CYCLOALKENYL BUTENONES AND FRAGRANCE COMPOSITIONS COMPRISING

The present invention refers to a novel class of substituted cycloalkenyl butenones possessing damascone-like odour notes and to their use as odorants. This invention relates furthermore to a method for their production and for fragrance compositions comprising them.

In the fragrance industry there is a constant demand for new compounds that enhance, modify or improve on odour notes. Damascones, also known as rose ketones, constitute an important class of perfume ingredients. They display particular floral

(rosy)-fruity notes reminiscent of dried fruits. Thus, there is a constant desire to find new compounds possessing a damascone-like odour note.

The a-, β-, &damascones (A) and ^-damascenone (B) can be considered as a subfamily in the floral-fruity domain of perfumery ingredients, as they display a very typical and complex odour of rose and fruit (such as apple or plum with blackcurrant aspects). Thus, while the scent of α-damascone is rose, apple, blackcurrant, the odour of is more blackcurrant, plum, and still rose. The olfactive notes of δ- damascone are more red rose and less apple than α-damascone and less plum than β- damascone, whereas ^-damascenone is olfactorily described as rose, plum, raspberry, sugary (A. Williams; Perfumer & Flavorist 2002, 27, 18-31).

B

A large number of cyclohexenylbutenones has been described in literature as damascone analogues. However, the geminal methyl groups of the cyclohexene ring of the damascones are usually retained. For example, isodamascone (C), possessing natural fruit-like and increasing wine-like and fresh flower-like nuances (US 3,822,315), or ^damascone, which is more fruity than α- and /?-damascone with a dominant floral,

rosy and green note (A. Williams; Perfumer & Flavorist 2002, 27, 18-31). Indeed, the structural analogues of damascone not possessing a gem-dimethyl group on the cyclohexene ring display odor notes that are very distinguishable from the typical damascone note. For example, 1-(but-2-enoyl)-2-methyl-cyclohex-1-ene (D), disclosed in GB 1335339, is described as flavour ingredient conferring dried fruit aspect to flavour compositions, whereas the addition of this compound to a fragrance composition, such as after-shave, was found to bring a fresh, pleasant leather note. Indeed, 1-(but-2- enoyl)- 2-methyl-cyclohex-1-ene presented after resynthesis and purification, beside fruity odor notes, i.e. apple, juicy, with cork aspects, a strong and characteristic medicinal odor note reminiscent of methyl benzoate, methyl salicylate and methyl nicotinate. This makes its use as damascone replacer in fragrance compositions inappropriate. Another example can be found in CH 616078, which discloses a mixture of 1-(2,3,6-trimethylcyclohex-1-enyl)but-2-en-1-one and 1-(2,5,6-trimethylcyclohex-1- enyl)but-2-en-1-one (E) which is described as being reminiscent of a- and β- damascone, but being more fruity, natural and less woody. It is thus suitable for the creation of new olfactive notes. Due to their inappropiate odour character, these compounds are not suitable for the replacement of compounds possessing the typical damascone-like odor note.

D

Accordingly, everything in the prior art indicates that the geminal methyl groups are an important structural feature of the compounds in order to retain the typical odour note of damascone.

Surprisingly, we have found that the presence of the geminal methyl groups on the cyclohexene ring is in some cases not necessary for the obtaining of strong dried-fruit odour notes, very similar to the odour note of the damascones.

Thus, the present invention refers in a first aspect to compounds of formula (I)

wherein n is 1 to 5, e.g. 2,3, or 4; R ¹ is H, CH ₃ , or C ₂ H ₅ ; and the bond between C-2 and C-3 is a single bond and the dotted line together with the bond between C-1 and C-2 represents a double bond; or the bond between C-1 and C-2 is a single bond and the dotted line together with the bond between C-2 and C-3 represents a double bond, and C-1 is optionally substituted with methyl or ethyl.

The compounds of formula (I) wherein the bond between C-2 and C-3 is a single bond and the dotted line together with the bond between C-1 and C-2 represents a double bond represent particular aspects of the invention.

The compounds of formula (I) comprise up to two chiral centres and as such may exist as a mixture of stereoisomers, or they may be resolved as isomerically pure forms. Resolving stereoisomers adds to the complexity of manufacture and purification of these compounds, and so it is preferred to use the compounds as mixtures of their stereoisomers simply for economic reasons. However, if it is desired to prepare individual stereoisomers, this may be achieved according to methods known in the art, e.g. preparative HPLC and GC, crystallization or stereoselective synthesis.

Particularly preferred compounds of formula (I) are 1-(2-ethylcyclohex-2-enyl)but-2-en- 1 -one, 1 -(2-ethylcyclohex-1 -enyl)but-2-en-1 -one, 1 -(2-ethyl-5-methylcyclohex-2- enyl)but-2-en-1-one, 1-(2-ethyl-5-methylcyclohex-1-enyl)but-2-en-1-one, 1-(2- ethylcyclohept-1-enyl)but-2-en-1-one, and 1-(2-ethyl-1-methylcyclohex-2-enyl)but-2-en- 1-one.

Amongst the invention's compound, one may cite 1-(2-ethyl-1-cyclohexen-1-yl)-2-buten- 1-one which has an odour characterized by a very diffusive and powerful damascone note, very fruity and apple-like.

The compounds according to the present invention may be used alone or in combination with known odorant molecules selected from the extensive range of natural and synthetic molecules currently available, such as essential oils and extracts, alcohols, aldehydes and ketones, ethers and acetals, esters and lactones, macrocycles and heterocycles, and/or in admixture with one or more ingredients or excipients conventionally used in conjunction with odorants in fragrance compositions, for example, carrier materials, and other auxiliary agents commonly used in the art.

The following list comprises examples of known odorant molecules, which may be combined with the compounds of the present invention:

- essential oils and extracts, e.g. oak moss absolute, basil oil, tropical fruit oils, such as bergamot oil and mandarine oil, mastic absolute, myrtle oil, palmarosa oil, patchouli oil, petitgrain oil, wormwood oil, lavender oil, rose oil, jasmin oil, ylang- ylang oil and sandalwood oil.

- alcohols, e.g. cis-3-hexenol, cinnamic alcohol, citronellol, Ebanol ^® , eugenol, farnesol, geraniol, menthol, nerol, rhodinol, Super Muguet™, linalool, phenylethyl alcohol, Sandalore ^® , terpineol and Timberol ^® (1-(2,2,6-Trimethylcyclohexyl)hexan-3- ol).

- aldehydes and ketones, e.g. citral, hydroxycitronellal, Lilial ^® , methylnonylacetaldehyde, anisaldehyde, allylionone, verbenone, nootkatone, geranylacetone, α-amylcinnamic aldehyde, Georgywood™, hydroxycitronellal, lso E

Super ^® , lsoraldeine ^® (methylionone), Hedione ^® , maltol, methyl cedryl ketone, and vanillin.

- ethers and acetals, e.g. Ambrox ^® , geranyl methyl ether, rose oxide or Spirambrene ^® .

- esters and lactones, e.g. benzyl acetate, cedryl actetate, γ-decalactone, Helvetolide ^® , ^•undecalactone, vetivenyl acetate, cinnamyl propionate, citronellyl acetate, decyl acetate, dimethylbenzylcarbinyl acetate, ethyl acetoacetate, cis-3-hexenyl isobutyrate, linalyl acetate and geranyl acetate.

- macrocycles, e.g. ambrettolide, ethylene brassylate or Exaltolide ^® .

- heterocycles, e.g. isobutylquinoline.

The compounds of the present invention may be used in a broad range of fragrance applications, e.g. in any field of fine and functional perfumery, such as perfumes, household products, laundry products, body care products and cosmetics. The compounds can be employed in widely varying amounts, depending upon the specific application and on the nature and quantity of other odorant ingredients. The proportion is typically from 0.0001 to 2 weight percent of the application. In one embodiment, compounds of the present invention may be employed in a fabric softener in an amount of from 0.0001 to 0.005 weight percent. In another embodiment, compounds of the present invention may be used in an alcoholic solution in amounts of from 0.01 to 3 weight percent, more preferably between 0.5 and 2 weight percent. However, these values are given only by way of example, since the experienced perfumer may also achieve effects or may create novel accords with lower or higher concentrations, e.g. up to about 20 weight percent based on the fragrance composition.

The compounds of the present invention may be employed into the fragrance application simply by directly mixing the fragrance composition with the fragrance application, or they may, in an earlier step, be entrapped with an entrapment material such as polymers, capsules, microcapsules and nanocapsules, liposomes, film formers, absorbents such as carbon or zeolites, cyclic oligosaccharides and mixtures thereof, or they may be chemically bonded to substrates, which are adapted to release the fragrance molecule upon application of an external stimulus such as light, enzyme, or the like, and then mixed with the application.

Thus, the invention additionally provides a method of manufacturing a fragrance application and consumer products resulting therefrom. The method comprises the incorporation therein of a compound of formula (I) as a fragrance ingredient, either by directly admixing the compound to the application or by admixing a fragrance composition comprising a compound of formula (I), which may then be mixed to a fragrance application, using conventional techniques and methods. Through the addition of an olfactory acceptable amount of a compound of the present invention, the odor notes of a fragrance application will be improved, enhanced or modified.

Thus, the invention furthermore provides a method for improving, enhancing or modifying a fragrance application through the addition thereto of an olfactory acceptable amount of a compound of formula (I), or a mixture thereof.

The invention also provides a fragrance application comprising: a) as odorant a compound of formula (I) or a mixture thereof; and b) a consumer product base.

As used herein, "fragrance application" means any products, such as fine fragrances, e.g. eaux de perfume and eaux de toilette; household products, e.g. detergents for dishwasher, surface cleaner, air freshener; laundry products, e.g. softener, bleach, detergent; body care products, e.g. after-shave lotion, shampoo, shower gel, shower and bath salt, hygiene product; and cosmetics, e.g. deodorants, vanishing creams, comprising an odorant. This list of products is given by way of illustration and is not to be regarded as being in any way limiting.

Compounds of formula (I) may be prepared by acylation of the appropriated 1-ethylcycloalkene (1) with crotonyl chloride or crotonic anhydride in the presence of a Lewis acid. When 1 is unsubstituted at position 2 the resulting mixture of isomers may be enriched in the diconjugated isomers by isomerisation, e.g., by heating, for example in toluene in the presence of an acid, such as PTSA, as shown in scheme 1.

Scheme 1 :

R ¹ has the same meaning as given for formula (I) and R' is H, methyl or ethyl.

Starting from a cycloalkene comprising a tetra-substituted double bond may result in a mixture of two isomers. The mixture of isomers may be separated under conditions known to the person skilled in the art, or they may be used as a mixture.

Compounds of formula (I) may also be prepared by condensation of acetaldehyde with methyl ketones obtainable from 2-ethylcycloalkanones by reaction with an acetylide followed by Rupe rearrangement, and subsequent water elimination leading to the desired butenones.

Thus, the present invention refers in a further aspect to a mixture of compounds comprising a compound of formula (I) and further comprising a compound of formula (I ¹ )

(I) (I ¹ ) wherein n is 1 to 5, e.g. 2,3, or 4;

R ¹ is H, CH ₃ , or C ₂ H ₅ ; and the bond between C-1 and C-2 represents a single bond and the dotted line together with the bond between C-2 and C-3 represents a double bond, and C-1 is substituted with methyl or ethyl; and R' is methyl or ethyl.

The invention is now further described with reference to the following non-limiting examples. These examples are for the purpose of illustration only and it is understood that variations and modifications can be made by one skilled in the art.

Example 1 : 1-(2-Ethylcvclohex-2-env0but-2-en-1-one

a) 1-Ethylcvclohexene

A solution of ethyl bromide (126.2 g, 1.6 mol) in diethyl ether (700 ml) was added to magnesium turnings (28.2 g, 1.6 mol). The reaction mixture was stirred for 1 h at room temperature (RT), cooled to O ⁰ C, and treated within 1h with a solution of cyclohexanone (103.6 ml, 1.0 mol) in diethyl ether (140 ml). The resulting mixture was then stirred for 18h at RT, cooled to O ⁰ C, and acidified with concentrated HCI to pH 1. The aqueous phase was extracted with diethyl ether. The combined organic phases were washed with water, aq. sat. NH ₄ CI solution, dried (Na ₂ SO ₄ ) and concentrated in vacuo to give crude 1-ethylcyclohexanol (169 g).

The crude 1-ethylcyclohexanol was treated, in a flask equiped with a V/greux-distillation apparatus, with phosphoric acid (130 g) and heated at 14O ⁰ C under vacuum (from 20 to 2 mbar). The distillate was decanted and the org. phase dried (Na ₂ SO ₄ ) to yield the crude product (122 g). W/dmer-distillation (300 to 100 mbar, bath temperature: 12O ⁰ C) gave a 88:12 mixture of 1-ethylcyclohexene/ethylidenecyclohexane (80 g, 73%).

b) 1 -(2-Ethylcvclohex-2-env0but-2-en-1 -one

Crotonyl chloride 90% (52.3 g, 0.45 mol) was added to a solution of tin tetrachloride

(221 g, 0.85 mol) in dichloromethane (850 ml) at -7O ⁰ C. After 15 min. stirring, a solution of a 88:12 mixture of 1-ethylcyclohexene/ethylidenecyclohexane (41 g, 0.37 mol) in dichloromethane (100 ml) was added during 20 min. The reaction mixture was stirred for 2.5h at -70 ⁰ C and poured into ice/NaHCO ₃ /H ₂ O. The org. phase was washed with aq. sat. NaCI solution. The aqueous phases were extracted with diethyl ether, the combined organic phases were dried (Na ₂ SO ₄ ), and the solvent evaporated. Short-path V7gret/x-distillation (0.7 mbar) of the crude product (63.3 g) followed by flash chromatography (FC) (300 g SiO ₂ , hexane/diethylether 90:0.5) of 15 g of the highest- boiling fraction (120-150°C, 30 g) gave a 53:28:19 mixture of 1-(2-ethylcyclohex-2- enyl)but-2-en-1-one/2-cyclohexenylhex-4-en-3-one/1-(2-ethylc yclohex-1-enyl)but-2-en- 1-one (4.14 g, 6.3%), a 75:25 mixture of 1-(2-ethylcyclohex-2-enyl)but-2-en-1-one/1-(2- ethylcyclohex-1-eny!)but-2-en-1-one (4.0 g, 6.1 %), and pure 1-(2-ethylcyclohex-2-enyl)- but-2-en-1-one (2.1 g, 3.1%). Boiling point: 70°C (0.7 mbar).

¹ H-NMR (400MHz, CDCI ₃ ): (56.95 (dq, J = 6.8, 15.5, H-C(3)), 6.25 (dq, J = 1.7, 15.5, H- C(2)), 5.70-5.67 (m, H-C(3')), 3.31 (td, J = 0.9, 6.2, H-C(I')), 1.90 (dd, J = 1.8, 6.8, MeC(3)), 2.17-1.69 (m, 6H), 1.68-1.45 (m, 2H), 0.96 (t, J = 7.5, MeCH ₂ ).

MS (El): 179 (2), 178 (11), 163 (6), 150 (2), 149 (4), 135 (2), 121 (2), 109 (14), 108 (6), 93 (4), 91 (7), 81 (6), 80 (3), 79 (16), 78 (3), 77 (11), 70 (4), 69 (100), 68 (3), 67 (31 ), 65 (5), 55 (8), 53 (7), 51 (4), 43 (3), 41 (32), 39 (20), 29 (30), 27 (4). IR: v _max 3036, 3015, 2964, 2934, 2876, 2861 , 2838, 1694, 1666, 1628, 1443, 1375, 1315, 1288, 1251, 1189, 1126, 1061, 970, 911 , 872, 810, 756 cm ^"1 .

Odour description: Top notes: damascone-like. Dry-down notes: damascone-like, apple, myrrh.

Example 2: 1-(2-Ethylcvclohex-1-envQbut-2-en-1-one

A mixture of 2-ethylcyclohexanol (50 g, 0.39 mol) and water (80 ml) was successively treated with sodium dichromate dihydrate (46.6 g, 0.16 mol) and with a solution of sulphuric acid (96%, 29 ml, 0.53 mol) in water (150 ml). The temperature rose to 66°C then decreased and the reaction mixture was extracted with diethyl ether. The combined organic phases were washed with aq. sat. NaHCU ₃ solution, aq. sat. NaCI solution, dried (MgSO ₄ ), and concentrated to give crude 2-ethylcyclohexanone (47.2 g, 96%). A solution of 2-ethylcyclohexanone (41.6 g, 0.33 mol) in THF (200 ml) was added dropwise to a solution of lithium acetylide ethylene diamine complex (95%, 45 g, 0.46 mol, 1.4 eq.) in THF (200 ml) at 30-34 ⁰ C. After 15h stirring the reaction mixture was poured into ice/aq. sat. NH ₄ CI solution. The aqueous phase was extracted twice with MTBE and the combined organic phases were washed with brine, dried (MgSO ₄ ), and concentrated to give the crude 2-ethyl-1-ethynylcyclohexanol (49 g, 98%).

A solution of 2-ethyl-1-ethynylcyclohexanol (4.9 g, 32 mmol) in formic acid (10 ml) was heated at 8O ⁰ C during 6h, cooled, and poured into ice/water. The aq. phase was extracted with diethyl ether and the combined organic phases washed with water, aq. sat. NaHCθ ₃ solution, brine, dried (MgSO ₄ ), and concentrated. FC (400 g SiO ₂ , hexane/diethyl ether 100:5) of the crude product gave 1 -(2-ethylcyclohex-1 - enyl)ethanone (2.4 g, 49%).

At -7O ⁰ C, a solution of diisopropylamine (2.8 ml, 19.8 mmol) in THF (17 ml) was treated dropwise with a solution of /7-butyl lithium (1.6 M in hexane, 12.3 ml, 19.7 mmol), warmed up to O ⁰ C, cooled again to -70 ⁰ C, and treated dropwise with a solution of 1-(2- ethyl-1-cyclohexen-i-yQethanone (2.4 g, 15.8 mmol) in THF (17 ml). The reaction mixture was stirred for 30 min., treated dropwise with a solution of acetaldehyde (1.3 ml, 23 mmol) in THF (20 ml), and stirred for 30 min. After addition of 2N HCI, the mixture was poured into ice/aq. sat. NH ₄ CI solution, extracted with diethyl ether, and the combined organic phases were washed with aq. sat. NH ₄ CI solution, dried (MgSO ₄ ), and concentrated. FC (300 g SiO ₂ , hexane/diethyl ether 2:1→ 1 :1 ) of the crude product gave 1-(2-ethylcyclohex-1-enyl)-3-hydroxybutan-1-one (1.78 g, 58%). A solution of 1-(2-ethylcyclohex-1-enyl)-3-hydroxybutan-1-one (1.36 g, 6.9 mmol) was treated with p-toluenesulfonic acid monohydrate (10 mg, 0.05 mmol) in toluene (10 ml), refluxed during 1h and poured into brine. The aq. phase was washed with diethyl ether and the combined org. phases dried (MgSO ₄ ) and concentrated. FC (200 g SiO ₂ ,

hexane/diethyl ether 100:5) of the crude product gave 1-(2-ethylcyclohex-1-en-1-yl)but- 2-en-1-one (0.8 g, 65%). Boiling point: 100 ⁰ C (0.8 mbar).

¹ H-NMR (400MHz, CDCI ₃ ): £6.81 (dq, J = 6.8, 15.6, H-C(3)), 6.16 (dq, J = 1.7, 15.7, H- C(2)), 2.16-2.11 (m, 2H), 2.08-2.03 (m, 2H), 2.00 (q, J = 7.5, MeCH ₂ ), 1.92 (dd, J = 1.5, 6.8, MeC(3)), 1.69-1.60 (m, 4H), 0.96 (t, J = 7.6, MeCH ₂ ).

MS (El): 179 (2), 178 (18), 164 (10), 163 (80), 150 (6), 149 (16), 137 (5), 136 (5), 135 (18), 131 (3), 122 (11), 121 (100), 119 (4), 117 (4), 109 (5), 108 (3), 107 (14), 105 (7), 93 (14), 91 (18), 81 (7), 80 (3), 79 (22), 78 (5), 77 (19), 69 (27), 67 (23), 66 (3), 65 (10), 55 (16), 53 (12), 52 (4), 51 (7), 43 (6), 41 (43), 40 (4), 39 (27), 29 (6), 27 (7).

IR: v _m8x 3027, 2964, 2933, 2875, 2859, 2839, 1726, 1694, 1648, 1442, 1375, 1284, 1250, 1173, 1137, 1101 , 1045, 1014, 972, 933, 870, 822, 757, 692 crτϊ ¹ .

Odour description: Top notes: fruity (apple), £-damascone-like, diffusive. Dry down notes: damascone-like, powerful.

Example 3: mixture of 1-(2-ethylcvclohex-2-enyl)but-2-en-1 -one/1 -(2-ethylcvclohex-i - enyl)but-2-en-1-one

A solution of 15 g of the highest-boiling fraction from Example 1 b and p-toluenesulfonic acid monohydrate (0.28 g, 1.47 mmol) in toluene (100 ml) was refluxed during 24h and poured into brine. The aq. phase was washed with diethyl ether and the combined organic phases were dried (Na ₂ SO ₄ ) and concentrated. The residue (23.6 g) was purified by FC (700 g SiO ₂ , hexane/MTBE 19:1) to give 2-(cyclohexen-1-yl)hex-4-en-3- one (1 g, 1.5%) and a 1 :2 mixture of 1-(2-ethylcyclohex-2-enyl)but-2-en-1-one/1-(2- ethylcyclohex-1-enyl)but-2-en-1-one (3.07 g, 4.7%).

2-(Cyclohexen-1-yl)hex-4-en-3-one: Boiling point: 65°C (0.8 mbar).

¹ H-NMR (400MHz, CDCI ₃ ): £6.89 (dq, J = 6.9, 15.5, H-C(5)), 6.24 (dq, J = 1.7, 15.5, H-

C(4)), 5.61-5.57 (m, H-C(2')), 3.21 (g, J = 6.9, H-C(2)), 2.09-1.50 (m, 8H), 1.87 (dd, J =

1.6, 6.9, MeC(S)), 1.15 (d, J = 6.8, C(I)H ₃ ).

MS (El): 179 (2), 178 (14), 163 (8), 150 (3), 149 (3), 135 (4), 121 (2), 110 (4), 109 (39), 108 (9), 107 (3), 93 (6), 91 (7), 81 (13), 80 (3), 79 (17), 77 (11), 70 (4), 69 (100), 67

(35), 66 (3), 65 (6), 55 (13), 53 (10), 52 (3), 51 (4), 43 (5), 42 (2), 41 (40), 40 (4), 39 (24), 29 (3), 27 (5).

IR: v _ma χ3038, 2970, 2932, 2878, 2859, 2837, 1695, 1670, 1630, 1444, 1372, 1317, 1283, 1194, 1132, 1043, 968, 917, 802, 712 cm ^"1 .

Odour description (mixture of 1-(2-ethylcyclohex-2-enyl)but-2-en-1-one/1-(2- ethylcyclohex-1-enyl)but-2-en-1-one): damascone-like, fruity, apple.

Example 4: 1-(2-Ethyl-5-methylcyclohex-2-env0but-2-en-1-one

A mixture of i-ethyl-4-methylcyclohexene and 1-ethylidene-4-methylcyclohexane (87:13) was prepared in 81% yield from 4-methylcyclohexanone and ethyl bromide as described for 1-ethylcyclohexene in Example 1a. At -60 ⁰ C, a solution of crotonyl chloride 90% (1.6 g, 13.8 mmol) in dichloromethane (5 ml) was added to a solution of silver tetrafluoroborate (5 g, 25.7 mmol) in 1 :1 dichloromethane/1 ,2-dichloroethane (60 ml). The resulting mixture was stirred for 5 min. at -60 ⁰ C, treated with 1-ethyl-4-methylcyclohexene (1.9 g, 15.3 mmol), stirred for further 15 min., and poured into aq. sat. NaHCO ₃ solution. The org. phase was washed with water, dried (Na ₂ SO ₄ ) and concentrated. FC (SiO ₂ , hexane/Et ₂ O) of the residue followed by Kuge/ro/?r-distillation gave a 88:12 mixture of 1 -(2-ethyl-5-methylcyclohex-2- en-1-yl)but-2-en-1-one (30:70 diastereomeric mixture )/2-(4-methylcyclohexen-1-yl)hex- 4-en-3-one (1 :1 diastereomeric mixture) (1.5 g, 56%). Boiling point: 105°C (0.12 mbar).

¹ H-NMR (400MHz, CDCI ₃ ): 1-(2-ethyl-5-methylcyclohex-2-enyl)but-2-en-1-one (1 :2 diastereomeric mixture): £6.96 (dq, J = 6.8, 15.4, 0.3 H-C(3)), 6.93 (dq, J = 6.8, 15.4, 0.7 H-C(3)), 6.26 (dq, J = 1.8, 15.4, 0.7 H-C(2)), 6.21 {dq, J = 1.7, 15.4, 0.3 H-C(2)), 5.67-5.62 (m, 1 H-C(3')), 3.37-3.45 (m, 0.3 H-C(I')), 3.32 (br. d, J = 6.6, 0.7 H-C(I')), 2.23-1.20 (m, 7 H), 1.91 (dd, J = 1.8, 6.8, 0.3 MeC(3)), 1.89 (dd, J = 1.8, 6.8, 0.7 MeC(3)), 0.97 (t, J = 7.5, 0.7 /WeCH ₂ ), 0.97 (t, J = 7.5, 0.3 MeCH ₂ ), 0.96 {d, J = 6.7, 0.3 MeC(5)), 0.90 (d, J = 6.3, 0.7 MeC(5')).

2-(4-Methylcyclohexen-1-yl)hex-4-en-3-one (1 :1 diastereomeric mixture): £6.89 (dq, J = 6.8, 15.4, H-C(5)), 6.88 (dq, J = 6.8, 15.4, H-C(5)), 6.24 (dq, J = 1.7, 15.4, H-C(4)), 6.23 (dq, J = 1.7, 15.4, H-C(4)), 5.58-5.54 (m, 2 H-C(2')), 3.22 (q, J = 6.9, 2 H-C(2)), 2.23- 1.20 (m, 14H), 1.86 (dd, J = 1.8, 6.8, MeC(5)), 1.86 (dd, J = 1.8, 6.8, MeC(5)), 1.16 (d, J

= 6.8, C(I)H ₃ ), 1.15 (of, J = 6.8, C(I)H ₃ ), 0.93 {d, J = 6.3, MβC(4')), 0.93 (d, J = 6.3, MeC(4')).

MS (El): 193 (2), 192 (14), 191 (1), 190 (2), 177 (19), 173 (3), 164 (3), 163 (6), 149 (4), 135 (5), 123 (15), 121 (24), 107 (5), 95 (4), 93 (10), 91 (11), 81 (28), 79 (14), 77 (11), 70 (4), 69 (100), 67 (9), 65 (5), 55 (12), 51 (3), 43 (4), 41 (31 ), 39 (15), 29 (4), 27 (4). IR: v _max 3035, 3015, 2958, 2923, 2914, 2871 , 2853, 2830, 1694, 1667, 1629, 1456, 1443, 1375, 1292, 1188, 1066, 971 crrf ¹ .

Odour description: Top notes: fruity (apricot, plum), damascone-like. Dry down notes: dry fruity, damascone-like, apple, plum, pear, raisin, fresh.

Example 5: 1-(2-Ethyl-5-methylcyclohex-1-envπbut-2-en-1-one

At -78°C, a solution of tin tetrachloride (5.3 ml, 45.1 mmol) in dichloromethane (60 ml) was treated with crotonyl chloride 90% (2.6 ml, 24.2 mmol). The resulting mixture was stirred for 5 min. and treated with a solution of 87:13 1-ethyl-4-methylcyclohexene/1- ethylidene-4-methylcyclohexane (3.3 g, 26.6 mmol) in dichloromethane (10 ml). The reaction mixture was stirred for 1h at -78 ⁰ C and poured into ice/NaHCO ₃ /aq. sat. NaHCO ₃ . The aq. phase was extracted with diethyl ether and the combined org. phases were washed with water, dried (Na ₂ SO ₄ ), and concentrated. The crude mixture was dissolved in toluene (40 ml), treated with p-toluenesulfonic acid monohydrate (148 mg, 0.8 mmol), refluxed during 6h, and poured into water. The aq. phase was extracted with diethyl ether and the combined org. phases washed successively with aq. sat. NaHCO ₃ solution and water, dried (Na ₂ SO ₄ ), and concentrated. A repeated FC (SiO ₂ , hexane/Et ₂ O) of the residue gave 1-(2-ethyl-5-methylcyclohex-1-enyl)but-2-en-1-one (199 mg, 4%). Boiling point: 60°C (0.2 mbar).

¹ H-NMR (400MHz, CDCI ₃ ): 56.80 (dq, J = 6.9, 15.7, H-C(3)), 6.16 (dq, J = 1.7, 15.7, H- C(2)), 2.20 (br. d, J = 16.0, 1 H), 2.14-2.08 (m, 2H), 2.01 (g, J = 7.6, MeCH ₂ ), 1.92 (dd, J

= 1.8, 6.8, MeC(3)), 1.82-1.53 (m, 3H), 1.24 (dddd, J = 6.9, 9.8, 10.9, 12.8, 1H), 0.98 (d,

J = 6.6, MeC(5)), 0.96 (t, J = 7.6, MeCH ₂ ).

IR: v _ma* 3027, 2951, 2915, 2872, 2854, 2833, 1727, 1694, 1649, 1455, 1443, 1376,

1308, 1287, 1263, 1249, 1204, 1177, 1158, 1136, 1115, 1099, 1071, 1053, 1019, 972, 931, 833, 784, 758, 682 cm ^"1 .

Odour description: Top notes: damascone-like, apple, green, fresh. Dry down notes: damascone-like, raisin, rum.

Example 6: 1-(2-Ethylcvclohept-1-env0but-2-en-1-one

A mixture of 1-ethylcycloheptene and ethylidenecycloheptane (75:25) was prepared in 73% yield from cycloheptanone and ethyl bromide as described for ethylcyclohexene in Example 1a.

Crotonyl chloride 90% (2.9 ml, 27.1 mmol) was added to a solution of antimony pentachloride (3.8 ml, 30.0 mmol) in dichloromethane (150 ml) at -78°C. The reaction mixture was stirred for 15 min., treated with a solution of 75:25 1- ethylcycloheptene/ethylidenecycloheptane (3.7 g, 30.0 mmol) and ethyldiisopropylamine (5.1 ml, 30.0 mmol, 1.1 eq.) in dichloromethane (40 ml), stirred for 1 h at -78°C and poured into hexane (300 ml) containing 2 ml water. The resulting mixture was stirred, filtered, and the filtrate was washed with water. The aq. phase was extracted with hexane and the combined organic phases were dried (Na ₂ SO ₄ ) and concentrated. A solution of the crude product and p-toluenesulfonic acid monohydrate (150 mg, 0.8 mmol) in toluene (150 ml) was refluxed during 5h, and poured into water. The aq. phase was extracted with diethyl ether and the combined org. phases were washed successively with aq. sat. NaHCθ3 solution and water, dried (Na ₂ SO ₄ ), and concentrated. A repeated FC (SiO ₂ , hexane/Et ₂ O) of the residue gave 1-(2- ethylcyclohept-1-enyl)but-2-en-1-one (150 mg, 3%). Boiling point: 55 ⁰ C (0.09 mbar).

¹ H-NMR (400MHz, CDCI ₃ ): £6.79 {dq, J = 6.9, 15.6, H-C(3)), 6.16 {dq, J = 1.7, 15.7, H- C(2)), 2.28-2.21 (m, 4H), 2.01 (q, J = 7.4, MeCW ₂ ), 1.92 (dd, J = 1.6, 6.9, MeC(3)), 1.81- 1.74 (m, 2H), 1.58-1.50 (m, 4H) ₁ 0.97 (t, J = 7.5, /WeCH ₂ ). MS (El): 193 (5), 192 (36), 191 (2), 178 (8), 177 (62), 164 (8), 163 (27), 151 (5), 150 (7), 149 (41), 137 (8), 136 (9), 135 (30), 123 (9), 122 (13), 121 (100), 119 (4), 109 (7), 107 (16), 105 (8), 95 (8), 93 (18), 91 (20), 81 (31), 79 (26), 77 (19), 69 (60), 67 (21), 65 (9), 55 (24), 53 (13), 41 (48), 39 (22), 29 (6).

IR: v _max 3027, 2966, 2921, 2872, 2850, 1648, 1442, 1375, 1351, 1289, 1263, 1207, 1170, 1139, 1082, 1041, 971, 949, 931, 834, 791, 721 cm ^"1 .

Odour description: Tope notes: fruity (plum, jam), damascone-iike. Dry down notes: fruity, damascone-like.

Example 7: 1-(2-Ethyl-1-methylcvclohex-2-env0but-2-en-1-one and 1-(1-ethyl-2-methyl- cvclohex-2-env0but-2-en-1 -one

1-Ethyl-2-methylcyclohexene (72% pure: contained 4% of 1-ethylidene-2- methylcyclohexane and 24% of 1 :1 mixture of 1-ethyl-6-methylcyclohexene/6-ethyl-1- methylcyclohexene) was prepared in 88% yield from 2-methylcyclohexanone and ethyl bromide as described for ethylcyclohexene in Example 1a. The crude product was prepared according to the Example 9a using the above described alkene mixture (3.7 g, 30 mmol) and purified by FC (250 ml SiO ₂ , hexane/Et ₂ O 95:5) to give a 2:1 mixture of 1-(2-ethyl-1-methylcyclohex-2-enyl)but-2-en- 1-one and 1-(1-ethyl-2-methylcyclohex-2-enyl)but-2-en-1-one (1.1 g, 21%). Boiling point: 75°C (0.1 mbar).

¹ H-NMR (400MHz, CDCI ₃ ): 56.94 [dq, J = 6.9, 15.4, 0.7 H-C(3)), 6.92 (dq, J = 6.9, 15.2, 0.3 H-C(3)), 6.47 (dq, J = 1.7, 15.2, 0.3 H-C(2)), 6.39 (dq, J = 1.7, 15.2, 0.7 H-C(2)), 5.78-5.74 (m, 0.3 H-C(3')), 5.67-5.64 (m, 0.7 H-C(3')), 2.16-2.03 (m, 2x0.7 H + 2x0.3 H), 1.86 {dd, J = 1.6, 6.8, 0.3 MeC(3)), 1.85 (dd, J = 1.6, 7.0, 0.7 MeC(3)), 1.94-1.55 (m, 5x0.7 H + 6x0.3 H), 1.54 (dt, J = 1.5, 2.0, 0.3H, MeC(2')), 1.44 (dddd, J = 0.8, 2.8, 5.3, 13.1 , 0.7 H), 1.24 (s, 0.7H, MeC(I')), 0.99 (t, J = 7.3, 0.7 /WeCH ₂ ), 0.85 (t, J = 7.6, 0.3 MeCH ₂ ). IR: w 3039, 2965, 2936, 2875, 2837, 1693, 1628, 1443, 1374, 1290, 1148, 1061, 971, 928, 898, 871, 837, 805, 762, 689 crrf ¹ .

Odour description: damascone-like, blackcurrant (fruity, floral, agrestic).

Example 8: example of a perfume composition for soap

Compound/Ingredient parts by weight 1/1000

Aldehyde C 11 Undecylenic (10-Undecenal) 2.0 Aldehyde lso C 11 (trans-9-Undecenal) 1.2

Ciπnamic Alcohol 18.0

Citronellol 130.0

Citronellyl Acetate 36.0

Diphenyl Oxide 64.0 Ebanol ^® (CAS 67801-20-1 ) 2.6

Geraniol 185.0

Indole at 10% in DPG 14.0

2-lsobutylquinoline at 10% in DPG (dipropylene glycol) 1.0 lsoeugenol 3.0 Isoraldeine ^® 70 ¹⁾ 14.0

Lilial ²⁾ 26.0

Linalool ³⁾ 28.0

Methyl Octyne Carbonate ⁴⁾ at 1 % in DPG 6.0

Iris Givco 204/2 * 2.4 Phenyl Ethyl Alcohol 360.0

Rosacetol ⁵⁾ 15.0

Rose Oxide 3.0

Vanillin at 10% in DPG 6.0

Verdyl Acetate 80.0 1-(2-Ethyl-1-cyclohexen-1-yl)-2-buten-1-one 2.8

* Fragrance base available from Givaudan SA (see Fragrance Ingredients Index 2004)

1 ) 4-(2,6,6-Trimethyl-2-cyclohexen-1 -yl)-3-buten-2-one and 1-(2,6,6-trimethyl-2- cyclohexen-1-yl)-1-penten-3-one (main components); origin: Givaudan SA

2) p-tert.Butyl-alpha-methyldihydrocinnamic aldehyde; origin: Givaudan SA

3) 3,7-Dimethyl-1 ,6-octadien-3-ol; origin: Givaudan SA

4) Methyl- 2-nonynoate; origin: Givaudan SA

5) Thchloromethyl phenyl carbinyl acetate; origin: Givaudan SA

The 1-(2-ethyl-1-cyclohexen-1-yl)-2-buten-1-one of Example 2 brings a rosy-fruity aspect to the composition, enhancing its diffusion and its volume.