WO2021161083A1

WO2021161083A1 - An efficient process for preparation of acyl derivatives of alkylenedioxybenzenes

Info

Publication number: WO2021161083A1
Application number: PCT/IB2020/056874
Authority: WO
Inventors: Manoj Kumar Mohapatra; Ramamohanrao Bendapudi; Abhijit Dattatray THORAT; Paul Vincent Menacherry; Vincent Paul
Original assignee: Anthea Aromatics Private Limited
Priority date: 2020-02-13
Filing date: 2020-07-22
Publication date: 2021-08-19

Abstract

The present disclosure provides a process of preparation of compounds of Formula I comprising the step of : reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent, wherein the step of reacting the alkylenedioxybenzene compound of Formula II with the acyl halide of Formula III is effected in presence of an amphoteric oxide and a Lewis acid so as to immediately quench the compound of formula H-X, formed during the course of the reaction, to substantially eliminate degradation of the compound of any of Formula I and II. The present disclosure also provides for process(es) for preparation of compound of Formula IVa, IVb and IVc.

Description

AN EFFICIENT PROCESS FOR PREPARATION OF ACYL DERIVATIVES OF

ALKYLENEDIOXYBENZENES

FIELD OF THE INVENTION

[0001] The present disclosure generally relates to the method of preparation of compounds of Formula I. In particular, the present disclosure relates to a process for preparation of the compound of Formula I by reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III without substantial degradation of the compounds of Formula I and Formula II during the course of reaction, wherein Rl, R2 and R3 independently represent H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R) group, wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n = 0, 1, 2, 3, 4, 5, 6, 7 or 8; and X = F, Cl, Br or I.

Formula I Formula II Formula III

[0002] The present disclosure also provides for process(es) for preparation of compound of Formula IVa, process(es) for preparation of compound of Formula IVb and process(es) for preparation of compound of Formula IVc:

Formula IV a Formula IVb Formula I Vc

[0003] wherein Rl, R2 and R3 independently represent H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R) group, wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n= 0, 1, 2, 3, 4, 5, 6, 7 or 8 and R4 = H or -(CH₂)_nCH₃.

[0004] More particularly, the present disclosure provides a process for preparation of sesamol of Formula VIII

Formula VIII

BACKGROUND OF THE INVENTION

[0005] The following background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[0006] In last few years, alkylenedioxybenzene derivatives have gained much importance in the pharmaceutical, pesticide, perfumery and food sectors due to their application as an end product or intermediates for the synthesis of wide range of finished products. A large number of processes are available in the existing art for the preparation of alkylenedioxybenzene derivatives, for example dihydrosafrole.

[0007] Dauksas et al. (Pharmaceutical Chemistry Journal, 1987, 21, 569-573) disclose a process involving 1,3-benzodioxole and acyl chloride as raw materials and using A1C13 or SnC14 as catalyst to prepare piperonyl ethyl ketone with a yield of -58%.

[0008] Zhu et al. (Chemical Research and Application, 2003, 15, 417-418) discloses acylation of 1,3-benzodioxole using propionyl chloride in the presence of catalytic A1C13 to obtain piperonyl ethyl ketone with a reported yield of 78%.

[0009] CN 1907980 discloses a method comprising Friedel -Crafts acylation of 1,3- benzodioxole using propionic anhydride as the acylating agent in the presence of perchloric acid as the catalyst with a yield of -72% with no data on purity.

[0010] CN100473650C discloses a 3 step process to prepare dihydrosafrole comprising

Friedel-Crafts acylation of catechol, catalytic hydrogenation followed by cyclization to obtain target product. However, the disclosed process requires zinc chloride in high stoichiometric quantity (1.2 moles per mole of catechol) to complete the acylation. Further, the document discloses that the reported yield of the product obtained is -74% with a purity of 98.2%.

[0011] CN102070596 discloses a process for the preparation of dihydrosafrole by Friedel-

Crafts acylation of 1,3-benzodioxole using propionyl chloride as acylating agent in the presence of Lewis acid catalyst like zinc chloride to prepare the acyl compound, followed by its reduction by Wolf- Kishner reaction using hydrazine hydrate with a yield of -82% with a purity of 99%. However, the disclosed process requires zinc chloride in high stoichiometric quantity (1.2 moles per mole of catechol) to complete the acylation. Further, the disclosed reaction requires the use of highly toxic and carcinogenic hydrazine hydrate.

[0012] W02000040575 discloses a process for the preparation of dihydrosafrole from

MDB and propionic anhydride using perchloric acid as catalyst followed by using 5% Pd/C during the hydrogenation stage to obtain dihydrosafrole with a yield of 79.5% on MDB with no disclosure of purity of the product.

[0013] US2015038465A1 discloses a process for preparation of higher alkyl derivatives

(C4 - CIO) of 1,3-benzodioxole, said process comprising use of the corresponding acyl chloride and zinc chloride as catalyst to obtain the final product with a reported yield of 39.3%.

[0014] It is seen that a large number of processes are reported in the prior art for the preparation of alkylenedioxybenzenes derivatives, particularly dihydrosafrole by acylation with an acyl halide in the presence of a Lewis acid catalyst such as zinc chloride. However, during the acylation reaction, the corresponding hydrogen halide, like hydrogen chloride, is formed that cleaves the -0-(CH2)m-0- ring of the starting and the final product. This results in the synthesis of product with low yield and high impurities

[0015] Further, alkylenedioxybenzene derivatives is an intermediate for one of the important compound 5-Hydroxy- 1,3-benzodioxole (Sesamol). Sesamol is serves as an important starting material for producing pharmaceuticals such as hypotensive agents. Sesamol also finds uses such as antioxidants, antibacterial agents, herbicides, and cosmetics. Recently sesamol has been found to exhibit many important biological activities and health-promoting benefits such as inducing growth arrest and apoptosis in cancer and cardiovascular cells and enhancing vascular fibrinolytic capacity. Conventionally known process employs a highly toxic selenium compound, is difficult to carry out on an industrial scale. Other methods are also difficult to carry out on an industrial scale, since these methods employ a halogen-containing solvent, whose use as been discouraged in recent years due to environmental impact. Another approach produces a large amount of heliotropic acid as a by-product, requiring the phase-separation of hydrolysis mixture to dissolve the by-product in the formed aqueous layer for removal thereof. Such approach suffers from shortcoming of increasing formation by-product yield of heliotropic acid, which reduces the yield of sesamol and generates solid deposits, thereby rendering handling of the reaction mass difficult. Hence, there is an unmet need to provide an efficient process for producing sesamol, particularly from the acylated product of 1,3-benzodioxole.

[0016] W09639133 discloses that the acylated product of 1,3-benzodioxole is difficult to purify and involved repeated treatments for decolorization.

[0017] Sarvari et al (Journal of Organic Chemistry, 69, 2004, 6953-6956] discloses the use of zinc oxide as a catalyst in Friedel-Crafts acylation of benzene compounds. However, the disclosed process requires zinc oxide in high stoichiometric quantity and the processes did not specifically pertain to acylation of alkylenedioxybenzene compounds.

[0018] From careful scrutinization of these documents amongst others, a person skilled in the art would immediately realize that the acylation of alkylenedioxybenzene compounds using conventional processes result in synthesis of the end product with very low yield and high impurities, as -0-(CH2)m-0- ring of the reactant and product are very susceptible to cleavage in the acidic condition. There is, therefore, a need in the art for an efficient process for preparation of alkyl and alkylene derivatives of alkylenedioxybenzene compounds without substantial degradation of any of the starting compound(s) and the desired product during the course of reaction.

OBJECTS OF THE INVENTION

[0019] It is an object of the present disclosure to overcome the problems associated with conventional process(es) for the acylation of alkylenedioxybenzene compound(s).

[0020] Another object of the present disclosure is to provide a process for the acylation of alkylenedioxybenzene without substantial degradation of alkylenedioxybenzene or acylated products formed therefrom.

[0021] Yet another object of the present disclosure is to provide a process for the acylation of alkylenedioxybenzene that substantially reduces the amount of Lewis acid, such as zinc chloride, required as catalyst.

[0022] Yet another object of the present disclosure is to provide a process for the acylation of alkylenedioxybenzene compounds at a preferred reaction temperature.

[0023] Yet another object of the present disclosure is to provide a process for the acylation of alkylenedioxybenzene compounds with high yield. [0024] Yet another object of the present disclosure is to provide a process for the acylation of alkylenedioxybenzene compounds with high purity.

[0025] Another object of the present disclosure is to provide an efficient process for preparation of alkyl and alkylene derivatives of alkylenedioxybenzene compounds without substantial degradation of any of the starting compound(s) and the desired product during the course of reaction.

[0026] Another object of the present disclosure is to provide an efficient process for preparation of sesamol.

[0027] Various objects, features, aspects and advantages of the present invention will become more apparent from the detailed description of the invention herein below along with the accompanying figures in which like numerals represent like components.

SUMMARY

[0028] The present disclosure in a general aspect provides a process of preparation of compounds of Formula I. In particular, the present disclosure relates to a process for preparation of the compound of Formula I by reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III without substantial degradation of the compounds of Formula I and Formula II during the course of reaction, wherein Rl, R2 and R3 independently represent H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R) group, wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; and X= F, Cl, Br or I.

Formula I Formula II Formula III

[0029] In an aspect in the compound of Formula II, when m=l and Rl, R2 and R3 = H, the corresponding compound is methylene dioxybenzene of Formula Ila:

Formula Ila [0030] In an aspect in the compound of Formula III, when X = Cl and n = 0, the corresponding compound of Formula III is acetyl chloride.

Formula Ilia.

[0031] In an aspect in the compound of Formula III, when X = Cl and n = 1, the corresponding compound of Formula III is propionyl chloride.

Formula Illb

[0032] In an aspect the present disclosure also provides for process(es) for preparation of compound of Formula IVa, process(es) for preparation of compound of Formula IVb and process(es) for preparation of compound of Formula IVc wherein Rl, R2 and R3 independently represent H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R) group, wherein R is selected from linear or branched alkyl group with carbon atoms ranging from C 1 to

C6; m = 1, 2, or 3; n= 0, 1, 2, 3, 4, 5, 6, 7 or 8 and R4 = H or -(CH )_nCH .

R2 R22 R2

Formula IVa Formula IVb Formula IVc

[0033] An aspect of the present disclosure relates to a process for preparation of compound of Formula I, said process comprising the step of reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent,

Formula I Formula II Formula ITT wherein Rl, R2 and R3 independently represent H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R) group, wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n = 0, 1, 2, 3, 4, 5, 6, 7 or 8; and X= F, Cl, Br or I; characterized in that the step of reacting the alkylenedioxybenzene compound of Formula II with the acyl halide of Formula III is effected in presence of at least one amphoteric oxide, and further characterized in that the quenching of inorganic compound of formula H-X, formed during the course of the reaction, is effected so as to substantially eliminate degradation of the compound of any of Formula I and II.

[0034] In an aspect, at least one amphoteric oxide is selected from a group consisting of Zinc oxide, Tin oxide, Aluminum oxide, Beryllium oxide, and mixtures thereof in a quantity ranging from 0.2 to 0.8 moles per mole of acid chloride.

[0035] In an aspect, the amphoteric oxide selected is Zinc oxide, and wherein Zinc oxide is used in a quantity ranging from about 0.4 moles to about 0.6 moles per mole of acyl chloride. [0036] In an aspect, at least one Lewis acid selected from a group consisting of Zinc chloride, Tin chloride, Aluminum Chloride, Beryllium chloride, and mixtures thereof is used in catalytic quantities as an initiator, in a quantity ranging from about 0.01 moles to about 0.5 moles per mole of acyl chloride.

[0037] In an aspect, the Lewis acid selected is Zinc chloride, and wherein Zinc chloride is used in a quantity ranging from about 0.01 moles to about 0.2 moles per mole of acyl chloride. [0038] In an asepct, the solvent is selected from the group consisting of dichloromethane, ethylene dichloride, 1 ,2-dichloropropane, or mixtures thereof.

[0039] In an asepct, the solvent selected is dichloromethane.

[0040] In an asepct, the acylation reaction temperature is maintained at a preferred reaction temperature of -10 °C to 30 °C and more preferably between 0 °C to 20 °C.

[0041] Another aspect of the present disclosure relates to a process for preparation of a compound of Formula IVa, said process comprising the steps of: (a) obtaining a compound of Formula I by reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent,

Formula I Formula II Formula III wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; and X= F, Cl, Br or I; and

(b) effecting selective reduction followed by dehydration of the compound of Formula I to obtain the corresponding compound of Formula IVa;

Formula IV a wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; and R4 = H or

-(CH₂)_nCH₃; characterized in that the reaction of said alkylenedioxybenzene compound of Formula II with said acyl halide of Formula III is effected in presence of at least one amphoteric oxide, and further characterized in that the quenching of compound of formula H-X, formed during the course of the reaction, is effected so as to substantially eliminate degradation of the compound of any of Formula I and II.

[0042] Still further aspect of the present disclosure relates to a process for preparation of a compound of Formula IVb, said process comprising the steps of: (a) obtaining a compound of Formula I by reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent,

Formula I Formula II Formula ITT wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; and X= F, Cl, Br or I; and

(b) reacting the compound of Formula I with hydrogen gas in presence of a composite catalyst comprising a Nickel catalyst and an acid catalyst to obtain the compound of Formula IVb;

Formula IVb wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; and n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; characterized in that the reaction of said alkylenedioxybenzene compound of Formula II with said acyl halide of Formula III is effected in presence of at least one amphoteric oxide, and further characterized in that the quenching of compound of formula H-X, formed during the course of the reaction, is effected so as to substantially eliminate degradation of the compound of any of Formula I and II.

[0043] In an embodiment, the Nickel catalyst is Raney Nickel. In an embodiment, the acid catalyst is selected from a group consisting of p-toluene sulfonic acid, anhydrous Sodium bisulphate, anhydrous Potassium bisulphate, Methane sulfonic acid, Nickel chloride, Ferrous sulphate, Zinc chloride or mixtures thereof.

[0044] In an embodiment, the compound of Formula IVb is dihydrosafrole of Formula VII.

Formula VII

[0045] Another aspect of the present disclosure relates to a process for preparation of a compound of Formula IVc, said process comprising the steps of: (a) obtaining a compound of Formula I by reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent,

(b) effecting Baeyer - Villiger oxidation followed by saponification and acidification of the compound of formula I to obtain the corresponding compound of formula IVc;

Formula IVc wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n = 0, 1, 2, 3, 4, 5, 6, 7 or 8 [0046] In an aspect, the compound of Formula IVc is Sesamol of Formula VIII

Formula VIII

[0047] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawings in which like numerals represent like components.

DETAILED DESCRIPTION OF THE INVENTION

[0048] Unless the context requires otherwise, throughout the specification which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.”

[0049] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details. This invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In addition, and as well be appreciated by one skilled in the art.

[0050] It is also to be understood that the technology disclosed herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0051] The term “about” means ±10%.

[0052] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0053] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

[0054] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.

[0055] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

[0056] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.

[0057] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

[0058] The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.

[0059] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments. Reference will now be made in detail to the exemplary embodiments of the present invention.

[0060] The present disclosure generally relates to the method of preparation of compounds of Formula I. In particular, the present disclosure relates to a process for preparation of the compound of Formula I by reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III without substantial degradation of the compounds of Formula I and Formula II during the course of reaction, wherein Rl, R2 and R3 independently represent H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R) group, wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; and X= F, Cl, Br or I.

Formula I Formula II Formula III

[0061] In an embodiment when m=l and Rl, R2 and R3 = H in the compound of Formula II, the corresponding compound is methylene dioxybenzene of Formula Ila:

Formula Ila

[0062] In an embodiment when X = Cl and n = 0 in the compound of Formula III, the corresponding compound of Formula III is acetyl chloride.

Formula Ilia.

[0063] In an embodiment when X = Cl and n = 1 in the compound of Formula III, the corresponding compound of Formula III is propionyl chloride.

Formula Illb

[0064] The present disclosure also provides for process(es) for preparation of compound of Formula IVa, process(es) for preparation of compound of Formula IVb and process(es) for preparation of compound of Formula IVc, wherein Rl, R2 and R3 independently represent H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R) group, wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; and R4 = H or -(CH₂)_nCH₃.

Formula IVa Formula IVb Formula IVc

[0065] An aspect of the present disclosure relates to a process for preparation of compound of Formula I, said process comprising the step of reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent,

Formula I Formula II Formula ITT wherein Rl, R2 and R3 independently represent H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R) group, wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; and X= F, Cl, Br or I; characterized in that the step of reacting the alkylenedioxybenzene compound of Formula II with the acyl halide of Formula III is effected in presence of at least one amphoteric oxide, and further characterized in that the quenching of compound of formula H-X, formed during the course of the reaction, is effected so as to substantially eliminate degradation of the compound of any of Formula I and II.

[0066] In an embodiment, at least one amphoteric oxide is selected from a group consisting of Zinc oxide, Tin oxide, Aluminum oxide, Beryllium oxide, and mixtures thereof, is used in a quantity ranging from about 0.2 moles to about 0.9 moles per mole of the acyl chloride. However, a person skilled in the art would appreciate that any other amphoteric oxide can be used to serve its intended purpose as laid down in the present disclosure without departing from the scope and spirit of the invention. In a preferred embodiment, the amphoteric oxide selected is Zinc oxide. Preferably, Zinc oxide is used in a quantity ranging from about 0.4 moles to about 0.6 moles per mole of the acyl chloride.

[0067] In an embodiment, at least one Lewis acid is selected from a group consisting of Zinc chloride, Tin chloride, Aluminum Chloride, Beryllium chloride, and mixtures thereof, in a quantity ranging from about 0.01 moles to about 0.5 moles per mole of acyl chloride. However, a person skilled in the art would appreciate that any other Lewis acid can be used to serve its intended purpose as laid down in the present disclosure without departing from the scope and spirit of the invention. In a preferred embodiment, the Lewis acid selected is Zinc chloride. In a preferred embodiment, Zinc chloride is used in a quantity ranging from about 0.01 moles to about 0.25 moles per mole of acyl chloride and most preferably, Zinc chloride is used in a quantity ranging from about 0.01 moles to about 0.1 moles per mole of acyl chloride.

[0068] In an embodiment, the solvent is selected from the group consisting of dichloromethane, ethylene dichloride, 1 ,2-dichloropropane, other chlorinated hydrocarbons or mixtures thereof. However, a person skilled in the art would appreciate that any other solvent can be used to serve its intended purpose as laid down in the present disclosure without departing from the scope and spirit of the invention. In a preferred embodiment, the solvent selected is dichloromethane.

[0069] In an embodiment, the acylation reaction temperature is maintained at a preferred reaction temperature of -10 °C to 30 °C and more preferably between 0 °C to 20 °C.

[0070] Another aspect of the present disclosure relates to a process for preparation of a compound of Formula IVa, said process comprising the steps of: (a) obtaining a compound of Formula I by reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent,

(b) effecting selective reduction followed by dehydration of the compound of formula I to obtain the compound of formula IVa;

-(CH₂)_nCH₃; characterized in that the reaction of said alkylenedioxybenzene compound of Formula II with said acyl halide of Formula III is effected in presence of at least one amphoteric oxide and at least one Lewis acid, and further characterized in that immediate quenching of compound of formula H-X, formed during the course of the reaction, is effected so as to substantially eliminate degradation of the compound of any of Formula I and II.

[0071] In an embodiment, selective reduction is carried out in presence of a metal catalyst. In an embodiment, the metal catalyst is selected from precious metal catalysts such as Palladium, Platinum, Ruthenium and the likes. In a preferred embodiment, the metal catalyst is Raney Nickel. However, any other catalyst as known to or appreciated by a person skilled in the art can be utilized to effect selective reduction without departing from the scope and spirit of the invention. In an embodiment, said metal catalyst is supported on conventional supports such as carbon, alumina, silica and the likes.

[0072] In an embodiment, dehydration is carried out in presence of a catalyst selected from p-toluene sulfonic acid, Sodium bisulphate, Potassium bisulphate, sulphuric acid and the likes. However, any other catalyst as known to or appreciated by a person skilled in the art can be utilized to effect dehydration without departing from the scope and spirit of the invention.

[0073] In a preferred embodiment, the compound of Formula IVa is isosafrole of Formula V.

[0074] In an embodiment, the compound of Formula Ila is reacted with the acyl chloride of Formula Ilia in the presence of an amphoteric oxide such as Zinc oxide in combination with catalytic quantity of Lewis acid such as Zinc chloride in a suitable solvent to obtain compound of Formula IA.

Formula

Ila Formula Ilia Formula la

[0075] In an embodiment, said compound of Formula la is subjected to selective reduction and dehydration to obtain the compound of Formula V in high yield (greater than 100% wt./wt. of the alkylenedioxybenzene consumed) and high purity (more than 99% by GC), as shown in Scheme 1 below.

Formula la Formula V

Scheme - 1

[0076] Still further aspect of the present disclosure relates to a process for preparation of a compound of Formula IVb, wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; and n= 0, 1, 2, 3, 4, 5, 6, 7 or 8;

Formula IVb said process comprising the steps of: (a) obtaining a compound of Formula I by reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent,

(b) reacting the compound of Formula I with hydrogen gas in presence of a composite catalyst comprising a Nickel catalyst and an acid catalyst to obtain the compound of Formula IVb; characterized in that the reaction of said alkylenedioxybenzene compound of Formula II with said acyl halide of Formula III is effected in presence of at least one amphoteric oxide and at least one Lewis acid, and further characterized in that immediate quenching of compound of formula H-X, formed during the course of the reaction, is effected so as to substantially eliminate degradation of the compound of any of Formula I and II.

[0077] In a preferred embodiment, the Nickel catalyst is Raney Nickel. However, any other nickel catalyst as known to or appreciated by a person skilled in the art can be utilized to serve its intended purpose without departing from the scope and spirit of the present invention. In an embodiment, the acid catalyst is selected from a group comprising p-toluene sulfonic acid, anhydrous Sodium bisulphate, anhydrous Potassium bisulphate, Nickel chloride, Ferrous sulphate, Zinc chloride or mixtures thereof. However, any other acid catalyst as known to or appreciated by a person skilled in the art can be utilized to serve its intended purpose without departing from the scope and spirit of the present invention.

[0078] In a preferred embodiment, the compound of Formula IVb is dihydrosafrole of Formula VII.

Formula VII

[0079] In an embodiment, the compound of Formula Ila is reacted with the acyl chloride of Formula Ilia in the presence of an amphoteric oxide such as Zinc oxide in combination with catalytic quantity of Lewis acid such as Zinc chloride in a suitable solvent to obtain compound of Formula IV A.

Formula Ila Formula Ilia Formula la

[0080] In an embodiment, the compound of Formula la is directly converted to the target compound of Formula VII by reacting the compound of Formula la with hydrogen in presence of a composite catalyst system, wherein the composite catalyst system comprises of a Nickel catalyst, such as Raney Nickel, in combination with an acid catalyst such as p-toluene sulfonic acid, anhydrous Sodium bisulphate, anhydrous Potassium bisulphate, Nickel chloride, Ferrous sulphate, Zinc chloride and the like, and in a suitable solvent such as methanol, ethanol, n- propanol, isopropyl alcohol, sec-butanol, t-butyl alcohol and the like. In an embodiment, the reaction is carried out in a single step.

[0081] Another aspect of the present disclosure relates to a process for preparation of a compound of Formula IVc, said process comprising the steps of: (a) obtaining a compound of Formula I by reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent,

Formula IVc wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n = 0, 1, 2, 3, 4, 5, 6, 7 or 8;

[0082] In a preferred embodiment, the compound of Formula IVc is Sesamol of Formula VIII

Formula VIII

[0083] The following non limiting examples are provided to illustrate further the present invention. It will be apparent to those skilled in the art many modifications, alterations, variations to the present disclosure, both to materials, method and reaction conditions, may be practiced. All such modifications, alterations and variations are intended to be within the spirit and scope of the present inventions. It should be understood that the present invention is not construed as being limited thereto.

[0084] The present invention is further described according to the following non-limiting working examples.

Example 1

Preparation of Piperonyl butoxide (PBO)

Example 1A

Preparation of 3,4-Methylenedioxypropiophenone (using 0.5 moles of Zinc Oxide and 0.05 moles of zinc chloride per mole of acyl chloride, and ethylene dichloride as solvent) [0085] 488 g of 1,3-benzodioxole and 500 g of ethylene dichloride were charged into a 3 litre reaction flask and the mixture was cooled to 0°C under stirring. 162 g of zinc oxide and 27 g of zinc chloride were added to the above mixture under stirring. Later, 370g of propionyl chloride was added in 4 hours, maintaining the temperature of the reaction medium between 0°C and 5°C under stirring. The reaction medium was stirred for another 1 hour until the complete acylation occurred. The reaction mass was subjected to aqueous workup to remove zinc chloride and propionic acid, and the organic layer was separated and distilled to recover 250 g of unreacted 1,3-benzodioxole, and 310 g of 3,4-Methylenedioxypropiophenone with a yield of 130.2% (wt./wt.) and GC purity > 99%.

Example IB

Preparation of dihydrosafrole

[0086] 310 g of 3,4-Methylenedioxypropiophenone was charged into a 2 litre autoclave along with 500 g of isopropyl alcohol, 15g of Raney nickel and 0.5 g of anhydrous sodium hydrogen sulphate. The mixture was maintained at 90 - 110°C under hydrogen at 100 psi pressure till unreacted 3,4-Methylenedioxypropiophenone reduced to less than 0.5% as observed by GC analysis. The catalyst was separated and the crude was distilled to give 270 g of dihydrosafrole with a yield of 113.4% (wt./wt. on 1,3-benzodioxole) and GC purity of >99%. Example 1C

Preparation of Piperonyl butoxide (PBO) from dihydrosafrole

[0087] 90g of paraformaldehyde and 730g of concentrated HC1 were charged into a 3 litre flask. Hydrogen chloride gas was passed rapidly through the reaction medium for 3 hours at 30 °C. Later, 328g of dihydrosafrole was added in the reactor at 30 °C under stirring. After reaction over, the aqueous portion was drained off and the organic portion was added to a reactor containing butyl carbitol (356g) and sodium hydroxide (120g) under stirring at 30°C. The reaction mass was subjected to aqueous work up and the organic layer was separated and distilled to give 523 g of Piperonyl butoxide with a yield of 181% (wt./wt. on 1,3-benzodioxole) and purity of > 95% by GC analysis.

Example 2

Preparation of 3,4-Methylenedioxypropiophenone (using 0.55 moles of Zinc Oxide per mole of acyl chloride and without addition of zinc chloride using ethylene dichloride as solvent) [0088] 122 g of 1,3-benzodioxole and 150 g of ethylene dichloride were charged into a 1 litre reaction flask and the mixture was cooled to 0°C under stirring followed by the addition of 44.5 g of zinc oxide under stirring. Later, 92.5 g of propionyl chloride was added in 3 hours while maintaining the temperature of the reaction medium between 0°C and 5°C under constant stirring. The reaction medium was stirred for another 1 hour until the complete acylation occurred. The reaction mass was subjected to aqueous workup to remove zinc chloride and propionic acid, and the organic layer was separated and distilled to recover 64 g of unreacted 1,3- benzodioxole and 71 g of 3,4-Methylenedioxypropiophenone with a yield of 122.4% (wt./wt.) and purity of > 99% by GC analysis .

Example 3

Preparation of 3,4-Methylenedioxypropiophenone (without addition of Zinc Oxide, 0.55 moles of zinc chloride per mole of acyl chloride using ethylene dichloride as solvent)

[0089] 122 g of 1,3-benzodioxole and 150 g of ethylene dichloride were charged into a 1 litre reaction flask and the mixture was cooled to 0°C under stirring. Add 75 g of zinc chloride to the above mixture under constant stirring at 0°C. Later, 92.5 g of propionyl chloride added in 3 hours maintaining the temperature of the reaction medium between 0°C and 5°C under stirring. The reaction medium was stirred for another 1 hour. However, it was observed that only 20% of the 1,3-benzodioxole was converted, therefore, the experiment was abandoned.

Example 4

Preparation of 3,4-Methylenedioxypropiophenone (without using Zinc Oxide, 1.00 moles of Zinc Chloride per mole of acyl chloride using ethylene dichloride as solvent)

[0090] 122 g of 1,3-benzodioxole and 150 g of ethylene dichloride were charged into a 1 litre reaction flask and the mixture was cooled to 0°C under stirring. Add 136 g of zinc chloride to the above mixture under constant stirring at 0°C. Later, 92.5 g of propionyl chloride added in 3 hours maintaining the temperature of the reaction medium between 0°C and 5°C under stirring. The reaction medium was stirred for another 1 hour till the complete acylation occurred. The reaction mass was subjected to aqueous workup to remove zinc chloride and propionic acid and the organic layer was separated and distilled to recover 39 g of unreacted 1,3-benzodioxole and 56 g of 3,4-Methylenedioxypropiophenone with a yield of 67.5% (wt./wt.). In this reaction, approximately 30 g of high boiling distillation residue was obtained. Example 5

Preparation of 3,4-Methylenedioxypropiophenone (using 0.5 moles of Zinc Oxide and 0.05 moles of Zinc Chloride per mole of acyl chloride using dichloromethane as solvent)

[0091] 488 g of 1,3-benzodioxole and 750 g of dichloromethane were charged into a 3 liter reaction flask and the mixture was cooled to 0°C under stirring. Add 162 g of zinc oxide and 27 g of zinc chloride into the above mixture under constant stirring at 0°C. Later, 370 g of propionyl chloride was added in 4 hours, maintaining the temperature of the reaction medium between 0°C and 5°C under stirring. The reaction medium was stirred for another 1 hour till the complete acylation occurred. The reaction mass was subjected to aqueous workup to remove zinc chloride and propionic acid and the organic layer was separated and distilled to recover 245 g of unreacted 1,3-benzodioxole, and 311 g of 3,4-Methylenedioxypropiophenone with a yield of 128% (wt./wt.) and purity of > 99% by GC analysis.

Example 6

Preparation of Isosafrole Example 6A

Preparation of 3,4-Methylenedioxypropiophenone (using 0.5 moles of Zinc Oxide and 0.05 moles of Zinc Chloride per mole of acyl chloride using ethylene dichloride as solvent)

[0092] 122 g of 1,3-benzodioxole and 150 g of ethylene dichloride were charged into a 1 litre reaction flask and the mixture was cooled to 0°C under stirring. Add 41 g of zinc oxide and 7 g of zinc chloride to the above mixture under stirring. Later, 92.5 g of propionyl chloride was added in 3 hours maintaining the temperature of the reaction medium between 0°C and 5°C under stirring. The reaction medium was stirred for another 1 hour till the complete acylation occurred. The reaction mass was subjected to aqueous workup to remove zinc chloride and propionic acid and the organic layer was separated and distilled to recover 60 g of unreacted 1,3- benzodioxole, and 80 g of 3,4-Methylenedioxypropiophenone with a yield of 129% (wt./wt.) and purity of > 99% by GC analysis.

Example 6B

Preparation of Isosafrole from 3,4-Methylenedioxypropiophenone

[0093] 80g of 3,4-Methylenedioxypropiophenone along with 125 g of isopropyl alcohol,

O.lg of sodium bicarbonate and 4.0 g of raney nickel catalyst were charged in a 1 liter autoclave. The mixture was hydrogenated under 100 p.s.i. hydrogen pressure at 110°C till the unreacted 3,4-Methylenedioxypropiophenone was reduced to less than 0.5% by GC analysis. The catalyst was separated by filtration and the crude was distilled to obtain 75 g of a-ethyl-1,3- benzodioxole-5-methanol with purity of >99% by GC analysis. The a-ethyl-l,3-benzodioxole-5- methanol along with 200 g of toluene and 0.5g of p-Toluenenesulfonic acid (PTSA) was refluxed at 95°C in a Dean-Stark apparatus for 2 hrs. The organic layer was subject to aqueous workup to remove PTSA, and distilled to obtain 65 g of isosafrole with a yield of 104.8% (wt./wt. on 1,3- benzodioxole) and purity of > 99% by GC analysis.

Example 7

Preparation of 5-butyl-l,3-Benzodioxole Example 7A

Preparation of l-(l,3-benzodioxol-5-yl)-l-butanone (using 0.5 moles of Zinc Oxide and 0.05 moles of zinc chloride per mole of acyl chloride using dichloromethane as solvent)

[0094] 122 g of 1,3-benzodioxole and 190 g of dichloromethane were charged into a 1 litre reaction flask and the mixture was cooled to 0°C under stirring. Add 41 g of zinc oxide and 7 g of zinc chloride to the above mixture under stirring. Later, 106.5 g of butanoyl chloride was added in 4 hours maintaining the temperature of the reaction medium between 0°C and 5°C under stirring. The reaction medium was stirred for another 1 hour until the complete acylation occurred. The reaction mass was subjected to aqueous workup to remove zinc chloride and butanoic acid and the organic layer was separated and distilled to recover 65 g of unreacted 1,3- benzodioxole and 75 g of l-(l,3-benzodioxol-5-yl)-l-butanone with a yield of 131.6% (wt./wt.) and purity of > 99% by GC analysis .

Example 7B

Preparation of 5-butyl-l,3-Benzodioxole from l-(l,3-benzodioxol-5-yl)-l-butanone [0095] 75 f of l-(l,3-benzodioxol-5-yl)-l-butanone was subjected to selective reduction and dehydration as discussed in Example IB to obtain 66 g of 5-butyl- 1,3-benzodioxole with a yield of 115.8% (wt./wt. on 1,3-benzodioxole) and purity of > 99% by GC analysis.

Example 8

Preparation of 6-propyl-l,4-benzodioxane Example 8A

Preparation of 6-Propionyl-l,4-benzodioxan (using 0.5 moles of Zinc Oxide and 0.05 moles of zinc chloride per mole of acyl chloride using dichloromethane as solvent) [0096] 136 g of 1 ,4-benzodioxane and 190 g of dichloromethane were charged into a 1 litre reaction flask and the reaction mixture was cooled to 0°C under stirring. Add 41 g of zinc oxide and 7 g of zinc chloride to the above mixture under constant stirring. Later, 92.5 g of propionyl chloride was added in 4 hours maintaining the temperature of the reaction medium between 0°C and 5°C under stirring. The reaction medium was stirred for another 1 hour till the complete acylation occurred. The reaction mass was subjected to aqueous workup to remove zinc chloride and propionic acid and the organic layer was separated and distilled to recover 85 g of unreacted 1 ,4-benzodioxane and 62 g of 6-Propionyl- 1 ,4-benzodioxan with a yield of 121.6% (wt./wt.) and purity of > 99% by GC analysis.

Example 8B

Preparation of 6-propyl-l,4-benzodioxane from 6-Propionyl-l,4-benzodioxan [0097] 62 g of 6-Propionyl- 1 ,4-benzodioxan was subjected to selective reduction and dehydration as discussed in example IB to obtain 53 g of 6-propyl- 1,4-benzodioxane with a yield of 103.9% (wt./wt. on 1,4-benzodioxane) and purity of > 99% by GC analysis.

Example 9

Preparation of Sesamol Example 9A

Preparation of 5-Acetyl-l,3-benzodioxole (using 0.5 moles of Zinc Oxide and 0.05 moles of zinc chloride per mole of acyl chloride using dichloromethane as solvent)

[0098] 488 g of 1,3-benzodioxole and 1000 g of dichloromethane were charged into a 5 litre reaction flask and the reaction mixture was cooled to 0°C under stirring. Add 160 g of zinc oxide and 28 g of zinc chloride to the above mixture under constant stirring. Later, 316 g of acetyl chloride was added in 4 hours maintaining the temperature of the reaction medium between 0°C and 5°C under stirring. The reaction medium was stirred for another 1 hour till the complete acylation occurred. The reaction mass was subjected to aqueous workup and the organic layer was separated and distilled to recover 261 g of unreacted 1,3-benzodioxole and 278 g of 5-Acetyl- 1,3-benzodioxole with a yield of 122.5% (wt./wt.) and purity of > 99% by GC analysis.

Example 9B

Preparation of Sesamol from 5- Acetyl- 1,3-benzodioxole [0099] 278 g of 5-Acetyl-l,3-benzodioxole and 550g of toluene charged into a 3 litre reaction flask at 30 °C under stirring. Add 730g of 22% peracetic acid in 2 hours under stirring. The reaction mass was subjected to aqueous work up followed by alkaline hydrolysis using 25% aq. NaOH (800 g) and acidification to obtain 32g of unreacted 5-Acetyl- 1,3-benzodioxole and 164g of 5 -Hydroxy- 1,3-benzodioxole (Sesamol) with a yield of 72.2% (wt./wt. on 1,3- benzodioxole) and purity of > 99% by GC analysis.

[00100] Any embodiments which could be reached by the motivation or teachings of the specification of this invention, but not explained by this specification will fall within the scope of this invention.

ADVANTAGES OF THE INVENTION

[00101] The present disclosure provides process(es) to overcome the problems associated with conventional process(es) for the acylation of alkylenedioxybenzene compound(s).

[00102] The present disclosure provides an efficient process for preparation of alkyl and alkylene derivatives of alkylenedioxybenzene compounds without substantial degradation of any of the starting compound(s) and the desired product during the course of reaction.

[00103] The present disclosure provides a process for the acylation of alkylenedioxybenzene without substantial degradation of alkylenedioxybenzene or acylated products formed therefrom. [00104] The present disclosure provides a process for the acylation of alkylenedioxybenzene that substantially reduces the amount of zinc chloride required as an initiator.

[00105] The present disclosure provides a process for the acylation of alkylenedioxybenzene compounds with high yield.

[00106] The present disclosure provides a process for the acylation of alkylenedioxybenzene compounds with high purity.

[00107] The present disclosure provides a process for preparation of sesamol with high purity.

Claims

We Claim:

1. A process for preparation of compound of formula I, said process comprising the step of reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent,

Formula I Formula II Formula III wherein Rl, R2 and R3 independently represent H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R) group, wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; and n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; characterized in that the step of reacting the alkylenedioxybenzene compound of Formula II with the acyl halide of Formula III is effected in presence of at least one amphoteric oxide and at least one Lewis acid, and further characterized in that immediate quenching of compound of formula H-X, formed during the course of the reaction, is effected so as to substantially eliminate degradation of the compound of any of Formula I and II.

2. The process as claimed in claim 1 , wherein said at least one amphoteric oxide is selected from a group consisting of zinc oxide, tin oxide, aluminum oxide, beryllium oxide, and mixtures thereof.

3. The process as claimed in claim 2, wherein said at least one amphoteric oxide is zinc oxide, and wherein zinc oxide is used in a quantity ranging from about 0.4 moles to about 0.6 moles per mole of acyl chloride.

4. The process as claimed in claim 1 , wherein said at least one Lewis acid is selected from a group consisting of zinc chloride, tin chloride, aluminum chloride, beryllium chloride, and mixtures thereof.

5. The process as claimed in claim 4, wherein said at least one Lewis acid is zinc chloride, and wherein zinc chloride is used in a quantity ranging from about 0.01 moles to about 0.1 moles per mole of acyl chloride.

6. The process as claimed in claim 1, wherein said solvent is selected from the group consisting of dichloromethane, ethylene dichloride, 1 ,2-dichloropropane, or mixtures thereof.

7. The process as claimed in claim 6, wherein said solvent is dichloromethane.

8. The process as claimed in claim 1, wherein the reaction temperature is maintained at a between -10 °C to 30 °C.

9. The process as claimed in claim 8, wherein said temperature is between 0 °C to 20 °C

10. A process for preparation of a compound of Formula IVa, said process comprising the steps of:

(a) obtaining a compound of Formula I by reacting an alkylenedioxybenzene compound of Formula II with an acyl halide of Formula III in presence of a solvent,

Formula I Formula II Formula III wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; and n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; and

IVb

wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; n= 0, 1, 2, 3, 4, 5, 6, 7 or

8; and R4 = H or (CH₂)_nCH₃; characterized in that the reaction of said alkylenedioxybenzene compound of Formula II with said acyl halide of Formula III is effected in presence of at least one amphoteric oxide and at least one Lewis acid, and further characterized in that immediate quenching of compound of formula H-X, formed during the course of the reaction, is effected so as to substantially eliminate degradation of the compound of any of Formula I and II.

11. A process for preparation of a compound of Formula IVb, said process comprising the steps of:

Formula I Formula II Formula ITT wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; and n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; and

(b) reacting the compound of Formula I with hydrogen gas in presence of a composite catalyst comprising a Nickel catalyst and an acid catalyst to obtain the compound of formula IB;

Formula IVb wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; and n= 0, 1, 2, 3, 4, 5, 6, 7 or 8; characterized in that the reaction of said alkylenedioxybenzene compound of Formula II with said acyl halide of Formula III is effected in presence of at least one amphoteric oxide and at least one Lewis acid, and further characterized in that immediate quenching of compound of formula H-X, formed during the course of the reaction, is effected so as to substantially eliminate degradation of the compound of any of Formula I and II.

12. The process as claimed in claim 10, wherein said Nickel catalyst is Raney Nickel.

13. The process as claimed in claim 10, wherein said acid catalyst is selected from a group consisting of p-toluene sulfonic acid, anhydrous sodium bisulphate, anhydrous potassium bisulphate, nickel chloride, ferrous sulphate, zinc chloride or mixtures thereof.

14. The process as claimed in claim 10, wherein said compound of Formula IVb is dihydrosafrole of Formula VII.

Formula VII

15. A process for preparation of a compound of Formula IVc, said process comprising the steps of:

Formula I Formula II Formula III wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; and n= 0, 1, 2, 3, 4, 5, 6, 7 or 8 in which said reacting the alkylenedioxybenzene compound of Formula II with the acyl halide of Formula III is effected in presence of at least one amphoteric oxide and at least one Lewis acid, and immediate quenching of compound of formula H-X, formed during the course of the reaction, is effected so as to substantially eliminate degradation of the compound of any of Formula I and II; and

(b) effecting Baeyer - Villiger oxidation followed by saponification and acidification of the compound of formula I to give the compound of Formula IVc ;

Formula IVc wherein Rl, R2 and R3 independently represents H, linear or branched Cl - CIO alkyl or alkenyl group, or alkoxy (-0-R), wherein R is selected from linear or branched alkyl group with carbon atoms ranging from Cl to C6; m = 1, 2, or 3; .

16. The process as claimed in claim 14, wherein said compound of Formula Ic is sesamol of Formula VIII.

Formula VIII

17. The process as claimed in claim 15, wherein said at least one amphoteric oxide is selected from a group consisting of zinc oxide, tin oxide, aluminum oxide, beryllium oxide, and mixtures thereof.

18. The process as claimed in claim 15, wherein said at least one amphoteric oxide is zinc oxide, and wherein zinc oxide is used in a quantity ranging from about 0.4 moles to about 0.6 moles per mole of acyl chloride.

19. The process as claimed in claim 15, wherein said at least one Lewis acid is selected from a group consisting of zinc chloride, tin chloride, aluminum chloride, beryllium chloride, and mixtures thereof.

20. The process as claimed in claim 15, wherein said at least one Lewis acid is zinc chloride, and wherein zinc chloride is used in a quantity ranging from about 0.01 moles to about 0.1 moles per mole of acyl chloride.

21. The process as claimed in claim 15, wherein said solvent in step (a) is selected from the group consisting of dichlorome thane, ethylene dichloride, 1,2-dichloropropane, or mixtures thereof.

22. The process as claimed in claim 21, wherein said solvent is dichloromethane.

23. The process as claimed in claim 15, wherein the reaction in step (a) is carried out at a temperature maintained between -10 °C to 30 °C.

24. The process as claimed in claim 23, wherein said temperature is between 0 °C to 20 °C.