Campholenic tertiary alcohol and its use as a perfuming ingredient

1,2-Dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol is useful as a perfuming ingredient, for the preparation of perfuming compositions and perfumed articles to which it imparts woody-sandalwood type odor notes.

BRIEF DESCRIPTION OF THE INVENTION 
An object of the present invention is to provide 
1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol 
. 
According to particular embodiments of the invention, the above-mentioned 
compound is provided in the form of an optically active isomer selected 
from the group consisting of: 
a) 
(-)-(1'R)-cis-1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-c 
yclohexen-1-ol; 
b) 
(-)-(1'R)-trans-1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2 
-cyclohexen-1-ol; 
c) 
(+)-(1'S)-cis-1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-c 
yclohexen-1-ol, and 
d) 
(+)-(1'S)-trans-1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2 
-cyclohexen-1-ol; or of an optically active mixture of two or more of said 
isomers. 
Another object of the invention is a method to confer, improve, enhance or 
modify the odor properties of a perfuming composition or a perfumed 
article, which method comprises adding to said composition or article a 
fragrance effective amount of 
1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol 
. 
The invention further concerns a perfuming composition or a perfumed 
article containing as an active perfuming ingredient 
1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol 
. 
Finally, the invention also relates to a process for the preparation of 
1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol 
, comprising the reaction of 
2-methyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-one 
with an appropriate Grignard reagent, under the conditions of a Grignard 
type reaction. 
BACKGROUND OF THE INVENTION 
The present invention relates to novel compounds which possess useful odor 
properties and, more particularly, it concerns a tertiary alcohol derived 
from campholenic aldehyde and the odor of which is of the sandalwood type. 
The prior art in perfumery is rich in examples of compounds having a 
sandalwood odor. Nevertheless, the sandalwood-type odor still constitutes 
a fragrance field wherein the reasearch of new compounds remains very 
active. This results from the fact that natural sandalwood essential oil 
is a much appreciated perfuming ingredient, but very expensive and 
available in limited quantities. In addition, the reproduction of the odor 
of the natural ingredient is extremely difficult, even by admixture of 
known synthetic products. It is, in fact, observed that every prior art 
compound which is capable of imparting a sandalwood note to the 
compositions into which it is incorporated, only provides, on its own, a 
contribution towards the reproduction of one or the other of the 
particular characters of natural sandalwood oil, and this only to a 
certain extent. None of these compounds possesses an odor identical to 
that of any other and each of them can find a very specific use in 
perfumery, thus enriching the perfumer's palette in the domain of the 
sandalwood notes. 
On the other hand, in spite of the rules established by a variety of 
researchers in order to define the relationship between the molecular 
structure and the sandalwood-type odor of the known compounds, rules 
designed to provide useful tools towards predicting the olfactive 
qualities of novel compounds on the basis of their molecular structure 
[see, for example, E. J. Brunke and E. Klein, Essential Oils, Ed. B. D. 
Mookherjee and C. J. Mussinan, page 83 and following, Allured Publishing 
Corp. (1981); R. E. Naipawer et al., ibid., page 105 and following; J. G. 
Witteveen et al., Recl. Trav. Chim. Pays-Bas 106, 29 (1987)], there can be 
no doubt that such rules establish structural requirements that, while 
seemingly essential, are by no means sufficient to make it possible to 
predict that a given molecular structure will imply, with certainty, a 
sandalwood odor, or, moreover, an odor of desirable quality, intensity and 
tenacity [see for example, J. G. Witteveen, cited reference, or yet, U.S. 
Pat. No. 4,501,341]. 
Therefore, the search for new compounds with sandalwood odor is evermore of 
actuality and the number of patents granted heretofore in this field, 
patents which recognize not only the novelty but also the inventive step 
of compounds whose structure is sometimes almost identical to that of 
prior known compounds, is a sure measure of the importance assigned to the 
discovery of new compounds of this type, the odor properties of which are 
undoubtedly advantageous over those of the previously described compounds. 
The present invention provides a new solution to this problem. 
THE INVENTION 
The invention concerns, more particularly, a tertiary alcohol which is a 
derivative of campholenic aldehyde, i.e. 
1,2-dimethyl-4-(2',2',3'-trimethyl3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol. 
It has been discovered that this compound possesses a powerful woody note, 
with a clear, very neat, sandalwood character which develops itself to 
become more powerful in the bottom note. It is, in fact, a very original 
note of excellent tenacity and which is also more powerful than that of 
most of the woody-sandalwood type compounds presently available on the 
market. 
For example, when compared to 
(1'R,E)-3,3-dimethyl-5-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-4-penten- 
2-ol, a product well appreciated by the perfumers and which is judged 
superior to many other commercial products with sandalwood odor [see, for 
example, EP 0 155 591], the compound of the present invention turns out to 
be of an easier use in composition, namely in fine perfumery applications. 
This results from the fact that, while possessing a slightly less powerful 
note than that of the cited known compound, the compound of the invention 
develops a cleaner and more natural sandalwood odor, which is also less 
animal than that of the cited prior art compound. 
This olfactive superiority of 
1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol 
is totally surprising and unexpected if one considers its molecular 
structure. In fact, notwithstanding the high number of known sandalwood 
compounds which have a campholenic sub-structure, they are mostly primary 
or secondary alcohol derivatives of campholenic aldehyde and, to our 
knowledge, only two prior art documents disclose tertiary alcohols having 
useful odor properties [see U.S. Pat. No. 4,149,020 and U.S. Pat. No. 
4,174,287], said tertiary alcohols being open chain campholenic 
derivatives. 
When one analyzes the literature related to the compounds whose structure 
is closer to that of the compound according to the invention, i.e. whose 
structure is bicyclic, one realizes then that there are no examples of 
olfactively useful tertiary alcohols, in spite of the number of compounds 
disclosed. In this context, one can cite for example U.S. Pat. No. 
4,173,585 which describes, amongst others, a mixture of compounds of 
formula 
##STR1## 
having a double bond in one of the positions indicated by the dotted 
lines, and a mixture of compounds of formula 
##STR2## 
wherein the dotted lines have the meaning indicated above. These two 
mixtures possess, respectively, a woody-sandalwood odor, with a 
"cyclamal/Lilial.RTM." character, and a sweet cedarwood, sandalwood odor. 
German patent DE 29 35 683 describes compounds of formula 
##STR3## 
wherein symbol R represents a cyclic group of formula 
##STR4## 
which can have an endocyclic double bond in the position indicated by the 
dotted line and wherein the exocyclic dotted line stands for a single 
bond, when X represents OH, or a double bond, X representing then an 
oxygen atom, and symbols R.sup.1, R.sup.2 and R.sup.3 represent a hydrogen 
atom or a lower alkyl radical, or R represents a cyclic group of formula 
##STR5## 
wherein the dotted lines and symbol X are defined as above. The compounds 
of formula (II) possess sandalwood notes of varied strength and character. 
1,2-Dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol 
according to the present invention belongs to a group of compounds whose 
molecular structure is more rigid than that of the cited known compounds 
of formula (I) or (II), while maintaining the distance which is judged to 
be optimum between the quaternary carbon atom 2' and the functional group 
1. These are compounds that can be represented by the following basic 
skeleton 
##STR6## 
which can have a double bond in one of the endocyclic positions indicated 
by the dotted lines, the exocyclic dotted line representing a single bond 
when X is an OH radical and a double bond when X represents an oxygen 
atom. The six-membered ring may possess ore or more substituent methyl 
groups in positions a, b, c and d. 
In view of the prior art, one might have expected that the increased 
rigidity of the cyclic chain containing the functional group would have 
had a more or less uniform effect over a group of compounds having the 
same basic skeleton (III) and that it would have brought about, by 
reducing the number of possible conformations of said cyclic chain, an 
improvement in the olfactive properties, relative to those of the known 
compounds. Yet, we have now discovered that, unlike what could have been 
predicted, amongst a good number of compounds having structure (III), some 
of which are reported here, only 
1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol 
possesses odor properties which are superior to those of the known 
compounds and an odor whose character best resembles that of natural 
sandalwood. As can be seen in the table presented hereinafter, there are 
other compounds with structure (III) which have sandalwood-type notes, but 
which are either too weak, or qualitatively less useful. 
TABLE I 
__________________________________________________________________________ 
Compounds Odor properties 
__________________________________________________________________________ 
##STR7## cumin, animal, woody, slightly sandalwood 
##STR8## sesquiterpenes, fruity, weak 
##STR9## woody, floral, sandalwood, vague 
##STR10## woody-weak, very slightly sandalwood, fruity 
##STR11## woody, phenolic, leather, slightly sandalwood 
##STR12## slightly sandalwood, weak 
##STR13## weak 
##STR14## weak, floral, dirty 
##STR15## floral, woody, vaguely sandalwood, weak 
##STR16## iris, slightly sandalwood 
##STR17## weak, vaguely floral, very vaguely sandalwood 
##STR18## woody, vaguely sandalwood 
__________________________________________________________________________ 
In view of this table, the olfactive quality of the compound of the 
invention is all the more surprising, since compounds having an almost 
identical structure exhibit olfactive characters which are not very 
distinctive, are too weak or which do not contain the desired sandalwood 
note. 
This was also observed when the odor properties of the instant compound 
were compared with those of known compounds, having a close structure, and 
obeying formulae (Ib) and (II) previously cited. For example, 
(-)-(1'R)-2-[2-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)ethylidene]-1-cycl 
ohexanol of formula 
##STR19## 
which was prepared as described in U.S. Pat. No. 4,173,585, but from a 
pure optically active starting product, possesses a weakly woody, resinous 
odor, with a very slight, sandalwood character. Likewise, 
(+)-(1'S)-3-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)methyl-1-cyclohexanol 
and 
(+)-(1'R)-4-methyl-3-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)methyl-1-cyc 
lohexanol of formula 
##STR20## 
obtained according to DE 29 35 683 but using pure optically active 
starting products, turned out to have a vaguely woody-sandalwood odor, 
without character and, respectively a vaguely sandalwood odor, even weaker 
than that of the preceding one. 
As a result of its olfactive properties, 
1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol 
is particularly advantageous for fine perfumery applications, for the 
preparation of perfumes and colognes of varied nature, namely of the 
woody-floral-oriental type, compositions to which it imparts a clear 
sandalwood character, while exalting the floral and animal aspect of the 
composition. 
The tenacity of its odor note renders the compound of the invention equally 
useful in technical perfumery, namely for perfuming detergents and fabric 
softeners. Other products which can be advantageously perfumed by means of 
the compound of the invention include soaps, shower and bath gels, 
shampoos, cosmetic preparations, body or air deodorants or household 
products. 
As it is often the case in perfumery, the compound can be used, as a 
perfuming ingredient, either alone or in admixture with other perfuming 
coingredients, solvents or adjuvants of current use. 
The concentrations in which the compound of the invention can be used for 
the above-mentioned applications vary in a wide range of values, which is 
a function, amongst other parameters, of the nature of the product to be 
perfumed and of the desired perfuming effect. By way of example, 
concentrations of the order of 1 to 10% by weight, or even more, can be 
cited when the compound is used in perfuming bases and concentrates. 
Considerably lower concentration values than those cited can be employed 
when the compound is used for perfuming the variety of articles mentioned 
above. 
It should be noted that the compound according to the invention can take 
several optically active forms, as a result of the plurality of chiral 
centers in the molecule. As is described below, these several isomers can 
be prepared by using appropriate optically active forms of the starting 
products. It was observed that the isomers thus obtained were all 
olfactively distinct from each other, both as regards the character and 
the strength of their sandalwood note. Generally, however, it was observed 
that these differences were not very marked and that all the compounds, as 
well as their mixtures, were equally convenient for the perfumery 
applications according to the invention. There was, nevertheless, a 
perfumers' preference for the isomers of (-)-(1'R) configuration and, 
amongst these, for 
(-)-(1'R)-cis-1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)2-cy 
clohexen-1-ol. 
When reference is made in the present specification to 
1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol 
, it is meant as a reference to any one of its optically active isomers, or 
to any mixture of the latter. 
The invention has also as its object a process for the preparation of 
1,2-dimethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-ol 
, which process comprises the reaction of 
2-methyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-one 
with an appropriate Grignard reagent, under the usual conditions of this 
type of reaction. The starting cyclohexenone in the process of the 
invention can take several optically active stereoisomer forms and, 
obviously, the latter determine the configuration of the final product. 
2-Methyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-cyclohexen-1-one, in 
the desired configuration, or in the form of a mixture of diastereomers, 
can be obtained from the appropriate stereoisomer form of campholenic 
aldehyde, by means of conventional reactions, such as illustrated in the 
following reaction scheme. In the latter, the above-mentioned 
cyclohexenone is represented, in the form of the 1'R (mixture of 4R/4S 
diastereomers) configuration isomer, by number 6 and the compound 
according to the invention, in the corresponding configuration, is 
indicated by number 22. 
##STR21## 
This scheme also illustrates the conventional type reactions which enable 
the preparation, starting from the same cyclohexenone, of many compounds 
obeying the basic structure (III), namely those cited in Table I. 
The process according to the invention will now be described in greater 
detail by way of the examples presented hereinafter, wherein the 
temperatures are indicated in degrees centigrade and the abbreviations 
have the usual meaning in the art. 
Other examples, presented further on, illustrate perfumery applications of 
the compound according to the invention.