WO2007111630A1

WO2007111630A1 - Compounds which release an odor on a change in ph

Info

Publication number: WO2007111630A1
Application number: PCT/US2006/029536
Authority: WO
Inventors: Luca Turin
Original assignee: Flexitral, Inc.
Priority date: 2005-07-29
Filing date: 2006-07-31
Publication date: 2007-10-04

Abstract

A compound having the formula: (I) wherein R1 is a residue of an aromachemical, R2 = H or a residue of an aromachemical and X is an organoleptically acceptable counterion. Uses of these compounds, compositions containing them and methods for their production are also described.

Description

COMPOUNDS WHICH RELEASE AN ODOR ON A CHANGE IN PH

Inventor: LUCA TURIN

[0001] The present invention relates to derivatives of aromachemicals, which break down to release the aromachemicals when subjected to a change in pH.

[0002] Fragrances such as perfumes are often added directly to personal care compositions, such as hair dye products.

[0003] One problem arising from the direct addition of perfume to base compositions is that there is no flexibility to simultaneously optimize fragrance display in the neat product or a component of a kit and during use of the product or kit. For example, the optimum fragrance level during use may result in the neat product or a component of a kit smelling too strongly. Likewise, the optimum fragrance level in the neat product or a component of a kit may lead to less satisfactory results during use. It would be desirable to be able to adjust the fragrance display independently in the neat product or a component of a kit and during use.

[0004] The listing or discussion of a prior-published document in this specification should not necessarily be taken as an acknowledgment that the document is part of the state of the art or is common general knowledge.

[0005] The invention is predicated on the finding that certain derivatives of certain aromachemicals are water soluble and are stable in a certain pH range but will break down to release the parent aromachemical when subjected to an increase and/or a decrease in pH.

[0006] The present invention provides derivatives of aromachemicals that are stable and typically exhibit little or no odor within a certain pH range but on alteration of the pH will break down to release the aromachemicals on which they are based.

[0007] By alteration of pH is meant an increase or a decrease in pH.

[0008] The compounds of the invention are derivatives of aromachemicals containing an aldehyde group or a ketone group. The compounds of the invention are derived from aromachemical aldehydes or ketones having the formula: O

R¹ R² . (I)

[0009] In the case of aldehydes, R¹ is the residue of an aromachemical and R² = H. In the case of ketones, both R¹ and R² are residues of an aromachemical. Unless otherwise stated, hereinafter these aldehyde and ketone compounds will be known as the parent aromachemicals.

[0010] Examples of ketones and aldehydes that can be used as the parent aromachemicals in the present invention can be found in, for example, "Perfume and Flavor Chemicals", Vol. I and II, S. Arctander, Allured Publishing, 1994, ISBN 0-931710-35-5.

[0011] Examples of such parent aromachemicals are compounds having the formula R⁵R⁶C=CR³R⁴ wherein R⁵ = CHO or C(O)R⁷ and R³, R⁴, R⁶ and R⁷ represent, independently, H, linear or branched or cyclic Ci_-I2 alkyl, alkenyl or alkoxy, substituted linear or branched or cyclic Ci-I₂ alkyl, alkenyl or alkoxy, substituted or unsubstituted aryl. Suitable substituents on the substituted alkyl, alkenyl, alkoxy or aryl groups include halo, hydroxyl, thiol, thioether, amine, carboxylic acid, ester, nitro, cyano, isocyano, sulfonic acid, urea and thiourea. In other words, these compounds are compounds of formula (I) above in which R¹ is -C(R⁶)=CR³R⁴. Preferably at least one of R⁴ and R⁶ is H, for example both of R⁴ and R⁶ may be H. Another preferred group for R⁶ is cyclohexyl.

[0012] Other examples of such parent aromachemicals are compounds having the formula R⁹R¹⁰C=O, wherein R⁹ and R¹⁰ represent, independently, linear or branched or cyclic C]_-J2 alkyl, alkenyl or alkoxy, substituted linear or branched or cyclic C]_-J2 alkyl, alkenyl or alkoxy, substituted or unsubstituted aryl, additionally R¹⁰ may be H independent of the nature of R⁹. Suitable substituents on the substituted alkyl, alkenyl or alkoxy or aryl groups include halo, hydroxyl, thiol, thioether, amine, carboxylic acid, ester, nitro, cyano, isocyano, sulfonic acid, urea and thiourea. In these compounds, the groups R⁹ and R¹⁰ correspond to the groups R¹ and R² above.

[0013] Preferably R⁹ and R¹⁰ are each independently linear or branched or cyclic C]_i₂ alkyl, alkenyl or alkoxy, substituted linear or branched Cj-I₂ alkyl, alkenyl or alkoxy, substituted or unsubstituted aromatic, more preferably linear or branched C]_-6 alkyl or alkenyl, additionally R¹⁰ may be H independent of the nature of R⁹. For example, R⁹ may be an alkyl group containing four carbon atoms such as -CH(CH₃)CH₂CH₃ or may contain an aromatic group, for example -CH₂CH(CH₃)(C₆H₅) and R¹⁰ may be hydrogen or a methyl group.

[0014] Further examples of such parent aromachemicals are compounds having the formula:

wherein Z is CH₂ or O, n is 0 or 1 , such that the ring is 5- or 6-membered, respectively, and R is alkyl, alkenyl or alkoxy having up to 10 carbon atoms. R " may be a straight chain or branched alkyl or alkenyl or alkoxy. Optionally, R¹² may be substituted. Suitable substituents include halo, hydroxyl, thiol, thioether, amine, carboxylic acid, ester, nitro, cyano, isocyano, sulfonic acid, urea and thiourea. These compounds are compounds of formula (I) above in which R¹ and R² together form a 5 or 6 membered cyclic group, optionally containing an O and substituted by a group R¹².

[0015] Yet other examples of such parent aromachemicals are compounds having the formula:

wherein the or each R¹³ is independently a straight or branched chain C]_-8 alkyl, alkenyl or alkoxy or two groups R^!3 together with the carbon atoms to which they are attached form a five or six membered ring which may be saturated or unsaturated (including aromatic), and which may be optionally substituted with from 1 to 3 Cj_-6 alkyl groups; and x is from 1 to 5. R¹³ may also be substituted by halo, hydroxyl, thiol, thioether, amine, carboxylic acid, ester, nitro, cyano, isocyano, sulfonic acid, urea or thiourea. These compounds are compounds of formula (I) above in which R¹ is the aromatic ring shown above substituted with one or more groups R¹³ and R² is H.

[0016] Preferably at least one R¹³ is a C] .₈ alkyl, alkenyl or alkoxy group or two groups R¹³ together with the carbon atoms to which they are attached form a five or six membered ring. Preferred substitutents on a ring formed by two groups R¹³ and the carbon atoms to which they are attached have from 1 to 4 carbon atoms. For example, at least one R¹³ may be a straight chained or branched C]_-4 alkyl, alkenyl or alkoxy group. In particular, at least one R¹³ may be ?-butyl and/or methoxy. In a preferred aspect, up to three groups R¹³ can be t-butyl and optionally one or more groups R¹³ can be methoxy. For example, a preferred parent aromachemical is (2,4-di-ϊ-butyl-5- methoxybenzaldehyde).

[0017] Examples of the ketone and aldehyde parent aromachemicals include but are not limited to buccoxime; iso jasmone; methyl beta naphthyl ketone; musk indanone; tonalid/musk plus; alpha-damascone, beta-damascone, delta-damascone, iso-damascone, damascenone, damarose, methyl- dihydrojasmonate, menthone, carvone, camphor, fenchone, alpha-ionone, beta- ionone, gamma-methyl so-called Ionone, fleuramone, dihydrojasmone, cis- jasmone, iso-E-Super, methyl-cedrenyl-ketone or methyl-cedrylone, acetophenone, methyl-acetophenone, para-methoxy-acetophenone, methyl-beta- naphtyl-ketone_? benzyl-acetone, benzophenone, para-hydroxy-phenyl-butanone, celery ketone or livescone, 6-isopropyidecahydro-2-naphtone, dimethyl-octenone, freskomenthe, 4-(l -ethoxyvinyl)-3,3,5,5,-tetramethyl-cyclohexanone, methyl- heptenone, 2-(2-(4-methyl-3-cyclohexen- 1 -yl)propyl)-cyclopentanone, 1 -(p- Menthen-6(2)-yl)- 1 -propanone, 4-(4-hydroxy-3-methoxyphenyl)-2-butanone, 2- acetyl-3,3-dimethyl-norbornane, 6,7-dihydro-l ,1 ,2,3,3-pentamethyl-4(5H)- indanone, 4-damascol, dulcinyl or cassione, gelsone, hexalon, isocyclemone E, methyl cyclocitrone, methyl -lavender-ketone, orivon, para-tertiary-butyl- cyclohexanone, verdone, delphone, muscone, neobutenone, plicatone, veloutone, 2,4,4,7-tetramethyl-oct-6-en-3-one, tetrameran, adoxal, anisic aldehyde, cymal, ethyl vanillin, florhydral, helional, heliotropin, hydroxycitronellal, koavone, lauric aldehyde, lyral, methyl nonyl acetaldehyde, P. T. bucinal, phenyl acetaldehyde, undecylenic aldehyde, vanillin, 2,6,10-trimethyl-9-undecenal, 3-dodecen-l-al, alpha-n-amyl cinnamic aldehyde, 4-methoxybenzaldehyde, benzaldehyde, 3-(4- tert butylphenyl)-propanal, 2-methyl-3-(para-methoxyphenyl) propanal, 2-methyl- 4-(2,6,6-trimethyl-2(l)-cyclohexen-l-yl)butanal, 3-phenyl-2-propenal, cis/trans- 3,7-dimethyl-2,6-octadien-l -al, 3,7-dimethyl-6-octen-l -al, [(3,7-dimethyl-6- octenyl)oxy] acetaldehyde, 4-isopropylbenzyaldehyde, 1 ,2,3, 4,5,6,7, 8-octahydro- 8,8-dimethyl-2-naphthaldehyde, 2,4-dimethyl-3-cyclohexen-l-carboxaldehyde, 2- methyl-3-(isopropylphenyl)propanal, 1 -decanal; decyl aldehyde, 2,6-dimethyl-5- heptenal, 4-(tricyclo[5.2.1.0(2,6)]-decylidene-8)-butanal, octahydro-4,7-methano- lH-indenecarboxaldehyde, 3-ethoxy-4-hydroxy benzaldehyde, para-ethyl-alpha, alpha-dimethyl hydrocinnamaldehyde, alpha-methyl-3 ,4-(methylenedioxy)- hydrocinnamaldehyde, 3,4-methylenedioxybenzaldehyde, alpha-n-hexyl cinnamic aldehyde, m-cymene-7-carboxaldehyde, alpha-methyl phenyl acetaldehyde, 7- hydroxy-3,7-dimethyl octanal, undecenal, 2,4,6-trimethyl-3-cyclohexene~l- carboxaldehyde, 4-(3)(4-methyl-3-pentenyl)-3-cyclohexen-carboxaldehyde, 1 - dodecanal, 2,4-dimethyl cyclohexene-3-carbox-aldehyde, 4-(4-hydroxy-4-methyl pentyl)-3-cylohexene-l -carboxaldehyde, 7-methoxy-3,7-dimethyloctan-l -al, 2- methyl undecanal, 2-methyl decanal, 1-nonanal, 1 -octanal, 2,6,10-trimethyl-5,9- undecadienal, 2-methyl-3-(4-tertbutyl)propanal, dihydrocinnamic aldehyde, 1- methyl-4-(4-methyl-3-pentenyl)-3-cyclo-hexene-l -carboxaldehyde, 5 or 6 methoxyohexahydro-4,7-methanoindan-l or 2-carboxaldehyde, 3,7- dimethyloctan-1-al, 1 -undecanal, 10-undecen-l-al, 4-hydroxy-3-methoxy benzaldehyde, 1 -methyl-3-(4-methylpentyl)-3-cyclohexene-carboxaldehyde, 7- hydroxy-3,7-dimethyl-octanal, trans-4-decenal, 2,6-nonadienal, para- tolylacetaldehyde; 4-methylphenylacetaldehyde, 2-methyl-4-(2,6,6-trimethyl-l - cyclohexen-l-yl)-2-butenal, ortho-methoxycinnamic aldehyde, 3,5,6-trimethyl-3- cyclohexene carboxaldehyde, 3 ,7-dimethyl -2 -methyl ene-6-octenal, phenoxyacetaldehyde, 5,9-dimethyl-4,8-decadienal, peony aldehyde (6,10- dimethyl-3-oxa-5,9-undecadien- 1 -al), hexahydro-4,7-methanoindan- 1 - carboxaldehyde, 2-methyl octanal, alpha-methyl-4-(l -methyl ethyl)-benzene acetaldehyde, 6,6-dimethyl-2-norpinene-2-propionaldehyde, para methyl phenoxy acetaldehyde, 2-methyl-3-phenyl-2-propen-l-al, 3,5,5-trimethyl hexanal, hexahydro-8,8-dimethyl-2-naphthaldehyde, 3-propyl-bicyclo[2.2.1]hept-5-ene-2- carbaldehyde, 9-decenal, 3-methyl-5-phenyl-l-pentanal, methylnonyl acetaldehyde, hexanal, trans-2-hexenal, 1-para-menthene-q-carboxaldehyde, 2- methyl-2-(para-iso-propylphenyl)-propionaldehyde, l-(2,6,6-trimethyl-2- cyclohexan-l-yl)-2-buten-l-one and/or para-methoxy-acetophenone, undecylenic aldehyde, undecalactone gamma, heliotropin, dodecalactone gamma, para-anisic aldehyde, para-hydroxy-phenyl-butanone, cymal, ionone alpha, damascenone, ionone beta, methyl-nonyl ketone, compounds having the formula:

wherein R¹⁴ and R¹⁵ are, independently, H or straight or branched chain C]_-6 alkyl or alkenyl or mixtures thereof. These compounds are compounds of formula (I) above in which R¹ is the substituted aromatic ring shown above R² is R¹⁴.

[0018] Suitable aldehydic musks for derivitization according to the present invention include the aromatic (benzenic), and polycyclic musks. The benzenic musks suitable for the present invention include (2,4-di-?-butyl-5- methoxybenzaldehyde) .

[0019] Suitable polycyclic musks are those having the structures:

wherein R and R may be the same or different and are a straight or branched chain, saturated or unsaturated C]_-8 alkyl or alkenyl and m is 1 to 4 and n is 1 to 6. These compounds are compounds of formula (I) above in which R¹ is the substituted aromatic ring shown above and R² is H.

[0020] Typical of such polycyclic musks include those having the structures:

[002 IJ Further suitable parent aromachemicals include indol, skatole, heliotropine, hydrocinnamaldehyde, alpha-methyl-3 ,4-(methylenedioxy) (Helional®), vanillin, straight chain or branched C]_-4 alkyl vanillins such as ethyl vanillin, methyl eugenol, methyl salicylate, benzyl salicylate, eugenol, iso- eugenol and methyl iso-eugenol.

[0022] Preferably, the compounds of the invention are derived from parent aromachemicals having the formula:

O

wherein R¹ and R² represent, independently, linear or branched or cyclic Ci-^ alkyl, alkenyl or alkoxy, substituted linear or branched or cyclic Cj_-I2 alkyl, alkenyl or alkoxy, substituted or unsubstituted aryl. Additionally, R² may be H independently of the nature of R¹. Suitable substituents on the substituted alkyl, alkenyl, alkoxy or aryl groups include halo, hydroxyl, thiol, thioether, amine, carboxylic acid, ester, nitro, cyano, isocyano, sulfonic acid, urea and thiourea.

[0023] Preferably, R¹ is C_MO alkyl, cyclic or acyclic Ci_-I0 alkenyl or aryl, each of which may be substituted by 1, 2, 3, 4 or 5 substituents selected from linear or branched Cj_-4 alkyl, hydroxyl, unsubstituted aryl or aryl substituted by a Ci_-4 alkyl; and R₂ is H or linear or branched Cj_-4 alkyl.

[0024] As used herein, Cj_-4 alkyl means methyl, ethyl, propyl (e.g. n- or i-propyl) or butyl (e.g. n-, i- or t-butyl). Preferably, the cyclic or acyclic Ci-I₀ alkenyl groups described above contain one or two C=C double bonds. Typically, the Cj_-I0 alkyl group is a saturated linear or branched group, preferably linear.

[0025] The term "aryl" includes carbocyclic or heterocyclic, monocyclic or fused polycyclic aryl group, for example, phenyl, furanyl, pyrrolyl, thienyl, pyridinyl, pyrimidinyl, oxazolyl, isoxazolyl, pyrazolyl, imidazolyl, thiazolyl, isothiazolyl, naphthalene, anthracene, indolizine, indole, isoindole, benzofuran, benzothiophene, indazole, benzimidazole, benzthiazole, purine, quinoline, isoquinoline, cinnoline, phthalazine, quinazoline, quinoxaline, 1 ,8-naphthyridine, pteridine, carbazole, acridine, phenazine, phenothiazine, phenoxazine and azulene. Phenyl is a preferred aryl group.

[0026] The compounds of the invention are sulfite adducts of the parent aromachemicals. Thus, the compounds of the invention have the formula:

wherein R¹ and R² are as defined above for the parent aromachemicals from which the adducts are derived, i.e. wherein R¹ is a residue of the parent aromachemical and R² = H or a residue of the parent aromachemical; and X is an organoleptically acceptable counterion.

[0027] Unless otherwise stated, as used herein the term "organoleptically acceptable" refers to materials (e.g. a counterion or sulfiting agent) compatible with the compounds of the invention and which do not affect the organoleptic properties of the latter. [0028] Typically, R¹ and R² represent, independently, linear or branched or cyclic C_]-]2 alkyl, alkenyl or alkoxy, substituted linear or branched or cyclic C_1- i₂ alkyl, alkenyl or alkoxy, substituted or unsubstituted aryl. Additionally R² may be H independently of the nature of R¹. Suitable substituents on the substituted alkyl, alkenyl, alkoxy or aryl groups include halo, hydroxyl, thiol, thioether, amine, carboxylic acid, ester, nitro, cyano, isocyano, sulfonic acid, urea and thiourea.

[0029] Preferably, R¹ is C]_-10 alkyl, cyclic or acyclic Ci_-I0 alkenyl or aryl, each of which may be substituted by 1, 2, 3, 4 or 5 substituents selected from linear or branched C]_-4 alkyl, hydroxyl, unsubstituted aryl or aryl substituted by a Ci_-4 alkyl; and R₂ is H or linear or branched Ci_-4 alkyl.

[0030] Many examples of parent aromachemicals have been described hereinbefore. The compounds of the invention include the sulfite adducts of any and all of these parent aromachemicals.

[0031] X is typically the counterion of an organoleptically acceptable sulfiting agent.

[0032] The compounds of the invention can be produced by methods known in the art for the production of sulfite adducts of aldehydes and ketones. For example, the compounds of the invention can be produced by the reaction of the parent aromachemical(s) defined above with a sulfite. Any suitable sulfite or sulfite generating species such as an alkali metal bisulfite (eg sodium bisulfite) may be used in this reaction.

[0033] Suitable sulfite or sulfite generating species for use in this reaction include water-soluble sulfites, bisulfites, hydrosulfites, metabisulfites and sulfur dioxide. For example, ammonium or alkali metal, particularly sodium or potassium sulfites, bisulfites, hydrosulfites and metabisulfites. Particularly preferred are sodium metabisulfite, sodium sulfite, sodium bisulfite and sodium hydrosulfite, potassium sulfite, potassium bisulfite, potassaium hydrosulfite and potassium metabisulfite, ammonium sulfite and ammonium bisulfite and sulfur dioxide. Sulfites and metabisulfites of alkaline earth metals such as calcium and barium may also be used. Sulfites and sulfite generating species which produce sodium salts are preferred. The safety of many of these compounds for use in applications such as cosmetic products has been confirmed in, for example, International Journal of Toxicology, 22 (Suppl. 2):63-88, 2003. Sulfites and metabi sulfites of alkaline earth metals such as calcium and barium may also be used.

[0034] In other words, in the compounds of the invention, X is preferably H₅ an alkali metal or ammonium (e.g. NH₄). More preferably, X is an alkali metal (e.g., sodium or potassium). Most preferably, X is sodium.

[0035] The reversible reaction of an aldehyde with a sulfite to form an adduct is a well known reaction and has been used to extract desirable aldehydes into an aqueous phase from an oily phase. Indeed, it has been used in a variety of industrial processes to extract vanillin (see for example U.S. 4,898,990).

[0036] The reaction to produce the compounds of the invention derived from the parent aromachemical can be summarised as follows:

_Ri

^R~

[0037] It will be understood by those skilled in the art that the present invention is applicable to any perfumery aldehyde or ketone, i.e., any aldehyde or ketone aromachemical that has odorant or flavorant utility.

[0038] The present invention is particularly suitable for use with aromachemicals having a relatively high volatility. Typically aromachemicals of this type comprise 12 or fewer carbon atoms. Aromachemicals of this type tend to exhibit a "top note" fragrance. However, the invention is also suitable for use with lower volatility aromachemicals such as the aldehyde musks described hereinbefore.

[0039] Some preferred parent aromachemicals to which the invention can be applied include but are not limited to the aldehydes Trifernal® (3- phenylbutyraldehyde), adoxal; florhydral; hydroxycitronellal; 3,7-dimethyl-6- octen-1-al, 2,4-dimethyl-3-cyclohexenyl-l-carbaldehyde, undecenal, 2-methyl undecanal, 1-nonanal and 1-octanal, the ketones acetophenone, 2-undecanone and 4-methyl-l-phenyl-2-pentanone and mixtures of the foregoing. These compounds are illustrated below.

[0040] Thus, the present invention provides a sulfite adduct of each of these compounds. In other words, some preferred compounds of the invention have the following structures.

[0041] A particularly preferred compound of the invention is the sulfite adduct of Trifernal®. This compound has the formula:

[0042] Preferably, X is sodium; however, it will be appreciated by the skilled artisan that the nature of the counterion is typically not important for function of the present invention, provided that it is organoleptically acceptable.

[0043] By way of example, the sulfite adduct of Trifernal® can be synthesised by adding equimolar amounts of Trifernal® and sodium hydrogen sulfite to water either at room temperature or under gentle heating to 50-60°C. The salt dissolves immediately and the Trifernal® dissolves only as the sulfite adduct is formed. The mixture is stirred until all of the Trifernal® has dissolved. Evaporation or precipitation yields the desired product as a white powder. This reaction is summarised below. NaHSO₃

[0044] Other compounds of the invention may be prepared in directly analogous methods, or by using another suitable organoleptically acceptable sulfating agent.

[0045] The present invention also provides a process for breaking down the compounds of the invention to release the aromachemical on which they are based (the parent aromachemical). This method comprises adding a substance ^■ which will cause an alteration in the pH of a composition containing a compound of the invention so as to increase or decrease the pH of the composition so as to cause the compound of the invention to break down and release the parent aromachemical. For example, this method may comprise adding a substance having a pH which is greater than or less than the pH of the composition containing the compound of the invention to that composition. For example, an acid or base may be added to the composition containing the compound of the invention. Alternatively, a compound that reacts with a component of the composition containing the compound of the invention to induce a change in pH may be added to the composition to cause a change in pH.

[0046] The present invention provides the use of a sulfiting agent for protecting a parent aromachemical (as defined hereinbefore) against decomposition to an undesirable product. Preferably, such a use comprises adding the sulfiting agent to the parent aromachemical to produce a compound or compounds of the invention. In this way, the sulfiting agents may be used to protect the parent aromachemicals, preferably in the form of the compounds of the invention, in hostile media in which they would not normally be stable or in which they may be stable for only a limited time period. Examples of hostile environments include acidic and basic environments. For example the sulfite adduct of Trifernal® is stable in acid while Trifernal® itself is not. Decomposition to an undesirable product includes chemical degradation of the parent aromachemicals, for example by chemical reaction (e.g. oxidation or polymerisation) caused, for example, by oxygen, light, heat, change in pH. In short, the sulfiting agent (and, in turn the sulfite moiety in the compounds of the invention) acts as a protecting group for the aldehyde or ketone moiety of the parent aromachemical.

[0047] The compounds of the invention often have improved acid stability compared with the aromachemicals on which they are based. Thus, the present invention provides for the use of a sulfite adduct of any one of the aromachemicals described above to enable the aromachemical to be introduce into and optionally stored in an acid environment. Thus, the present invention also provides an acidic composition (pH less than 6, preferably less than 4) comprising a compound of the invention, which is stable in an acidic environment.

[0048] It will be appreciated by those skilled in the art that some of the compounds of the invention may have improved stability in basic environments compared to the compounds of which they are based. Thus, the present invention also provides a basic composition (pH greater than 8, preferably less than 10) comprising a compound of the invention, which is stable in a basic environment.

[0049] The compounds of the invention are typically more water soluble than the aromachemicals from which they are derived. The compounds of the invention typically have little or no odor but break down when subjected to an appropriate change in pH to release the parent aromachemical. For example, when a 1% aqueous solution of a compound of the invention (such as the sulfite adduct of Trifernal®) is subjected to an appropriate change in pH (for example an increase in pH to 8 or above), the parent aromachemical, which is typically not soluble in water, comes out of solution and vaporises thus releasing the fragrance of the parent aromachemical (it will be appreciated that the intensity of the fragrance released will depend on a number of factors such as the nature of the aromachemical, it volatility and the temperature).

[0050] Typically, the compounds of the invention are stable at certain pH ranges but are not stable at all pH ranges. When subjected to pH above or below the pH range at which they are stable the compounds of the invention break down and release the aromachemical. The pH range at which the compounds of the invention are stable can readily be determined using methods well known in the art. For example, an aqueous solution at a certain pH may be prepared and then an acid or a base added dropwise until the aroma of the parent aromachemical is detected indicating that the compound of the invention is not stable at the adjusted pH.

[0051] The compounds of the invention can be used as pro-fragrances and/or pro-flavorants to provide the parent aromachemicals from which they are derived.

[0052] As used herein, unless otherwise stated, by the terms "pro- odorant" and "pro-flavorant" we mean compounds which themselves have substantially little or no odor or flavor but degrade over time and/or under certain conditions to provide the odorant or flavorant molecule on which they are based and thus provide the odor or flavor of that parent molecule.

[0053] The present invention also provides a composition comprising one or more compounds of the invention. The compounds and/or compositions of the invention can be included in any products, preparations or articles of manufacture, including those which undergo or are subject to a change or alteration in pH during use. Such products/preparations/articles include kits containing two or more components which are mixed/brought into contact with each other before or during use. Such products, preparations or articles of manufacture may have improved aroma, fragrance or odor characteristics.

[0054] The present invention also provides a method to confer, improve, enhance or modify the taste or flavor property of a composition, product, preparation or article which comprises adding thereto a flavor effective amount of a composition or compound(s) of the invention as described above.

[0055] The compounds of the invention can be included in virtually any article of manufacture that can include the parent aromachemical, or for that matter, other fragrances, whether natural or artificial. Examples include bleach, detergents, flavorings and fragrances, beverages, including alcoholic beverages, and the like. The compounds of the invention can be used in applications like soaps, shampoos, hair dyes, body deodorants and antiperspirants, solid or liquid detergents for treating textiles, fabric softeners, detergent compositions and/or all-purpose cleaners for cleaning dishes or various surfaces, for both household and industrial use. Of course, the use of the compounds is not limited to the above-mentioned products, as they be used in other current uses in perfumery, namely the perfuming of soaps and shower gels, hygiene or hair-care products, as well as of body deodorants, air fresheners and cosmetic preparations, and even in fine perfumery, namely in perfumes and colognes.

[0056] The compounds of the invention also find utility in foods, flavorings, beverages such as beer and soda, denture cleansers (tablets), flavored orally-delivered products such as lozenges, candies, chewing gums, matrices, pharmaceuticals and the like. These uses are described in more detail below.

[0057] In all of the above applications, the compounds of the invention can be used alone, in admixture with each other, or in admixture with other perfuming ingredients, solvents or adjuvants of current use in the art. The nature and the variety of these co-ingredients do not require a more detailed description here, which, moreover, would not be exhaustive, and the person skilled in the art will be able to choose the latter through its general knowledge and as a function of the nature of the product to be perfumed and of the desired olfactive effect.

[0058] These perfuming ingredients typically belong to chemical classes as varied as alcohols, aldehydes, ketones, esters, ethers, acetates, nitrites, terpene hydrocarbons, sulfur- and nitrogen containing heterocyclic compounds, as well as essential oils of natural or synthetic origin. A large number of these ingredients described in reference textbooks such as the book of S. Arctander, Perfume and Flavor Chemicals, 1969, Montclair, N.J., USA or its more recent versions, or in other works of similar nature.

[0059] The proportions in which the compounds of the invention can be incorporated in the various products vary within a large range of values. These values depend on the nature of the article or product that one desires to perfume and the odor effect searched for, as well as on the nature of the co -ingredients in a given composition when the compounds are used in admixture with perfuming co-ingredients, solvents or adjuvants of current use in the art. These values will also depend upon the extent and speed at which the compound(s) of the invention is broken down to its parent aromachemical.

[0060] As an example, the compounds of the invention are typically present at concentrations between about 0.1 and about 10%, or even more, by weight of these compounds relative to the weight of the perfuming composition in which they are incorporated. Higher concentrations than those mentioned above (e.g. greater than 20%, 30%, 40%, 50% up to about 80% by weight) can be used when the compounds of the invention are broken down slowly over time, releasing the parent aromachemical gradually.

[0061] The compounds may be used in detergents containing bleaching agents and activators such as, for example, tetraacetylethylenediamine (TAED), hypohalites, in particular hypochlorite, peroxygenated bleaching agents such as, for example, perborates, etc. The compounds can also be used in body deodorants and antiperspirants, for example, those containing aluminum salts.

[0062] In addition to the compounds of the invention, the compositions herein may include a detersive surfactant and optionally one or more additional detergent ingredients, including materials for assisting or enhancing cleaning performance, treatment of the substrate to be cleaned, or to modify the aesthetics of the detergent composition (e.g., perfumes, colorants, dyes, etc.). Non-limiting examples of synthetic detersive surfactants useful herein typically at levels from about 0.5% to about 90%, by weight, include the conventional Ci_-18 alkyl benzene sulfonates ("LAS") and primary, branch-chain and random Ci_O-20 alkyl sulfates ("AS"), and the like. Preferred compositions incorporating only synthetic detergents have a detergent level of from about 0.5% to 50%. Compositions containing soap preferably comprise from about 10% to about 90% soap.

[0063] The compositions described herein can contain other ingredients such as pH adjusting agents, enzymes, bleaches, fabric softening agents, dye transfer inhibitors, suds suppressors, and chelating agents, all well known within the art.

[0064] The compounds of the invention can be incorporated into beverages and impart various flavorings to the beverages. The beverage composition can be a cola beverage composition, and can also be coffee, tea, dairy beverage, fruit juice drink, orange drink, lemon-lime drink, beer, malt beverages, or other flavored beverage. The beverages can be in liquid or powdered form. The beverage compositions can also include one or more flavoring agents; artificial colorants; vitamin additives; preservatives; caffeine additives; water; acidulants; thickeners; buffering agents; emulsifiers; and/or fruit juice concentrates.

[0065] Flavored food and pharmaceutical compositions including one or more of the compounds of the invention can also be prepared. The compounds of the invention can be incorporated into conventional foodstuffs using techniques well known to those of skill in the art. Alternatively, the compounds can be incorporated within polymeric particles, which can, in turn, be dispersed within and/or over a surface of an orally-deliverable matrix material, which is usually a solid or semi-solid substrate. When used in chewable compositions, the compounds of the invention can be released into the orally-deliverable polymeric matrix material as the composition is chewed and held in the mouth, thus prolonging the flavor of the composition. In the case of dried powders and mixes, the flavor can be made available as the product is consumed or be released into the matrix material as the composition is further processed. When two flavors are combined with the polymeric particles, the relative amounts of the additives can be selected to provide simultaneous release and exhaustion of the compounds.

[0066] Flavored compositions of the invention may include an orally-deliverable matrix material; a plurality of water insoluble polymeric particles dispersed in the orally-deliverable matrix material, where the polymeric particles individually define networks of internal pores and are non-degradable in the digestive tract; and one or more compounds of the invention entrapped within the internal pore networks. The compounds of the invention are released as the matrix is chewed, dissolved in the mouth, or undergoes further processing selected from the group consisting of liquid addition, dry blending, stirring, mixing, heating, baking, and cooking. The orally-deliverable matrix material can be selected from the group consisting of gums, latex materials, crystallized sugars, amorphous sugars, fondants, nougats, jams, jellies, pastes, powders, dry blends, dehydrated food mixes, baked goods, batters, doughs, tablets, and lozenges.

[0067] A flavorless gum base can be combined with a compound or a mixture of compounds of the invention to a desired flavor concentration. In one method for producing such gum based products a blade mixer is heated to about 110 ⁰F, the gum base is preheated so that it is softened, and the gum base is then added to the mixer and allowed to mix for approximately 30 seconds. The compound or compounds of the invention are then added to the mixer and mixed for a suitable amount of time. The gum can be then removed from the mixer and rolled to stick thickness on waxed paper while warm. [0068] In the flavored food/pharmaceutical/gum compositions described above, the compositions of the invention may break down upon contact with the conditions in the mouth, thus releasing the parent aromachemical.

[0069] In any solid compositions, products, preparations or articles of manufacture described above containing compounds of the invention, the pH of a solution or suspension of such compositions, products, preparations or articles of manufacture (e.g. in the case of detergent tablets, soap, or the like) may be such in use (or may be adjusted in use) so as to break down the compound of the invention to its parent aromachemical.

[0070] For simplicity and by way of example, we refer often hereinafter to the compound of the invention derived from Trifernal® (eg l-hydroxy-3- phenylbutane-1 -sulfonic acid sodium salt). However, the skilled person will appreciate that the following description may be applied to any compound of the invention.

[0071] Trifernal® sulfonic acid sodium salt is stable at pHs of about 7.5 and below (for example it is stable at pH 7) but when the pH is increased to 8 or above the sulfonic acid salt breaks down and releases Trifernal® which has a powerful "green" odor.

[0072] In use the Trifernal® sulfonic acid salt may be included in media in which it is stable such neutral and acidic aqueous media. The addition of a base or a substance which reacts with a component of the Trifernal® sulfonic acid salt containing media to increase the pH to 8 or above typically causes the release of Trifernal®.

[0073] The pH of the composition/component in which a compound or mixture of compounds of the invention are included will typically be selected to promote long term storage stability of the composition/compound but also to allow for the pH to be increased or decreased to the level necessary to release the parent aromachemical(s). The pH of the composition/component in which a compound or mixture of compounds of the invention are included may be a pH at which the parent aromachemical(s) are not themselves stable. [0074] One area in which the Trifernal® sulfonic acid salt or other compounds of, the invention may be used is in the production of permanent hair dye compositions and kits as explained in more detail below.

[0075] The two main ingredients in any hair coloring process are hydrogen peroxide (also known as the developer or oxidising agent) and ammonia (often in the form of ammonium hydroxide), which allows for lightening by acting as a catalyst when the hair colour comes together with the peroxide.

[0076] In many hair dye products the smell of ammonia during use can be very intense. Much work has been done in the past to try to reduce/mask this smell but with only limited success.

[0077] Typical hair dye kits comprise two main components, a colour component comprising ammonia and a developer component comprising hydrogen peroxide. These components are typically mixed together before or during use. Many fragrances are unstable in the colour component or do not have a sufficiently intense odor to sufficiently mask the smell of ammonia. However, the inclusion of a fragrance in the developer component is also difficult. This is because some aromachemicals are not stable when stored in the hydrogen peroxide containing environment. Alternatively, the odor of other aromachemicals when contained in the developer component in an amount sufficient to potentially mask the smell of the ammonia when mixed with the colour component may typically be too intense.

[0078] The compounds of the invention can be used to address these problems.

[0079] For example, compounds of the invention which are stable in neutral and/or acid environments but which break down in an alkali environment to release the aromachemical are potentially useful. More particularly, sulfite salts which are stable in the developer component but break down due to the increase in pH when the developer is added to the colour component may be included in the developer.

[0080] Mixing of the developer and the colour component before or during use results in an increase in the pH of the developer. By careful selection of the compound of the invention used, mixing of the developer and the colour component can cause the break down of the compound of the invention and the release of the parent aromachemical. Thus, the fragrance of the parent aromachemical at least in part masks the smell of the ammonia.

[0081] As discussed above the compounds of the invention typically have little or no odor of their own. Thus, the inclusion of an amount of a compound of the invention such as a sulfite adduct of Trifernal® which is sufficient to release enough of the parent compound to at least partially mask the smell of ammonia in the developer component does not result in the developer component having an overly intense fragrance.

[0082] The present invention provides a kit of parts for dying (human) hair which comprises (i) a "color" component comprising ammonia (e.g. in the form of ammonium hydroxide) and (ii) a "developer" component comprising hydrogen peroxide and a compound of the present invention (such as a sulfonic acid salt of Trifernal® e.g., l-hydroxy-3-phenylbutane-l -sulfonic acid sodium salt). The kit may also comprise (iii) a conditioning component.

[0083] Each of the components of the kit of parts for dying hair according to the present invention may also contains other ingredients known to those skilled in the art for inclusion in hair dye products. Typical ingredients include, but are not limited to, water, surfactants (e.g., deceth-3, laureth-12, oleth- 30, trideceth-2, polyquaternium-37), emollients (e.g. glycerin), moisturisers, alcohols (e.g. oleyl and cetearyl alcohol, aminophenol), oils (e.g. wheat germ or jojoba seed oil), preservatives (e.g. methylparaben, ascorbic acid), stabilisers, fragrances (e.g. linalool, limonene, citronellol) and antibacterials (e.g. chlorhexidine dichloride).

[0084] It will be appreciated that the compounds of the invention can be used in any other compositions, products, articles, preparations or kits in which the release of a flavor or fragrance on a change in pH may be desirable, such as other cosmetic products, and food or beverage products as described hereinbefore.

[0085] The invention is illustrated by the following non-limiting examples.

Example 1: preparation of l-hydroxy-3-phenylbutane-l -sulfonic acid sodium salt (Trifernal® sulfonic acid sodium salt). [0086] Equimolar amounts of Trifernal® and sodium hydrogen sulfite were added to water and stirred at room temperature until the Trifernal® had completely dissolved. The water was removed in vacuo and the Trifernal® sulfonic acid sodium salt was obtained as a white powder.

Example 2: stability test of Trifernal® sulfonic acid sodium salt on reduction of pH.

[0087] A 1% solution of Trifernal® sulfonic acid sodium salt in 50 mL of a phosphate buffer having a pH . of about 7 was prepared. To this stirred solution at room temperature was added about 100 μL IM HCl dropwise, with an interval of about 30 seconds between each drop until the pH of the solution was about 2. Even at pH 2 no smell of Trifernal® was detected, indicating that the compound produced in Example 1 is stable in an acid environment of pH 2 or greater.

Example 3: stability test of Trifernal® sulfonic acid sodium salt on increasing the pH.

[0088] A 1% solution of Trifernal® sulfonic acid sodium salt in 50 mL of a phosphate buffer having a pH of about 7 was prepared. To this stirred solution at room temperature was added about 100 μL IM NaOH dropwise, with an interval of about 30 seconds between each drop. When the pH reached 8 to 8.5, a very intense aroma of Trifernal® was detected, indicating that the Trifernal® sulfonic acid sodium salt is not stable in alkali media.

Claims

1. A compound having the formula:

wherein R is a residue of an aromachemical, R = H or a residue of an aromachemical and X is an organoleptically acceptable counterion.

2. A compound according to claim 1, wherein

(i) R¹ is -C(R⁶)=CR³R⁴, R² is H or R⁷, wherein R³, R⁴, R⁶ and R⁷ represent, independently, H, linear or branched or cyclic Cj_-12 alkyl, alkenyl or alkoxy, substituted linear or branched or cyclic C_1- _J2 alkyl, alkenyl or alkoxy, substituted or unsubstituted aryl, and any substituents are selected from halo, hydroxyl, thiol, thioether, amine, carboxylic acid, ester, nitro, cyano, isocyano, sulfonic acid, urea and thiourea;

(ii) R¹ is R⁹ and R² is R¹⁰, wherein R⁹ and R¹⁰ represent, independently, linear or branched or cyclic C_1-J2 alkyl, alkenyl or alkoxy, substituted linear or branched or cyclic C]_-J2 alkyl, alkenyl or alkoxy, substituted or unsubstituted aryl, additionally R¹⁰ may be H independent of the nature of R⁹, and any substituents are selected from halo, hydroxyl, thiol, thioether, amine, carboxylic acid, ester, nitro, cyano, isocyano, sulfonic acid, urea and thiourea;

(iii) R¹ and R² together form a 5 or 6 membered cyclic group, optionally containing an O and optionally substituted by a group R¹²; wherein R¹² is an optionally substituted straight chain or branched C]-J₀ alkyl, alkenyl or alkoxy, and any substituent is selected from halo, hydroxyl, thiol, thioether, amine, carboxylic acid, ester, nitro, cyano, isocyano, sulfonic acid, urea and thiourea; or

(iv) R¹ is a six membered aromatic ring substituted with one or more groups R¹³, and R² is H, wherein the or each R¹³ is independently a straight or branched chain Ci_-8 alkyl, alkenyl or alkoxy or two groups R¹³ together with the carbon atoms to which they are attached form a five or six membered ring which may be saturated or unsaturated (including aromatic), and which is optionally substituted with from 1 to 3 straight chained or branched C_1-6 alkyl groups; and wherein one or more groups R¹³ is optionally substituted by halo, hydroxyl, thiol, thioether, amine, carboxylic acid, ester, nitro, cyano, isocyano, sulfonic acid, urea or thiourea.

3. A compound according to claim 1 wherein:

R¹ is Ci-)_O alkyl, a cyclic or acyclic C]_-I0 alkenyl or aryl, each of which is optionally substituted by 1, 2, 3, 4 or 5 substituents selected from linear or branched Ci_-4 alkyl, hydroxyl, unsubstituted aryl or aryl substituted by a Cj_-4 alkyl;

R₂ is H or linear or branched C]_-4 alkyl; and

X is H, an alkali metal or ammonium.

4. A compound according to claim 1 selected from:

5. A compound according to claim 1 having the formula:

6. A compound according to claim 1 wherein X is an alkali metal.

7. A compound according to claim 1 wherein X is sodium.

8. A method of preparing a compound according to claim 1, the method comprising reacting a parent aromachemical of formula:

with an organoleptically acceptable sulfiting agent, wherein R¹ and R² are as defined in claim 1.

9. A method according to claim 8 wherein the parent aromachemical is selected from:

10. A method according to claim 8 wherein the parent aromachemical is:

11. A method according to any of claim 8 wherein X is an alkali metal.

12. A method according to claim 11 wherein X is sodium.

13. A composition comprising a compound or mixture of compounds according to claim 1 and a suitable carrier or diluent, said compound or mixture of compounds being present in an amount effective to provide predetermined organoleptic properties when added to a substrate and subjected to conditions which release the aromachemical.

14. A product, preparation or article comprising (i) one or more compounds according to claim 1 and a suitable carrier or diluent or (ii) a composition according to claim 13.

15. A kit of parts comprising at least two separately contained components wherein one component comprises one or more compounds according to claim 1 or a composition according to claim 13 or a product, preparation or article according to claim 14.

16. A process for breaking down a compound or mixture of compounds according to claim 1 to release one or more parent aromachemicals, the process comprising subjecting the compound or mixture of compounds to conditions in which the compound or compounds is/are unstable.

I

17. A process according to claim 16, wherein the compound or mixture of compounds is in the form of a composition according to claim 13, a product, preparation or article according to claim 14 or a kit of parts according to claim 15.

18. A process according to claim 16 comprising adding a substance to the compound, composition, product, preparation, article or component of the kit which alters the pH of the compound, composition, product, preparation, article or component of the kit, thereby causing the compound or mixture of compounds to at least partially break down and release the or each parent aromachemical.

19. A process according to claim 18 comprising adding an acid or base.

20. A process according to claim 19 comprising adding a base.

21. A kit of parts for use in hair coloring comprising at least two separately contained components wherein the first component comprises a compound or mixture of compounds according to claim 1 or a composition according to claim 13 or a product, preparation or article according to claim 14.

22. A kit according to claim 21 comprising a second component comprising ammonia.

23. A kit according to claim 22 wherein upon mixing of the first component and the second component, at least a portion of the compound or mixture of compounds breaks down to release the parent aromachemical and thus at least partially mask the smell of ammonia.

24. A kit according of claim 22 wherein the ammonia is in the form of ammonium hydroxide.

25. A kit according to claim 21 wherein the first component comprises hydrogen peroxide.

26. A process for imparting a flavor or fragrance to a product, the process comprising adding to the product a compound or mixture of compounds according to claim 1.

27. A process for introducing an aromachemical or mixture of aromachemicals of formula:

wherein R¹ and R² are as defined in claim 1 into a product, which process comprises adding to the product or a precursor of the product a compound or mixture of compounds according to claim 1.

28. A process according to claim 26 or 27, which includes the step of subjecting the compound or mixture of compounds to conditions which cause the compound or mixture of compounds to break down to release the parent aromachemical or mixture of aromachemicals of formula: O

R' R'

29. A process according to claim 28, wherein the step of subjecting the compound or mixture of compounds to conditions which cause the compound or mixture of compounds to break down to release the parent aromachemical(s) comprises subjecting the compound or compounds to acidic or basic conditions.

30. The use of a compound or mixture of compounds according to claim 1 in the manufacture of a product or an article of manufacture.

31. The use of a compound or mixture of compounds according to claim 1 as a profragrance and/or proflavorant.

32. The use of a compound or mixture of compounds according to claim 1 to provide an aromachemical or mixture of aromachemicals of formula:

O

R¹^R² to a product or article of manufacture.

33. In a method for imparting a fragrance or flavor to a product, the method comprising adding to the product a flavor or fragrance effective amount of a compound or mixture of compounds of formula:

wherein R¹ and R² are as defined in claim 1, the improvement comprising substituting for said compound or said mixture of compounds one or more compounds according claim 1.

34. A method according to claim 33, which includes the step of subjecting the compound or compounds to conditions which cause those compounds to break down to release one or more compounds of the formula:

35. A method according to claim 34, wherein the step of subjecting the compound or compounds to conditions which cause those compounds to break down to release the parent aromachemical comprises subjecting the compound or compounds to acidic or basic conditions.

36. The use of a sulfiting agent for protecting a parent aromachemical having the formula

wherein R¹ and R² are as defined in any one of claims 1 to 5, against decomposition of the parent aromachemical to an undesirable product.

37. The use according to claim 36, comprising adding the sulfiting agent to the parent aromachemical to produce a compound or compounds according to claim 1.

38. The use according to claim 36 wherein decomposition to an undesirable product comprises chemical degradation of the parent aromachemical.