Patent Description:
Fragrance compositions are usually blends of volatile individual ingredients, both natural and synthetic, carefully blended by skilled perfumers to bring out an overall desired hedonic character. The individual ingredients are selected to add to this particular desired character.

A very common class of fragrance ingredient is the ester. Esters are found in the essential oils of many plants and are known for their sweet, fruity odor. As a result, they are a popular choice for fragrance compositions. Typical examples of popular fragrance esters include benzyl acetate, bornyl acetate (<NUM>,<NUM>,<NUM>-trimethylbicyclo[<NUM>. <NUM>]heptan-<NUM>-yl acetate), <NUM>-tert-butyl-cyclohexylacetate (Agrumex™) and octahydro-<NUM>,<NUM>-methano-3aH-indene-3a-carboxylic acid, ethyl ester (Fruitate™), and <NUM>,<NUM>-cyclohexadiene-<NUM>-carboxylic acid, <NUM>,<NUM>,<NUM>-trimethyl-, ethyl ester (Ethyl Safranate™). All of these are known to have pleasant, desirable odors.

It has now been found that the addition of a particular ingredient can enhance the desirable characteristics of ester-containing fragrance compositions. There is therefore provided a fragrance composition comprising a blend of fragrance ingredients, at least one of which ingredients is an ester, the composition additionally comprising <NUM> to <NUM>% by weight of ethyl cyclohexanoate.

Ethyl cyclohexanoate, sometimes referred to as ethyl cyclohexyl carboxylate (<NPL>), has an odour described as "fruity, cheesy, winey" in the database of the Good Scents Company, a well-known flavour and fragrance resource. It is known to occur in various natural oils, for example, in virgin olive oil (see, for example, <NPL>) and rum (see <NPL>). However, although known and characterized, it has never been produced as a commercial fragrance material and there is no disclosure of fragrance compositions comprising said compound.

It has been found uniquely to enhance the odour characteristics of esters; it has no perceptibly effect on other class of fragrance ingredients, such as alcohols, ketones or aldehydes.

Moreover, it has been found that, in order to achieve this desirable effect, the proportion of ethyl cyclohexanoate must be used within strict limits - too little, and there will be no enhancing effect, too much and there will be an undesirable "cheesy" odor. The ethyl cyclohexanoate should therefore be used at concentrations <NUM> to <NUM>% by weight, , which includes <NUM> - <NUM>% by weight (e.g., <NUM>% or <NUM>% or <NUM>% by weight), based on the fragrance composition. However the amounts of ethyl cyclohexanoate present in a fragrance composition may vary, depending on the other fragrance ingredients present. In a further aspect of the present invention, the ratio of ethyl cyclohexanoate to ester should be used within strict limits to avoid that the undesirable "cheesy" odor will be recognized. The ethyl cyclohexanoate should therefore be used at a weight ratio of from <NUM> : <NUM>'<NUM>'<NUM> to <NUM> : <NUM>'<NUM> (which includes <NUM> : <NUM>'<NUM>'<NUM> and <NUM> : <NUM>'<NUM>'<NUM> to <NUM> : <NUM>'<NUM>) of the ester component of the fragrance composition (ethyl cyclohexanoate : ester(s)), and wherein the ester is a compound of formula (I)
<CHM>
having a molecular weight of <NUM> to <NUM> and wherein.

There is also provided a method of enhancing the fragrance quality of a fragrance composition containing at least one ester, comprising the addition thereto <NUM> to <NUM>% by weight (e.g. <NUM>, <NUM>, <NUM>, <NUM>, <NUM> % by weight) of ethyl cyclohexanoate.

In a further embodiment there is provided a method of enhancing the odor characteristics of esters, in particular of esters providing fruity odor characteristics. By "enhancing the fruity character" is meant that the addition of ethyl cyclohaxane-carboxylated results odor characteristics which are preserved as more juiciness and more natural overall character. Thus there is provided a method of enhancing the fruity characteristics of esters of formula (I) as herein defined, comprising the step of adding ethyl cyclohexanecarboxylate to a flavor or fragrance composition. For example it enhances the impression of juiciness and ripe fruits such as grapefruit, mango, citrus, orange and the like.

By "enhancing" is meant that the hedonic qualities of the ester, and of the fragrance composition in which it is incorporated, are improved from the point of view of being not only more pleasant, but also more balanced, more natural and/or more intense. The overall hedonic effect is much improved and more desirable, and in general more preferred compared to compositions which are free of ethyl cyclohexanoate.

By "ester" is meant a compound of formula (I)
<CHM>
having a molecular weight of <NUM> to <NUM> (e.g. <NUM> to <NUM>) and wherein.

As used in relation to compounds of formula (I) unless otherwise indicated "hydrocarbon radical" includes linear, branched, mono-, bi- or tri-cyclic alkyl, linear, branched, mono-, bi- or tricyclic alkenyl (comprising one or more double bonds), and aryl, wherein the ring (such as cyclic alkyl, cyclic alkenyl, aryl) is optionally substituted with alkyl.

Non-limiting examples of esters are compounds of formula (I) wherein either R<NUM> or R<NUM> is not alkyl.

Further specific examples of known esters according to formula (I) are: <NUM>-(tert-butyl)cyclohexyl acetate; ethyl <NUM>-methylpentanoate (Manzanate); hexyl salicylate; methyl <NUM>-oxo-<NUM>-pentylcyclopentaneacetate (Hedione); <NUM>-tert-butyl-cyclohexylacetate (Agrumex™); octahydro-<NUM>,<NUM>-methano-3aH-indene-3a-carboxylic acid, ethyl ester (Fruitate™); and <NUM>,<NUM>-cyclohexadiene-<NUM>-carboxylic acid, <NUM>,<NUM>,<NUM>-trimethyl-, ethyl ester (Ethyl Safranate™). Further specific esters according to formula (I) are methyl <NUM>,<NUM>-dihydroxy-<NUM>,<NUM>-dimethylbenzoate (<NPL>); allyl heptanoate (<NPL>; dimethyl benzyl carbinyl acetate (CAS <NUM>-<NUM>-<NUM>); dimethyl benzyl carbinyl butyrate (<NPL>); 3a,<NUM>,<NUM>,<NUM>,<NUM>,7a-hexahydro-<NUM>-<NUM>,<NUM>-methanoinden-<NUM>-yl propionate (<NPL>); and (Z)-hex-<NUM>-en-<NUM>-yl acetate (<NPL>).

The esters may be synthetic ingredients or they may occur in natural fragrance oils. The individual esters present in a known natural fragrance oil can be found by reference to Journals commonly used by those skilled in the art such as "<NPL>" or "<NPL>", or listed in reference texts such as the book by <NPL>).

A fragrance composition as hereinabove described may, in addition to at least one ester, contain any of the other natural or synthetic ingredients known to the art to be useful in fragrance compositions. Non-limiting examples of such compositions include.

Fragrance composition comprising ethyl cyclohexanoate and at least one ester, as hereinabove described, may be used in a broad range of fragranced articles, for example, in any field of fine and functional perfumery, such as perfumes, air care products, household products, laundry products, body care products and cosmetics. The composition can be employed in widely varying amounts, depending upon the specific application and on the nature and quantity of other odorant ingredients. The proportion is typically from <NUM> to <NUM> weight percent of the application. In one embodiment, the composition of the present invention may be employed in a fabric softener or shampoo in an amount of from <NUM> to <NUM> weight per cent (e.g. <NUM> - <NUM> weight %). In another embodiment, the fragrance composition comprising ethyl cyclohexanoate and at least one ester may be used in fine perfumery in amounts of from <NUM> to <NUM> weight per cent (e.g. up to about <NUM> weight per cent). However, these values are given only by way of example, as the experienced perfumer may also achieve effects or may create novel accords with lower or higher concentrations.

Moreover it has been found, that the odor performance is enhanced when a fragranced article comprising a fragrance composition as hereinabove described, is diluted with water. Thus, there is provided as one specific embodiment, the use of a fragrance composition comprising ethyl cyclohexanoate and at least one ester, as hereinabove described, in rinse-off products, such as shampoo, and shower gel, but also in high dilutions in water, like hand wash fabric detergents (liquid or powder) or multi-purpose floor cleaners.

It was also observed that ethyl cyclohexanecarboxylate significantly reduces a perceived malodor, such as kitchen malodor, bathroom malodor, sweet malodor and the like. Thus one may cited as a further example air care products to which ethyl cyclohexanecarboxylate may by admixed.

The fragrance composition as described hereinabove may be employed in a consumer product base simply by directly mixing the fragrance composition with the consumer product base, or it may, in an earlier step, be entrapped with an entrapment material, for example, polymers, capsules, microcapsules and nanocapsules, liposomes, film formers, absorbents such as carbon or zeolites, cyclic oligosaccharides and mixtures thereof.

All percentages and ratios as used herein are by weight unless otherwise indicated.

The invention is now further described with reference to the following non-limiting examples. These examples are for the purpose of illustration only and it is understood that variations and modifications can be made by one skilled in the art.

Cyclohexanecarboxylic acid (<NUM>, <NUM> mol) and p-toluenesulfonic acid (<NUM>, <NUM> mol) in cyclohexane (<NUM>) were heated to <NUM>. Ethanol (<NUM>, <NUM> mol) was added over <NUM> and the reaction mixture was stirred at reflux for an additional <NUM> while the aq. phase was gradually eliminated over time. After cooling the reaction mixture to r. phase was washed with H<NUM>O, <NUM>% aq. Na<NUM>CO<NUM>-solution and H<NUM>O. phase was concentrated and distilled to yield <NUM> (<NUM>%) of ethyl cyclohexanecarboxylate as a colorless oil.

<NUM>H NMR (CDCl<NUM>, <NUM>): δ = <NUM> (q, J = <NUM>, <NUM>), <NUM> (tt, J = <NUM>, <NUM>, <NUM>), <NUM>-<NUM> (m, <NUM>), <NUM>-<NUM> (m, <NUM>), <NUM>-<NUM> (m, <NUM>), <NUM>-<NUM> (m, <NUM>), <NUM>-<NUM> (m, <NUM>), <NUM> (t, J = <NUM>, <NUM>) ppm.

<NUM>C-NMR (CDCl<NUM>, <NUM>): δ = <NUM> (s), <NUM> (t), <NUM> (d), <NUM> (2t), <NUM> (t), <NUM> (2t), <NUM> (q) ppm.

MS (El, tR = <NUM>): <NUM> (<NUM>, [M]+·), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>).

The two alcoholic solutions above were mixt at a ratio of <NUM>:<NUM>.

Both, solution B alone and the mixture of A+B was olfactively evaluated in a triangular test on a blotter in a randomized order. The trained panel was asked to describe the olfactory difference, if any. The results are summarized in Table <NUM> below.

As can be seen from the results above, the addition of ethyl cyclohexanoate to a fragrant ester results in a more pleasant, more balanced, more natural and/or more intense composition which is more preferred compared to the esters alone. On the other hand, such a benefit was not observed when ethyl cyclohexanoate was added to a fragrant aldehyde, ketone or alcohol.

Ethyl cyclohexanoate (A) was evaluated on blotter in combination with several odorant esters as indicated at different concentrations.

The fragrance accord comprising <NUM> weight % of esters according to formula (I) and a variable amount of ethyl cyclohexanoate (A) in DPG as indicated in Table <NUM>, first column, was assessed by a trained panel neat (on a blotter), in a shampoo (fragrance accord @ <NUM> weight %), and in a shampoo (fragrance accord @ <NUM> weight %) diluted with water. The results are given in Table <NUM> below.

Claim 1:
A fragrance composition comprising <NUM> to <NUM> weight % ethyl cyclohexanecarboxylate and at least one odorant ester, and wherein the weight ratio between ethyl cyclohexanecarboxylate and the at least one odorant ester is from <NUM> : <NUM>'<NUM>'<NUM> to <NUM> : <NUM>'<NUM> (ethyl cyclohexanecarboxylate : ester) and wherein the odorant ester is a compound of formula (I)
<CHM>
having a molecular weight of <NUM> to <NUM> and wherein
i) R<NUM> is selected from methyl, ethyl, C<NUM> to C<NUM> alkyl, and C<NUM> to C<NUM> alkenyl, and
R<NUM> is a hydrocarbon radical containing <NUM>-<NUM> C-atoms, optionally comprising one, two, or three functional groups selected from -OH, -C(O), and -O-; or
ii) R<NUM> is a hydrocarbon radical containing <NUM> to <NUM> C-atoms , optionally comprising one, two, or three functional groups selected from -OH, -C(O), and -O-, and R<NUM> is selected from methyl, ethyl, C<NUM> to C<NUM> alkyl, and C<NUM> to C<NUM> alkeny.