DI-SUBSTITUTED BENZODIOXEPINONES COMPOUND AS FRAGRANCES SOURCE AND IN PERFUME COMPOSITIONS. FIELD OF THE INVENTION: The present invention relates to a novel benzodioxepinones compounds. More particularly, the present invention relates to benzodioxepinones compound of formula (I) and preparation thereof. The present invention further also relates to use of benzodioxepinones compound of formula (I) as fragrances source and in perfume compositions. BACKGROUND OF THE INVENTION: A large number of natural fragrance sources such as flowers, fruits, musk or the like have been used since early times. Recently, due to the development of synthetic chemistry in recent years, a large number of synthetic fragrance materials have been produced and used as useful fragrance sources. The most well-known benzodioxepinone compounds for their marine and ozonic notes are ( Helvetica Chimica Acta, 2007, 90, 1245-1265 ) such as Calone® (Pfizer and Co., USA) or 7- methyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one ( US 3517031 ) or like Azurone® or 7- (3- methylbutyl) benzo [B] [1,4] dioxepin-3-one ( EP1136481 ). The Benzodioxepinone compounds are of use in fragrances to impart marine and ozone nuances to perfume compositions. Watermelon ketone or Calone is the ingredient responsible for many occean breeze fragrances. Since the discovery of Calone 1951® (7-methyl-2H-1,5- benzodioxepin-3(4H)-one), first synthesised by Beereboom, Cameron and Stephens (Pfizer) (U.S. Patent 3,517,031) many other substituted benzodioxepinones such as Transluzone, Aldolone, Azurone, Cascalone, Conoline have been used in fragrances. The major benzodioxepinones compounds which are of use in fragrances are unsubstituted or mono substituted. Particularly substitution at 7 position is important for this class of compounds. The perfume and aroma industries are always on the lookout for new organoleptic compounds, exhibiting intense olfactory power, while having production costs that are as low as possible. Certain types of organoleptic compounds are more difficult to obtain than others, such as, for example, compounds with marine and floral notes. Inventors of the present invention have found novel di-substituted benzodioxepinones compounds in contrary to the compound known in this class which are useful to provide diverse and distinct fragrance accords. With the novel di-substituted benzodioxepinones compounds it is possible to explore novel combinations of aquatic / marine and muguet / floral accords. The present invention provides a novel benzodioxepinones compounds as a diverse fragrance source. OBJECTS OF THE INVENTION: The main objective of the present invention is to provide a novel benzodioxepinones compounds of formula (I). Another objective of the present invention is to use of benzodioxepinones compound of formula (I) as fragrances source or in perfume compositions. SUMMARY OF THE INVENTION: Accordingly, the present invention provides benzodioxepinones compounds of formula (I), Formula (I) wherein R ¹ , R ² , and R ³ are as defined in detail description. In one aspect, the present invention provides a process for preparing the benzodioxepinones compounds of formula (I). In another aspect, the present invention provides use of compound of formula (I), as fragrances source or in perfume compositions. DETAILED DESCRIPTION OF THE INVENTION: The perfume and aroma industries are always on the lookout for new organoleptic compounds, exhibiting intense olfactory power, while having production costs that are as low as possible. The present invention provides a novel and advantageous solution to this exact problem. Inventors of the present invention have found novel di-substituted benzodioxepinones compounds in contrary to the compounds known in this class which can provide access to unusual fragrance molecules. Moreover, the odor of compounds described in the present invention is totally distinct from that of its analogues and homologues described in the patent mentioned beforehand and of which, according to our knowledge, the 7-methyl-2H,4H-1,5-benzodioxepin-3-one is the only product of the described series which has been the object of commercial exploitation (product commercialized under the name of CALONE®; origin: C.A.L. SA, Grasse, France). The said objective was achieved according to the present invention by providing a novel benzodioxepinones compounds of formula (I), Formula (I) wherein, R ¹ is selected from the group consisting of halogen, C1-C6 alkyl, C2-C6 alkenyl, and C3- C ₆ cycloalkyl and C ₃ -C ₆ cycloalkyl-C ₁ -C ₃ alkyl; R ² is selected from the group consisting of hydrogen and halogen; R ³ is selected from the group consisting of halogen, C1-C6 alkyl, C2-C6 alkenyl, and C3- C ₆ cycloalkyl and C ₃ -C ₆ cycloalkyl-C ₁ -C ₃ alkyl; or R ¹ and R ² together with the atom to which they are attached may form 4-7 membered cycloalkyl or cycloalkenyl ring optionally substituted with R ^a ; or R ² and R ³ together with the atom to which they are attached may form 4-7 membered cycloalkyl or cycloalkenyl ring optionally substituted with R ^a ; R ^a is selected from the group consisting of halogen, C ₁ -C ₄ alkyl, and C ₂ -C ₄ alkenyl; In a preferred embodiment, the benzodioxepinones compounds of formula (I), Formula (I) wherein, R ¹ is selected from the group consisting of C ₁ -C ₆ alkyl, C ₂ -C ₆ alkenyl, cyclopropyl and cyclopropyl methyl; R ² is selected from the group consisting of hydrogen; R ³ is selected from the group consisting of C1-C6 alkyl, C2-C6 alkenyl, and C3-C6 cycloalkyl; or R ¹ and R ² together with the atom to which they are attached may form 4-7 membered cycloalkyl or cycloalkenyl ring optionally substituted with R ^a ; or R ² and R ³ together with the atom to which they are attached may form 4-7 membered cycloalkyl or cycloalkenyl ring optionally substituted with R ^a ; R ^a is selected from the group consisting of halogen, C1-C4 alkyl, and C2-C4 alkenyl. In more preferred embodiment, the benzodioxepinones compounds of formula (I), Formula (I) wherein, R ¹ is selected from the group consisting of methyl, ethyl, (n- or iso-) propyl, (n- or iso-, sec- or tert-) butyl and (n- or iso- or sec- or tert- or neo) pentyl; R ² is selected from the group consisting of hydrogen; R ³ is selected from the group consisting of C1-C6 alkyl, C2-C6 alkenyl, cyclopropyl, cyclobutyl, cyclopropyl methyl and cyclobutyl methyl; In another more embodiment, the preferred compounds of benzodioxepinones compounds of formula (I), are selected from: 8-ethyl-6-methyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 6-methyl-8-propyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 6-methyl-8-(propan-2-yl)-3,4-dihydro-2H-1,5-benzodioxepin-3- one; 8-butyl-6-methyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 6-methyl-8-(2-methylpropyl)-3,4-dihydro-2H-1,5-benzodioxepin -3-one; 8-cyclopropyl-6-methyl-3,4-dihydro-2H-1,5-benzodioxepin-3-on e; 8-(cyclopropylmethyl)-6-methyl-3,4-dihydro-2H-1,5-benzodioxe pin-3-one; 8-ethenyl-6-methyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 6-ethyl-8-methyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 6,8-diethyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 6-ethyl-8-propyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 6-ethyl-8-(propan-2-yl)-3,4-dihydro-2H-1,5-benzodioxepin-3-o ne; 8-butyl-6-ethyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 6-ethyl-8-(2-methylpropyl)-3,4-dihydro-2H-1,5-benzodioxepin- 3-one; 8-cyclopropyl-6-ethyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one ; 8-(cyclopropylmethyl)-6-ethyl-3,4-dihydro-2H-1,5-benzodioxep in-3-one; 8-ethenyl-6-ethyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 8-methyl-6-propyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 8-ethyl-6-propyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 6,8-dipropyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 8-(propan-2-yl)-6-propyl-3,4-dihydro-2H-1,5-benzodioxepin-3- one; 8-butyl-6-propyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 8-(2-methylpropyl)-6-propyl-3,4-dihydro-2H-1,5-benzodioxepin -3-one; 8-cyclopropyl-6-propyl-3,4-dihydro-2H-1,5-benzodioxepin-3-on e; 8-methyl-6-(propan-2-yl)-3,4-dihydro-2H-1,5-benzodioxepin-3- one; 8-ethyl-6-(propan-2-yl)-3,4-dihydro-2H-1,5-benzodioxepin-3-o ne; 6-(propan-2-yl)-8-propyl-3,4-dihydro-2H-1,5-benzodioxepin-3- one; 6,8-bis(propan-2-yl)-3,4-dihydro-2H-1,5-benzodioxepin-3-one; 8-butyl-6-(propan-2-yl)-3,4-dihydro-2H-1,5-benzodioxepin-3-o ne; 8-(2-methylpropyl)-6-(propan-2-yl)-3,4-dihydro-2H-1,5-benzod ioxepin-3-one; 8-methyl-6-(2-methylpropyl)-3,4-dihydro-2H-1,5-benzodioxepin -3-one; 8-ethyl-6-(2-methylpropyl)-3,4-dihydro-2H-1,5-benzodioxepin- 3-one; 6-(2-methylpropyl)-8-propyl-3,4-dihydro-2H-1,5-benzodioxepin -3-one and 8-cyclopropyl-6-(2-methylpropyl)-3,4-dihydro-2H-1,5-benzodio xepin-3-one. In yet another embodiment, the more preferred compounds of benzodioxepinones compounds of formula (I), are selected from: 6-methyl-8-(2-methylpropyl)-2H-1,5-benzodioxepin-3(4H)-one and 8-methyl-6-(2- methylpropyl)-2H-1,5-benzodioxepin-3(4H)-one. The term “alkyl” and “C ₁ -C ₆ -alkyl” includes, straight or branched C ₁ -C ₆ -alkanes; non limiting example includes methyl; ethyl; n-, iso-propyl; n-, iso-, sec- and t-butyl; n-, iso-, sec-, t- and neo pentyl; n-hexyl; 1,3-dimethylbutyl; 3,3-dimethylbutyl. The term “alkenyl” and “C ₂ -C ₆ -alkenyl” includes straight or branched C ₂ -C ₆ -alkenes; non limiting examples includes ethenyl; n-, iso-propenyl; n-, iso-, sec- and t-butenyl; n-pentenyl; n-hexenyl; 1,3-dimethylbutenyl. The term “cycloalkyl” and “C ₃ -C ₆ -cycloalkyl” means alkyl closed to form ring. Non limiting examples includes cyclopropyl; cyclobutyl; cyclopentyl; cyclohexyl. The term “cycloalkylalkyl” and “C ₃ -C ₆ cycloalkyl-C ₁ -C ₃ alkyl” means alkyl closed ring attached to alkyl. Non limiting examples includes cyclopropyl methyl; cyclopropyl ethyl; cyclobutyl methyl; or cyclopentyl methyl. The term “halogen” includes fluorine (F), chlorine (Cl), bromine (Br) or iodine (I). The compounds of present invention compound of formula (I) can be separated by chromatography, crystallization, or the mixture can be converted further without purification. In one embodiment, a compound of formula (I) of a present invention is used as a fragrant agent in composition or article comprising said substance. In one embodiment, a of compound of formula (I) of a present invention is used as masking or neutralizing an odor in a substance, or in composition or article comprising said substance. In one embodiment, the compound of formula (I) of the present invention is used as valuable perfume odor agents. The present invention further relates to compounds for switching, amplifying and / or modifying an odor and / or flavor with a marine, aldehydic, ozone, watery-fresh, fruity and / or floral note, over prior art compounds. In one embodiment the compound of formula (I) of the present invention also concerns the preferred use of the above-mentioned compound in applications however not limited to the products mentioned beforehand, and this compound also lends itself to all other current uses in perfumery, namely the preparation of perfumes and colognes, the perfuming of Soaps and shower gels, hygiene or hair-care products, as well as of air freshener or yet cosmetic preparations; also Such as Soaps, Shampoos, liquid or Solid detergents for the treatment of textiles, fabric Softeners, or yet detergent compositions or all-purpose household cleaners for the cleaning of dishes or various Surfaces, whether they are intended for household or industrial use. In one embodiment, a present invention provides a composition comprising at least one compound of general formula (I), and/or at least one solvent, and/or at least one additive. In one embodiment, the present invention provides a combination of compound of formula (I) of a present invention, wherein at least one compound of formula (I) is added in combination with at least one other flavouring or perfuming ingredient, and/or at least one solvent, and/or at least one additive. In another embodiment the proportions in which the compound according to the invention can be incorporated in the various products mentioned beforehand vary within a large range of values. These values depend on the nature of the article or products that one desires to perfume and the olfactive effect Searched for, as well as on the nature of the co-ingredients in a given composition when the compound of the invention is used in admixture with perfuming co- ingredients, Solvents or adjuvants of current use in the art. In these applications, it can be used alone or in admixture with other perfuming ingredients, Solvents or adjuvants of current use in perfumery. The nature and the variety of these co- ingredients do not require a more detailed description here, which, moreover, would not be exhaustive, and the person skilled in the art will be able to choose the latter through its general knowledge and as a function of the nature of the product to be perfumed and of the desired olfactive effect. These perfuming ingredients belong to chemical classes as varied as alcohols, aldehydes, ketones, esters, ethers, acetates, nitrites, terpene hydrocarbons, sulfur- and nitrogen- containing heterocyclic compounds, as well as essential oils of natural or Synthetic origin. A large number of these ingredients is moreover listed in reference textbooks Such as the book of S. Arctander, Perfume and Flavor Chemicals, 1969, Montclair, N.J., USA, or its more recent versions, or in other works of similar nature. In one embodiment, the present invention provides a compound of formula (I) wherein the said compounds confer, modifies or boosts the organoleptic properties of said substance, a composition or article. In one embodiment, the present invention provides compositions comprising compound of formula (I) and/or at least one solvent/auxiliaries, and/or at least one additive. In one embodiment, the present invention provides compositions comprising compound of formula (I) wherein said composition selected from the group consisting of perfumery compositions, topical compositions, cosmetics, and cleaning products. In one embodiment, the present invention provides compositions comprising compound of formula (I), wherein said composition further comprising at least one other fragrancing substance. In one embodiment, the present invention provides a use of at least one compound of formula (I) as described in one of the embodiments, wherein the said compound comprising in composition or article, as a fragrant agent or compound. In one embodiment, the present invention provides the use of at least one compound of formula (I) as described in one of the embodiments, wherein the said compound comprising in composition or article, as an odor-masking or odor-neutralizing agent. In one embodiment, the present invention provide process for the preparation of compound of formula (I). The process for the preparation of benzodioxepinones compounds of formula (I), wherein said process comprising the steps of: A. reacting ortho halo phenol compound of formula (V) with the compound of formula (IV), in presence of a base and a solvent to afford the compound of formula (III), as shown in following Scheme-1, Scheme-1: wherein, X represent halogen selected from the group of Cl, F, Br, or I, R represents C ₁ -C ₄ -alkyl or two R groups together with the atom to which they are attached may form 3- to 6- membered ring and R ¹ R ² and R ³ are as defined above; B. the compound of formula (II) can be obtained by cyclising compound of formula (III) in presence of a catalyst and a ligand, optionally in presence of a base and a solvent, as shown in following Scheme-2, Scheme-2: ; wherein, X and R ¹ as defined above; C. hydrolysing compound of formula (II) in presence of an acid and a solvent to get compound of formula (I), as shown in following Scheme-3, Scheme-3: R, R ¹ , R ² and R ³ are as defined above. In one embodiment, the present invention provide process for the preparation of compound of formula (I) wherein step b of said process comprising the steps of: A. the compound of formula (III-A) can be obtained from compound of formula (III) in presence of a base and a solvent, as shown in following Scheme-2a, wherein Formula (II-A) is optionally isolated, Scheme-2a: , wherein, G represent OH or O- M+, M+ represents metal cation; X represents halogen X; R, R ¹ , R ² and R ³ are as defined above; B. cyclising compound of formula (III-A) to obtain the compound of formula (II) in the presence of a solvent, as shown in following Scheme-2, Scheme-2: , wherein, X, R, R ¹ , R ² and R ³ are as defined above. The process of preparation of compound of formula (I), wherein reaction conversions of the present invention are performed within a temperature range from 10 °C. to +150 °C. The process of preparation of compound of formula (I), wherein the solvent is selected from aliphatic, alicyclic or aromatic hydrocarbons, for example petroleum ether, n-hexane, n- heptane, cyclohexane, methylcyclohexane, benzene, toluene, xylene or decalin, and halogenated hydrocarbons, for example chlorobenzene, dichlorobenzene, dichloromethane, chloroform, carbon tetrachloride, dichloroethane or trichloroethane; nitriles such as acetonitrile, propionitrile, n- or isobutyronitrile or benzonitrile; ethers such as dioxane, tetrahydrofuran, 1,2-dimethoxyethane, 1,2-diethoxyethane or anisole; amides such as N,N- dimethylformamide, N,N-dimethylacetamide, N-methylformanilide, N-methylpyrrolidone or hexamethylphosphoramide; sulphoxides such as dimethyl sulphoxide, or sulphones such as sulpholane, water or mixture thereof. The process of preparation of compound of formula (I), wherein the suitable catalyst is selected from copper powder, copper bronze, copper oxide (I), copper iodide (I) or copper bromide (I). The process of preparation of compound of formula (I), wherein the suitable ligand is selected from N’,N’dimethylethylenediamine, 4-morpholinopyridine, 4-pyrrolidinopyridine, 8- hydroxyquinoline, trans-1,2-diaminocyclohexane picolinic acid N,N'-dimethylcyclohexane- 1,2-diamine or 1,10-phenanthroline. The process of preparation of compound of formula (I), wherein the suitable base is selected from organic or inorganic base. The suitable base is selected from but not limited to inorganic bases such as alkali metal hydroxides, for example lithium, sodium or potassium hydroxide, alkali metal carbonates, for example Li2CO3, Na2CO3, K2CO3, Cs2CO3 and acetates, for example NaOAc, KOAc, LiOAc, and alkoxides, for example NaOMe, NaOEt, NaOt-Bu, KOt- Bu. or organic bases such as trialkylamines, alkylpyridines, phosphazenes and 1,8- diazabicyclo[5.4.0]undecene (DBU). In one embodiment, the present invention provides a compound of formula Z, wherein, R represents C1-C4 alkyl or two R groups together with the atom to which they are attached may form 3- to 6- membered ring; R ¹ is selected from the group consisting of halogen, C ₁ -C ₆ alkyl, C ₂ -C ₆ alkenyl, and C ₃ - C6 cycloalkyl, C3-C6 cycloalkyl-C1-C3 alkyl; R ² is selected from the group consisting of hydrogen or halogen; R ³ is selected from the group consisting of halogen, C ₁ -C ₆ alkyl, C ₂ -C ₆ alkenyl, and C ₃ - C6 cycloalkyl, C3-C6 cycloalkyl-C1-C3 alkyl; or R ¹ and R ² together with the atom to which they are attached may form 4-7 membered cycloalkyl or cycloalkenyl ring optionally substituted with R ^a ; or R ² and R ³ together with the atom to which they are attached may form 4-7 membered cycloalkyl or cycloalkenyl ring optionally substituted with R ^a ; R ^a is selected from the group consisting of halogen, C1-C4 alkyl, and C2-C4 alkenyl. and G represent X, OH or O- M+, M+ represents metal cation; X represents halogen selected from the group of Cl, F, Br, or I. Any person skilled in the art knows the best work-up of the reaction mixtures after the end of the respective reactions. Without further elaboration, it is believed that any person skilled in the art who is using the preceding description can utilize the present invention to fullest extent. The following examples are therefore to be interpreted as merely illustrative and not limiting of the disclosure in any way whatever. The invention will now be described in a more detailed manner in the following examples. Examples: Example-1: 6-methyl-8-(2-methylpropyl)-3,4-dihydro-2H-1,5-benzodioxepin -3-one (Compound No-5) Step a: Synthesis of 1-bromo-2-(3-bromo-2,2-dimethoxypropoxy)-5-isobutyl-3- methylbenzene: 2-bromo-4-isobutyl-6-methylphenol (5gm, 20.5mmole), K2CO3 (7.1gms, 51.4mmole), 18- crown-6 (1.35gms, 5.1mmole) were taken in a round bottom flask. DMF (50mL) was added to this and stirred at room temperature under N2 atmosphere. A solution of 1,3-dibromoacetone- dimethylketal (7gms, 26.7mmole) in DMF (35mL) was added to this solution slowly and the reaction mixture was continued stirring at reflux temperature. Reaction was stopped after 32hrs, DMF was evaporated under reduced pressure. The reaction mixture obtained was washed with water, extracted with ethyl acetate. The combined ethyl acetate fraction was dried over Na ₂ SO ₄ and concentrated under reduced pressure to give the crude product. This was purified by column chromatography to give the product-1-bromo-2-(3-bromo-2,2- dimethoxypropoxy)-5-isobutyl-3-methylbenzene (light yellow liquid, 4.45gms, 51%). ¹ H NMR (400 MHz, DMSO-d6): δ 7.18 (s, 1H, Ar-H), 6.96 (s, 1H, Ar-H), 3.88 (s, 2H, CH2), 3.55 ( s, 2H, CH ₂ ), 3.24 (s, 6H, OCH ₃ ), 2.36 (d, 2H, J= 7.0Hz, CH ₂ ), 2.29 (s, 3H, CH ₃ ), 1.74-1.84 (m, 1H, CH), 0.83 (overlapping s,3H, CH3), 0.81 (overlapping s,3H, CH3). Step b: Synthesis of 3-[2-bromo-6-methyl-4-(2-methylpropyl)phenoxy]-2,2- dimethoxypropan-1-ol: 1-bromo-2-(3-bromo-2,2-dimethoxypropoxy)-5-isobutyl-3-methyl benzene (4gms, 9.43 mmole) and KOH (21.1gms, 377 mmole) were taken in a hydrothermal autoclave containing a mixture of water and dimethylacetamide (DMA) or trimethyl benzene (2:3 ratio, 31mL). The reaction mixture was stirred at 140°C for overnight (30hrs). Reaction mixture was washed with dil. HCl, extracted with ethyl acetate followed by washing with water and brine. The combined ethyl acetate fractions were concentrated under reduced pressure to give the crude product. This was purified by column chromatography to yield the pure product, 3-[2-bromo-6-methyl- 4-(2-methylpropyl)phenoxy]-2,2-dimethoxypropan-1-ol (light yellow liquid, 1.02gm, 30% yield) ¹ H NMR (400 MHz, DMSO-d ₆ ): δ 7.22 (s, 1H, Ar-H), 7.0 (s, 1H, Ar-H), 4.84 (t, 2H, J= 5.4Hz, OH), 3.83 (s, 2H, CH2), 3.60 ( d, 2H, J=5.6Hz, O-CH2), 3.24 (s, 6H, OCH3), 2.36 (d, 2H, J= 7.2Hz, CH2), 2.29 (s, 3H, CH3), 1.74-1.84 (m, 1H, CH), 0.85 (overlapping s,3H, CH3), 0.83 (overlapping s,3H, CH ₃ ). Step c: Synthesis of 3,3-dimethoxy-6-methyl-8-(2-methylpropyl)-3,4-dihydro-2H-1,5 - benzodioxepine: To K2CO3 (1.15gms, 8.3mmole), CuI (53mg, 0.27mmole), ligand-DMEDA (N,N’- dimethylethylenediamine) (91mg, 0.55mmole) in mesitylene (8mL), 3-[2-bromo-6-methyl-4- (2-methylpropyl)phenoxy]-2,2-dimethoxypropan-1-ol (1gm, 2.7mmole) in mesitylene (6mL) was added and the reaction mixture was stirred at reflux temperature for 24 hrs. Reaction mixture was allowed to cool down to room temperature. Reaction mixture was then filtered through a celite bed, washed with EtOAc. The filtrate was then concentrated under reduced pressure to get the crude material. This was purified by column chromatography (Hexane: EtOAc:: 95:5) to get pure product, 3,3-dimethoxy-6-methyl-8-(2-methylpropyl)-3,4-dihydro- 2H-1,5-benzodioxepine (light yellow liquid, 403mg, 52% yield) ¹ H NMR (400 MHz, DMSO- d ₆ ): δ 6.58 (s, 1H, Ar-H), 6.52 (s, 1H, Ar-H), 4.11 (overlapping s, 4H, O-CH ₂ ), 3.21 (s, 6H, OCH3), 2.27 (d, 2H, J= 7.2Hz, CH2), 2.10 (s, 3H, CH3), 1.70-1.77 (m, 1H, CH), 0.83 (overlapping s,3H, CH3), 0.81 (overlapping s,3H, CH3). Step d: Synthesis of 6-methyl-8-(2-methylpropyl)-2H-1,5-benzodioxepin-3(4H)-one: 3,3-dimethoxy-6-methyl-8-(2-methylpropyl)-3,4-dihydro-2H-1,5 -benzodioxepine (400mg) was taken in 80% HCOOH (7mL) and stirred at 50-55°C for 4-5hrs. At the end of the reaction, reaction mixture was diluted with water and neutralized with 10N NaOH solution, extracted into EtOAc. Organic fraction was then washed with water, brine, dried over Na2SO4 and concentrated to get the crude product which was purified by column chromatography (Hexane: EtOAc::95:5 ) to get pure 6-methyl-8-(2-methylpropyl)-2H-1,5-benzodioxepin-3(4H)-one (off-white solid, 274mg, 82% yield) ¹ H NMR (400 MHz, DMSO-d6): δ 6.68 (s, 1H, Ar-H), 6.64 (s, 1H, Ar-H), 4.75 (overlapping s, 4H, O-CH ₂ ), 2.31 (d, 2H, J= 7.2Hz, CH ₂ ), 2.15 (s, 3H, CH ₃ ), 1.73-1.83 (m, 1H, CH), 0.86 (overlapping s,3H, CH ₃ ), 0.83 (overlapping s,3H, CH ₃ ). ¹³ C NMR (400 MHz, DMSO-d6): δ 205 (C=O), 147 (Ar-C), 144 (Ar-C), 135 (Ar-C), 129 (Ar-C), 125 (Ar-CH), 118 (Ar-CH), 75 (CH2*2), 43 (CH2), 29 (CH), 20 (2*CH3), 15.97 (CH3). 8-methyl-6-(2-methylpropyl)-2H-1,5-benzodioxepin-3(4H)-one (Compound No:33) was also synthesized in the same manner following the above procedures. 8-methyl-6-(2-methylpropyl)-2H-1,5-benzodioxepin-3(4H)-one (Compound No:33) Table -1 disclosed preferred benzodioxepinone compounds according to the present invention; Formula (I) Table :1 Me: methyl, Et: ethyl, n-Pr: n-propyl, i-Pr: isopropyl, c-Pr:cyclopropyl, n-Bu: n-butyl, i-Bu: isobutyl, t-Bu : tert butyl. Having said that the present invention described the invention with reference to certain preferred embodiments, other embodiments will become apparent to one skill in the art from the consideration of specification. It will be apparent to those skilled in the art that many modifications, both to materials and methods, maybe practiced without departing from the scope of the invention