Perfume compositions – Perfume compositions
Reexamination Certificate
2000-11-28
2002-06-25
Dees, Jose′ G. (Department: 1616)
Perfume compositions
Perfume compositions
C424S065000, C424S070100, C424S401000, C510S119000, C510S130000, C510S135000, C510S102000, C510S158000, C510S159000, C510S276000, C512S006000, C514S530000, C514S844000
Reexamination Certificate
active
06410504
ABSTRACT:
BRIEF SUMMARY OF THE INVENTION
The present invention relates to the field of perfumery. It concerns, more particularly, the compounds of formula
wherein X represents a C≡N group or a C(H)═O group and the C
5
-ring is either saturated or carries a double bond in one of the positions indicated by the dotted lines, or any mixture of two or more compounds of formula (I), and their use in perfumery.
BACKGROUND OF THE INVENTION
The compounds as defined by the above formula (I) are novel compounds, and their use in perfumery has never been described or suggested. They carry an aldehyde function or a nitrile function and all have a characteristic, green-lemon type odor which is of considerable value in perfumery.
One embodiment of the invention is drawn to the compounds of the above formula (I) in which X is a C≡N group, i.e. belonging to the nitrile chemical family, which are particularly appropriate for use in aggressive media. A further embodiment are the corresponding aldehydes of similar chemical structure which show the same odor type as the said nitriles.
It should be mentioned that a large number of compounds belonging to the nitrile chemical family are known in the perfume industry. In the context of the present invention, one can cite the nitrites specified hereinafter, which are currently used in perfumery, in particular in functional perfumery.
Geranyl nitrile (3,7-dimethyl-2,6-octadienenitrile) possesses a strong green, chemical odor resembling that of citral (Z-3,7-dimethyl-2,6-octadienal), the latter being itself a compound of widespread use in perfumery applications and of natural occurrence.
Citronellyl nitrile (3,7-dimethyl-6-octenenitrile) shows an olfactive note reminiscent of the odor of lemon, with an undernote characteristic of the nitrites. The citrus note is likewise quite pronounced in Ozonil® (mixture of 2-tridecenenitrile and 3-tridecenenitrile; origin: Haarmann & Reimer, Germany), but there are also present notes of the mandarine-fruity, peach type, which are associated with a floral undernote.
Finally, citronitrile (3-methyl-5-phenyl-2-pentenenitrile) shows an odor of the same type as the compounds mentioned beforehand, namely of the fruity-citrus type.
Detergents, deodorants or antiperspirants and soaps are examples of products which are aggressive media, in which citral, for example, which can be considered as the typical compound representing the citrus-type odor, with its powerful citrus-green note, is unstable, preventing it from being used in functional perfumery, and this in spite of its odor which is very prized by perfumers.
Now, in spite of showing olfactive similarities with citral, the known nitrites described above do not possess its olfactive quality. Their odor notes are less characteristic of lemon, less fresh-citrus, and a fatty-metallic connotation is found in all these nitrites. For these reasons, the search for nitrites stable in aggressive media and possessing an odor close to the citrus-green note of the odor of citral continues to be a task of actuality.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides novel compounds having this desired odor and brings an original solution to exactly this problem.
We have in fact found that, in particular, the compounds of formula
having a double bond in one of the positions indicated by the dotted lines, or any mixture of two or more of these compounds, not only possess an excellent stability in aggressive media, but also an odor which is very similar to that of citral.
Thus, the odor of the compounds of formula (I′), or of the mixtures of these, possess the same fresh-citrus connotation as citral, quite unexpected for a nitrile. There is also found a green connotation reminiscent of lime, and the compounds of the invention do not have the fatty-metallic connotation generally found in nitrites of current use in perfumery (see above for current examples). Generally speaking, the odor of the compounds of the invention is very fresh and clean.
According to the invention, it is preferred to use as perfuming ingredient, a mixture of the compounds of formula (I′) containing at least about 30% by weight of the compound of formula
Even more preferred are the above-mentioned mixtures containing, besides the compound (I′a) in the specified amount, about 60% by weight of the compound of formula
having an endocyclic double bond in position 3′ of the ring.
According to an even more preferred embodiment of the invention, there will be used a compound of formula (I′a) in its pure state, representing at its best the fresh-citrus, green-lime note of citral.
It has however been found that the above-mentioned olfactive characteristics are also present in the mixtures as specified above, satisfactory for the perfumers' criteria and thus the said mixtures are also useful as perfuming ingredients. The advantage of the use of these mixtures, compared to that of the compounds contained therein in their pure state is an economical one, given the fact that these mixtures can be directly obtained from the synthesis described below, without requiring the use of particular separation techniques.
The nitrites of the present invention are accessible by a multi-stage synthesis which makes use of 3-isopropenyl-1,2-dimethyl-1-cyclopentanol, or one of its optically active isomers, as starting product. This cyclic alcohol is a commercially available compound, formed in the pyrolysis reaction of (−)-R-linalool and leading to a mixture of four diastereomers (see H. Strickler, G. Ohioff and E.sz.Kovàts, HelV. Chim. Acta 1967 50, 759).
The synthesis we have developed for the nitrites of formula (I) is outlined in the scheme below:
The first step of this synthesis comprises the hydroformylation of the cyclic starting alcohol, to form the corresponding aldehyde. The hydroformylation reaction being known to a person skilled in the art, the latter can choose the appropriate reaction conditions, for example the catalyst, solvent or pressure giving good results, without a more detailed description being necessary here.
The thus-obtained aldehyde is then transformed into the corresponding nitrile, for example by using hydroxylamine or a salt thereof, in the presence of a base. In the following step, the compound obtained is esterified with a current esterifying agent, for example acetic anhydride. It was found to be advantageous not to isolate the above-mentioned intermediate nitrile from the reaction mixture, but to directly esterify said nitrile in the same medium in which it had been prepared.
The last step of the process is the elimination reaction of the thus-obtained ester (II), preferably of 3-(2′-cyano-1-methylethyl)-1,2-dimethyl-1-cyclopentyl acetate, leading to the desired final product, namely the unsaturated nitrites of formulae (I′a) and (I′b). The elimination reaction can be carried out under various conditions which are known to a person skilled in the art. In this context, one should mention the use of an acid, for example p-toluenesulfonic acid, to carry out the elimination reaction.
The best results were however obtained by a thermal treatment, i.e. a pyrolysis of the nitrile ester, resulting in a crude product containing an olfactively satisfactory amount of the most desired nitrile (I′a), whereas the elimination reaction with an acid often results in the preferential formation of nitrites having double bonds in endocyclic position, i.e. those of above formula (I′b) and of formula (I′c) below:
which are less appreciated from an olfactive point of view.
We have found that products containing about 30% by weight of the nitrile of formula (I′a) could be obtained when the pyrolysis reaction was carried out at a temperature range from about 400 to 550° C., preferably from about 430 to 500° C., and under a pressure from about 10 to 50×10
2
Pa. These mixtures contain, besides the compound (I′a), the nitrites of formulae (I′b) and (I′c), with their respective amounts varying accordin
Dees Jose′ G.
Firmenich SA
Lamm Marina
Winston & Strawn
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