FIELD OF THE INVENTION The present invention relates to 3,3-dimethyl-5-cyano-benzoxepine derivatives and their use for the preparation of 3,3-dimethyl-5-formyl-2,3-dihydro- benzoxepine derivatives.

BACKGROUND OF THE INVENTION 3,3-dimethyl-5-formyl-2,3-dihydrobenzoxepine derivatives (formula II):

(II) are disclosed in EP 1140893 B1 and US 6596758 patents as intermediates for the preparation of 5-(3,3-dimethyl-2,3-dihydro benzoxepin-5-yl)-2,4-pentadienoic acid derivatives, which in turn are usefui for treating dyslipidemias, atherosclerosis and diabetes. In these patents, compounds of formula Il are prepared according to the following scheme :

Scheme 1 : a benzoxepinone is reacted with an organometallic compound CH3-M in which M is -Mg-hal (where hal is a halogen atom) or else M is Li. This synthetic method involves four chemical steps starting from benzoxepinone and the yields, as reported, are moderate. Furthermore, this synthetic pathway cannot be easily scaled up to commercial implementation. It now has been found a novel improved synthetic route for preparing the compounds of formula (II) which is unexpectedly applicable at industrial scale. Advantageously, the compounds of formula (II) can be obtained in only three steps, each being characterized by high yields. As another advantage, the invention provides an economical and efficient route for preparing the compounds of formula (II). According to the present invention, compounds of formula (II) are prepared from new compounds of formula (I). Thus, in one aspect, the present invention is related to compounds of general formula (I) :

(D Each of R is independently chosen from a halogen atom; a cyano group; a nitro group; a carboxy group; an optionally halogenated (Ci-Ci8)alkoxycarbonyl group; an R3-CO-NH- or RaRbN-CO- group [in which Ra and Rb independently represent optionally halogenated (Ci-Ci8)alkyl; a hydrogen atom; (C6-Cio)aryl or (C6-Cio)aryl(Ci-C5)alkyl (where the aryl parts are optionally substituted by a halogen atom, by an optionally halogenated (C-i-C5)alkyl group or by an optionally halogenated (Ci-C5)aikoxy group); (C3-Ci2)cycloalkyl optionally substituted by a halogen atom, by an optionally halogenated (d-C5)alkyl group or by an optionally halogenated (Ci-C-5)alkoxy group]; an optionally halogenated (Ci-C-|8)alkyl group; optionally halogenated (Ci-Ci8)alkoxy; and (C6-Cio)aryl, (C6-Cio)aryl(Ci-C5)alkyl, (Cβ-C-i 0)aryloxy, (C3-Ci2)cyclo-alkyl, (C3-Ci2)cycloalkenyl, (C3-Ci2)cycloalkyloxy, (C3-C-]2)cycloalkenyloxy ; (C6-Cio)aryloxycarbonyl or (C6-Ci0)arylcarbonyl ; in which the aryl, cycloalkyl and cycloalkenyl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-C5)alkyl or by an optionally halogenated (Ci-C5)alkoxy; p represents 0, 1 , 2, 3 or 4; The formula (I) encompasses all types of geometric isomers and stereoisomers of the compounds of formula (I) or mixtures thereof. As used above and throughout the description of the invention, the following terms, unless otherwise indicated, shall be understood to have the following meanings. "Alkyl" means an aliphatic hydrocarbon group which may be straight or branched, having 1 to 18 carbon atoms in the chain. Preferred alkyl groups have 1 to 12 carbon atoms in the chain. "Branched alkyl" means that one or more lower alkyl groups such as methyl, ethyl or propyl are attached to a linear alkyl chain. "Lower alkyl" means an alkyl group with 1 to about 4 carbon atoms in the chain which may be straight or branched. Exemplary alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, tert- butyl, isobutyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl or octadecyl. The alkyl group may be substituted by one or more halogen atoms representing thus an "halogenoalkyl" group. "Halogen atoms" means fluorine, chlorine, bromine or iodine atoms. Preferred are fluorine, chlorine or bromine atoms and more preferred is fluorine atoms. The "halogenoalkyl" groups may thus refer to "perfluoroalkyl", which means groups corresponding to the formula "-CnF2n+i" wherein n represents 1 to 18. Examples of perfluoroalkyl groups are pentafluoroethyl or trifluoro-methyl. "Alkoxy" means an alkyl-O- group wherein the alkyl group is as herein described. Exemplary alkoxy groups include methoxy, ethoxy, isopropyloxy, butoxy and hexyloxy radicals. "Cycloalkyl" means a non-aromatic mono- or multicyclic ring system of about 3 to 12 carbon atoms. Preferred ring sizes of the ring system include about 3 to 8 and more preferably 5 to 6 ring atoms. The cycloalkyl is optionally substituted with one or more "ring system substituents" which may be the same or different, and are as defined herein. Exemplary monocyclic cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl and the like. Exemplary multicyclic cycloalkyl include 1-decalyn, norbomyl and the like. "Cycloalkenyl" means a non-aromatic mono- or multicyclic ring system of about 3 to about 12 carbon atoms, preferably of about 5 to about 10 carbon atoms, and which contain at least one carbon-carbon double bond. Preferred ring size of rings of the ring system include about 5 to about 6 ring atoms. The cycloalkenyl is optionally substituted with one or more "ring system substituents" which may be the same or different, and are as defined herein. Exemplary monocyclic cycloalkenyl include cyclopentenyl, cyclo-hexenyl, cycloheptenyl and the like. An exemplary multicyclic cycloalkenyl is norbornylenyl. "Aryl" means an aromatic monocyclic or multicyclic ring system of about 6 to about 10 carbon atoms. The aryl is optionally substituted with one or more "ring system substituents" which may be the same or different and are as defined herein. Exemplary aryl groups include phenyl or naphtyl, or substituted phenyl or substituted naphtyl. "Alkenyl" means an aliphatic hydrocarbon group containing one or more carbon-carbon double bond and which may be straight or branched, having about 2 to about 12 carbon atoms in the chain, and more preferably about 2 to about 4 carbon atoms in the chain. "Branched alkenyl" means that one or more lower alkyl or alkenyl groups such as methyl, ethyl or propyl are attached to a linear alkenyl chain. "Lower alkenyl" means about 2 to about 4 carbon atoms in the chain, which may be straight or branched. The alkenyl group may be substituted by one or more halogen atoms. Exemplary alkenyl groups include ethenyl, propenyl, n-butenyl, i- butenyl, 3-methylbut-2-enyl, n-pentenyl, heptenyl, octenyl, cyclohexyl-butenyl and decenyl. "Aryloxy" means an aryl-O- group wherein the aryl group is as defined herein. Exemplary groups include phenoxy and 2-naphtyloxy. "Aryloxycarbonyl" means an aryl-O-CO- group wherein the aryl group is as defined herein. Exemplary aryloxycarbonyl groups include phenoxy-carbonyl and naphtoxycarbonyl. "Arylcarbonyl" refers to an aryl-CO- group wherein the aryl group is as defined herein. Exemplary arylcarbonyl group includes benzoyl. The (C-6-C-io) aryl, (C3-C12) cycloalkyl, (C3-C-12) cycloalkenyl are optionally substituted by one or more "ring system substituents". "Ring system substituents" mean substituents attached to aromatic or non- aromatic ring systems, inclusive of halogen atoms, an optionally halogenated (C-1-C5) alkyl, or an optionally halogenated (C1-C5) alkoxy, halogen, alkyl and alkoxy being as defined herein, The wording "in which the aryl, cycloalkyl and cycloalkenyl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-C5)alkyl or by an optionally halogenated (C-i-C-5)alkoxy" means that the aryl, cycloalkyi, cycloalkenyl groups are optionally substituted by one or more substituents selected from the group consisting of : - halogen atoms ; - alkyl groups optionally substituted by one or more halogen atoms, and - alkoxy groups optionally substituted by one or more halogen atoms. The wording "optionally halogenated" means, in the context of the , description, optionally substituted by one or more halogen atoms. Preferably, each of R independently represents a halogen atom, an optionally substituted halogenated (C6-Ci0) arylcarbonyl, an optionally halogenated (Ci-C18) alkyl, an optionally halogenated (Ci-Ci8) alkoxy, or an optionally halogenated (C6- C10) aryl. Examples of preferred halogen atoms include fluorine, bromine and chlorine atoms. Examples of optionally substituted halogenated (C6-Ci0) arylcarbonyl include the groups ortho, meta or para chlorobenzoyl, or ortho, meta, para-bromobenzoyl. Examples of preferred optionally halogenated (Ci-Ci8) alkyl include notably perfluoroalkyl groups such as trifluoromethyl. Examples of preferred optionally halogenated (Ci-C-I8) alkoxy include notably optionally halogenated (Ci-C6) alkoxy, particularly (C1-C4) alkoxy such as methoxy, ethoxy, isopropyloxy, n-butoxy, isobutoxy. Examples of particularly preferred optionally halogenated (C6-Cio) aryl include notably phenyl. More preferably, R represents a (Ci-Ci8) alkoxy group, more preferably a (C1-C4) alkoxy group and, most preferably, a methoxy group. Preferably, p is 1 or 2 and more preferably 1. R may be located in position 6, 7, 8 or 9 on the benzoxepine structure, as represented hereafter.

(I) Preferred compounds of formula (I) are chosen from: 3,3-dimethyl-5-cyano-7-bromo-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-cyano-9-methoxy-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-cyano-7,8-dichloro-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-cyano-7-fluoro-8-chloro-2,3-di-hydrobenzoxepi ne, 3,3-dimethyl-5-cyano-7-(para-chlorobenzoyl)-2,3-dihydrobenzo xepine, 3,3-dimethyl-5-cyano-7-trifluoromethyl-2,3-di-hydrobenzoxepi ne, 3,3-dimethyl-5-cyano-7-fluoro-2,3-dihydrobenzoxepine, S.S-dimethyl-δ-cyano-T-chloro^.S-dihydrobenzoxepine, 3,3-dimethyl-5-cyano-7,8-dimethoxy-2,3-dihydro-benzoxepine, 3,3-dimethyl-5-cyano-7-phenyl-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-cyano-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-cyano-7-methoxy-2,3-dihydrobenzoxepine as well as their geometric isomers and stereoisomers or mixtures thereof.

A more preferred compound of formula (I) is 3,3-dimethyl-5-cyano-7- methoxy-2,3-dihydrobenzoxepine :

(IA) as well as its geometric isomers and stereoisomers or mixtures thereof.

Methods for preparing compounds of formula (II) starting from compounds of formula (I) According to the invention, the compounds of formula (I) are used for the preparation of compounds of formula (II) according to scheme 2 :

(D (H) Scheme 2

Thus, in another aspect, the present invention is directed to a method for preparing compounds of formula (II), comprising : a) reacting the compounds of formula (I) with a reducing agent ; and optionally b) hydrolyzing the resulting mixture ; and optionally c) isolating the obtained compound of formula (II).

Step a) The conversion of the compound of formula (I) into the compound of formula (II) is carried out in the presence of a reducing agent. There is no particular restriction on the nature of the reducing agent used in this reaction and any reducing agent conventionally used in a reaction of this type may equally be used here, provided that it has no adverse effect on other parts of the molecule. Suitable reducing agents for reducing the nitrile compound of formula (I) to aldehyde include metal hydride reducing agents such as LiAIH4, NaAIH4, LiAIH (Oalkyl)3< LiAIH2(Oalkyl)2, LiAIH(NR2)3 where R is H or an alkyl group and JPr2AIH, JBu2AIH, also called DIBAL-H, the DIBAL-H being particularly preferred. Another suitable method for reducing the nitrile to aldehyde, known as the Stephen reduction, involves reacting the nitrile with HCI and SnCI2. More particularly, it generally involves treating the nitrile with HCI, reducing the formed intermediate with SnCI2 and hydrolyzing the obtained imine to the corresponding aldehyde. The conditions described in the following publications may be applied or adapted to the reduction of (I) to (II) when implementing the indicated reducing agents : - JPr2AIH (Angew. Chem. Int. Ed., 1973, 12, 497) ; - JBu2AIH (many references, notably J. Org. Chem., 1970, 35, 858, Marshall, Andersen, Schlicher) ; - LiAH(OEt)3 (J. Amer. Chem. Soc, 1964, 86, 1085, Brown et Garg) ; - LiAIH2(OEt)2 (J. Org. Chem., 1979, 44, 4603) ; - NaAIH4 (Bull. Acad. Sci. USSR, Div. Chem. ScL, 1964, 1415, Zakharkin, Maslin, Gavrilenko). Other reactants may be used for the conversion of (I) into (II), such as Et3SiH (J. Org. Chem., 1981 , 46, 802), Ni Raney (Org. Synth., 1971 , 51 , 20, Van Es, Staskun) or Zinc-cobalamine (HeIv. Chim. Acta, 1978, 61 , 2560, Fischli). The amount of reducing agent is for example 1.0 to 2 moles and more preferably 1.1 to 1.5 moles relative to 1 mole of compound (I). There is no particular restriction on the nature of the solvent employed, provided that it has no adverse effect on the reactions or on the reagents involved. Suitable solvents for step a) are aromatic solvents, ethers, halogenated hydrocarbons and aliphatic hydrocarbons and mixtures thereof. Examples of aromatic solvents are benzene, toluene, xylene and ethylbenzene. Examples of ethers include dialkyl ethers such as diethyl ether, dibutyl ether, dioxane, tetrahydrofurane. Examples of halogenated hydrocarbons include notably dichloromethane, chloroforme, 1 ,2-dichloroethane. Examples of aliphatic hydrocarbons include notably pentane, hexane, heptane and octane. Preferably, anhydrous conditions are used. The reaction of step a) can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, it has been found convenient to carry out the reaction at a temperature from about -200C to room temperature and preferably from -100C to 0°C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period from about δminutes to about 20 hours will usually be sufficient.

Step b) In accordance with a preferred embodiment, the method for preparing the compound of formula (II) further comprises the step of hydrolyzing the compound obtained in step a). Indeed, when reducing nitrils to aldehydes involve using a metal hydride, the method may generally lead to the intermediate formation of an imine derivative that may be hydrolyzed in order to give the aldehyde (II). This hydrolysis is preferably performed in situ. The following scheme 3 is given as an illustration of this reaction pathway and is not to be considered as limiting the invention in its scope.

Scheme 3

Preferably, the hydrolysis is performed under acid conditions. Suitable acids for the hydrolysis of the compounds obtained in step a) include inorganic acids, such as hydrochloric acid, sulphuric acid, nitric acid and phosphoric acid ; sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid and paratoluenesulfonic acid. Inorganic acids are most preferred and notably hydrochloric acid. Excess amount of acid is generally used and the amount of acid is for example 5 to 10 moles relative to 1 mole of compound (I). In that context, the mixture is stirred, for example for 0.5 hour to 2 hours and preferably for 1 hour to 1.5 hour. In that context, it has been found convenient to carry out the reaction at a temperature that does not exceed 4O0C, for example from about room temperature to about 4O0C. The time required for each reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period from about 0.5 hour to about 2 hours will usually be sufficient for the hydrolysis step.

Step c) The compounds thus prepared may be recovered from the reaction mixture by conventional means, for example the compounds may be recovered by distilling of the solvent from the reaction mixture or, if necessary, optionally after distilling of the solvent from the reaction mixture, pouring the residue into water, followed by extraction with a water-immiscible organic solvent and distilling of the solvent from the extract. Additionally, the product can, if desired, be further purified by various well known techniques, such as recrystallization, reprecipitation or the various chromatography techniques, notably column chromatography or preparative thin layer chromatography. Preferred compounds of formula (II) which may conveniently be prepared starting from corresponding compounds of formula (I) according to the present invention can be chosen from the group consisting in: 3,3-dimethyl-5-formyl-7-bromo-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-formyl-9-methoxy-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-formyl-7,8-dichloro-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-formyl-7-fluoro-8-chloro-2,3-di-hydrobenzoxep ine, 3,3-dimethyl-5-formyl-7-(para-chlorobenzoyl)-2,3-dihydrobenz oxepine, 3,3-dimethyl-5-formyl-7-trifluoromethyl-2,3-di-hydrobenzoxep ine, 3,3-dimethyl-5-formyi-7-fluoro-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-formyl-7-chloro-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-formyl-7,8-dimethoxy-2,3-dihydro-benzoxepine, 3,3-dimethyl-5-formyl-7-phenyl-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-formyl-2,3-dihydrobenzoxepine, 3,3-dimethyl-5-formyl-7-methoxy-2,3-dihydrobenzoxepine. Methods for preparing the compounds of formula (I) The compounds useful according to the invention may be prepared by the application or adaptation of known methods, by which are meant methods used heretofore or described in the literature, for example those described by R. C. Larock in Comprehensive Organic Transformations, VCH Publishers, 1989.

Thus, in a further aspect, the invention provides a method for preparing the compounds of formula (I) comprising : i) reacting a compound of formula (III):

(III) with CN" or a species providing CN"; ii) hydrolyzing the resulting mixture ; and optionally iii) isolating the obtained compound of formula (I).

Step i) The reaction of step i) consists in converting the cetone of formula (III) into the corresponding cyanohydrin. This reaction requires the presence of CN" ions; these may be provided in a free form in the reaction mixture or, alternatively, may be obtained by using a species providing such CN' ions. Such species include a alkali metal cyanide, such as NaCN or KCN, diethylaluminum cyanide (Et2AICN) or trialkyl- or triaryl-silylcyanide. Other suitable species include equivalents of trialkylsilylcyanide such as notably KCN-Me3SiCI (Tetrahedron Asymmetry, 2001 , 12(2), 279-286, Effenberger F., Oswald S.), LiCN-Me3SiCI (Synthesis, 1986, 12, 1054-1055, Yoneda R., Santo K., Harusawa S., Kirihara T.). Preferably, the reaction is carried out in the presence of trialkylsilylcyanide such as trimethylsilylcyanide (MeβSiCN), trimethylsilylcyanide being most preferred. When trialkylsilylcyanide or triarylsilylcyanide are used, it is particularly preferred to carry out the reaction of step i) in the presence of a Lewis acid or a base. Examples of suitable basis include alkali metal hydrides, such as lithium hydride, sodium hydride and potassium hydride; (C1-C10) alkyllithium compounds such as methyllithium, butyllithium, hexyllithium ; alkali metal alkoxides such as sodium methoxide and sodium ethoxide ; and alkali metal carbonates such as potassium carbonate and sodium carbonate. Of these, the alkyllithium compounds and notably the butyllithium are particularly preferred. Alternatively, other Lewis acids or bases may be used such as LiCIO4, LiBF4, Zn(CN)2, ZnI2, KCN, Bu4NCN, DABCO (diazabicyclooctane),Ti(OiPr)4, CaF2, Lewis acid-amberlite-trimethylsilyl triflate. The amount of base is generally catalytic and is for example 0.01 to 0.5 moles and preferably 0.1 to 0.25 moles relative to 1 mole of compound (III). There is no particular restriction on the nature of the solvent to be used, provided that it has no adverse effect on the reaction or on the reagent involved. Examples of suitable solvents include hydrocarbons, such as hexane, cyclohexane, benzene, toluene and xylene; aprotic polar solvents such as N,N-dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, pyridine. Of these, hexane and pyridine are particularly preferred. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, it has been found convenient to carry out the reaction at a temperature from about room temperature (200C) to 1500C, and more preferably of from 200C to 500C. The molar ratio of CN" or the species providing CN" relative to compound (III) may vary from 1.0 to 1.5 equivalent, preferably from 1.05 to 1.25.

Step in The reaction of the compound of formula (III) with CN' or CN" providing species generally lead to an intermediate cyanohydrin compound, which in turn leads after hydrolysis to the compound of formula (I). This hydrolysis can be carried out in situ, straight after step i). Examples of acids suitable for said hydrolysis include, but are not limited to, hydrochloric acid, sulphuric acid, nitric acid and phosphoric acid ; trifluoroacetic acid ; sulphonic acid, such as methane sulfonic acid, ethane sulfonic acid, benzene sulfonic acid and paratoluene sulfonic acid. In case trialkyl- or triaryl- silylcyanide is used, the hydrolysis is preferably performed in the presence of a chlorinating agent such as phosphorus oxychloride (POCI3), thionyl chloride (SOCb), sulfuryl chloride (SO2CI2) ; or in the presence of trifluoroacetic acid (CF3CO2H), paratoluene sulphonic acid and hydrochloric acid (gaz). The molar ration of said chlorinating agent relative to compound of formula (III) is from 1 to 2 equivalents, preferably 1.5 equivalents. There is no particular restriction on the nature of the solvent to be used, provided that it has no adverse effect on the reaction or on the reagent involved. As step ii) can be conducted in situ, the same solvents as for step i) can be used. Examples of suitable solvents include hydrocarbons, such as hexane, cyclohexane, benzene, toluene and xylene; aprotic polar solvents such as N1N- dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, pyridine. Of these, hexane and pyridine are particularly preferred. The reaction can take place over a wide range of temperatures, arid the „ precise reaction temperature is not critical to the invention. In general, it has been found convenient to carry out the reaction at a temperature from about room temperature (2O0C) to 15Q°C, preferably of from 200C to the boiling temperature of the solvent, more preferably 900C. The reaction can be conducted for a time sufficient to obtain a satisfactory reaction rate, usually between 1 and 10 hours.

Step iiO The compounds thus prepared may be recovered from the reaction mixture by conventional means, for example the compounds may be recovered by distilling of the solvent from the reaction mixture or, if necessary, optionally after distilling of the solvent from the reaction mixture, pouring the residue into water, followed by extraction with a water-immiscible organic solvent and distilling of the solvent from the extract. Additionally, the product can, if desired, be further purified by various well known techniques, such as recrystallization, reprecipitation or the various chromatography techniques, notably column chromatography or preparative thin layer chromatography. The following scheme 4 is given as an illustration of the method for preparing the compounds of formula (I) but is not to be considered as limiting the invention in its scope.

(III) The invention is illustrated by the following representative and non-limiting examples :

Example 1 : 3,3-dimethyl-5-cyano-7-methoxy-2,3-dihydro-benzoxepine (IA) :

A mixture of compound (III) (1 kg, 4.54 moles), trimethylsilylcyanide (0.518 kg, 1.15 eq.) and n butyllithium 2.5 M in hexane (0.031 kg, 0.025 eq.) in pyridine is stirred at 20-250C for 5 hours. Then, phosphorus oxychloride (1.044 kg, 1.5 eq.) is added and the mixture is heated at approximately 9O0C for 6 hours. The reaction mixture is cooled to 50-600C and poured onto a mixture of toluene and water previously cooled to approximately O0C. After stirring at 20-250C for half an hour, the aqueous phase is separated and the organic phase is washed successively with diluted aqueous sodium hydroxide - sodium hypochlorite mixture, aqueous sodium chloride, diluted aqueous sulphuric acid and aqueous sodium chloride. The toluene solution is finely partially concentrated at atmospheric pressure, treated with active charcoal and used without further purification (yield : 65-83 %). MP : 720C. 1HRMNδ ppm : 1.08(6H,s); 3.7(3H,s); 3.8(2H,s); 6.8-7.1(4H,m) 13CRMNδppm : 24.9; 42.6; 55.9; 78.5; 109.9; 115.9; 119.3; 122; 122.4; 153.4; 155.1 ; 157.3

Example 2 : 3,3-dimethyl-5-formyl-7-methoxy-2,3-dihydrobenzoxepine (formula (II) : R = methoxy, p=1) A toluene solution of compound (IA) (1 kg, 4.36 moles) is cooled to approximately -1O0C and a 20% toluene solution of diisobutylaluminum hydride (3.41 kg, 1.1 eq.) is added while maintaining the temperature between -100C and 0°C. The mixture is stirred at this temperature for 1. hour and the end of the reaction is controlled by TLC. The reaction mixture is then poured onto 5N hydrochloric acid at such a rate that the temperature does not exceed 400C. The mixture is stirred for 1 hour and the aqueous phase is separated. The organic phase is washed with water and concentrated to dryness under vacuum. The residue is dissolved in ethanoi and treated with an aqueous solution of sodium metabisulfite (1.32 kg, 1.6 eq.) at reflux for 3 hours. The end of the reaction is controlled by TLC and the ethanoi is removed by distillation. The solution obtained is cooled, washed with toluene at approximately 300C, cooled to 150C and basified with 30% aqueous sodium hydroxide. The suspension is stirred at approximately 15°C for half an hour and the solid is separated, washed with water and dried at 50-55°C (yield : 68-78%). This compound was identical to the compound obtained in example 16i) of EP 1140893 B1.