Perfume base composition

The present invention relates to a perfume base composition comprising a carrier and a benzyl-substituted cyclohexanol having formula (1), wherein the dashed line denotes an optional double bond and the benzyl group is in the 2-, 3- or 4-position of the cyclohexanol ring, with the proviso that the benzyl group is in the 4-position when a double bond is present in the cyclohexanol ring. The composition has not only a well-balanced fragrance but also excellent retentivity of fragrance.

TECHNICAL FIELD 
The present invention relates to a perfume base composition which 
excellently retains its fragrance. This composition can be used for the 
production of perfume and other products to be scented such as detergents, 
cosmetics and sprays. 
BACKGROUND ART 
A great number of perfume base materials having a floral fragrance have 
heretofore been known. Among others, aldehyde type perfume bases are the 
most important perfume base materials. However, since aldehydes are not 
always stable in fragrant products having different pHs and product forms, 
these products often do not smell fresh and natural. Moreover, these 
products do not retain their fragrance for a very long time, which is 
disadvantageous. 
It is accordingly the object of the present invention to provide a perfume 
base composition which has a floral fragrance and high stability and can 
impart excellent retentivity of fragrance to blending systems. 
DISCLOSURE OF THE INVENTION 
This object is achieved by the use of specific benzyl-substituted 
cyclohexanols, which compounds can impart freshness to the perfume base 
composition and the products made therefrom. Due to the use of these 
benzyl-substituted cyclohexanols the articles made from the perfume base 
composition additionally have a natural, soft and voluminous feeling. 
According to the present invention, there is thus provided a perfume base 
composition comprising a benzyl-substituted cyclohexanol having the 
following formula (1): 
##STR2## 
wherein the dashed line denotes an optional double bond and the benzyl 
group is in the 2-, 3- or 4-position of the cyclohexanol ring, with the 
proviso that the benzyl group is in the 4-position when a double bond is 
present in the cyclohexanol ring. 
BEST MODE FOR CARRYING OUT THE INVENTION 
The benzyl-substituted cyclohexanols (1) are known compounds. For example, 
2-benzylcyclohexanol is described in Tetrahedron, 48, 2059 (1992), 
Tetrahedron Lett., 36, 123 (1994) and J. Chem. Soc., 1809 (1956); 
3-benzylcyclohexanol is described in J. Chem. Soc., 1809 (1956); and 
4-benzylcyclohexanol and 4-benzyl-2-cyclohexen-1-ol are described in 
Tetrahedron, 48, 2059 (1992). These documents, however, do not disclose 
the use of benzylcyclohexanols as a fragrance. Moreover, the prior art 
does not suggest to use these compounds to retain the fragrance of perfume 
base compositions and of the products made therefrom. 
Examples of the benzyl-substituted cyclohexanols (1) useful in the practice 
of the present invention include 2-benzylcyclohexanol, 
3-benzylcyclohexanol, 4-benzylcyclohexanol and 4-benzyl-2-cyclohexen-1-ol. 
Of these, 2-benzylcyclohexanol, 3-benzylcyclohexanol and 
4-benzylcyclohexanol are preferred with 3-benzylcyclohexanol being 
particularly preferred. 
Cis-trans isomerism exists in the benzyl-substituted cyclohexanols (1) 
according to the substitution state between the benzyl group and the 
hydroxyl group on the cyclohexane ring (or cyclohexene ring). In the 
present invention both cis- and trans-benzylcyclohexanols and mixtures 
thereof may be used. Among these isomers, the cis-form is particularly 
preferred. 
The benzyl-substituted cyclohexanols (1) can be prepared in accordance with 
the processes described in the above literature. For example, 
2-benzylcyclohexanol (1a) can be prepared by subjecting benzaldehyde (2) 
and cyclohexanone (3) to aldol condensation and hydrogenating the 
resulting enone (4) (see the following reaction scheme). 
##STR3## 
3-Benzylcyclohexanol (1b) can be prepared by subjecting a Grignard reagent 
(5) prepared from a benzyl halide, and 2-cyclohexen-1-one (6) to 
1,4-addition and hydrogenating the resulting ketone (7) (see the following 
reaction scheme). 
##STR4## 
4-Benzylcyclohexanol (1c) and 4-benzyl-2-cyclohexen-1-ol (1d) can be 
prepared by using an enamine (9) obtained by the dehydration-condensation 
of 3-phenylpropionaldehyde (8) and morpholine to form 
4-benzyl-2-cyclohexen-1-ol (10) by Robinson annellation and selectively 
hydrogenating only the carbonyl of the compound (10) to form 
4-benzyl-2-cyclohexen-1-ol (1d) or hydrogenating both olefin and carbonyl 
of the compound (10) to form 4-benzylcyclohexanol (1c) (see the following 
reaction scheme). 
##STR5## 
Since most of the benzyl-substituted cyclohexancls (1) obtained in such a 
manner are mixtures of cis- and trans-forms, their isomers have to be 
separated from each other by column chromatography, recrvstallization from 
a hydrocarbon solvent, superfractionation and/or the like if necessary. 
The benzyl-substituted cyclohexanols (1) may be used as a deodorant 
component either singly or in combination with a carrier. Any carrier may 
be used without any limitation so far as it does not impair the fragrance 
of the benzyl-substituted cyclohexanols (1). Examples thereof include 
gaseous, liquid and solid carriers, which may contain other perfume 
compounds. The examples of the preferable gaseous carriers include a gas 
for propelland agents. The preferable liquid carriers include water, 
various organic solvents, and volatile oily substances. The preferable 
solid carriers include solid oily substances such as various waxes, and 
polymers. The amount of the benzyl-substituted cyclohexanol (1) to be 
incorporated in the perfume base composition according to the present 
invention varies according to the kind of the formulated perfume base used 
in combination, the kind and intesity of the intended fragrance, and the 
like, and no particular limitation is imposed on the amount. However, it 
is generally preferable to use it in a proportion of 0.1-90 wt. %, 
particularly preferably 0.5-70 wt. % based on the perfume base 
composition. 
In addition to the benzyl-substituted cyclohexanol (1) and the carrier, 
optional components routinely incorporated in perfume base compositions 
may be incorporated into the perfume base composition according to the 
present invention within limits not impeding the effect of the present 
invention. 
The perfume base composition according to the present invention can be 
obtained by mixing and stirring the benzyl-substituted cyclohexanol (1), 
carrier and optional components in accordance with a method known per se 
in the art. 
The perfume base composition according to the present invention may be 
suitably applied to products required to be scented, such as perfumes, 
detergents, cosmetics, various sprays and fragrances, in particular, 
toiletry products such as soap, shampoos and rinses. 
The perfume base composition according to the present invention has a 
well-balanced fragrance and is also excellent in retentivity of fragrance.

EXAMPLES 
The present invention will hereinafter be described in more detail by the 
following examples. 
Preparation Example 1 
A 1-liter four-necked flask equipped with a Dean-Stark trap and a 
thermometer was charged with 71 g of morpholine and 400 ml of toluene, and 
100 g of 3-phenylpropionaldehyde were added dropwise thereto while 
chilling with ice water, followed by azeotropic dehydration for 1 hour. 
After cooling the reaction mixture, excess morpholine was distilled off 
with toluene. The residue was dissolved in 400 ml of toluene. In a 1-liter 
four-necked flask equipped with a thermometer and a condenser, 70 g of 
methyl vinyl ketone were added dropwise under reflux to the solution over 
1 hour. After aging under reflux for 1 hour, the reaction mixture was 
cooled, and 10% sulfuric acid was added dropwise to the reaction mixture 
until the pH of the reaction mixture reached 3. The thus-acidified 
reaction mixture was then stirred at room temperature for 1.5 hours. After 
separating the resulting lower water layer, the residual organic layer was 
neutralized, washed with water, dried and concentrated, thereby obtaining 
137 g of a crude product. Dissolved in 500 ml of methanol were 137 g of 
the crude product, and 4 ml of 4.5 mol/liter aqueous KOH were added 
dropwise to the solution at room temperature, followed by stirring for 3 
hours at the same temperature. After neutralizing the resultant mixture 
with acetic acid, methanol was distilled off. After the residue was 
charged into a 1-liter four-necked flask equipped with a Dean-Stark trap 
and a thermometer to dissolve it in 500 ml of toluene, 2 g of 
p-toluenesulfonic acid were added to the solution, followed by azeotropic 
dehydration for 3 hours. After cooling, the residue was neutralized and 
washed with water, and the resultant organic layer was dried and 
concentrated, thereby obtaining 119 g of a crude product. This product was 
purified by column chromatography to obtain 41 g (yield: 30%) of 
4-benzyl-2-cyclohexen-1-one. 
To a suspension of 3.2 g of lithium aluminum hydride in 500 ml of ether, 30 
g of 4-benzyl-2-cyclohexen-1-one were added dropwise at 0.degree. C. After 
stirring the mixture for 2 hours at the same temperature, it was washed 
with diluted hydrochloric acid and water, and the resultant organic layer 
was dried and concentrated, thereby obtaining 31 g of a crude product. 
This product was purified by column chromatography to obtain 30 g (yield: 
98%) of 4-benzyl-2-cyclohexen-1-ol. A ratio of a cis-form to a trans-form 
was found to be 32:68 by .sup.1 H-NMR. 
4-Benzyl-2-cyclohexen-1-ol: 
.sup.1 H-NMR .delta.: 1.17-2.77(8H,m), 4.10-4.30(1H,m), 5.1-5.35(2H,m) 
7.1-7.35(5H,m). 
Besides, 30 g of the above-obtained 4-benzyl-2-cyclohexen-1-one were 
hydrogenated at room temperature for 6 hours using 5 g of Raney nickel in 
methanol under hydrogen pressure (3 kg/cm.sup.2) until the absorption of 
hydrogen was stopped. After an organic layer was collected by decantation 
and concentrated, the residue was purified by column chromatography, 
thereby obtaining 13 g of cis-4-benzylcyclo-hexanol and 14 g of 
trans-4-benzylcyclohexanol (yield: 90% in total). 
Cis-4-benzylcyclohexanol: 
.sup.1 H-NMR .delta.: 1.30-1.80(10H,m), 2.54(2H,d,J=6.97 Hz), 
3.90-4.01(1H,br), 7.08-7.32(5H,m). 
Trans-4-benzylcyclohexanol: 
.sup.1 H-NMR .delta.: 0.87-1.30(4H,m), 1.35-1.62(1H,m), 1.63-1.85(2H,m), 
1.85-2.03(3H,m), 2.47(2H,d,J=7.1 Hz), 3.42-3.62(1H,m), 7.08-7.35(5H,m). 
Preparation Example 2 
A 500-ml four-necked flask equipped with a thermometer and a condenser was 
charged with 2.4 g of a piece of magnesium and 120 ml of absolute ether, 
to which a part of 17 g of benzyl bromide was added with heating. After a 
reaction started, the remaining amount of benzyl bromide was added 
dropwise to such a degree that reflux continued. After completion of the 
drop addition, the resultant mixture was stirred further for 1 hour at 
room temperature to obtain a liquid reaction mixture. A 500-ml four-necked 
flask equipped with a thermometer was charged with a suspension of 1 g of 
copper iodide in 60 ml of absolute ether, to which the liquid reaction 
mixture was added dropwise at -5.degree. C. After stirring the resultant 
mixture for 1 hour at the same temperature, it was cooled to -20.degree. 
C. A solution of 8.6 g of 2-cyclohexen-1-one in 10 ml of absolute ether 
was added dropwise to the mixture, and the temperature of the resulting 
liquid reaction mixture was then raised to room temperature while stirring 
for 24 hours. The liquid reaction mixture was washed with water, dried, 
filtered and concentrated, and 21 g of the resulting crude product were 
purified by column chromatography, thereby obtaining 9.6 g (yield: 57%) of 
3-benzylcyclohexenone. 
Then, 9.6 g of 3-benzylcyclohexenone were hydrogenated at room temperature 
using 1 g of Raney nickel in methanol under hydrogen pressure (3 
kg/cm.sup.2) until the absorption of hydrogen was stopped. After an 
organic layer was collected by decantation and concentrated, the residue 
was purified by column chromatography, thereby obtaining 4.5 g of 
cis-3-benzylcyclohexanol and 4.5 g of trans-3-benzylcyclohexanol (yield: 
92% in total). 
Cis-3-benzylcyclohexanol: 
.sup.1 H-NMR .delta.: 0.9-1.15(1H,m), 1.17-1.82(8H,m), 1.87-2.15(1H,m), 
2.55(2H,d), 7.1-7.4(1H,m), 7.12-7.35(5H,m). 
Trans-3-benzylcyclohexanol: 
.sup.1 H-NMR .delta.: 0.75-1.35(4H,m), 1.45-1.85(4H,m), 1.85-2.03(2H,m), 
2.24-2.62(2H,m), 3.42-3.62(1H,m), 7.08-7.35(5H,m). 
Preparation Example 3 
A 500-ml four-necked flask equipped with a thermometer was charged with 53 
g of benzaldehyde, 25 ml of water and 1 g of sodium hydroxide, to which 68 
g of cyclohexanone were added dropwise at 30.degree. C. over 30 minutes. 
The resultant mixture was stirred for 1 hour at the same temperature. 
After neutralizing the reaction mixture to separate liquid layers from 
each other, the resultant reaction product was dissolved in 500 ml of 
toluene. To the solution, 0.5 g of PTS (p-toluenesulfonic acid) was added 
to conduct azeotropic dehydration for 3 hours in a 1-liter four-necked 
flask equipped with a Dean-Stark trap and a thermometer. After cooling, 
the residue was neutralized and washed with water, and the resultant 
organic layer was dried and concentrated, thereby obtaining 119 g of a 
crude product. This product was purified by column chromatography to 
obtain 24 g (yield: 28%) of 2-benzylidenecyclohexanone. 
Then, 10 g of 2-benzylidenecyclohexanone were hydrogenated at room 
temperature using 1 g of Raney nickel in methanol under hydrogen pressure 
(3 kg/cm.sup.2) until the absorption of hydrogen was stopped. After an 
organic layer was collected by decantation and concentrated, the residue 
was purified by column chromatography, thereby obtaining 4.6 g of 
cis-2-benzylcyclohexanol and 4.4 g of trans-2-benzylcyclohexanol (yield: 
88% in total). 
Cis-2-benzylcyclohexanol: 
.sup.1 H-NMR .delta.: 1.1-1.35(1H,m), 1.35-1.85(9H,m), 
2.53(1H,dd,J=7.7,13.4 Hz), 2.70(1H,dd,J=9.2,13.3 Hz), 3.75-3.82(1H,bs), 
7.12-7.35(5H,m). 
Trans-2-benzylcyclohexanol: 
.sup.1 H-NMR .delta.: 0.8-1.85(9H,m), 1.91-2.08(1H,m), 
2.34(1H,dd,J=9.2,13.3 Hz), 3.17(1H,dd,J=4.0,13.3 Hz), 3.28-3.4(1H,m), 
7.12-7.35(5H,m). 
The fragrance of the benzyl-substituted cyclohexanols (1) obtained in the 
above-described preparation examples are shown in Table 1. 
4-benzyl-2-cyclohexen-1-ol, 2-benzyl-cyclohexanol, 3-benzylcyclohexanol and 
4-benzylcyclohexanol will hereinafter be referred to as "1d", "1a", "1b" 
and "1c", respectively. Numerals in (: ) following each of the symbols 
indicate the porportions of the cis-form and the trans-form. For example, 
1c (0:100) means that the ratio of the cis-form to the trans-form in 
4-benzylcyclohexanol is 0:100. 
TABLE 1 
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Compound Odor 
______________________________________ 
1d (32:68) Floral-Green-Muguet Rose-Geranium 
1c (100:0) Floral-Rose-Geranium 
1c (0:100) Floral-Green-Sweet 
1b (100:0) Floral-Grapefruit-Woody-Vetiver 
1b (0:100) Floral-Grapefruit-Vetiver 
1a (100:0) Floral-Grapefruit 
1a (0:100) Floral-Grapefruit 
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Example 1 
1c (100:0) or the like were added to a rose base having a composition shown 
in Table 2 and the effect brought about by the addition was evaluated in 
accordance with an organoleptic test by 5 expert panelists. Organoleptic 
evaluation standard: 
1: The effect of the addition was recognized to a very desirable extent; 
2: The effect of the addition was recognized to a desirable extent; 
3: The effect of the addition was scarcely recognized; 
4: No effect of the addition was recognized, and the balance of fragrance 
was poor. 
TABLE 2 
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Invention 
Comparative 
Comparative 
product 1 
product 1 product 2 
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Rose base: 
Geraniol 400 400 400 
Phenylethyl alcohol 
80 80 80 
Geranyl acetate 
80 80 80 
Geranium oil 50 50 50 
Rhodinol 50 50 50 
.alpha.-Ionone 
50 50 50 
Diphenyl oxide 
40 40 40 
Linalol 30 30 30 
1c (100:0) 220 -- -- 
l-Citronellol -- 220 -- 
Dipropylene glycol 
-- -- 220 
Total (parts by weight) 
1000 1000 1000 
Organoleptic evaluation 
1 2 4 
______________________________________ 
The invention product 1 had a voluminous, well-balanced, rose-like 
fragrance. The comparative product 1 had a rose-like fragrance, but was 
lacking in a voluminous feeling. The comparative product 2 had an 
ill-balanced fragrance not associated with roses. 
Example 2 
A composition having a gorgeous, soft, voluminous, lily of the valley-like 
fragrance was obtained in accordance with the following formulation. 
______________________________________ 
(Components) (parts by weight) 
______________________________________ 
Phenylethyl alcohol 
250 
Hydroxycitronellal 
250 
Bergamot oil 100 
Jasmine oil 100 
Heliotropin 100 
Linalyl benzoate 
50 
Phenylethyl acetate 
10 
Cinnamic alcohol 
10 
1c (100:0) 130 
Total 1000 
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Example 3 
A floral perfume base for soap, which had a soft, sweet fragrance, was 
obtained in accordance with the following formulation. In particular, 
voluminous sweetness was recognized during its use. 
______________________________________ 
(Components) (parts by weight) 
______________________________________ 
Bois de Rose oil 250 
Terpineol 150 
Lavender oil 100 
Cederwood oil 100 
Citronella oil 150 
Eugenol 50 
Linalyl acetate 50 
Diphenyl oxide 30 
Pearlide BB (product of Kao Corporation) 
70 
Styrax resinoid 20 
1c (0:100) 80 
Total 1000 
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Example 4 
Added to a grapefruit base having a composition shown in Table 3 were 1a 
(50:50) or 1b (50:50), thereby obtaining grapefruit type perfume base 
compositions. These compositions were organoleptically evaluated. 
TABLE 3 
______________________________________ 
Invention 
Invention 
product 2 
product 3 
______________________________________ 
Grapefruit base: 
Orange oil 718 718 
Orange terpeneless oil 
20 20 
Fruitate*.sup.1 20 20 
Pollenal II*.sup.2 20 20 
Linalol 10 10 
Ethyl octanoate 10 10 
2-Methyl-4-propyl-1,3-oxathiane 
2 2 
1a (50:50) 200 -- 
1b (50:50) -- 200 
Total (parts by weight) 
1000 1000 
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*.sup.1 Kao's specialty chemical; ethy1bicyclo5.2.1.0.sup.2,6 
decane-2-carboxylate. 
*.sup.2 Kao's specialty chemical; 2cyclohexylpropanal. 
As a result, the invention product 2 was found to have a grapefruit type 
natural fragrance with better softness. On the other hand, the invention 
product 3 was found to have a grapefruit type, natural, fresh, voluminous, 
and long-lasting fragrance. Of these, the formulated fragrance of the 
invention product 3, in which 1b (50:50) had been incorporated, was very 
excellent from the viewpoint of freshness. 
Example 5 
1a (50:50) or 1b (50:50) were added to a citron base having the composition 
shown in Table 4 to obtain citron type perfume base compositions. These 
compositions were organoleptically evaluated. 
TABLE 4 
______________________________________ 
Invention 
Invention 
product 4 
product 5 
______________________________________ 
Citron base: 
Orange oil 298 298 
Mandarin oil 150 150 
.gamma.-Terpinene 100 100 
Linalol 200 200 
Dihydromyrcenol 50 50 
Dimethyloctenone 50 50 
Dihydrojasmonate 50 50 
2-Methyl-4-propyl-1,3-oxathiane 
2 2 
1a (50:50) 100 -- 
1b (50:50) -- 100 
Total (parts by weight) 
1000 1000 
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As a result, the invention product 4 was found to be a citron type natural 
perfume base composition having better softness. On the other hand, the 
invention product 5 was found to be a natural, fresh citron type perfume 
base composition feeling like the rind of a citron. Of these, the 
formulated fragrance of the invention product 5, in which 1b (50:50) had 
been incorporated, was very excellent from the viewpoint of freshness.