Perfumery composition comprising 2-cyclohexylpropionic acid or its derivative

Disclosed is a perfumery composition comprising a 2-cyclohexylpropionic acid or its derivative represented by the following formula (I): ##STR1## wherein R is a hydrogen atom, an alkyl group having 1-4 carbon atoms, or an alkenyl group having 2-4 carbon atoms. The compounds have a wide variety of odors and a wide application as perfumery compositions such as high-grade perfumery compositions, perfumes, soaps, shampoos, rinses, detergents, cosmetics, sprays, room fragrances, and the like.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a perfumery composition comprising 
2-cyclohexylpropionic acid or its derivative. 
2. Description of the Background Art 
There are many compounds known as possible odorizing substances for 
perfumery. These perfumery compounds are required to be easy to 
synthesize, economical, chemically stable, compatible with other 
ingredients and novel in their odor. It is, therefore, very important to 
examine the possibility of various compounds for use as a 
fragrance-imparting agent. 
In view of the fact that carboxylic acids or esters having a cyclohexyl 
group can readily be synthesized and are appropriate for industrial 
application, the present inventors have conducted extensive studies on 
their aromaticity and their applicability as a fragrance-imparting agent. 
As a result, the inventors have found that 2-cyclohexylpropionic acid or 
its derivatives can provide various kinds of odors when incorporated as a 
perfume ingredient in perfumery compositions. Such a finding has led to 
the completion of the present invention. 
SUMMARY OF THE INVENTION 
Accordingly, an object of this invention is to provide a perfumery 
composition comprising a 2-cyclohexylpropionic acid or its derivative 
represented by the following formula (I): 
##STR2## 
wherein R is a hydrogen atom, an alkyl group having 1-4 carbon atoms, or 
an alkenyl group having 2-4 carbon atoms. 
Other objects, features and advantages of the invention will hereinafter 
become more readily apparent from the following description.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS 
2-Cyclohexylpropionic acid and its derivatives of formula (I) are known 
compounds. Processes for synthesizing these compounds have been disclosed 
in the art. Included as these compounds are 2-cyclohexylpropionic acid 
disclosed in J. Chem. Soc., 1483, (1933); methyl 2-cyclohexylpropionate 
disclosed in Tetrahedron Lett., 22, 1891, (1981), Ann. N. Y. Acad. Sci., 
415, 148, (1983), Chem. Ber., 119, 509, (1986), etc.; ethyl 
2-cyclohexylpropionate disclosed in Tetrahedron Lett., 24, 1315, (1983) 
etc.; and tert-butyl 2-hexylpropionate disclosed in Organometallics, 2, 
363, (1983). However, the aromaticity or benefit of these compounds as a 
fragrance-imparting agent have never been reported in the above 
publications. 
The compounds of formula (I) used in the perfumery compositions of the 
present invention can be prepared according to the processes described in 
the above publications or by either of the following processes (A)-(E): 
Process (A) 
2-Phenylpropionate is hydrogenated according to the following reaction 
scheme to obtain 2-cyclohexylpropionate. 
##STR3## 
wherein R.sup.1 is an alkyl group having 1-4 carbon atoms. 
It is desirable that this reaction be carried out using 0.001-0.1 
equivalent of Raney nickel, platinum, palladium, ruthenium or rhodium 
catalyst under a hydrogen pressure of 10-200 atm at a temperature of 
80.degree.-200.degree. C. 
Process (B) 
2-Cyclohexylpropionate is hydrolyzed according to the following reaction 
scheme to obtain 2-cyclohexylpropionic acid. 
##STR4## 
wherein R.sup.1 has the same meaning as defined above. 
It is desirable that this reaction be carried out using aqueous sodium 
hydroxide, potassium hydroxide, or the like as an alkali at a temperature 
of 20.degree.-100.degree. C. to produce a salt of carboxylic acid, 
followed by neutralization with sulfuric acid or other mineral acid. 
Process (C) 
2-Cyclohexylpropanal is oxidized using air or oxygen according to the 
following reaction scheme to produce 2-cyclohexylpropionic acid. 
##STR5## 
It is preferable that this reaction be carried out by blowing air or oxygen 
into 2-cyclohexylpropanal in the absence or presence of a metal catalyst, 
e.g. cobalt, manganese, nickel, chromium, copper, vanadium, as required, 
at 20.degree.-100.degree. C. without any solvent. 
Process (D) 
2-Cyclopropionic acid is reacted with an alcohol in the presence of an acid 
catalyst according to the following reaction scheme to obtain 
2-cyclohexylpropionate. 
##STR6## 
wherein R.sup.2 is an alkyl group having 1-4 carbon atoms or an alkenyl 
group having 2-4 carbon atoms. 
It is desirable that this reaction be carried out by azeotropic dehydration 
using 1-10 equivalent of an alcohol; 0.001-0.1 equivalent of sulfuric 
acid, p-toluene sulfonic acid, or the like as an acid catalyst; and 
dichloromethane, chloroform, or the like as a reaction solvent. 
Process (E) 
2-Cyclohexylpropionic acid is reacted with isobutene in the presence of an 
acid catalyst according to the following reaction scheme to obtain 
tert-butyl 2-cyclohexylpropionate. 
##STR7## 
It is desirable that this reaction be carried out at a temperature of 
0.degree.-30.degree. C. using 1-10 equivalent of isobutene; 0.001-0.1 
equivalent of sulfuric acid, boron trifluoride diethyl ether, or the like 
as an acid catalyst; and ether as a reaction solvent. 
The compound (I) is incorporated in the perfumery composition of the 
present invention without any limitations as to the amount, but preferably 
in an amount of 0.1-50% by weight, particularly preferably of 5-40% by 
weight. 
By using the compounds (I) of the present invention as a 
fragrance-imparting agent in an admixture with conventional 
fragrance-imparting agents and a carrier thereof, various odors are 
imparted to perfumery compositions. The compounds can be used in a wide 
variety of products which require pleasant odors or fragrances such as 
high-grade perfumery compositions, perfumes, soaps, shampoos, rinses, 
detergents, cosmetics, sprays, room fragrances, and the like. 
Other features of the invention will become apparent in the course of the 
following description of the exemplary embodiments which are given for 
illustration of the invention and are not intended to be limiting thereof. 
EXAMPLES 
Preparation Example 1 
Synthesis of methyl 2-cyclohexylpropionate 
Into a 100 ml autoclave 50 g of methyl 2-phenylpropionate, 0.5 g of 
ruthenium catalyst on 5% activated carbon as a carrier (manufactured by 
Nippon Engerhard Co.) were charged. The mixture was reacted under a 
hydrogen pressure of 50 Kg/cm.sup.2 at 150.degree. C. for 8 hours. After 
completion of the reaction, the catalyst was removed by filtration to 
obtain 50.5 g of a product. The product was analyzed by means of gas 
chromatography and confirmed that methyl 2-cyclohexyl-propionate of 99% 
purity was formed (yield: 97%). The compound obtained had a grassy, 
drygrassy, and woody odor. 
Boiling Point: 70.degree. C. at 5 mmHg 
IR (liquid film, cm.sup.-1): 2932, 2854, 1743, 1455, 1197, 1167, 1149 
NMR (CDCl.sub.3, TMS internal standard, .delta. ppm): 
1.08(d, J=7Hz, 3H), 1.2-2.0(m, 11H), 2.15(m, 1H), 3.60(s, 3H) 
GC-MS(M.sup.+): 170 
Preparation Example 2 
Synthesis of 2-cyclohexylpropionic acid 
Into a 500 ml round bottom flask 50 g of methyl 2-cyclohexylpropionate and 
70 g of 25% sodium hydroxide were charged. The mixture was stirred at 
80.degree. C. for 8 hours. To the reaction mixture 120 g of 20% sulfuric 
acid was gradually added under ice-cooling to separate a carboxylic acid. 
The carboxylic acid was extracted with hexane. The mixture obtained was 
distilled to obtain 42.3 g of 2-cyclohexylpropionic acid having a civet- 
and animal-like odor (yield: 92%, purity: 99.9%). 
Boiling Point: 114.degree. C. at 2 mmHg 
IR (KBr tablet, cm.sup.-1): 3600-2400, 2920, 2848, 2662, 1701, 1290, 1245, 
1209, 940 
NMR (CDCl.sub.3, TMS internal standard, .delta. ppm): 
1.13(d, J=7Hz, 3H), 1.2-2.0(m, 11H), 2.23(m, 1H) 
Preparation Example 3 
Synthesis of 2-cyclohexylpropionic acid 
Into a 500 ml round bottom flask was charged 300 g of 2-cyclohexylpropanal 
and was fed a stream of oxygen at a rate of 100 ml per minute at 
60.degree. C. for 80 hours through a sintered liquid filter for liquid 
chromatography. The reaction mixture was analyzed by means of gas 
chromatography and confirmed that 2-cyclohexylpropionic acid was obtained 
in an yield of 65% and 35% of the 2-cyclohexylpropanal remained unreacted 
in the reaction mixture. 
Preparation Example 4 
Synthesis of ethyl 2-cyclohexylpropionate 
Into a 500 ml round bottom flask equipped with a Soxhlet extractor filled 
with molecular sieves, 50 g of 2-cyclo-hexylpropionate, 100 g of ethanol, 
0.5 g of p-toluene sulfonic acid, and 200 ml of chloroform were charged. 
The mixture was reacted under refluxing for 40 hours. The reaction mixture 
was washed with water and distilled under reduced pressure to obtain 56.4 
g of ethyl 2-cyclohexylpropionate (yield: 96%, purity: 99.4%). The 
compound obtained had a fruity (namely aldehyde C-16 and apple-like) odor. 
Boiling Point: 80.degree. C. at 5 mmHg 
IR (Liquid film, cm.sup.-1): 2980, 2932, 2854, 1737, 1191, 1173, 1149 
NMR (CDCl.sub.3, TMS internal standard, .delta. ppm): 
1.08(d, J=7Hz, 3H), 1.25(t, J=7Hz, 3H), 1.2-2.0(m, 11H), 2.18(m, 1H), 
4.13(q, J=7Hz, 2H) 
GC-MS(M.sup.+): 184 
Preparation Example 5 
Synthesis of isopropyl 2-cyclohexylpropionate 
Isopropyl 2-cyclohexylpropionate was prepared in the same manner as in 
Preparation Example 4 in an yield of 80%, except that instead of ethanol 
100 g of isopropanol was used. The compound obtained had a floral, woody, 
and fruity odor. 
Boiling Point: 90.5.degree. C. at 5 mmHg 
IR (Liquid film, cm.sup.-1): 2980, 2932, 2854, 1734, 1194, 1176, 1149, 1110 
NMR (CDCl.sub.3, TMS internal standard, .delta. ppm): 
1.08(d, J=7Hz, 3H), 1.24(d, J=7Hz, 6H), 1.2-2.0(m, 11H), 2.15(m, 1H), 
5.03(sep, J=7Hz, 1H) 
GC-MS(M.sup.+): 198 
Preparation Example 6 
Synthesis of allyl 2-cyclohexylpropionate 
Allyl 2-cyclohexylpropionate was prepared in the same manner as in 
Preparation Example 4 in an yield of 67%, except that instead of ethanol 
100 g of allyl alcohol was used. The compound obtained had a fruity and 
allylic odor. 
Boiling Point: 85.degree. C. at 5 mmHg 
IR (Liquid film, cm.sup.-1): 3140, 2932, 2854, 1737, 1170, 1146 
NMR (CDCl.sub.3, TMS internal standard, .delta. ppm): 
1.13(d, J=7Hz, 3H), 1.2-2.0(m, 11H), 2.23(m, 1H), 4.54(d, J=6Hz, 2H), 
5.20(br. d, J=9Hz, 1H), 5.38(br. s, 1H), 5.5-6.3(m, 1H) 
GC-MS(M.sup.+): 196 
Preparation Example 7 
Synthesis of tert-butyl 2-cyclohexylpropionate 
Into a 500 ml round bottom flask 30 g of 2-cyclohexylpropionic acid and 200 
ml of ether were charged and cooled to 0.degree. C. After 100 g of 
isobutene gas was introduced, 0.5 g of sulfuric acid was charged into the 
mixture, the mixture was then stirred at 0.degree. C. for 40 hours. The 
reaction mixture was washed with water and distilled under reduced 
pressure to obtain 4.5 g of tert-butyl 2-cyclohexylpropionate having a 
woody and floral odor (yield: 11%, purity: 98.7%). 
Boiling Point: 80.degree. C. at 5 mmHg 
IR (Liquid film, cm.sup.-1): 2974, 2932, 2854, 1731, 1146 
NMR (CDCl.sub.3, TMS internal standard, .delta. ppm): 
1.08(d, J=7Hz, 3H), 1.2-2.0(m, 11H), 1.50(s, 9H), 2.15(m, 1H) 
GC-MS(M.sup.+): 212 
Example 1 
Apple-type Perfumery Composition 
______________________________________ 
2-Methylbutyl n-butylate 
20 parts by weight 
Cis-3-hexenol 5 
Cis-3-hexenyl acetate 
5 
Ligustral *1 10 
2-Cyclohexylpropanal 
20 
.delta.-decalactone 
10 
Fruitate *2 50 
Geranial n-butylate 
100 
Diethyl malonate 100 
.alpha.-Damascone 20 
Sagetone V *3 200 
Nerolidol 60 
600 
______________________________________ 
*1: 2,4dimethyl-3-cyclohexene-1-carboxyaldehyde, Specialty Chemical 
manufactured by Quest Inc. 
*2: Ethyltricyclo[5.2.1.0.sup.2,6 ]decane 2carboxylate, Specialty Chemica 
manufactured by Kao Corporation. 
*3: Spiro[bornane3,1cyclopenta-2-one], Specialty Chemical manufactured by 
Kao Corporation. 
An apple-type perfume was prepared by blending 600 parts by weight of the 
above components and 400 parts by weight of ethyl 2-cyclohexylpropionate. 
The perfume possessed a fresh and fruity odor. 
Example 2 
A natural, fresh and green-floral perfume was prepared by using methyl 
2-cyclohexylpropionate as a fragrance-imparting agent. 
Example 3 
A citrus-floral perfume with an intensified natural scent was prepared by 
using 2-cyclohexylpropionic acid as a fragrance-imparting agent. 
Example 4 
A fruity-floral perfume was prepared by using isopropyl 
2-cyclohexylpropionate as a perfume substance. 
Example 5 
A pineapple-like, fruity-floral perfume was prepared by using allyl 
2-cyclohexylpropionate as a perfume substance. 
Example 6 
A soft and floral perfume was prepared by using tert-butyl 
2-cyclohexylpropionate as a perfume substance. 
Obviously, numerous modifications and variations of the present invention 
are possible in light of the above teachings. It is therefore to be 
understood that within the scope of the appended claims, the invention may 
be practiced otherwise than as specifically described herein.