20. The method as claimed in claim 19, wherein the ratio of two acids are in a range of 1:100 to 100:1, 1:50 to 50:1, 1:25 to 25:1, 1:20 to 20:1, 1:10 to 10:1, or 1:5 to 5:1.

21. The method as claimed in claim 1 or 3, wherein cyclising is carried out at temperatures in a range of 0 to 200 °C, 10 to 180 °C, 25 to 160 °C, 25 to 140 °C or 25 to 130 °C.

22. The method as claimed in claim 1, wherein the cyclizing is carried out in the presence of 1 to 20, 1 to 15, 1 to 10, 1 to 7, or 1 to 5 molar equivalents of the mixture of acids with respect to the compounds of formula (IV).

23. The method as claimed in claim 13, wherein the source of CN“ ions in carrying out the cyanation reactions is selected from metal cyanide particularly, sodium cyanide (NaCN), potassium cyanide (KCN), copper(I)cyanide (CuCN), zinc(II) cyanide (Zn(CN)2), sodium ferrocyanide (Na4Fe(CN)e and potassium hexacyanoferrate (II) (K4[Fe(CN)6]).

24. The method as claimed in claim 13, wherein the ligand is selected from 1,1- dimethylethylenediamine (DEMDA), ethylenediamine, 1 -butyl- IH-imidazole, 2- picoline, 3-picoline, 2,6-lutidine, 2-hydroxypyridine and 1-methyl pyrolidine.

25. The method as claimed in claim 13, wherein the reaction is carried out in the presence of a catalyst selected from copper salts such as copper (I) iodide (Cui), copper (I) chloride, copper (I) bromide, copper acetate and potassium salts such as potassium iodide (KI).

26. The method as claimed in claim 1, wherein the oxidizing agent is selected from oxygen, chlorine, sodium hypochlorite, chromium trioxide, 3- chloroperoxybenzoic acid, hydrogen peroxide, tert-butyl hydroperoxide, peroxyacetic acid, potassium peroxy mono sulfate, potassium permanganate, and combinations thereof.

27. The method as claimed in claim 1, wherein the base is selected from the group consisting of sodium carbonate (Na2COs), calcium carbonate (CaCCh), cesium carbonate (CS2CO3), lithium carbonate (Li2COs), potassium carbonate (K2CO3), lithium hydroxide (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), cesium hydroxide (CsOH), calcium hydroxide (Ca(OH)2), sodium diphosphate (Na2HPO4), sodium phosphate (Na3PO4), potassium diphosphate (K2HPO4), and potassium phosphate (K3PO4).

28. The method as claimed in claim 1, wherein the reaction is carried out in the presence of 1 to 5; 1 to 4; 1 to 3; 1 to 2; or 1 molar equivalents of a suitable amine (IX) H2N-R4, with respect to the compound of formula (VI).

29. The method as claimed in claim 1, wherein the reaction is carried out in the presence of 1 to 20; 1 to 15; 1 to 10; 1 to 7; 1 to 5; 1 to 2 or 1 molar equivalents of a suitable oxidizing agent, with respect to the compound of formula (VI).

Images