ALPHA, BETA-UNSATURATED KETONES AND THEIR USE AS AROMA CHEMICALS

Abstract: Described are α,β-unsaturated ketones of the general for­ mula: wherein R¹, R² and R³ may be the same or different and each represents a lower alkyl group. The ketones are useful as aroma chemicals.

Description: &alpha;,ss-UNSATURATED KETONES AND THEIR USE AS AROMA CHEMICALS Field of the Invention The present invention relates to &alpha;,ss-unsaturated ketones, fragrance compositions containing said &alpha;,ss-un- saturated ketones, and the use of said , -unsaturated ketones as aroma chemicals (fragrances) for imparting odors or flavors to substrate materials. Background of the Invention It has been reported that 2-substituted-5-methyl- 4-hexen-l-als such as 2,2,5-trimethyl-4-hexen-l-al, 2,5-dimethyl-2-ethyl-4-hexen-1-al, 2,5-dimethyl-2-n-propyl- 4-hexen-1-al and 2,2-diethyl-5-methyl-4-hexen-1-al have sweet odors [cf. S. Watanabe et al., Yukagaku (Journal of the Japan Oil Chemists Society), Vol. 31, pages 295-299 (1982)]. It is desirable to provide aroma chemicals (fragrances) which have odors different from the odors of known aroma chemicals (fragrances; flavor materials), so that when such compounds are mixed with known aroma chemicals (fragrances) or finished fragrances, the resulting composition has a different odor note. SUMMARY OF THE INVENTION Accordingly, one object of the present invention is to provide CC, 8-unsaturated ketones, which have sweet odors and yet have odor notes which are different from the odor notes of known aroma chemicals (fragrances). Another object of the present invention is to provide a, ss -unsaturated ketones which are useful as aroma chemicals to be mixed with other aroma chemicals or perfumes. The invention furthermore relates to the use of said ketones as aroma chemicals for imparting odor or odor notes to a wide variety of substrate materials such as cosmetics and soaps or technical products. Thus the present invention relates to a,p ,ss -un- saturated ketones of the general formula I EMI2.1 wherein R1, R2 R3 are the same or different and each re- presents a straight or branched lower alkyl group. Furthermore the present invention relates to fragrance compositions or perfumes which contain an olfactorily sensible amount of at least one of said &alpha;,ss-un- saturated ketones. The present invention also relates to the use of said &alpha;,ss -unsaturated ketones as aroma chemicals (fragrances) for imparting an odor note to a substrate material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the general formula (I) above, each of the R1, R and R3 substituents is a straight or branched lower alkyl group, preferably an alkyl group having from 1 to 4 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl. Examples of particularly preferred &alpha;,ss-unsaturated ketones of the present invention are: 5,5,8-trimethyl-3,7-nonadien-2-one; 5,8-dimethyl-5-ethyl-3,7-nonadien-2-one; S,8-dimethyl-5-(n-propyl)-3,7-nonadien-2-one; 5-(n-butyl)-5-ethyl-8-methyl-3,7-nonadien-2-one; 6,6,9-trimethyl-4,8-decadien-3-one; 2,6,6,9-tetramethyl-4,8-decadien-3-one; 7,7,10-trimethyl-5,9-undecadien-4-one'.. 8,8,11-trimethyl-6,10-dodecadien-5-one. The a,ss -unsaturated ketones of the present invention can be produced, for example by the following synthetic route: EMI4.1 R11 R2 and R3 are as defined above. Thus, a 2-substituted-5-methyl-4-hexen-l-al of the general formula (II) is reacted with a ketone of the general fon=ia (III) in the presence of a base to give an &alpha;, ss-unsaturated ketone of the general formula (I). The ketone (III) is generally used in an approximately equimolar amount or excess amount relative to the 2-substituted-5methyl-4-hexen-l-al (II). Examples of suitable bases include sodium hydroxide, potassium hydroxide, sodium methoxide, sodium ethoxide, potassium tert-butoxide and the like. The base is generally employed in a catalytic amount to an approximately equimolar amount relative to the ketone (III). The reaction is conducted in the presence or absence of a solvent. Examples of suitable solvents include methanol, ethanol, tert-butyl alcohol and water. The reaction may be conducted at temperatures ranging from about -70 C to about 150"C. The &alpha;,ss-unsaturated ketones of the general formula (I) have various floral aromas. By way of example, 5,5,8 trimethyl-3,7-nonadien-2-one has a woody odor witb an -ozone-like note accompanied by a green top note, while 6,6,9-trimethyl-4,8-decadien-3-one has a floral odor accompanied by a sweet honey-like odor note.The a,S- unsaturated ketones of the general formula (I)- have high diffusivity and retentivity and blend. well with many other fragrances, and aroma chemicals and is thus of value as a raw material to be compounded with a fragrance or a fragrance caFosition which has a floral odor note such as muguet, rose, hyacinth or lilac. The a,B-unsaturated ketones of the general2form:1a (I) can be added to perfumes and fragrance compositions in a pure form or as a mixture to provide the desired odor note to a finished perfume. The perfume and fragrance compositions obtained according to the present invention are suitable for use in a wide variety of perfumed articles and can also be used to enhance, modify or reinforce natural fragrant products The term "perfume and fragrance composition", as used herein, means a mixture of compounds including, for example, natural oils, synthetic oils, alcohols, aldehydes, ketones, esters, lactones, and frequently hydrocarbons which are admixed so that the combined odors of the individual components produce a pleasant or desired odor note. Such perfume and fragrance compositions usually contain (a) top notes which are usually lowboiling fresh-smelling fragrances, (b) a bouquet (middle note), c) modifiers which round off and accompany the bouquet and, (d) end notes including fragrances which lend a particular note to the composition throughout all stages of evaporation and substances which retard evaporation. Such perfume and fragrance compositions of the present invention can be used in conjunction with carriers, vehicles, solvents, dispersants, emulsifiers, surface-active agents, aerosol propellants and the like. In perfume and fragrance compositions, the individual components contribute their particular olfactory characteristics to the composition, but the overall effect of the perfume and fragrance composition will be the sum of the effects of each ingredient. Thus, the a,8-unsaturated ketone of i general formula (z) canbeused to alter the odor note of a perfume and fragrance composition, for example, by highlighting or moderating the olfactory reaction contributed by another ingredient of the composition. The perfume and fragrance compositiorsaccording to the present invention contain an olfactorily sensible amount of an a,B-unsaturated ketone of the general formula (I), which varies according to the intended use of the composition; for example, it may range from about 0.005 weight percent to 95 weight percent. The perfume and fragrance composition of the present invention can be used in a large variety of ways. For example, it can be used as it is or in soaps; deodorants; perfumes and eau de Cologne; cosmetic preparations such as lotions, creams, etc.; bath additives such as bath oil,.bath salts, etc.; hair preparations such as hair tonics, pomades, hair liquids, hair creams, stick pomades, shampoos, rinses, etc.; cleansers; detergents and the like. In addition, the perfume and fragrance composition can be used for imparting an odor to technical products such as textile fibers and fabrics or paper products. The a,B-unsaturated ketonesof the general formula (I) are also useful as an ingredient for the preparation of artificial flavors and as flavor additives in foodstuffs, animal feeds, beverages, pharmaceutical preparations and tobacco products. The term "foodstuff" is used in this specification in its broadest sense and is meant to include products such as coffee, tea and cocoa. When the a,6-unsaturated ketones of the general formula (I)are used as a flavoring agent or an additive for modifying the organoleptic properties of foodstuffs, animal feeds, beverages, pharmaceutical preparations and tobacco products, the ,ss- unsaturated ketones can be used in proportions ranging from 0.1 to 10 ppm, based on the weight of the products to be flavored. However, these proportions can be increased beyond 10 ppm up to about 100 ppm in order to achieve special flavoring effects. In the preparation of flavoring compositions by admixing an a,6-unsaturated ketone the general formla (I) with other anne chemicals, the same can be used, for example, in proportions of about 0.l to about 15% of the total weight of the flavoring composition. In many cases, average proportions of about l to 10% by weight will give the desired results. The above-mentioned fragrance compositions provided by this invention have a modern and high-quality which makes the best use of the odor of the &alpha;, ss- unsaturated ketones-of the general formula (I). Having generally described this invention, a further understanding can be obtained by reference to certain specific examDles which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified. Example 1 Svnthesis of 5,5 ,8-trimethvl-3 ,7-nonadien-2-one EMI9.1 To a mixture of 250 g (1.79 mol) of 2,2,5 trimethyl-t-hexen-l-al and 750 g (12.9 mol) of acetone was added a solution of 36 g (0.643 mol) of potassium hydroxide in 1250 g of methanol and the whole mixture was stirred at 40-500C for 23 hours. The reaction mixture was then cooled with ice and adjusted to a pH of about 4 with diluted hydrochloric acid, followed by addition of 10 g of sodium hydrogen carbonate. The reaction mixture was stirred for 2 hours, at the end of which time it was filtered and the filtrate was distilled under reduced pressure to remove a lowboiling fraction. The water was removed from the distillation residue and the remaining liquid was further subjected to vacuum distillation (510C/266 Pa) to give 200 g (1.11 mol) of 5,5,8-trimethyl-3,7nonadien-2-one as a colorless liquid. Yield 62%. The physical data of this product are as follows: Mass spectrum (m/e): 180 [M+ CDCl3: 1H-NMR spectrum (90 MHz) # HMS 6.70 (d, J=16Hz, 1H), 5.88 (d, J=16Hz, 1H), 5.154.87 (m, lH), 2.16 (s, 3H), 1.95 (d, J=8Hz, 2H), 1.61 (s, 3H), 1.50 (s, 3H), 0.97 (s, 6H) Example 2 Svnthesis of 6,6,9-trimethvl-4,8-decadien-3-one EMI10.1 To a mixture of 230 g (1.64 mol) of 2,2,5 trimethyl-4-hexen-l-al and 1018 g (14.1 mol) of methyl ethyl ketone was added a solution of 33 g (0.59 mol) of potassium hydroxide in 1150 g of methanol and the whole mixture was stirred at 400C for 13.5 hours and, then, at 500C for 27 hours. The reaction mixture was cooled with ice and adjusted to a pH of about 4 with diluted hydrochloric acid, followed by addition of 10 g of sodium hydrogen carbonate. The reaction mixture was stirred for 2 hours at the end of which time it was filtered and the filtrate was distilled under reduced pressure to remove the low-boiling fraction. The water was removed from the residue and the remaining fluid was further subjected to vacuum distillation (80-820C/ 266 Pa) to give 156 g (0.80 mol) of 6,6,9-trimethyl-4,8decadien-3-one as a colorless liquid. Yield 49%. The physical data of this product are as follows: Mass spectrum (m/e): 194 [M+] 1H-NMR spectrum (90 MHz) dCDCl3 6.73 (d, J=16Hz, 1H), 5.91 (d, J=16Hz, 1H), 5.13- 4.87 (m, 1H), 2.46 (q, J=7Hz, 2H), 1.94 (d, J=8Hz, 2H), 1.60 (s, 3H), 1.49 (s, 3H), 1.00 (t,) J=7Hz, 3H), 0.96 (s, 6H). Examples 3-5 EMI11.1 The reaction and work-up procedures of Example 1 were repeated except that various 2-substituted-5methyl-4-hexen-1-als were used in lieu of 2,2,5trimethyl-4-hexen-1-al to give the corresponding &alpha;,ss-unsaturated ketone compounds. The yields and physical data of the products are shown in Table 1. Table 1 2-Substituted-5-methyl- &alpha;,ss-Unsaturated ketone Example 4-hexen-1-al of formula of formula (II') (I') R1 R2 Yield Mass spectrum (%) (m/e) 3 CH3 C2H5 55 194 tM+) 4 CH3 n-C3H7 52 208 [M+] 5 C2H5 n-C4H9 48 236 [M+] Examples 6 and 7 EMI13.1 The reaction and work-up procedures of Example 2 were repeated except that various other ketones were used in lieu of methyl ethyl ketone to give the corresponding &alpha;,ss-unsaturated ketone compounds. The yields and physical data of the products are shown in Table II. Table II Example Ketone of formula &alpha;,ss-Unsaturated ketone (III) of formula (I") R3 Yield Mass spectrum (%) (m/e) 6 i-C3H7 45 208 [M+] 7 n-C4H9 46 222 [M+] Example 8 Perfume and Fracrance Composition of the Muauet Type A perfume and fragrance composition having a muguet-like odor was prepared from the following ingredients. Parts by weight Phenethyl alcohol 15 Hydroxycitronellal 30 tinalool 5 Benzyl alcohol S Benzyl salicylate 3 Geraniol 5 &alpha;-Terpineol 5 Linalyl acetate 5 Ylang ylang oil 2 Jasmin compound 5 Tetrahydrolinalool 2 He liotrcp ine 3 Musk ketone 2 5,5,8-Trimethyl-3 r 7-nonadierr-2-one 5 92 Example 9 Perfume and Fraarance Composition of the White Rose Type A perfume and fragrance composition having a white rose-like odor was prepared from the following ingredients. Parts by weight Ceraniol 20 Benzyl acetate 10 Phenethvl alcohol 10 Rhodinol 10 Geranium oil 5 Phenethyl acetate 5 Bergamot oil .5 Linalool 10 Patchouli oil 2 Hydroxvcitronellal 5 a-Ionone 5 Eugenol 3 Musk tincture 5 5,5,8-Trimethyl-3,7-nonadien-2-one 5 100 Examole 10 Perfume and Frarance Comosition of the Violet Type A perfume and fragrance composition having a violet-like odor was prepared from the following ingredients: : Parts by weight a-Ionone 20 Methylionone 20 Phenethyl alcohol 10 Benzyl alcohol 5 Linalool 5 Bergamot oil 3 Cananga oil 2 Rose compound 5 Jasmin compound 5 Hydroxycitronellal 5 Violet leaf oil 3 Labdanum resin 2 Vetiver oil 3 Sandalwood oil 2 Musk ambrette 5 5,5,8-Trimethyl-3,7-nonadien-2-one 5 100 Example 11 Perfume and Fraarance Composition of the Hvacinth Type A perfume and fragrance composition having a hyacinth-like odor was prepared from the following ingredients: : Parts by weight Phenethyl alcohol 15 Phenylacetaldehyde 10 Benzyl acetate 5 Methylionone 5 &alpha;-Ionone 5 Ylang ylang oil 5 Bergamot oil 5 Jasmin absolute 3 Rose absolute 3 Cinnamic alcohol 10 D iinethylbenzylcarbirol 3 Linalyl acetate 5 Musk tincture 3 5,5,8-Trimethyl-3,7-nonadien-2-one 5 82 Example 12 Perfume and Fragrance Composition of the Modern Bouquet Type A perfume and fragrance composition having a modern bouquet-like odor was prepared from the following ingredients: : Parts by weight Phenethyl alcohol 20 Geraniol 15 Benzyl acetate 15 Methyl dihydrojasmonate 10 Pose compound S Jasmin compound 5 Bergamot oil 5 Me thylionone 5 Aldehyde C-10 (10%) 3 Aldehyde C-li (10%) 3 Sandalwood oil 3 Heliotropine 3 Musk ambrette 3 6,6,9-Trimethyl-4,8-decadien-3-one 5 100 Example 13 Perfume and Fragrance Comoosition of the Lilac Tvpe A perfume and fragrance composition having a lilac-like odor was prepared from the following ingredients: : Parts by weight a-Tersineol 20 Hydroxycitronellal 15 Linalool 15 Phenethyl alcohol IS Benzyl alcohol 5 Ylang ylang oil 5 Geraniol 5 Cinnamic alcohol 5 Jasmin absolute 2 Styrax resin 3 Heliotropine 5 6,6,9-Trimethyl-4,8-decadien-3-one 5 100 Example 14 Perfume and Fragrance Composition of the Jasmin Type A perfume and fragrance composition having a jasmin-like odor: was prepared from the following ingredients: Parts by weight &alpha;-Amylcinnamic aldehyde 25 Benzyl acetate 30 Hydroxycitronellal 5 Phenethyl alcohol 5 Linalyl acetate 5 Ylang ylang oil 5 Methylionone 5 Methyl dihydrojasnonate 5 Jasmin absolute 2 Isojasmone 1 Indole (1%) 2 Peru balsam 2 Heliotropine 3 6,6,9-Trimethyl-4,8-decadien-3-one 5 100 Example 15 Perfume and Fragrance Comsosition of the Rose TvDe A perfume and fragrance composition having a roselike odor was prepared from the following ingredients: : Parts by weight Phenethyl alcohol 30 Linalool 5 Linalyl acetate 3 Benzyl acetate 10 a-Ionone 5 G2raniol 20 Citronellol 10 Geranium oil 5 Eugenol 1 Rose absolute 2 Musk ambrette 4 6,6,9-Trimethyl-4,8-decadien-3-one 5 100 Example 16 Plum Flavorina Composition A plum flavoring composition for food use was prepared from the following ingredients: Parts by weight Ethyl acetate 15 Ethyl butyrate 10 Ethyl formate 5 Aldehyde C-16 4 #-Nonyllactone 2 Benzaldehyde 2 Amyl alcohol 7 Amyl formate 12 Amyl butyrate 15 Allyl caproate 1 Citral 1 Orange oil 10 Clove oil 2 Coriander oil 2 Vanillin 2 6,6,9-Trimethyl-4,8-decadien-3-one 10 100 Example 17 RasDberrv Flavorina ComDosition A raspberry flavoring composition for food use was prepared from the following ingredients: : Parts by weight Ethyl acetate 10 Phenethvl alcohol 10 Amyl propionate 5 Geraniol 5 Benzyl acetate 5 Lemon oil 10 Isobutyl acetate 5 Clove oil 2 Hexyl acetate 5 Ethyl caproate 3 Methylionone 2 Anisaldehvde 3 cis-3Hexen-l-ol 1 Aldehvde C-9 3 Aldehvde C-20 15 Coumarin 1 6,6,9-Trimethyl-4,8-decadien-3-one 15 100

Claims: WHAT IS CLAIMED IS: 1. An a,6-unsaturated ketone of the general formula I EMI25.1 wherein R1, R2 and R3 are the same or different and each represents a straight or branched lower alkyl group. 2. A fragrance or perfume composition, which comprises: an olfactorily sensible amount of an &alpha;,ss- unsaturated ketone of the general formula I EMI25.2 wherein R1, R2 and R3 are the same or different and each represents a straight or branched lower alkyl group. 3. A process for Imparting an aroma to a substrate material, comprising: adding an olfactorily sensible amount of an a, unsaturated ketone of the general formula I EMI26.1 wherein R1, R2 and R3 are the same or different and each represents a straight or branched lower alkyl group to the substrate material. 4. The use of an &alpha;,ss-unsaturated ketone according to claim 1 as a fragrance or aroma chemical for imparting aromas to substrate materials.

Inventors: FUJITA, YOSHIJI, KANEHIRA, KOICHI
Applicants: KURARAY CO., LTD.
Application year: 1987
Main classification: C07C49
IPC codes: C07C45, A23L1, C07C49, A61K8, C11B9, C11D3, C07C67, A61Q13