Prior Art Several systems for releasing fragrant compounds have been described in the prior art. WO 99/60990, which was filed by the applicant, describes a fragrance delivery system which releases fragrant alcohols, aldehydes or ketones upon exposure to light.

Said system comprises 2-benzoyl benzoates or o-keto esters which are used as fragrance precursors.

There exists, in perfumery, a particular interest in compounds which are capable of"fixing"fragrant molecules, for example by chemical bonding or intramolecular forces like adsorption, and releasing said fragrant molecules over a prolonged period of time, for example by the action of heat, enzymes, or even sunlight (fragrant molecules have to be volatile in order to be perceived). Although many known fragrant compounds show a good substantivity, i. e. they will remain on a surface to which they have been applied for several days and can hence be perceived over such a period of time, a great number of fragrant compounds are very volatile, and their characteristic odour can no longer be perceived several hours after their application.

It is thus desirable to dispose of fragrance delivery systems which are capable of releasing the fragrant compound or compounds in a controlled manner, maintaining a desired scent over a prolonged period of time.

Therefore, in view of their importance in the field of perfumery, systems allowing the slow release of fragrant compounds constitute an object of intensive research in order to find new precursors capable of releasing different odorous compounds.

Phenyl ketones are known to be photolabile molecules. In fact, the photochemistry of these compounds was extensively studied in the prior art. One can cite for instance P. J. Wagner, in Acc. Chem. Res., 1971,4,168-171, or in Top. Curr. Chem.

1976,66,1-52.

Moreover, W. W. Epstein et al. disclose in Anal. Biochem. 1982,119,304-312 the use of alkyl phenyl ketones as photolabile linkage inserted in a detergent in order to cleave the latter under photolysis and to form a water soluble compound and an olefin.

However, the prior art has never disclosed any use of phenyl ketones as precursors of fragrant compounds, masking agents, antimicrobial agents or other active compounds or as being part of perfuming, masking, antimicrobial, insect repelling or insect attracting compositions or products, the latter providing systems of slow release of said active compounds.

Description of the Invention Now, we have been able to establish that some phenyl and pyridyl ketones can be advantageously used within the scope of the slow release of active compounds such as fragrant molecules, masking agents, antimicrobial agents or insect repelling or attracting agents. In fact, they constitute useful precursors of terminal alkenes.

The invention thus relates to a perfuming, masking, antimicrobial, insect repelling or attracting composition or article comprising, together with one or more perfuming ingredients, masking agents, antimicrobial agents, insect repelling or attracting ingredients, solvents or adjuvants of current use, at least one compound of formula wherein Y represents a pyridyl group, or a phenyl group of formula (la)

wherein R3 represents a hydrogen atom, a CF3 group or a linear or branched alkoxy group from Cl to C12, R4 represents a hydrogen atom, a linear or branched alkyl group from Cl to C4, or a CF3 group, R5 represents a hydrogen atom, a linear or branched alkyl group from Cl to C4, a CF3 group or a linear or branched alkoxy group from Cl to C12 ; and Rl and R2 are the substituents of a terminal alkene of formula wherein Ri represents a linear or branched alkyl or alkylene group from Ci to C35, an unsubstituted or substituted mono-or poly-cycloalkyl group having 3 to 8 carbon atoms, or an unsubstituted or substituted phenyl group, said alkyl, alkylene, mono-or poly-cycloalkyl and phenyl groups possibly comprising one or several hetero-atoms selected from the group consisting of oxygen, nitrogen, phosphorous and sulphur ; and R2 represents a hydrogen atom, a linear or branched alkyl or alkylene group from Ci to C3s, an unsubstituted or substituted mono-or poly-cycloalkyl group from C3 to C8, or an unsubstituted or substituted phenyl group, said alkyl, alkylene, mono-or poly-cycloalkyl and phenyl groups possibly comprising one or several hetero-atoms selected from the group consisting of oxygen, nitrogen, phosphorous and sulphur.

The compounds of formula (I) are capable of releasing, under irradiation, an active alkene of formula (i). Non limiting examples of active compounds released by the precursors of formula (I) include fragrant molecules, masking agents, antimicrobial agents or insect repelling or attracting compounds. Therefore, the nature of the substituents Rl and R2 is defined by the structure of the active molecule, namely the alkene of formula CH2=CRIR2.

In a preferred embodiment of the invention, the active compound of formula (i) is a fragrant molecule. In this preferred embodiment, when Ri and/or R2 represent a linear or branched alkyl or alkylene group, the latter comprises from 1 to 20 carbon atoms.

In a particular embodiment, the precursor of the perfuming, masking, antimicrobial, insect repelling or attracting alkene is of formula wherein R3, R4 and Rs have the same meaning as in formula (I), n is an integer varying from 0 to 10, and R* represents a hydrogen atom, a linear or branched alkyl or alkylene group from Ci to C20, an unsubstituted or substituted mono-or poly-cycloalkyl group from C3 to Cs, or an unsubstituted or substituted phenyl group, said alkyl, alkylene, mono-or poly-cycloalkyl and phenyl groups possibly comprising one or more hetero- atoms selected from the group consisting of oxygen, nitrogen, phosphorous and sulphur.

In the above definitions, when reference is made to a masking agent, there is meant a compound which is able to enhance or to mask the characteristic odour of a material. Moreover, an antimicrobial agent is a compound which presents an antimicrobial activity, i. e. which is capable of reducing or preventing the development of microbial or bacterial activity. Examples of these compounds are given by J. J. Kabara in Cosmet. Sci. Technol. Ser. (16), 1997,181-208, for example.

Similarly, when reference is made to a fragrant terminal alkene, there is meant an alkene which not only has an odour, but which is also known to a person skilled in the art as being useful as perfuming ingredient for the formulation of perfumes or perfumed articles. The criteria a useful perfuming ingredient has to fulfil are known to a person skilled in the art and include, amongst other, a certain originality of the odoriferous note, stability and a certain price/performance ratio. Non limiting examples of alkenes which can be used within the scope of the invention will be mentioned below.

One of the advantages of the composition or product of the present invention lies in its capacity to slowly release the active alkene of formula (i) from which the phenyl or pyridyl ketone formula (I) is derived. The release occurs when said ketone is exposed to daylight in particular. Therefore, once applied in any kind of surface and upon absorption of energy from said light, the ketone undergoes a photoreaction in the course of which

the active compound is released from the precursor molecule into the surroundings, thus generating a specific activity coming from the surface treated with the ketone of the invention. Said release occurs in a controlled manner, i. e. a more or less constant amount of active molecule is released over a period of time, without an initial burst of very intense action (odour, antimicrobial activity, repelling or attracting activity) which becomes rapidly imperceptible, as is the case with volatile terminal alkenes for instance.

Because the release of the alkene can occur over several days or weeks, the use of the system of the present invention obviates the drawbacks of many molecules which show an important specific activity but are also very volatile.

Good examples of volatile fragrant molecules are styrene and allyl heptanoate which can only be perceived over a short period of, say, a few hours, when applied to the surface of, for example, tiles and windows in the course of a cleaning procedure using liquid cleaners ; even in solution, the typical scent of said fragrant molecules disappears within several hours. It goes without saying that the concentration of the precursor in the application plays an important role in the time during which the active molecules can be perceived.

In an embodiment of the invention, the precursors of formula (I) are capable of releasing, under the action of light, a fragrant molecule of formula (i) wherein Rl represents a linear or branched alkyl or alkylene group from Cl to C20, an unsubstituted or substituted mono-or poly-cycloalkyl group from C3 to C8, or an unsubstituted or substituted phenyl group, wherein said alkyl, alkylene, mono-or poly-cycloalkyl and phenyl groups may comprise one or several hetero-atoms selected from the group consisting of oxygen, nitrogen, phosphorous and sulphur; and R2 represents a hydrogen atom, a linear or branched alkyl or alkylene group from Cl to C20, an unsubstituted or substituted mono-or poly-cycloalkyl group from C3 to C8, or an unsubstituted or substituted phenyl group, wherein said alkyl, alkylene, mono-or poly-cycloalkyl and phenyl groups may comprise one or several hetero-atoms selected from the group consisting of oxygen, nitrogen, phosphorous and sulphur. Perfuming compositions or perfumed products to which these precursors are added can thus release in a controlled and prolonged manner fragrant compounds upon exposure to light.

In a particularly appreciated embodiment, the composition or product of the invention in the form of a perfuming composition or product, comprises at least one compound of formula (II) as defined above, the latter being susceptible of releasing, under the action of light, a compound of formula

wherein m is varying from 1 to 10 and R* has the same meaning as in formula (II).

The compounds of formula (I) are capable of releasing a fragrant terminal alkene of formula (i), upon exposure to light. This system is particularly advantageous because said fragrant molecules, namely terminal alkenes, represent a class of volatile compounds of great importance in the field of perfumery. With the system of the present invention, the typical odour of terminal alkenes of formula (i) is perceived over a considerably longer period of time, when compared with the phenyl ketones or pyridyl ketones as such of the fragrance delivery system, which are not or are sparingly volatile. The fragrance delivery system remains as such on the surface to which it is applied or in the solution into which it is incorporated, and it is only upon exposure to light that the fragrant alkene is released. It is clear that this reaction can provide perceptible amounts of the alkene over days or weeks, depending, amongst others, on the amount or the concentration of the fragrance precursor, the time of exposure to light, the intensity and wavelength of the latter. Moreover, and contrary to what has been disclosed in the prior art, the light induces, in this particular embodiment of the invention, a C-C cleavage. In other words, as the cleaved bond is not particularly labile, the precursor is thus very stable and can therefore be advantageously used in any kind of medium, particularly in an aggressive medium such as bleaches and bleaching detergents or antiperspirants, with a limited risk of reacting.

As non limiting examples of terminal alkenes which can be used in the present invention, one can cite allyl acetate, allyl anthranilate, allyl benzoate, allyl butanoate, allyl cyclohexaneacetate, allyl 3-cyclohexylpropanoate, allyl 2-furoate, allyl heptanoate, allyl hexanoate, allyl 2,4-hexadienoate, allyl 3-methylbutanoate, allyl nonanoate, 1- allyloxy-2-methoxybenzene, allyl phenoxyacetate, allyl phenylacetate, allyl phenyl-2- propenoate, allyl propanoate, allyl salicylate, 9-decen-1-ol, 9-decen-1-yl acetate, 9- decenylpropanoate, decyl vinyl ether, Dynascone (1- (3, 3-dimethyl-1-cyclohexen-1-yl)- 4-penten-1-one ; origin: Firmenich SA, Geneva, Switzerland), 1- (5, 5-dimethyl-1- cyclohexen-1-yl)-4-penten-1-one, 3,7-dimethyl-1,6-octadien-3-ol, 1,5-dimethyl-1-vinyl- 4-hexenyl acetate, 1, 5-dimethyl-1-vinyl-4-hexenyl benzoate, 1, 5-dimethyl-l-vinyl-4- hexenyl formate, 1, 5-dimethyl-1-vinyl-4-hexenyl isobutyrate, 1, 5-dimethyl-l-vinyl-4-

hexenyl propanoate, 3,7-dimethyl-1-vinyloxy-2,6-octadiene, 3,7-dimethyl-1-vinyloxy-6- octene, 2-ethylhexyl 2-propenoate, ethyl 2-propenoate, ethyl 10-undecanoate, 6-hepten- 2-ol, 8-nonen-1-ol, 1-octene, 1-penten-3-ol, 2-phenylethyl vinyl ether, 10-undecen-1-ol, vinyl acetate, vinylbenzene, 4-allyl-1, 2-dimethoxybenzene, 1-allyl-4-methoxybenzene, 4- allyl-2-methoxyphenol, 1,3-dimethyl-3-butenylisobutyrate, 2,6-dimethyl-7-octen-2-ol, 1, 8-p-menthadien-7-ol, 8-p-menthadien-2-one, 8-p-menthen-1-ol, 10-undecenal.

It is quite obvious, however, that the phenyl and pyridyl ketones comprised in the compositions of the invention can be derived from many other alkenes which the skilled person is quite able to choose from the general knowledge in the art and as a function of the olfactory, masking, antibacterial or insect repelling or attracting effect it is desired to achieve. The above list is more illustrative for fragrant compounds which are known to a person skilled in the art, and whose delivery can be improved, but it is clearly quite impossible to cite in an exhaustive manner all compounds of formula (i) which have a pleasant odour or an effective activity of some other useful type and the phenyl and pyridyl ketones which can be used in the compositions of the present invention.

The composition of the invention may comprise more than one alkene precursor of formula (1). For instance, a mixture of compounds of formula (I), being capable of releasing different fragrant alkenes, each possessing its proper odour, may be incorporated in a composition according to the invention so that, under the action of light, more than only one fragrant molecule is released, thus providing a fragrant harmony.

Moreover, when Y represents a phenyl group of formula (Ia), besides the desired alkenes, the photo-fragmentation of the precursor of formula (I) yields equimolar amounts of a substituted or unsubstituted acetophenone of formula wherein the symbols have the same meaning as in formula (I), and which may also be useful as perfuming ingredients. Non limiting examples of fragrant acetophenones include 1- (4-methoxyphenyl)-l-ethanone, 1- (4-methylphenyl)-1-ethanone, 1-phenyl-1- ethanone or 1- (4-tert-butylphenyl)-l-ethanone.

The compositions or products of the invention, comprising at least one compound of formula (I), or even a compound of formula (I) on its own, can be deposited on a surface which will be exposed to light, in order to perfume, attenuate undesirable odours or impart an antibacterial or insect repelling or attracting activity coming from the latter.

A further object of the present invention is therefore a method for generating a specific activity coming from a surface which comprises treating the latter with a compound of formula (I) and exposing said surface to light. Non limiting examples of surfaces which may be treated with a compound of formula (I) include skin or hair, floors, windows, tiles, furniture, fabric or cloth, plants such as flowers or trees.

The release of the above-mentioned active compounds from the precursors occurs upon the exposure to light, e. g. the normal daylight which can penetrate through ordinary windows in houses and which is not particularly rich in UV-radiation. It goes without saying that upon exposure to bright sunlight, in particular outdoors, the release of the active terminal alkene will occur faster and to a greater extent than upon exposure to the light indoors. Of course, the reaction which releases the active compound from the precursor can also be initiated by an appropriate artificial lamp.

The precursors of the present invention can be used in any application in which a prolonged, defined release of the above-mentioned fragrant, odour masking, antimicrobial or insect repelling or attracting compounds is desired. They mostly find use in functional perfumery, in products or articles which are exposed to daylight when in use or which are applied to other articles which thereafter are exposed to daylight.

Suitable examples include air-fresheners in liquid and solid form which, with the precursors of the present invention, can still release a fragrance when conventional air- fresheners, i. e. those not containing a precursor of the present invention, are exhausted.

Other kinds of aerosols, namely products such as antibacterial products or insect repelling or attracting products can also comprise a compound of formula (I). Other examples of products are various cleaners for the cleaning of surfaces of all kinds, e. g. window and, household cleaners, all-purpose-cleaners and furniture polishes. The surfaces which have been cleaned with such cleaners will generate the specific activity of the released compound, such as the fragrance of a perfume, much longer than when cleaned with conventional cleaners. Other representative examples include detergents for fabric wash, fabric conditioners and fabric softeners which can also contain the precursors of the present invention and which products can be in the form of powders, liquids or tablets. The fabrics and clothes washed or treated with such detergents or

softeners will diffuse the active compound even after having been stored for weeks or even months, in a dark place, like a wardrobe.

Examples of detergents which can be used include those described in WO 97/34986. Moreover, as softening bases one may select those described in the patents US 4,137,180, US 5,236,615 or EP 799 885. Other typical compositions of detergents and softeners which may be used are described in works such as Ullmann's Encyclopedia of Industrial Chemistry, Vol. A8, pp. 315-448 (1985) and Vol. A25, pp. 747-817 (1994); E. W. Flick, Advanced Cleaning Product Formulations; Noyes Publication Park Ridge, N. J. (1989); M. S. Showell (Ed.) in Surfactant Science Series, Vol. 71; Powdered Detergents, Marcel Dekker, New York, N. Y. (1998); Proceeding of the 4th World Conference on Detergents; Strategies for the 215t century, A. Cahn (Ed.), AOCS Press, Champaign (1998). Of course, the use of the compounds of the invention is not limited to the products mentioned above.

The release of the active compound occurs in all the above-mentioned application examples. All possible types of window cleaners, household, all-purpose cleaners, air-fresheners, aerosols for a specific purpose, detergents, fabric washers and fabric softeners can be used with the precursors of the present invention, which have revealed themselves to be useful in all types of these above-mentioned application examples. The nature of the latter is quite immaterial as the person skilled in the art is able to adjust their composition or form, should this prove necessary, as a function of the effect desired and in much the same way as it does now with any current perfuming, masking, antimicrobial, insect repelling or attracting composition.

In the field of body care, the compositions comprising a fragrance precursor according to the present invention have shown themselves to be particularly appropriate for an application in the hair care area, and specific examples include shampoos, hair conditioners, in particular leave-on conditioners, hairsprays and other hair care products.

It can be said that generally all products which can be applied to a surface which is exposable to light can advantageously contain the precursors of the present invention. Examples include surfaces which belong to the human body, such as skin or hair, surfaces in buildings and apartments, like floors, windows, tiles or furniture, or surfaces of fabrics, e. g. clothes, plants such as flowers or trees. It is clear that the precursors of the invention can also be used to release active compounds, notably fragrances, from liquids, like in liquid air-fresheners or air-freshening devices in the form of gels.

Of course, the above examples are only illustrative and non-limiting as they relate to preferred embodiments. All other current articles or products in functional and fine perfumery may contain the precursors of the present invention, and these articles or products include soaps, bath or shower gels, cosmetic preparations, body deodorants, and even perfumes or colognes.

In the above-cited applications, the precursor of the present invention can be used alone, in mixture with other precursors, and/or with other active ingredients such as perfuming ingredients, solvents and adjuvants of current use in the art. The nature and variety of these co-ingredients do not require a detailed description which, moreover could not be exhaustive, and a person skilled in the art is able to choose said co- ingredients by his general knowledge and in function of the nature of the product to be treated and the generated effect sought. These perfuming co-ingredients belong to such varied chemical classes as alcohols, aldehydes, ketones, esters, ethers, acetates, nitriles, terpene hydrocarbons, nitrogen-or sulphur-containing heterocyclic compounds, as well as essential oils of natural or synthetic origin. By way of example, embodiments of compounds can be found in standard reference works, such as the book of S. Arctander, Perfume and Flavour Chemicals, 1969, Montclair, New Jersey, USA, or more recent versions thereof, or in other works of similar nature.

The proportions in which the compound of formula (I) can be incorporated in the various above-mentioned consumer products vary within a wide range of values.

These values depend on the nature of the active compound to be released, the nature of the article or product which has to be prepared and the desired generated effect, as well as on the nature of the co-ingredients in a given composition when the compounds of the present invention are used in admixture with perfuming, masking, antimicrobial, insect repelling or attracting co-ingredients, solvents or adjuvants of current use in the art.

By way of example, one can cite typical concentrations of the order of 0.01 to 5%, or even 10% by weight relative to the weight of the consumer products cited above into which it is incorporated. Higher concentrations than those mentioned above can be used when, in particular, a fragrance precursor is applied in perfuming compositions, perfumes or colognes.

Several methods can be employed for the preparation of compounds of formula (1). One route for the preparation of these compounds (I) wherein Y represents a phenyl group starts with the esterification of an oxo-phenyl acid with sulphuric acid in methanol, followed by protection of the carbonyl function with ethylene glycol. The intermediate

ketal (A) can be reduced with LiAlH4 in ether to obtain an alcohol which is esterified under dicyclohexylcarbodiimide (DCC) coupling conditions. Deprotonation of the ketal with hydrochloric acid in tetrahydrofuran (THF) finally affords a series of phenyl ketones of formula (I) in a five step sequence.

Moreover, saponification of the same intermediate (A) with LiOH and treatment with methyllithium affords a carbonyl compound which can be further derived. For example, a Grignard-type reaction with 5-bromo-2-methyl-2-pentene, followed by acetalisation of the tertiary alcohol function and deprotection of the carbonyl protecting group affords another phenyl ketone according to formula (I).

An alternative route used for the preparation of a series of phenyl ketones as well as for the preparation of pyridyl ketones starts from oxo-phenyl chlorides, respectively oxo-pyridyl chlorides. In a first step, the carbonyl function is protected with ethylene glycol. Etherification with an alcoholate in tetrahydrofuran, followed by deprotection of the carbonyl function leads to further series of compounds which can be expressed by formula (I) in a three steps sequence.

Schemes 1 and 2 below illustrate the general preparation of said compounds : Scheme 1 R3 0 0 R3 0 1.) H2S04 R OH CH30H 2.) ethylene 5 T 3 glycol, R5 r R3 (A R4 p-TsOH, R4 R4 p-TsOH, R4 toluene LiOH, CH3Li LiAIH4 ether Zu R 0 OH zon 5 I! 3 5 jT 3 R4 R4 R4 Ru 1.) Mg, ether < Br 1.) RCOOH, DCC, DMAP, CH2CI2 2.) N, N-diethylaniline, 2.) HCI, THF AcCI,CH2CI2 3.) HCI, THF zu R3 0 0 R3 0 0 3 O 3 R4. R R4 \ OJ' R n R Rs R3 I R5 R3 R4 R4

n=0-10 n=0-10 wherein R3, R4, Rs have the same meaning as in formula (I) and R represents a hydrogen atom, a linear or branched alkyl or alkylene group from Cl to C20, an unsubstituted or substituted mono-or poly-cycloalkyl group from C3 to Cg, or an unsubstituted or substituted phenyl group, wherein said alkyl, alkylene, mono-or poly-cycloalkyl and phenyl groups may comprise one or several hetero-atoms selected from the group consisting of oxygen, nitrogen, phosphorous and sulphur.

Scheme 2 R3 0 R4 \ R4 X n ci R5 R3 R R "5 j"3 R4 1.)ethylene g!yco!, glycol, p-TsOH, toluene 2.) KH, THF t, HO4R' Zu Ra I n 0 R' R in 5 R4 HCI, THF R3 O Rus 0 Vin R "R Rs/tR3 R4

n = 0-10 wherein R3, R4, Rs have the same meaning as in formula (I) and R'represents a hydrogen atom, a linear or branched alkyl or alkylene group from Cl to C20, an unsubstituted or substituted mono-or poly-cycloalkyl group from C3 to C8, or an unsubstituted or substituted phenyl group, wherein said alkyl, alkylene, mono-or poly-cycloalkyl and phenyl groups may comprise one or several hetero-atoms selected from the group consisting of oxygen, nitrogen, phosphorous and sulphur.

p-TsOH: p-toluenesulfonic acid DCC: dicyclohexylcarbodiimide DMAP 4-dimethylaminopyridine AcCI : acetyl chloride The invention will now be described in greater detail in the following examples in which the temperatures are indicated in degrees centigrade and the abbreviations have the usual meaning in the art.

Embodiments of the invention General Commercially available reagents and solvents were used without further purification if not stated otherwise. The following chemicals were obtained from commercial sources: 5-oxo-5-phenylpentanoic acid, sulfuric acid, p-toluenesulfonic acid, lithium aluminium hydride, dicyclohexylcarbodiimide (DCC), 4-dimethylaminopyridine (DMAP), heptanoic acid, hydrochloric acid, 3-cyclohexylpropanoic acid, phenoxyacetic acid, 1,4-diphenyl-1- butanoate, methyl lithium, lithium hydroxide, N, N diethylaniline, acetyl chloride, 4- <BR> <BR> <BR> <BR> chloro-1-(4-methylphenyl)-1-butanone, 4-chloro-1-(4-methoxyphenyl)-1-butanonen 1-(4- tert-butylphenyl)-4-chloro-1-butanone, 2-phenylethanol, decanol and potassium hydride.

Reactions were carried out in standard glassware under N2 if not stated otherwise.

5-Bromo-2-methyl-2-pentane was prepared from 1-cyclopropyl-1-ethanone in an analogous manner to the method described by Biernacki and Gdula in Synthesis, 1979,-37-38 Example 1 Preparation of substituted and unsubstituted phenyl ketones 1. Preparation of 5-oxo-5-phenylpentyl heptanoate a) Synthesis of methyl S-oxo-5-phenylpentanoate A solution of 50.0 g of 5-oxo-5-phenylpentanoic acid (260 mmol) (origin: Fluka) and 70 ml of conc. H2SO4 in 1400 ml of methanol was heated under reflux for

1 h. The reaction mixture was cooled down to room temperature and added to 21 of water and extracted with ether (2x). The organic phase was washed with water (1x), an aq. solution of NaHC03 (10%, 2x), again with water (2x), dried (Na2SO4) and concentrated to give 47.9 g (90%) of a slightly yellow oil, which slowly crystallises at 4°C.

Analytical data: UV/Vis (hexane): 369 (sh, 2), 355 (sh, 12), 339 (sh, 33), 322 (45), 309 (sh, 41), 287 (600), 278 (800), 248 (sh, 7900), 238 (13200).

IR (neat): 3061w, 3022w, 2949m, 2902w, 1730s, 1681s, 1597m, 1580m, 1447m, 1435m, 1412m, 1370m, 1315m, 1277m, 1254m, 1207s, 1174s, 1146s, 1073m, 1055m, 1013m, 1000m, 990m, 975m, 931w, 879m, 843w, 739s, 689s, 657w.

H-NMR (360 MHz, CDC13) : 8.02-7.92 (m, 2 H) ; 7.59-7.52 (m, 1 H) ; 7.50-7.41 (m, 2 H) ; 3.68 (s, 3 H) ; 3.05 (t, J = 7. 1,2 H) ; 2.45 (t, J = 7. 3,2 H); 2.08 (quint., J=7. 2,2H).

C-NMR (90.6 MHz, CDC13) : 199.35 (s) ; 173.69 (s); 136.82 (s) ; 133.08 (a) ; 128.60 (d) ; 128. 02 (d) ; 51.56 (q) ; 37.44 (t) ; 33.11 (t) ; 19.34 (t).

MS (EI) : 206 (M+, 7), 175 (10), 174 (3), 147 (8), 146 (8), 133 (3), 120 (14), 106 (8), 105 (100), 78 (3), 77 (35), 59 (3), 55 (5), 51 (10). b) Synthesis of methyl 4-(2-phenyl-1,3-dioxolan-2-yl)butanoate A solution of 47.9 g (230 mmol) of methyl 5-oxo-5-phenylpentanoate obtained under a), 45 ml of ethylene glycol and : w 1 g of p-toluenesulfonic acid was heated for 23 h under reflux with azeotropic removal of water. After cooling down to room temperature, the reaction mixture was extracted with ether (2x), washed with a sat. aq. solution of NaHCO3 (2x), water (2x) and a sat. aq. solution of NaCl. The organic phase was dried (Na2S04) and concentrated to give 63.1 g (100%) of a colourless oil, containing 2-hydroxyethyl 4-(2-phenyl-1, 3-dioxolan- 2-yl) butanoate (a) in addition to methyl 4-(2-phenyl-1, 3-dioxolan-2-yl) butanoate (b).

Analytical data for (a):

IR (neat): 3447ru (br.), 2948m, 2918w, 2885m, 1730s, 1487w, 1472w, 1446m, 1416w, 1382ru, 1346w, 1307w, 1290w, 1257m, 1218m, 1166s, 1075m, 1038s, 1026s, 947s, 904w, 882m, 841w, 826w, 765m, 702s, 654m.

1H-NMR (360 MHz, CDC13) : 7.47-7.40 (m, 2 H); 7.37-7.25 (m, 3 H); 4.22-4.15 (m, 2 H); 4.06-3.96 (m, 2 H) ; 3.83-3.71 (m, 4 H); 2.40 (t, J= 6.1,1 H); 2.35 (t, J= 7.3,2 H); 1.97-1.89 (m, 2 H); 1.78-1.66 (m, 2 H).

3C-NMR (90.6 MHz, CDC13) : 173.67 (s) ; 142.27 (s) ; 128.16 (aC) ; 127.93 (d) ; 125.63 (a0 ; 110.11 (s) ; 65.93 (t) ; 64.49 (t) ; 61.13 (t) ; 39.53 (t) ; 33.96 (t) ; 19.10 (t).

MS (EI) : 219 (7), 203 (3), 150 (11), 149 (100), 105 (24), 99 (8), 55 (3).

Analytical data for (b): UV/Vis (hexane): 287 (sh, 18), 280 (sh, 21), 271 (sh, 30), 266 (sh, 70 (weak)), 263 (160), 256 (200), 250 (190), 245 (180), 240 (180), 235 (sh, 160), 215 (sh, 4700), 210 (sh, 8600), 205 (10000).

IR (neat): 2949m, 2918w, 2885m, 1733s, 1489w, 1473w, 1446m, 1435m, 1363w, 1309w, 1290w, 1257m, 1217m, 1189s, 1165s, 1086w, 1069m, 1039s, 1027s, 990m, 947m, 919m, 879w, 851w, 827w, 764m, 701s, 654m.

H-NMR (360 MHz, CDC13) : 7.47-7.40 (m, 2 H); 7.37-7.23 (m, 3 H); 4.06-3.94 (m, 2 H); 3.81.3.71 (m, 2 H); 3.63 (s, 3 H); 2.30 (t, J= 7.5,2 H); 1.96-1.87 (m, 2 H) ; 1.75-1.63 (m, 2 H).

C-NMR (90.6 MHz, CDC13) : 173.90 (s) ; 142.41 (s) ; 128.12 (a9 ; 127.86 (d) ; 125.68 (a0 ; 110.10 (s) ; 64.51 (t) ; 51.42 (q) ; 39. 69 (t) ; 33. 92 (t) ; 19.17 (t).

MS (EI) : 219 (5), 173 (4), 150 (10), 149 (100), 105 (30), 99 (8), 77 (11). c) Synthesis of 4-(2-phenyl-1, 3-dioxolan-2-yl)-1-butanol A solution of 63.1 g of the mixture obtained under b) in 350 ml of ether was added dropwise during 3 h at 0°C under N2, to a suspension of 9.6 g (250 mmol) of LiAlH4 in 350 ml of ether. After the introduction, the reaction mixture was left heating up to room temperature and then brought to reflux for 3 h. After cooling down to 0°C, 5 ml of a sat. aq. solution of Na2S04 were added and the formation of a precipitate was observed. The reaction mixture was filtered and the organic

phase dried over Na2S04 and concentrated to give 47.6 g (86%) of a slightly yellow oil.

Analytical data: UV/Vis (hexane): 286 (sh, 15), 271 (sh, 24), 267 (sh, 50 (weak)), 263 (140), 257 (170), 251 (140), 245 (sh, 90), 240 (sh, 66), 235 (sh, 46), 215 (sh, 4000), 211 (8000), 206 (9500).

IR (neat): 3353m (br.), 2943m, 2916w, 2878m, 1489w, 1473w, 1458w, 1447m, 1342w, 1310w, 1275w, 1231m, 1207m, 1186m, 1155m, 1070m, 1041s, 1026s, 1000m, 967m, 945m, 906m, 875m, 764m, 701s.

H-NMR (360 MHz, CDC13) : 7.48-7.41 (m, 2 H) ; 7. 38-7. 24 (m, 3 H) ; 4.06-3.95 (m, 2 H) ; 3.82-3.71 (m, 2 H); 3.59 (t, J= 5.5,2 H) ; 1.97-1.88 (m, 2 H) ; 1.59-1.48 (m, 3 H); (1.48-1.35 (m, 2 H).

C-NMR (90.6 MHz, CDC13) : 142.50 (s) ; 128.09 (a0 ; 127.81 (a) ; 125.70 (a) ; 110.38 (s) ; 64.48 (t) ; 62.73 (t) ; 40.13 (t) ; 32.67 (t) ; 19. 83 (t).

MS (EI) : 150 (10), 149 (100), 145 (3), 106 (3), 105 (36), 91 (3), 77 (16), 55 (3), 51 (4), 31 (3) d) Synthesis of 4-(2-phenyl-1, 3-dioxolan-2-yl) butyl heptanoafe A solution of 1.66 g of heptanoic acid (12.7 mmol), 0.15 g (1.3 mmol) of DMAP (4-dimethylaminopyridine) and 5.00 g (23.0 mmol) of 4- (2-phenyl-1, 3-dioxolan- 2-yl)-1-butanol obtained under c) in 30 ml of dichloromethane was cooled on an ice-bath, before a solution of 3.00 g (14.8 mmol) of DCC (dicyclohexylcarbodiimide) in 16 ml of dichloromethane was added during 15min. The reaction mixture was stirred for 10 min at 0°C, then at room temperature for 4 h. The precipitate formed in the reaction was filtered off and the filtrate taken up in ether, washed with water (3x), HC1 (10%, 3x), and a sat. solution of Na2C03 (3x). The organic layer was dried (Na2SO4), concentrated and chromatographed (SiO2, heptane/ether 8: 2) to give 3.15 g (74%) of a colourless oil.

Analytical data: Rf (heptane/ether 8: 2): 0.32.

UV/Vis (hexane): 286 (sh, 28), 278 (sh, 35), 271 (sh, 50), 267 (sh, 85), 263 (180), 256 (230), 250 (220), 245 (240), 240 (240).

IR (neat): 2951m, 2926m, 2871m, 1732s, 1488w, 1458m, 1447m., 1421w, 1390w, 1377w, 1348w, 1309w, 1296m, 1276m, 1233m, 1211m, 1163s, 1101m, 1043s, 1026s, 970m, 945m, 918m, 898m, 886m, 764m, 701s.

H-NMR (360 MHz, CDCl3) : 7.47-7.40 (m, 2 H) ; 7. 37-7. 24 (m, 3 H); 4.06-3.94 (m, 4 H); 3.82-3.70 (m, 2 H); 2.25 (t, J = 7.5,2 H); 1.96-1.86 (m, 2 H); 1.67-1.51 (m, 4 H) ; 1.47-1.20 (m, 8 H) ; 0.88 (t, J= 6. 7,3 H).

C-NMR (90.6 MHz, CDC13) : 173.92 (s) ; 142.49 (s) ; 128.08 (a0 ; 127.80 (a0 ; 125.69 (a0 ; 110.27 (s) ; 64.49 (t), 64.16 (t) ; 40.09 (t) ; 34.36 (t) ; 31.46 (t) ; 28.82 (t) ; 28.65 (t) ; 24.94 (t) ; 22.48 (t) ; 20.14 (t) ; 14.04 (q).

MS (EI) : 150 (11), 149 (100), 143 (3), 105 (21), 77 (8), 55 (3), 43 (8), 41 (4), 29 (3). e) Synthesis of 5-oxo-5-phenylpentyl heptanoate 2.32 ml of a 1N solution of HCl were added to a solution of 4.37 g (13.0 mmol) of 4- (2-phenyl-1, 3-dioxolan-2-yl) butyl heptanoate obtained under d) in 18 ml of THF (tetrahydrofurane). The reaction mixture was heated to 40°C for 24 h, cooled down to room temperature, extracted with ethyl acetate (2x) and washed with a sat. solution of NaCI (3x). The organic phase was dried (Na2S04) and concentrated. Column chromatography (SiO2, heptane/ether 8: 2) afforded 2.74 g (73%) of a colourless oil, which crystallises at 4°C.

Analytical data: Rf (heptane/ether 8: 2): 0.28.

W/Vis (hexane): 373 (sh, 2), 354 (sh, 14), 339 (sh, 32), 323 (44), 310 (sh, 40), 286 (1000), 277 (1200), 247 (sh, 7700), 239 (12600).

IR (neat): 3059w, 2952m, 2928m, 2857m, 1730s, 1685s, 1597m, 1580m, 1448m, 1413w, 1376m, 1356m, 1322w, 1297w, 1257m, 1232m, 1202m, 1166s, 1101na, 1076w, 1058w, 1026w, 1101m, 979m, 888. w, 752m, 732m, 689s, 654m.

H-NMR (360 MHz, CDC13) : 7.99-7.92 (m, 2 H); 7.60-7.51 (m, 1 H); 7.50-7.41 (m, 2 H) ; 4.12 (t, J = 6. 3,2 H); 3.02 (t, J = 6. 9,2 H); 2.29 (t, J = 7. 7,2 H) ; 1.88-1.68 (m, 4 H); 1.65-1.55 (m, 2 H); 1.38-1.22 (m, 6 H); 0.88 (t, J= 6.7, 3 H).

13C-NMR (90.6 MHz, CDC13) : 173.95 (s) ; 136.93 (s) ; 133.03 (ef) ; 128.60 (d) ; 128. 01 (d), 63. 90 (t) ; 37.89 (t) ; 34.36 (t) ; 31.45 (t) ; 28.83 (t) ; 28.24 (t); 24.96 (t) ; 22.48 (t) ; 20.65 (t) ; 14.02 (q).

MS (EI) : 177 (5), 161 (12), 160 (21), 120 (4), 106 (7), 105 (100), 77 (18), 55 (4), 51 (3), 43 (10), 51 (5), 29 (3).

2. Preparation of 5-oxo-5-phenylpentyl 3-cyclohexylpropionate a) Synthesis of 4-62-phenyl-1, 3-dioxolan-2-yl) butyl 3-cyclohexylpropionate This compound was synthesised as described under l. d) with 1.98 g (12. 7 mmol) of 3-cyclopropionic acid for 3 h. Column chromatography (SiO2, heptane/ether 1 : 1-> ether) gave 4.12 g (90%) of a slightly yellow oil.

Analytical data: Rf(heptane/ether 1 : 1): 0.59.

UV/Vis (hexane) : 295 (sh, 40), 287 (sh, 100), 262 (510), 256 (550), 251 (500), 245 (sh, 450), 241 (sh, 400), 227 (sh, 530).

IR (neat): 2920s, 2849m, 1732s, 1489w, 1447m, 1390w, 1354w, 1348w, 1309m, 1292w, 1274m, 1250m, 1209m, 1162s, 1123m, 1075m, 1043s, 1026m, 969m, 946m, 917w, 888m, 841w, 764m, 701s.

1H-NMR (360 MHz, CDCl3) : 7.47-7.40 (m, 2 H); 7.37-7.23 (m, 3 H) ; 4.07-3.94 (m, 4 H); 3.82-3.72 (m, 2 H) ; 2.31-2.22 (m, 2 H); 1.96-1.86 (m, 2 H); 1.76- 1.35 (m, 11 H); 1.33-1.05 (m, 4 H) ; 0.96-0.79 (m, 3 H).

C-NMR (90.6 MHz, CDCl3) : 174.21 (s) ; 142.49 (s) ; 128.08 (et) ; 127.80 (d) ; 125.69 (d) ; 110.26 (s) ; 64.49 (t) ; 64.18 (t) ; 40.09 (t) ; 37.23 (a0 ; 32.96 (t) ; 32.35 (t) ; 31.93 (t) ; 28.64 (t) ; 26.55 (t); 26.23 (t) ; 20.15 (t).

MS (EI) : 161 (4), 150 (10), 149 (100), 145 (3), 143 (3), 105 (19), 77 (7), 55 (7), 41 (4). b) Synthesis of 5-oxo-5-phenylpentyl 3-cyclohexylpropionate This compound was synthesised as described under l. e) with 2.0 ml of a IN solution of HCI, 4.12 g (11.4 mmol) of 4-(2-phenyl-1, 3-dioxolan-2-yl) butyl 3-cyclohexylpropionate obtained under a) in 20 ml of THF for 19 h. Column chromatography (SiO2, heptane/ether 3: 2) afforded 2.15 g (60%) of a yellow oil

containing small amounts of impurities, which can be distilled off (Kugelrohr, 150°C/lx102 Pa).

Analytical data: Rf (heptane/ether 8: 2): 0.29.

UV/Vis (hexane): 370 (sh, 3), 355 (sh, 13), 337 (sh, 35), 322 (45), 311 (sh, 42), 287 (750), 278 (980), 272 (sh, 920), 247 (sh, 8100), 238 (12600).

IR (neat): 2920s, 2845m, 1729s, 1684s, 1596m, 1579m, 1447m, 1413m, 1392m, 1356m, 1322na, 1308m, 1293m, 1274m, 1250m, 1228m, 1202m, 1178s, 1162s, 1123m, 1077m, 1060w, 1027w, 1000m, 969m, 885m, 842m, 786w, 752m, 732m, 689s, 654m.

H-NMR (360 MHz, CDCl3) : 8. 00-7.92 (m, 2 H) ; 7.61-7.52 (m, 1 H); 7.51-7.42 (m, 2 H) ; 4.12 (t, J = 6.3,2 H); 3.06-2.97 (m, 2 H); 2.34-2.25 (m, 2 H); 1.91-1.58 (m, 9 H) ; 1.57-1.46 (m, 2 H); 1.30-1.05 (m, 4 H) ; 0.96-0.80 (m, 2 H).

13C_NMR (90.6 MHz, CDC13) : 199.76 (s) ; 174.25 (s) ; 136.93 (s) ; 133.03 (d) ; 128.60 (4 ; 128.01 (4 ; 63.93 (t) ; 37.90 (t) ; 37.24 (a) ; 32.96 (t) ; 32.37 (t) ; 31.93 (t) ; 28.22 (t) ; 26.53 (t) ; 26.22 (t) ; 20.65 (t).

MS (EI) : 177 (6), 162 (5), 161 826), 160 (32), 138 (4), 133 (3), 121 (4), 120 (5), 106 (8), 105 (100), 95 (3), 77 (17), 69 (3), 67 (3), 55 (10), 41 (7).

3. Preparation of 5-oxo-5-phenylpentyl phenoxyacetate a) Synthesis of 4- (2-phenyl-1, 3-dioxolan-2-yl) butylphenoxyacetate This compound was synthesised as described under 1. d) with 1. 93 g (12. 7 mmol) of phenoxyacetic acid. Column Chromatography (SiO2, heptane/ether 1 : 1-> 2: 8) gave 3.58 g (79%) of a slightly yellow solid.

Analytical data: Rf (heptane/ether 1: 1): 0.48.

UV/Vis (hexane): 276 (1500), 270 (1800), 263 (1400), 257 (sh, 890), 250 (sh, 510), 244 (sh, 360).

IR (neat): 3059w, 3027w, 2951m, 2914m, 2885m, 1756s, 1732m, 1598m, 1588m, 1493s, 1456w, 1446m, 1394w, 1371w, 1335w, 1307m, 1286m, 1273m, 1185s, 1172s, 1086s, 1072s, 969m, 946m, 916w, 883m, 839w, 818w, 786m, 752s, 702s, 689s.

H-NMR (360 MHz, CDC13) : 7.47-7.40 (m, 2 H); 7.38-7.22 (m, 5 H) ; 7.03-6.94 (nz, 1 H); 6.93-6.84 (m, 2 H); 4.58 (s, 2 H); 4.15 (t, J= 6.7,2 H); 4.05-3.93 (m, 2 H); 3.82-3.70 (m, 2 H); 1.96-1.86 (m, 2 H); 1.69-1.57 (m, 2 H); 1.47- 1.34 (m, 2 H).

3C-NMR (90.6 MHz, CDC13) : 168.98 (s) ; 157.82 (s) ; 142.42 (s) ; 129.54 (a) ; 128.11 (a) ; 127.84 (c0 ; 125.68 (d) ; 121.69 (a0 ; 114.66 (a0 ; 110.18 (s) ; 65.33 (t) ; 65.23 (t) ; 64.49 (t) ; 39.97 (t) ; 28.48 (t) ; 20.01 (t).

MS (EI) : 150 (10), 149 (100), 107 (4), 105 (21), 77 (15), 51 (3). b) Synthesis of 5-oxo-5-phenylpentyl phenoxyacetate This compound was synthesised as described under l. e) with 1.45 ml of a IN solution of HC1, 2.90 g (8.1 mmol) of 4-(2-phenyl-1, 3-dioxolan-2-yl) butyl phenoxyacetate obtained under a) in 13ml of THF for 17 h. Column chromatography (Si02, heptane/ether 8: 2) afforded 1.98 g (78%) of a slightly yellow oil.

Analytical data: Rf (heptane/ether 8: 2): 0.09.

W/Vis (hexane): 371 (sh, 1), 355 (sh, 8), 337 (sh, 24), 321 (32), 310 (sh, 31), 286 (540), 277 (1800), 270 (1900), 263 (sh, 1400), 247 (sh, 6600), 238 (10300), 223 (sh, 8500), 219 (8900).

IR (neat): 3061w, 3031w, 2951m, 1754s, 1732m, 1681s, 1597s, 1587m, 1493s, 1447m, 1409w, 1394w, 1372w, 1357w, 1334w, 1286m, 1270m, 1230m, 1191s, 1172s, 1026m, 1000m, 974m, 884m, 836w, 817w, 785m, 751s, 734m, 688s.

H-NMR (360 MHz, CDC13) : 7.99-7.91 (m, 2 H); 7.60-7.52 (m, 1 H); 7.50-7.42 (m, 2 H); 7.34-7.23 (m, 2 H); 7.05-6.84 (m, 3 H); 4.62 (s, 2 H); 4.26 (t, J = 6.1,2 H); 2.99 (t, J= 6. 7,2 H); 1. 86-1.69 (m, 2 H).

13C-NMR (90.6 MHz, CDC13) : 199.63 (s) ; 169.08 (s) ; 157.79 (s) ; 136.87 (s) ; 133.08 (d) ; 129.56 (d) ; 128.62 (a) ; 128.00 (d) ; 121. 73 (d) ; 114.63 (d) ; 65. 32 (t) ; 65.01 (t) ; 37.73 (t) ; 28. 07 (t) ; 20.42 (t).

MS (EI) : 312 (M+, 7), 162 (9), 161 (76), 152 (9), 107 (12), 106 (8), 105 (100), 79 (6), 78 (5), 77 (45), 55 (4), 51 (10), 39 (3)

4. Preparation of 1, 5-dimethyl-l- (4-oxo-4-phenylbutyl)-4-hexenyl acetate a) Synthesis of 4-(2-phenyl-1, 3-dioxolan-2-yl) butanoic acid A solution of 1.06 g (0.044 mol) of LiOH in 40 ml of water was added during 10 min to 10.0 g (0.04 mol) of methyl 4- (2-phenyl-1, 3-dioxolan-2-yl) butanoate obtained under 1. b) in 200 ml of water. The reaction mixture was left stirring for 2.5 h and quenched with 30 ml of HCl (5%). Extraction with ethyl acetate (4x), drying (Na2S04) and concentrating gave 8.76 g (93%) of a slightly yellow solid.

Analytical data: IR (neat): 3054m, 2956m, 2915m, 2885m, 2767w, 2697w, 2632w, 1734m, 1689s, 1674s, 1596m, 1580m, 1480w, 1461m, 1445m, 1431m, 1412m, 1376m, 1349w, 1333w, 1319w, 1307m, 1288m, 1270m, 1231m, 1210m, 1184s, 1155w, 1144m, 1087m, 1072m, 1065m, 1054m, 1038m, 1025m, 1000m, 971m, 944m, 936s, 918m, 858w, 841m, 772m, 759m, 734m, 781m, 691s, 659m.

'H-NMR (360 MHz, CDC13) : 7.47-7.40 (m, 2 H); 7.37-7.23 (m, 3 H) ; 4.05-3.96 (m, 2 H); 3.80-3.71 (m, 2 H); 2.39-2.27 (m 2 H); 1.98-1.87 (m, 2 H); 1.77- 1.63 (m, 2H).

3C-NMR (90.6 MHz, CDC13) : 179.39 (s) ; 142.32 (s) ; 128.14 (et) ; 127.89 (a) ; 125.65 (4 ; 110.08 (s) ; 64.49 (t) ; 39.50 (t) ; 33.82 (t) ; 18.86 (t).

MS (EI) : 175 (13), 174 (3), 150 (4), 149 (30), 147 (11), 146 (12), 120 (10), 106 (9), 105 (100), 91 (4), 86 (4), 78 (5), 77 (41), 55 (8), 51 (12), 45 (5), 43 (3), 42 (7), 41 (4), 39 (3). b) Synthesis of 5-(2-phenyl-1, 3-dioxolan-2-yl)-2-pentanone A well stirred solution of 5.0 g (0.021 mol) of 4-(2-phenyl-1, 3-dioxolan-2- yl) butanoic acid obtained under a) in 50 ml of THF was cooled down to 0° before 12.5 ml of methyl lithium (1.69M, 1 eq.) were added during 1 h. The mixture took up in mass and 30 ml of THF were added to get a white solution. The reaction mixture was left stirring for 30 min while warming up to room temperature.

Another 25 ml of methyl lithium (2 eq.) were added during 2 h to give a yellow solution, which was poured onto ice. The THF was evaporated and the crude reaction mixture taken up in ether, washed with a saturated solution of NaCI, dried (Na2S04) and concentrated. Column chromatography (Si02, heptane/ether

3: 2) gave 2.36 g (48%) of 5-(2-phenyl-1, 3-dioxolan-2-yl)-2-pentanone (a) and 1.50 g (29%) of 2-methyl-5- (2-phenyl-1, 3-dioxolan-2-yl)-2-pentanol (b) as yellow oils.

Analytical data for (a): Rf (heptane/ether 3: 2): 0.25.

W/Vis (hexane): 287 (sh, 370), 276 (sh, 540), 267 (sh, 610), 263 (670), 256 (660), 250 (sh, 640), 246 (660), 240 (660), 225 (sh, 580).

IR (neat): 3058w, 3025w, 2955m, 2918w, 2885m, 1711s, 1668w, 1600w, 1487w, 1480w, 1446m, 1410m, 1357m, 1305m, 1284w, 1254m, 1231w, 1217m, 1187m, 1161m, 1072m, 1040s, 1026s, 974m, 946m, 908m, 852w, 762na, 736w, 701s.

H-NMR (360 MHz, CDC13) : 7.48-7.39 (m, 2 H); 7.38-7.24 (m, 3 H); 4.07-3.95 (m, 2 H); 3.82-3.70 (m, 2 H); 2.41 (t, J= 7.5,2 H); 2.09 (s, 3 H); 1.93-1.84 (m, 2 H) ; 1.73-1.58 (m, 2 H).

3C-NMR (90.6 MHz, CDC13) : 208.79 (s) ; 142. 40 (s) ; 128.12 (a) ; 127. 86 (a9 ; 125.67 (a9 ; 110. 17 (s); 64.49 (t) ; 43.52 (t) ; 39. 62 (t) ; 29.81 (q) ; 18.03 (t).

MS (EI) : 150 (10), 149 (100), 105 (31), 99 (6), 77 (13), 51 (3), 43 (8).

Analytical data for (b): Rf (heptane/ether 3: 2): 0.09.

UV/Vis (hexane): 295 (sh, 47), 287 (sh, 120), 279 (sh, 190), 270 (sh, 250), 263 (370), 257 (410), 245 (sh, 720), 238 (840), 228 (sh, 720).

IR (neat): 3412m (br.), 3060w, 3025w, 2960m, 2916w, 2881m, 1711w, 1684w, 1598w, 1581w, 1488w, 1468w, 1446m, 1371m, 1294m, 1259m, 1213m, 1181m, 1152m, 1076w, 1038s, 1025s, 990m, 971m, 947m, 914s, 824w, 813w, 756m, 736w, 700s.

H-NMR (360 MHz, CDC13) : 7.48-7.41 (m, 2 H); 7.37-7.24 (m, 3 H); 4.07-3.95 (m, 2 H); 3.82-3.70 (m, 2 H); 3.95-1.84 (m, 2 H), 1.49-1.36 (m, 4 H); 1.17 (s, 6 H).

3C-NMR (90.6 MHz, CDCl3) : 142.61 (s) ; 128.08 (d) ; 127. 78 (a) ; 125.69 (d) ; 110.3 9 (s); 70.94 (s) ; 64.46 (t) ; 43.81 (t), 40.86 (t) ; 29. 19 (q) ; 18.43 (t).

MS (EI) : 173 (3), 150 (10), 149 (100), 133 (4), 121 (5), 105 (24), 77 (11), 59 (4), 43 (5).

c) Synthesis of 4, 8-dimethyl-1-(2-phenyl-1, 3-dioxolan-2-yl)-7-nonen-4-ol A Grignard reagent of 3.50 g (0.021 mol) of 5-bromo-2-methyl-2-pentene in 13 ml of ether and 0.62 g (0.026 mol) of magnesium turnings in 14 ml of ether was added slowly at-25° under N2 to a stirred solution of 5.54 g (0.024 mol) of 5- (2-phenyl-1, 3-dioxolan-2-yl)-2-pentanone obtained under b) in 20 ml of ether.

During the introduction, the temperature was left rising up to-5°C and the reaction mixture left stirring for 45 min. Then a saturated solution of NH4C1 was added and the formation of a white precipitate was observed. Extraction with ether (2x), washing with water (3x), drying (Na2SO4) and concentrating gave 6.24 g of the crude product. Column chromatography (SiO2, heptane/ether 7: 3) gave 2.53 g (38%) of a yellow oil.

Analytical data: Rf (heptane/ether 7: 3): 0.12 IR (neat): 3433m (br.), 3059w, 3025w, 2958m, 2915m, 2881m, 1488w, 1445m, 1373m, 1337w, 1308w, 1291w, 1255w, 1214m, 1182m, 1116m, 1075w, 1038s, 1025s, 972m, 945m, 914m, 840w, 809w, 759m, 701s.

H-NMR (360 MHz, CDC13) : 7.48-7.41 (m, 2 H) ; 7.37-7.24 (m, 3 H) ; 5.14-5.06 (m, 1 H); 4.07-3.95 (m, 2 H); 3.82-3.71 (m, 2 H) ; 2.06-1.94 (m, 2 H); 1.94- 1.85 (m, 2 H) ; 1.67 (s, 3 H) ; 1.59 (s, 3 H) ; 1.47-1.34 (m, 6 H) ; 1.12 (s, 3 H).

3C-NMR (90.6 MHz, CDC13) : 142.63 (s) ; 131.65 (s) ; 128.08 (a0 ; 127.77 (d) ; 125.69 (d) ; 124.49 (a) ; 110.38 (s) ; 72.74 (s) ; 64.47 (t) ; 41.89 (t) ; 41.57 (t) ; 40.92 (t) ; 26.71 (q) ; 25.70 (q) ; 22.63 (t) ; 18.01 (t) ; 17.63 (q).

MS (EI) : 318 (M+, 0.1), 150 (9), 149 (100), 147 (4), 142 (9), 134 (3), 133 (7), 121 (10), 109 (4), 105 (30), 99 (3), 93 (3), 91 (3), 77 (11), 71 (4), 69 (9), 67 (3), 58 (3), 55 (7), 43 (13), 41 (13). d) Synthesis of 1,5-dimethyl-1-[3-(2-phenyl-1,3-dioxolan-2-yl)propyl]-4-hexe nyl acetate A stirred solution of 2.38 g (7.5 mmol) of 4, 8-dimethyl-1- (2-phenyl-1, 3-dioxolan- 2-yl)-7-nonen-4-ol obtained under c), 3.34 g (22mmol) of N, N-diethylaniline, 1.75 g (22 mmol) of acetyl chloride in 150 ml of CH2Cl2 was heated under reflux for 3 days. Another equivalent of N, N diethyl aniline (1.1 g, 7.3 mmol) and acetyl chloride (0.6 g, 7.3 mmol), respectively, were added after 24,48,65 and 71 h.

The reaction mixture was cooled down to room temperature, acidified with

2M HC1, extracted with ether (2x), washed with a saturated solution of NaHC03 (2x), dried (Na2S04) and concentrated. Column chromatography (Si02, heptane/ether 4: 1) gave 2.04 g (76%) of a yellow oil.

Analytical data: Rf (heptane/ether4 : 1): 0.17 IR (neat): 2960m, 2917m, 2879m, 2851w, 1727s, 1488w, 1463w, 1447m, 1375m, 1365m, 1342w, 1303w, 1243s, 1216m, 1186m, 1154m, 1112m, 1075m, 1038s, 1026s, 973m, 947m, 931m, 873w, 833w, 761m, 702s, 654w.

'H-NMR (360 MHz, CDC13) : 7.48-7.39 (m, 2 H) ; 7.38-7.24 (m, 3 H) ; 5.11-5.01 (m, 1 H); 4.07-3.94 (m, 2 H); 3.82-3.70 (m, 2 H); 1.98-1.75 (m, 6 H); 1.92 (s, 3 H) ; 1.75-1.52 (m, 2 H); 1.66 (s, 3 H); 1.57 (s, 3 H); 1.44-1.14 (m, 2 H); 1.36 (s, 3H).

3C-NMR (90.6 MHz, CDC13) : 170.33 (s) ; 142.59 (s) ; 131.58 (s) ; 128.06 (d) ; 127.76 (J) ; 125.69 (a) ; 124.02 (d) ; 110.35 (s) ; 84.54 (s) ; 64.47 (t) ; 40. 61 (t) ; 38. 25 (t) ; 38. 07 (t) ; 25. 68 (q) ; 23.68 (q) ; 22.34 (t, q) ; 17.78 (t) ; 17.54 (q).

MS (EI) : 238 (10), 169 (3), 150 (10), 149 (100), 142 (5), 136 (5), 133 (3), 121 (12), 105 (31), 99 (4), 93 (7), 91 (3), 77 (10), 69 (6), 43 (4), 41 (5). e) Synthesis of 1, 5-dimethyl-l- (4-oxo-4-phenylbutyl)-4-hexenyl acetate 1.76 ml of HCl (IN) was added slowly to a solution of 1.63 g (4.53 mmol) of 1,5- dimethyl-1- [3- (2-phenyl-1, 3-dioxolan-2-yl) propyl]-4-hexenyl acetate obtained under d) in 30 ml of THF. The reaction mixture was stirred at 40° or 4 h, cooled down to room temperature, extracted with ether, washed with a saturated solution of NaCl (3x), dried (Na2SO4), filtered and concentrated. Column chromatography (sitz, heptane/ether 4: 1) yielded 1. 34 g (94%) of a slightly yellow oil.

Analytical data: Rf (heptane/ether 4 : 1) : 0.29 W/Vis (hexane): 370 (sh, 4), 356 (sh, 14), 341 (sh, 34), 322 (52), 311 (52), 287 (1400), 279 (sh, 1600), 246 (sh, 10000), 239 (13000).

IR (neat): 2962m, 2921m, 2878m, 2853m, 1725s, 1684s, 1597m, 1580m, 1467w, 1448m, 1408w, 1364m, 1304w, 1272m, 1246s, 1204m, 1178m, 1158m, 1109m, 1089m, 1065w, 1045w, 1016m, 1001m, 978m, 938m, 888w, 829w, 794w, 751m, 732m, 690s, 656w.

H-NMR (360 MHz, CDC13) : 7.99-7.91 (m, 2 H) ; 7.60-7.52 (m, 1 H) ; 7.51-7.41 (m, 2 H); 5. 15-5.05 (m, 1 H); 2.98 (t, J= 7.1,2 H); 2.05-1.55 (m, 8 H); 1. 97 (s, 3 H) ; 1.68 (s, 3 H); 1.60 (s, 3 H); 1.45 (s, 3 H). t3C-NMR (90.6 MHz, CDCl3) : 199.96 (s) ; 170.44 (s) ; 136.98 (s) ; 132.99 (a) ; 131.70 (s) ; 128.59 (at) ; 128.00 (a) ; 123.93 (a0 ; 84.42 (s) ; 38. 65 (t) ; 38. 24 (t) ; 37.81 (t) ; 25. 69 (q) ; 23.71 (q), 22.36 (t, q) ; 18.39 (t) ; 17. 58 (q).

MS (EI) : 257 (3), 256 (14), 241 (3), 238 (6), 223 (4), 214 (3), 213 (17), 195 (3), 188 (3), 187 (14), 174 (9), 173 (5), 172 (3), 171 (21), 169 (3), 151 (3), 147 (9), 145 (3), 137 (6), 136 (48), 134 (8), 133 (30), 131 (3), 123 (3), 122 (3), 121 (24), 120 (26), 119 (3), 115 (3), 110 (3), 109 (37), 107 (9), 106 (9), 105 (100), 95 (4), 94 (6), 93 (41), 92 (9), 91 (9), 82 (6), 81 (7), 80 (8), 79 (5), 78 (5), 77 (31), 69 (23), 67 (8), 60 (3), 55 (6), 53 (3), 51 (3), 43 (9), 41 (10).

5. Preparation of 4-(decyloxy)-1-(4-methoxyphenyl)-1-butanone a) Synthesis of 2- (3-chloropropyl)-2- (4-methoxyphenyl)-1, 3-dioxolane A solution of 20.0 g (94.0 mmol) of 4-chloro-l- (4-methoxyphenyl)-l-butanone (origin: Acros), 19 ml of ethylene glycol and ca. 1 g of p-toluenesulfonic acid in 120 ml of toluene was heated under reflux with azeotropic removal of water for 16 h. After cooling down to room temperature, ether was added and the organic phase extracted with a saturated solution of NaHC03 (2x), washed with water (2x), dried (Na2SO4) and concentrated in vacuo to give 24.6 g (99%) of the crude compound, which was used for further functionalisation. Column chromatography of 2 g (Si02, heptane/ether 9: 1) afforded 1.15 g of a slightly yellow oil.

Analytical data: Rf (heptane/ether 9: 1): 0.25 IR (neat): 2956na, 2882m, 2831m, 1610m, 1583m, 1508m, 1463m, 1442m, 1412w, 1372w, 1347w, 1300m, 1239s, 1169s, 1142m, 1108m, 1079w, 1030s, 1009m, 946m, 907m, 855w, 830s, 814m, 800m, 781w, 764w, 746w, 722w.

H-NMR (360 MHz, CDC13): 7.39-7. 32 (m, 2 H); 6.91-6.83 (m, 2 H) ; 4.06-3.94 (m, 2 H); 3.84-3.71 (m, 2 H); 3.80 (s, 3 H); 3.52 (t, J= 6.7,2 H); 2.06-1.97 (m, 2 H) ; 1.91-1.79 (m, 2 H).

3C-NMR (90.6 MHz, CDC13): 159.34 (s) ; 134.38 (s) ; 126.92 (a) ; 113.49 (a9 ; 109.95 (s) ; 64.47 (t) ; 55.25 (q) ; 45.16 (t) ; 37.85 (t) ; 27. 16 (t).

MS (EI) : 256 (M+, 0.4), 180 (18), 179 (100), 149 (4), 136 (7), 135 (68), 121 (3), 107 (6), 92 (7), 77 (8). b) Synthesis of 2-3- (decyloxy) propylJ-2- (4-methoxyphenyl)-l, 3-dioxolane.

13.80 g of potassium hydride (30% in oil, 0.1 mol) were washed with pentane (3 x) and THF (3 x). Then, 75 ml of THF were added and the suspension was heated to reflux before a solution of 11.70 g (74 mmol) of decanol in 19 ml of THF was added during 5-10 min. After keeping at reflux for 2.5 h, a solution of 19.00 g (74 mmol) of 2- (3-chloropropyl)-2- (4-methoxyphenyl)-1, 3-dioxolane obtained under a) in 19 ml of THF was added during 15 min and the reaction mixture left stirring under reflux for 65 h. After cooling down to room temperature, the excess of KH was quenched by adding dropwise ca. 10 ml of water. The reaction mixture was concentrated, taken up in dichloromethane, extracted with water and HCl (10%), washed with water, dried (Na2S04) and concentrated to give 24.19 g of the crude compound. Column chromatography of 10 g (Si02, heptane/ether 9: 1) afforded 2.71 g (23%) of a yellowish oil.

Analytical data: Rf (heptane/ether 9: 1): 0.15 IR (neat): 2921m, 2851m, 2795w, 1664w, 1610m, 1581w, 1510m, 1484w, 1464m, 1442m, 1418w, 1377w, 1381w, 1301m, 1244s, 1196m, 1168s, 1110s, 1033s, 1010m, 989m, 952m, 83Is, 811m, 801m, 754w, 738w, 720w, 694w, 662w.

H-NMR (360 MHz, CDC13) : 7.40-7.32 (m, 2 H); 6.90-6.81 (m, 2 H) ; 4.07-3.95 (m, 2 H); 3.84-3.70 (m, 2 H); 3.80 (s, 3 H) ; 3.36 (t, J= 6.9,2 H); 3.34 (t, J= 6.9,2 H); 1.97-1.88 (m, 2 H); 1.71-1.57 (m, 2 H); 1.57-1.46 (m, 2 H) ; 1.38- 1.17 (m, 14 H) ; 0.88 (t, J= 6. 9,3 H).

13C-NMR (90.6 MHz, CDC13) : 159.21 (s) ; 134.73 (s) ; 127.00 (d) ; 113.36 (d) ; 110.33 (s) ; 70. 87 (t) ; 70.71 (t) ; 64.46 (t) ; 55.23 (q) ; 37.18 (t) ; 31.92 (t) ; 29.76 (t) ; 29. 63 (t) ; 29.60 (t) ; 29.52 (t) ; 29.35 (t) ; 26.19 (t) ; 24.14 (t) ; 22.70 (t) ; 14.13 (q).

MS (EI) : 181 (4), 180 (35), 179 (100), 177 (12), 163 (3), 151 (4), 150 (11), 136 (7), 135 (63), 121 (5), 113 (3), 107 (6), 92 (4), 77 (5), 69 (3), 57 (3), 55 (3), 43 (5), 41 (4).

c) Synthesis of 4-(decyloxyM 4-methoxyphenyl)-1-butanone 3 ml of HCl (1N) were added to a solution of 2.64 g (6.9 mmol) of 2- [3- (decyloxy) propyl]-2- (4-methoxyphenyl)-1, 3-dioxolane obtained under b) in 50 ml of THF. The reaction mixture was heated at 40° for 2 h. After cooling down to room temperture, ether was added and the reaction mixture washed with a saturated solution of NaCI (3x). The organic phase was dried (Na2S04) and concentrated to give 2.29 g (99%) of a slightly red oil that solidifies at 4°.

Analytical data: UV/Vis (hexane): 398 (sh, 3), 379 (sh, 7), 362 (sh, 15), 346 (sh, 47), 332 (sh, 90), 318 (sh, 120), 298 (sh, 900), 277 (sh, 17700), 271 (sh, 24700), 262 (31300), 220 (sh, 19900), 213 (27700).

IR (neat): 3052w, 2952w, 2928m, 2915m, 2849m, 2802w, 1667s, 1593s, 1510m, 1491w, 1469m, 1456m, 1444m, 1414w, 1374w, 1356m, 1342w, 1312m, 1281w, 1260s, 1243m, 1234w, 1213m, 1188w, 1170s, 1132w, lllls, 1073w, 1060w, 1025m, 1012m, 990m, 964m, 921m, 889w, 879w, 854w, 835s, 815m, 800w, 786w, 757m, 739w, 720m, 668w.

H-NMR (360 MHz, CDCl3) : 7.99-7.91 (m, 2 H); 6.99-6.88 (m, 2 H) ; 3.86 (s, 3 H); 3.49 (t, J = 6. 1,2 H); 3.40 (t, J = 6. 7,2 H); 3.02 (t, J = 7. 1,2 H); 2.06- 1.95 (m, 2 H); 1.61-1.49 (m, 2 H) ; 1. 38-1.17 (m, 14 H); 0.88 (t, J= 6.7,3 H). t3C-NMR (90.6 MHz, CDC13): 198.69 (s) ; 163.36 (s) ; 130.32 (a0 ; 130.22 (s) ; 113.65 (d) ; 70.98 (t) ; 69.84 (t) ; 55.42 (q) ; 34.82 (t) ; 31.92 (t) ; 29.77 (t) ; 29.64 (t) ; 29.60 (t) ; 29.53 (t) ; 29.35 (t) ; 26.23 (t) ; 24.55 (t) ; 22.70 (t) ; 14.12 (q).

MS (EI) : 177 (4), 151 (10), 150 (100), 136 (3), 135 (31), 92 (3), 77 (4), 43 (3).

6. Preparation of 1- (4-methoxyphenyl)-4- (2-phenylethoxy)-1-butanone a) Synthesis of 2- (4-methoxyphenyl)-2-3- (2-phenylethoxy) propylJ-1, 3-dioxolane This compound was synthesised as described under 5. b) with 2.00 g of potassium hydride (30% in oil, 15.0 mmol) in 10ml of THF, 1.40 g (11.5 mmol) of 2-phenylethanol in 3 ml of THF and 3.0 g (11.7 mmol) of 2- (3-chloropropyl)-2- (4- methoxyphenyl)-1, 3-dioxolane obtained under 5. a) in 3 ml of THF. Column chromatography (SiO2, heptane/ether 4: 1) afforded 1.21 g (31%) of a yellow oil.

Analytical data: Rf (heptane/ether 4: 1): 0.17 IR (neat): 3061w, 3023w, 2944m, 2856m, 2791w, 1662w, 1609m, 1581m, 1508m, 1495m, 1463m, 1452m, 1442m, 1412w, 1359m, 1300m, 1243s, 1191m, 1168ni, 1109s, 1030s, 1011w, 977w, 951m, 907w, 830s, 814w, 802w, 748m, 731w, 698s, 663w.

H-NMR (360 MHz, CDC13) : 7.38-7.32 (m, 2 H); 7.31-7.23 (m, 2 H); 7.22-7.15 (m, 3 H); 6.88-6.82 (m, 2 H); 4.04-3.93 (m, 2 H); 3.82-3.70 (m, 2 H); 3.80 (s, 3 H); 3.57 (t, J= 7.3,2 H); 3.40 (t, J= 6.7,2 H); 2.84 (t, J= 7.3,2 H); 1.95- 1.88 (m, 2 H); 1.68-1.57 (m, 2 H).

13C-NMR (90.6 MHz, CDC13) : 159.21 (s) ; 139.10 (s) ; 134.68 (s) ; 128.90 (d) ; 128.29 (d), 126.99 (a9 ; 126.10 (a9 ; 113.38 (a9 ; 110.30 (s) ; 71.68 (t) ; 70.82 (t) ; 64.46 (t) ; 55.25 (q) ; 37.10 (t) ; 36.35 (t) ; 24.08 (t).

MS (EI) : 180 (11), 179 (100), 135 (19), 105 (4), 91 (3), 77 (3). b) Synthesis of 1-(4-methoxyphenyl)-4-(2-phenylethoxy)-1-butanone This compound was synthesised as described under 5. c) with 0.8 ml of HCl (1N) and 0.65 g (1.9 mmol) of 2- (4-methoxyphenyl)-2- [3- (2-phenylethoxy) propyl]- 1,3-dioxolane obtained under a) in 50 ml of THF. Column chromatography (Si02, heptane/ether 4: 1) gave 0.44 g (78%) of white crystals.

Analytical data: Rf (heptane/ether 4: 1): 0.13 UV/Vis (hexane): 361 (sh, 5), 345 (sh, 35), 331 (sh, 78), 315 (110), 306 (110), 277 (sh, 9800), 270 (sh, 14800), 264 (18400), 220 (sh, 10800), 212 (19400).

IR (neat): 3062w, 3051w, 3026w, 3001w, 2955m, 2936m, 2900m, 2864m, 2802w, 1669s, 1833w, 1595s, 1535w, 1511m, 1493m, 1486m, 1469m, 1464m, 1451m, 1438w, 1410m, 1377w, 1362s, 1310s, 1276w, 1255s, 1211s, 1174s, 1147m, 1120m, 1lllls, 1096s, 1086m, 1068w, 1046w, 1027m, 1014s, 1008m, 977s, 912w, 908w, 875w, 938s, 926s, 816m, 796w, 766m,-749s, 720w, 698s.

H-NMR (360 MHz, CDC13) : 7.96-7.87 (m, 2 H) ; 7.31-7.14 (m, 5 H); 6.95-6.87 (m, 2 H) ; 3. 85 (s, 3 H) ; 3.63 (t, J = 7.1, 2 H) ; 3.51 (t, J = 5. 9,2 H); 2.96 (t, J = 7. 1,2 H); 2.87 (t, J = 7. 1,2 H); 1. 99 (quint, J= 6. 6,2 H).

13C-NMR (90.6 MHz, CDCl3) : 198. 66 (s) ; 163.34 (s) ; 139.13 (s) ; 130.32 (a0 ; 130.17 (s), 128. 92 (a) ; 128.30 (a) ; 126.13 (d) ; 71.63 (t) ; 69.89 (t); 55.44 (q) ; 36.34 (t) ; 34.72 (t) ; 24.45 (t).

MS (EI) : 178 (3), 177 (20), 151 (10), 150 (100), 136 (5), 135 (57), 121 (4), 107 (5), 105 (6), 104 (3), 92 (7), 91 (6), 79 (3), 77 (11).

7. Preparation of 4-(decyloxy)-1-(4-methylphenyl)-1-butanone a) Synthesis of 2-(3-chloropropyl)-2-(4-methylphenyl)-1,3-dioxolane This compound was synthesised as described under 5. a) with 20.0 g (101.6 mmol) of 4-chloro-1- (4-methylphenyl)-1-butanone (origin: Acros), 20 ml of ethylene glycol and ca. 1 g of p-toluenesulfonic acid in 120 ml of toluene to give 25.2 g (99%) of the crude compound, which was used for further functionalisation. Column chromatography of 2 g (SiO2, heptane/ether 9: 1) afforded 1.51 g of a yellow oil.

Analytical data: Rf (heptane/ether 9: 1): 0.33 IR (neat): 3023w, 2956m, 2918m, 2882m, 1910w, 1683m, 1607m, 1573w, 1509m, 1471m, 1403m, 1374m, 1300w, 1307m, 1300m, 1287m, 1230m, 1179s, 1141m, 1110m, 1081w, 1038s, 1018s, 945s, 908s, 856w, 815s, 780m, 746w, 719m.

H-NMR (360 MHz, CDC13) : 7.32 (d, J=8. 3,2 H); 7.14 (d, y= 7. 9,2 H) ; 4.05- 3.93 (m, 2 H) ; 3.82-3.70 (m, 2 H) ; 3.51 (t, J= 6.7,2 H); 2.34 (s, 3 H) ; 2.06- 1.97 (m, 2 H); 1.91-1.79 (m, 2 H).

13C-NMR (90.6 MHz, CDC13) : 139.28 (s) ; 137.63 (s) ; 128.87 (d) ; 125.59 (d) ; 110.03 (s) ; 64.48 (t) ; 45.15 (t) ; 37.79 (t) ; 27.12 (t) ; 21.11 (q).

MS (EI) : 195 (3), 164 (24), 163 (100), 151 (4), 149 (12), 128 (3), 120 (8), 119 (74), 117 84), 115 (6), 105 (7), 91 (25), 90 (3), 89 (4), 65 (5). b) Synthesis of 2-3- (decyloxy) propyl]-2- (4-methylphenyl)-1, 3-dioxolane This compound was synthesised as described under 5. b) with 14.90 g of potassium hydride (30% in oil, 0.11 mol) in 80 ml of THF, 13.10 g (82. 7 mmol) of decanol in 20 ml of THF and of 20.00 g (83. 0 mmol) of 2- (3-chloropropyl)-2- (4-methylphenyl)-1, 3-dioxolane obtained under a) in 20 ml of THF for 41 h to

give 29.49 g of the crude compound. Repetitive column chromatography of ca.

10 g batches (SiOz, heptane/ether 9: 1) afforded a total of 5.05 g (17%) of a yellow oil.

Analytical data: Rf (heptane/ether 9: 1): 0.21.

IR (neat): 2952na, 2922s, 2851s, 2795w, 1685m, 1626w, 1606m, 1573w, 1509w, 1465m, 1455m, 1405w, 1375m, 1359m, 1298m, 1255m, 1224m, 1196m, 1179m, 1112s, 1042s, 1019m, 991m, 953m, 897w, 840w, 818s, 772w, 724m, 662w. tH-NMR (360 MHz, CDC13) : 7.33 (d, J= 7.9,2 H) ; 7.13 (d, J = 7. 9,2 H); 4.04- 3.93 (m, 2 H) ; 3.82-3.70 (m, 2 H) ; 3.36 (t, J= 7. 5,2 H); 3.33 (t, J= 6. 7,2 H) ; 2.33 (s, 3 H); 1.96-1.89 (m, 2 H); 1.69-1.58 (m, 2 H); 1.58-1.46 (m, 2 H); 1.36-1.19 (m, 14 H); 0.88 (t, J= 6.9,3 H).

13C_NMR (90.6 MHz, CDC13) : 139.62 (s) ; 137.36 (s) ; 128.74 (a9 ; 125.69 (a9 ; 110.42 (s); 70.86 (t) ; 70.72 (t) ; 64.47 (t); 37.14 (t) ; 31.92 (t) ; 29.77 (t) ; 29.60 (t, 2x); 29.53 (t) ; 29.36 (t) ; 26.20 (t) ; 24.10 (t) ; 22.70 (t) ; 21.10 (q) ; 14.13 (q).

MS (EI) : 271 (5), 164 (30), 163 (100), 161 (8), 135 (8), 134 (3), 120 (4), 119 (46), 113 (4), 105 (3), 91 (12). c) Synthesis o4-(decyloAy)-1-(4-methylphenyl)-1-butanone This compound was synthesised as described under 5. c) with 4.4 ml of HCl (1N) and 4.33 g (11.9 mmol) of 2- [3- (decyloxy) propyl]-2- (4-methylphenyl)-1, 3- dioxolane obtained under b) in 100 ml of THF to give 3.82 g (99%) of a slightly yellow oil that solidifies at 4°.

Analytical data: UV/Vis (hexane): 400 (sh, 2), 381 (sh, 6), 365 (sh, 12), 352 (sh, 26), 336 (sh, 51), 320 (64), 308 (sh, 62), 288 (sh, 1200), 277 (sh, 2400), 254 (sh, 14300), 248 (17400), 211 (sh, 16400).

IR (neat): 3032w, 2921s, 2851s, 2792w, 1682s, 1624w, 1606m, 1573w, 1484w, 1466m, 1454m, 1443m, 1408m, 1380m, 1319m, 1293m, 1268m, 1251m, 1238m, 1224ni, 1204m, 1179m, lllls, 1036m, 1018w, 1001m, 983m, 965w, 916w, 898w, 839w, 806m, 776m, 757m, 721m, 664w.

1H-NMR (360 MHz, CDC13) : 7.87 (d, J= 7.9,2 H); 7.24 (d, J= 7.9,2 H); 3.49 (t, J=6. 3, 2 H) ; 3.39 (t, J=6. 5, 2 H) ; 3.04 (t, J=7. 1, 2 H) ; 2.39 (s, 3 H) ; 2.01 (quint, J= 6. 6,2 H); 1.63-1.48 (m, 2 H); 1.38-1.17 (m, 14 H); 0.88 (t, J= 6.9, 3 H).

13C-NMR (90.6 MHz, CDC13) : 199.67 (s) ; 143.59 (s) ; 134.66 (s) ; 129.21 (d) ; 128.19 (a) ; 70.99 (t) ; 69.81 (t) ; 35.06 (t) ; 31.94 (t) ; 29.79 (t) ; 29.67 (t) ; 29.62 (t) ; 29. 55 (t) ; 29.38 (t) ; 26.25 (t) ; 24.46 (t) ; 22.72 (t) ; 21. 60 (q) ; 14.13 (q).

MS (EI) : 318 (M+, 3), 185 (8), 183 (4), 161 (10), 147 (6), 135 (16), 134 (100), 120 (5), 119 (54), 92 (4), 91 (18), 65 (3).

8. Preparation of 1- (4-methylphenyl)-4- (2-phenylethoxy)-1-butanone a) Synthesis of 2- (4-methylphenyl)-2-C3- (2-phenylethoxy) propyl]-1, 3-dioxolane This compound was synthesised as described under 5. b) with 3.1 g of potassium hydride (30% in oil, 23.2 mmol) in 10 ml of THF, 2.1 g (17.2 mmol) of 2-phenylethanol in 4 ml of THF and 4.0 g (16.6 mmol) of 2- (3-chloropropyl)-2- (4- methylphenyl)-1, 3-dioxolane obtained under 7. a) in 4 ml of THF for 68 h.

Column chromatography (SiO2, heptane/ether 4: 1) afforded 2.64 g (49%) of a slightly yellow oil.

Analytical data: Rf (heptane/ether 4: 1): 0.31.

IR (neat): 3085w, 3058w, 3022w, 2948m, 2916m, 2855m, 2790w, 2731w, 1604w, 1510m, 1494m, 1472w, 1452m, 1405w, 1359m, 1303m, 1254m, 1225m, 1192m, 1179m, 1166m, 1109s, 1037s, 951s, 907w, 844w, 817s, 770w, 748m, 724m, 698s, 665w. tH-NMR (360 MHz, CDC13) : 7.36-7.22 (m, 4 H) ; 7.22-7.10 (m, 5 H); 4.05-3.93 (m, 2 H); 3.82-3.70 (m, 2 H); 3.56 (t, J=7.3,2 H); 3.40 (t, J= 6.7,2 H) ; 2.84 (t, J= 7.3,2 H); 2.34 (s, 3 H); 1.96-1.87 (m, 2 H); 1.69-1.57 (m, 2 H).

3C-NMR (90.6 MHz, CDC13) : 139.56 (s) ; 139.09 (s) ; 137.42 (s) ; 128.90 (a) ; 128.75 (J) ; 128.29 (d) ; 126.10 (a0 ; 125.68 (a) ; 110.38 (s); 71.67 (t) ; 70.83 (t); 64.48 (t) ; 37.05 (t) ; 36.35 (t) ; 24.02 (t) ; 21.11 (q).

MS (EI) : 235 (8), 165 (4), 164 (51), 163 (50), 161 (26), 147 (3), 145 (3), 135 (8), 134 (3), 133 (3), 131 (4), 129 (3), 128 (3), 120 (11), 119 (100), 118 (4), 117

86), 115 (7), 113 (8), 106 (3), 105 (34), 104 (4), 103 (8), 92 (6), 91 (56), 90 (5), 89 (4), 79 (8), 78 (3), 77 (9), 69 (3), 65 (10). b) Synthesis of 1-64-methylphenylJ-4-(2-phenylethoxy)-I-butanone This compound was synthesised as described under 5. c) with 2.3 ml of HCl (1N), 2.05 g (6.3 mmol) of 2- (4-methylphenyl)-2- [3- (phenylethoxy) propyl]-1, 3- dioxolane obtained under a) in 50 ml of THF for 3 h to give 1.81 g (99%) of a slightly yellow oil that solidifies at 4°C.

Analytical data: UV/Vis (hexane): 352 (sh, 18), 336 (sh, 43), 318 (59), 308 (58), 287 (sh, 800), 276 (sh, 1200), 256 (sh, 9800), 246 (14800).

IR (neat): 3082w, 3060w, 3025w, 2921m, 2855m, 2790w, 1679s, 1605m, 1571w, 1494m, 1484w, 1452m, 1439w, 1407m, 1359m, 1317m, 1276w, 1250m, 1239w, 1219w, 1202m, 1179m, 1108s, 1029m, 1001m, 981m, 900w, 842w, 807m, 769w, 747m, 698s, 858w.

1H-NMR (360 MHz, CDC13) : 7.83 (d, J= 8.3,2 H); 7.30-7.14 (m, 7 H); 3.63 (t, J =7. 1,2 H); 3.52 (t, J = 6. 1,2 H); 2.98 (t, J=7. 1, 2 H); 2.86 (t, J=7. 1, 2 H) ; 2.40 (s, 3 H) ; 2.05-1.94 (m, 2 H).

3C-NMR (90.6 MHz, CDC13) : 199.71 (s) ; 143.63 (s) ; 139. 11 (s) ; 134.58 (s) ; 129.19 (d) ; 128.92 (d) ; 128.29 (cl) ; 128.19 (a0 ; 126.13 (cf) ; 71.64 (t) ; 69.87 (t) ; 36.33 (t) ; 34.98 (t) ; 24.33 (t) ; 21.62 (q).

MS (EI) : 191 (3), 177 (4), 162 (7), 161 (57), 160 (3), 149 (6), 147 (4), 135 (10), 134 (100), 120 (8), 119 (90), 106 (3), 105 (25), 104 (41), 103 (5), 92 (7), 91 (48), 90 (3), 89 (4), 79 (6), 77 (7), 65 (12), 39 (3).

9. Preparation of 1-(4-tert-butylphenyl)-4-(2-phenylethoxy)-1-butanone a) Synthesis of 2-(4-tert-butylphenyl)-2-(3-chloropyl)-1,3-dioxolane This compound was synthesised as described under 5. a) with 20.0 g (83.8 mmol) of 1- (4-tert-butylphenyl)-4-chloro-1-butanone (origin: Acros), 16 ml of ethylene glycol and ca. 1 g of p-toluenesulfonic acid in 120 ml of toluene for 16 h to give 24.1 g (99%) of the crude compound, which was used for further functionalisation. Column chromatography of 3 g (Si02, heptane/ether 4: 1) afforded 2.48 g of a slightly yellow oil.

Analytical data: Rf (heptane/ether 4: 1): 0.49.

IR (neat): 2958m, 2883m, 1915w, 1684w, 1610w, 1505m, 1473m, 1460m, 1443na, 1397m, 1362m, 1310m, 1300m, 1288m, 1267m, 1235m, 1186s, 1149w, 1107m, 1080w, 1039s, 1017s, 945s, 909s, 857w, 829s, 783w, 762w, 744w, 734w, 713w.

1H-NMR (360 MHz, CDCl3) : 7.35 (s, 4 H); 4.05-3.95 (m, 2 H) ; 3.84-3.73 (m, 2 H); 3.53 (t, J= 6.7,2 H); 2.06-1.99 (m, 2 H) ; 1.91-1.81 (m, 2H); 1.32 (s, 9 H). i3C-NMR (90.6 MHz, CDCl3) : 150.80 (s) ; 139.23 (s) ; 125.27 (at) ; 125.05 (d) ; 110.03 (s) ; 64.55 (t) ; 45.21 (t) ; 37.79 (t) ; 34.50 (s) ; 31.36 (q) ; 27.09 (t).

MS (EI) : 206 (23), 205 (100), 195 (4), 190 (9), 189 (3), 162 (3), 161 (30), 149 (4), 146 (4), 145 (4), 131 (4), 118 (6), 117 (4), 115 (5), 105 (3), 91 (4). <BR> <BR> <BR> <BR> <BR> <BR> <BR> <BR> b) Synthesis of 2- (4-tert-butylphenylyl)-2-3- (2-phenylethoxy) propylJ-1, 3-dioxolane This compound was synthesised as described under 5. b) with 1. 30 g of potassium hydride (30% in oil, 9.7 mmol) in 5 ml of THF, 0.86 g (7.0 mmol) of 2- phenylethanol in 2 ml of THF and 2.0 g (7.1 mmol) of 2- (4-tert-butylphenyl)-2- (3-chloropropyl)-1, 3-dioxolane obtained under a) in 2 ml of THF for 90 h.

Column chromatography (SiO2, heptane/ether 4: 1) afforded 1. 04 g (40%) of a white solid.

Analytical data: IR (neat): 2947m, 2920m, 2882m, 2861m, 2794w, 1604w, 1508w, 1496m, 1480m, 1466m, 1454m, 1446m, 1432w, 1413w, 1396m, 1360m, 1305m, 1290m, 1265m, 1237m, 1191m, 1167m, 1133w, 1102s, 1080m, 1040s, 1016s, 1002w, 984s, 956s, 945s, 912m, 880w, 846m, 833s, 776w, 754s, 715w, 704s, 680w.

H-NMR (360 MHz, CDC13) : 7.38-7.30 (m, 4 H); 7.30-7.22 (m, 2 H) ; 7.22-7.14 (m, 3 H) ; 4.05-3.92 (m, 2 H) ; 3.85-3.72 (m, 2 H) ; 3.57 (t, J=7. 1,2 H); 3.40 (t, J= 6.7,2 H); 2.84 (t, J= 7.3,2 H); 1.98-1.87 (m, 2 H); 1.71-1.57 (m, 2 H); 1.31 (s, 9 H).

13C_NMR (90.6 MHz, CDCl3) : 150.57 (s) ; 139.48 (s) ; 139. 07 (s) ; 128.89 (d) ; 128. 28 (d) ; 126.09 (d) ; 125.35 (d) ; 124.92 (d) ; 110.37 (s) ; 71.70 (t) ; 70.87 (t) ; 64.53 (t) ; 37.03 (t) ; 36.35 (t) ; 34.48 (s) ; 31.37 (q) ; 24.04 (t).

MS (EI) : 206 (16), 205 (100), 203 (3), 161 (11), 118 (3), 105 (5), 91 (5).

c) Synthesis of 1- (4-tert-butylphenyl)-4- (2-phenylethoxy)-1-butanone This compound was synthesised as described under 5. c) with 2 ml of HCl (1N) and 2.00 g (5.4 mmol) of 2- (4-tert-butylphenyl)-2- [3- (2-phenylethoxy) propyl]- 1,3-dioxolane obtained under b) in 50 ml of THF to give 1.77 g (99%) of a yellow oil.

Analytical data: LTV/Vis (hexane): 352 (sh, 21), 333 (sh, 54), 321 (64), 308 (sh, 62), 287 (sh, 900), 277 (sh, 1400), 258 (sh, 10900), 248 (17800).

IR (neat): 3085w, 3060w, 3026w, 2957m, 2930m, 2904m, 2861m, 2795w, 1679s, 1604m, 1585w, 1494m, 1474m, 1463m, 1452m, 1440m, 1405m, 1361m, 1320m, 1295m, 1268m, 1249m, 1212m, 1190m, 1158w, 1106s, 1030m, 997m, 923w, 901w, 840m, 825m, 767w, 747m, 734m, 697s.

'H-NMR (360 MHz, CDC13) : 7.92-7.84 (m, 2 H) ; 7.50-7.42 (m, 2 H); 7.30-7.14 (m, 5 H) ; 3.63 (t, J= 6. 9,2 H); 3.51 (t, J= 6. 1,2 H); 3.00 (t, J= 7. 1,2 H); 2.86 (t, J= 6. 9,2 H); 2.00 (quint., J= 6. 6,2 H) ; 1.34 (s, 9 H).

3C-NMR (90.6 MHz, CDC13) : 199.71 (s) ; 156.56 (s) ; 139.10 (s) ; 134.48 (s) ; 128.90 (d) ; 128.29 (d) ; 128.03 (d) ; 126.11 (d) ; 125.44 (a) ; 71.64 (t) ; 69. 85 (t) ; 36. 32 (t) ; 35.06 (s) ; 34.95 (t) ; 31. 10 (q) ; 24.34 (t).

MS (EI) : 219 (3), 204 (8), 203 (51), 188 (3), 187 (5), 177 (12), 176 (88), 162 (13), 161 (100), 147 (4), 146 (9), 145 (6), 133 (4), 132 (4), 131 (3), 118 (12), 117 (8), 115 (5), 105 (20), 104 (25), 103 (5), 91 (15), 79 (4), 77 (6).

Example 2 Release of fragrant terminal alkenes after irradiation of different phenyl ketones in solution Execution of photorelease assays and analysis of phenyl ketones Photorelease Assays The photorelease assays were carried out in undegassed solution with either a Xenon lamp (Heraeus Suntest CPS at 460 W/m2) or outdoor sunlight (Geneva, spring 2000), respectively, and quantified by GC. Ca. 0.08 M solutions of the different phenyl ketones in the indicated solvent were prepared by adding 1 ml of a 0.01 M solution of dodecane

(which was used as an internal standard for the GC analysis) to 5 ml of a 0.01 M solution of the phenyl ketone. Three samples of these solutions were then irradiated during 3 h in 10 ml borosilicate volumetric glass flasks (Pyrex@). In each case a dark control experiment (an additional sample being wrapped in aluminium foil) was carried out. The identity of the products formed was systematically verified based on GC retention times and GC-MS analyses of the irradiated samples.

Analysis GC analyses were carried out on a Carlo Erba MFC 500 chromatograph equipped with a Fisons AS 800 autosampler, a flame ionisation detector and a J&W Scientific DBI capillary column (15 m, 0.32 mm i. d.) at 70° for 10 min then to 260° (10°C/min), helium pressure 50 kPa, injection volume 0.5 jul, injection temperature 250°, detector temperature 260°. GC-MS analyses were carried out on a HP 5890 or 6890 GC System equipped with a Supelco SPB-1 capillary column (30 m, 0.25 mm i. d.) at 70° for 10 min then to 260° (10°/min), helium flow ca 1 ml/min, coupled with a HP MSD 5972 or 5973 quadrupole mass spectrometer, electron energy ca 70 eV, fragment ions mlz (rel. int. in % of the base peak).

The release of 1, 5-dimethyl-1-vinyl-4-hexenyl acetate, decylvinyl ether, 2-phenylethyl- vinyl ether, allyl heptanoate, allyl 3-cyclohexylpropionate, allyl phenoxy-acetate and vinylbenzene as well as the corresponding acetophenone residues from phenyl ketones precursors was investigated by photoirradiation in solution, as described above.

Table 1 reports the yields of compounds released in mol-%: Table 1 : Results of the photoirradiations of different phenyl ketones in solution Yield of Corresponding Alkenes and Acetophenones IrradtatedS. 1. r. i r in/i - E Light Released [mol-%] Compound of Light Released [mol-%] Source Toluene 2-Propanol Acetonitrile 3h 3h 3h R3 O R3 O R3 O R3 O R, R, R, R", Y R, R R, 1 2 R3 Rz RS R3 R2 R4 R4 R4 o n Xenon 61 41 49 55 H 1 sunlight n. d. a) 32 n. d. 43 Yield of Corresponding Alkenes and Acetophenones Irradiated s Light Released [mol-%] Source Toluene 2-Propanol Acetonitrile Formula (1) z 3 h 3 h 3 h R3 O R3 O R3 O R3 O R, ; R4 4 R, 4 R, R"Y R, R4 I R R R. R3 112 Rs R. 3 Ru o Xenon 71 68 26 36 48 72 Iso 2 o o sunlight n. d. 80 32 41 44 66 o o Xenon 72 66 23 31 41 68 i 0 3 sunlight n. d. 76 29 37 33 62 0 0 Xenon 64 55 24 15 51 64 0 4 sunlight 26 19 47 60 0 0 Xenon 62 54 32 57 40 46 0 5 sunlight 69 53 54 40 zu o o Xenon 28 21 30 31 25 26 6 sunlight 30 25 54 35 o o Xenon 31 35 n. d. 64 34 48 7 sunlight 39 38 35 38 o o Xenon 26 32 21 32 sunlight 35 38 22) 48b) s o < 9 Xenon 52 43 47 46 9 sunlight 60 44 55 38 s Yield of Corresponding Alkenes and Acetophenones Irradiated Light Released [mol-%] Compound of 0 Source Toluene 2-Propanol Acetonitrile Formula (1) z 3 h 3 h 3 h R3 O R3 O R3 p R3 p R R, R, R I R, R4 I lyR s W Rs a Rs \ Ra z Rs \ Ra z Rs Ra R R R R 0 O 1 o Xenon 49 47 34 44 10 sunlight 37 37 47 32 w

All numbers are average values of 3 samples; a) n. d. = not determined quantitatively.<BR> <BR> <BR> b) ca. 0.04M solution Example 3 Release of fragrant terminal alkene after irradiation of different phenyl ketones in a fabric softener For this experiment, 0.8 mass-% of precursors 1,2,3 and 4 (see Table 1), respectively, were dosed in an perfumed textile softener containing Esterquats (Stepantex and Stepanquat @) of the following composition: Ingredients % by weight Stepantex @ VS90 or VHR90 * 16. 7 Stepanquat F * 0.4 1% colorant solution ** 0. 3 Water 82.6 Total 100.0 * Source : Stepan, France ** Sandolan Milling Blue N-LN 180 ; source: Clariant, Switzerland Cotton towels (28 x 28 cm) were washed one by one with an perfumed detergent powder in a Linitests container. Rinsing with the fabric softener containing either the precursor or a molar equivalent of the corresponding alkene to be released, respectively, was then carried out in a beaker by adding cold water. The towels with the precursors

were then compared on a blind test to the one with the corresponding alkene by 13 or 14 panellists after the washing. Each panellist estimated the perceived intensity of the samples on a scale of 1 (no odour) to 10 (very intense odour) and indicated the preferred sample. After being dried at room temperature overnight the towels were exposed to natural indoor daylight (with an average light intensity of 3600 lux) in Pyrex glass containers and the panel evaluation was repeated after 1 day and 6 days, respectively.

Table 2 reports the average intensities perceived by the panellists and between brackets the number of panellists preferring the corresponding sample, obtained in the blind pairwise evaluation of alkenes as compared to their corresponding precursors 1,2,3 and 4 respectively.

Table 2 Evaluated sample No Wet Dry (1 day) Dry (6 days) 1* 4.0 (6/13) 2.1 (4/14) 2.2 (4/13) t~2 1 2.3 (5/13) 2.1 (3/14) 3.4 (8/13) 2* 7.9 (12/13) 2.4 (4/14) 2.3 (3/13) o o 2 2.8 (1/13) 2.1 (6/14) 2.8 (8/13) U 0 jazz 3* 7.6 (12/13) 2.8 (4/13) 2.6 (4/14) o o i I o 3 2.1 (1/13) 2.4 (2/13) 2.8 (9/14) 0 o 4* 7.3 (9/13) 3.2 (4/13) 2.8 (6/14) 0 0 i I o°/'4 2.3 (2/13) 2.5 (2/13) 2.6 (8/14) kjkj

Whereas the free perfumery compound was perceived to be very strong on the wet fabric, its intensity decreased rapidly once the towels were dry. In the case of the samples containing the precursor, the odour intensity was judged to remain constant over the time

of the experiment, thus nicely illustrating the desired slow release effect. Whereas the panellists generally preferred the unmodified alkenes on the wet fabric, the inverse was observed for the evaluation of the dry towels, where most of the panellists preferred the sample containing the precursor. As an example, eight out of 13 panellists preferred the cotton towel with precursor 2 after 6 days of exposure to sunlight and 3 panellists the sample with unmodified alkene 2*.

Similar results could be observed with any other type of fabric softener formulations such as those described above.

Example 4 Dynamic headspace analysis in all purpose cleaners (APC) In order to follow the perfume release under realistic application conditions, the formation of allyl cyclohexylpropionate and acetophenone from its precursor in an all purpose cleaner (APC) application was investigated by quantitative dynamic headspace analyses. For the experiments, given that the particular nature of the APC base is not relevant within the context of the invention, a standard APC base of the following composition was used: Ingredients % by weight demineralised water 96.4 Tergitol 15-S-12 (ethoxylated secondary alcohol) * 3.6 * origin : Union Carbide, USA A total of 2.5 g of the APC base containing 0.3 mass-% of the precursor (5-oxo-5- phenylpentyl 3-cyclohexylpropanoate) and 0.3 mass-% of a solubiliser (Triton X 100, Rohm&Haas) were deposed as a thin film on the bottom of a standard glass surface (325 x 225 x 50 mm, ; : i 3.5 1). The surface was exposed to outdoor sunlight for 6 h and continuously flushed with an air stream (58 ml/min). During irradiation, the air flow through the container was decontaminated with a charcoal filter. Every 40 min the volatiles contained in the air stream were adsorbed on 100 mg Tenax TA cartridges

(during 5 min) and the light intensity was measured at the beginning and the end of each sampling with a luxmeter and averaged. Altogether 8 samplings were made. The cartridges were desorbed thermally in a Perkin Elmer TurboMatrix ATD desorber and the volatiles analysed with a Carlo Erba MFC 500 gas chromatograph equipped with a J&W Scientific DB1 capillary column (15 m, 0.45 mm i. d.) at 70° for 10 min then to 260° (10°C/min) and a He pressure of 50 kPa. The respective concentrations of allyl cyclohexylpropionate and acetophenone released in the headspace were determined by external standard calibrations. The results obtained for a typical experiment are surnmarised in Table 2 and Figure 1.

Similar experiments could be carried out on any kind of surface.

Table 2 Amount of Acetophenone Amount of Allyl Sunlight Time [s] Released Cyclohexylpropionate Released Intensity [ng l-l] [ng l-l] [lux] 2700 3268 2922 47300 5400 11538 4149 31895 8100 19110 7014 66000 10800 24021 9881 69400 13500 22604 9437 49100 16200 25385 11162 52350 18900 25580 11788 52650 21600 23457 11652 15575 Figure 1 0 0 0 0 wl o n- wl +o kj'k LJ short time clouded sunlight direct clouded sunlight direct (during sampling) sunlight sunlight - H H 50 8 7 40 light intensity 5 30 103 104 Cons Light Cone roi Light acetophenone 3 [lux] 10- 10 allyl cyclohexylpropionate w,,, O O 0 5 10 15 20 25 time 103 [s] o

The obtained results clearly show that the desired compounds are released under real daylight conditions from an APC base. Plotting the amount of the fragrances released from the precursor together with the light intensity against time (Figure 1) nicely illustrates the direct dependency of the perfume release on the intensity of the irradiation.

In general, good reproducibility of outdoor sunlight conditions is very difficult to achieve, since the light intensity varies during the day, reaching a maximum value around noon. Furthermore, the appearance of clouds strongly influences the light intensity. The dotted line in Figure 1 represents ideal sunlight conditions measured at an entirely clear, non clouded day. The first minimum observed in the light intensity curve of the present measurement (after ca 5000 s) is due to a short time clouding of the sky during sampling, which does not influence the release of the perfumery compounds.

Longer clouding times (as observed between 10000 and 20000 s) however, result in a decrease of fragrance release; as soon as the light intensity re-increases, an increase of both compounds released into the headspace can be observed.

Example 5 Dynamic headspace analysis for the controlled release on hair In order to test the performance of the light induced controlled release of fragrances in typical body care applications, dynamic headspace analysis on hair swatches were carried out. The amount of alkene and acetophenone released from the precursor was compared to the quantity of the corresponding fragrance molecules respectively, using an unperfumed leave-in conditioner base of the following composition: Ingredients % by weight Phytantriol 0. 10 Renex s 690 2) 0.50 Propylene glycol 2.00 D-Panthenol @ 3) 0.30 Ethoquad O/12 4) 0.70 Crosilk @ Liquid 5) 0. 10 Mackpro# NSP6) 0.10 Arginine HC1 0.20 DOW Coming 929 cationic emulsion 7) 1.00 Kathone CG 8 0.05 GlydantQ 9) 0. 20 Gemiall 0 11 0.20 Sodium phosphate 0.25 Phosphoric acid (42% aq.) 0.40 Demineralised water 93.90 Total 100.00 1) 3,7,11,15-tetramethylhexadecane-1,2,3-triol 2) nonoxynol-10; origin: ICI Surfactants 3) origin: Roche 4) isopropyl alcohol and PEG-2 oleammonium chloride; origin: Akzo Nobel

5) silk powder; origin: Croda 6) quaternium-79 hydrolised silk; origin: McIntyre 7) origin: DOW Coming 8) methylchloroisothiazolinone and methylisothiazolinone; origin: Rohm&Haas 9) 1,3 bis (hydroxymethyl)-5, 5-dimethylimidazolidine-2, 4-dione; origin: Lonza 10) diazolidinyl urea ; origin: Sutton This composition is typical of this type of application but the invention is not limited to this particular base and any other base of leave-on hair conditioner would be similarly suitable.

A total of 0.4 g of the perfumed leave-on conditioner base containing either 0.33 mass-% of the precursor (5-oxo-5-phenylpentyl 3-cyclohexylpropanoate), 0.20 mass- % of allyl 3-cyclohexylpropanoate or 0.15 mass-% of acetophenone (molar equivalents) and 0.34 mass-% of solubiliser (Renex 690, origin: ICI Surfactants), respectively, were sprayed in four portions on a lock of hair ( 5 g weight), previously washed with an perfumed shampoo base. The samples were then irradiated for 3.25 h in a homemade Pyrex glass tube of approx. 300 ml volume with a Xenon lamp (Heraeus Suntest CPS) at a constant light intensity of ca. 108500 lux and under a constant air flow of 80 ml/min (corresponding to 4 renewals of air/sampling). During irradiation, the glass tube was connected to a charcoal filter for air purification. At t = 0,1,2 and 3 h the constituents of the headspace were adsorbed for 15min onto 100mg Tenax TA cartridges. The cartridges were desorbed thermally with a Perkin Elmer ATD 400 desorber and the volatiles analysed with a Perkin Elmer Autosystem XL gas chromatograph. The analyses were effected using a Supelco SPB-1 capillary column (30m, 0.53mm i. d., film 1.5 micron) from 60° to 250° (10°/min) with He as carrier gas at a linear velocity of 25 cm/sec.

Table 3 : Comparison of the dynamic headspace of free acetophenone and allyl cyclohexylpropanoate and their respective precursors in a leave-on hair conditioner irradiated with a Xenon lamp Time [h] Amount of free Amount of free Allyl Amount of Amount of Allyl 3- Acetophenone 3-cyclohexyl-Acetophenone cyclohexylpropanoate [ng l-1] propanoate Released Released [ng l-1] [ng l-1] [ng l-1] 0 27890 15290 1350 530 1 17220 3600 1570 980 2 5770 800 1510 950 3 3210 340 1400 790 Figure 2 iooo zoo + 100-ma amount of 100-" unmodified amount of acetophonone acetophenone tncTnr) amountof '' f, -ll 1 released amountof amount of alkene unmodified released alkene 1 0-0.25 1-1.25 2-2.25 3-3.25 time [h] 0-

Figure 2 and Table 3 illustrate that the concentration of free allyl 3-cyclohexylpropanoate and acetophenone decrease rapidly with time, whereas the amount of the corresponding compounds released from the precursors remain almost constant during the experiment (at constant light intensity). After ca. two hours of irradiation, the concentration curve of allyl 3-cyclohexylpropanoate released from the precursor crosses the concentration curve of the unprotected alkene, thus illustrating that the desired long lasting effect of the precursor system becomes efficient after a relatively short irradiation time.