Background to the Invention Violet nitrile (2,6-nonadiene nitrile) is a known perfume ingredient but it is not possible, in general, to predict the olfactive nature of unsaturated nitriles.

Summarv of the Invention In one aspect, the present invention provides the novel diene nitrile, 2,7-octadiene nitrile.

The formula of 2, 7-octadiene nitrile is shown in formula 1 below: (Formula 1) The invention also covers fragrance compositions and fragranced products comprising 2,7- octadiene nitrile, especially such compositions and products comprising this compound in olfactively effective amounts. Also within the scope of the invention is use of 2,7- octadiene nitrile to impart fragrance properties to a fragrance composition or a fragranced product.

The invention further provides a method of imparting fragrance properties to a fragrance composition or a fragranced product by incorporating therein 2,7-octadiene nitrile.

Also within the scope of the invention is a process for preparing fragrance compositions, comprising adding to known fragrance materials an olfactively effective amount of 2,7- octadiene nitrile.

A"fragrance composition", as used herein, means a composition comprising various fragrance materials, and optionally a solvent, formulated to have certain useful fragrance characteristics. In most cases fragrance compositions are formulated to have a fragrance generally considered at least inoffensive and, preferably, pleasing to intended users of the composition. Fragrance compositions are used for imparting a desired odour to the skin and/or any product for which an agreeable odour is indispensable or desirable. The term "fragranced product"is used herein to mean a product having fragrance characteristics (generally attractive or inoffensive in nature) due to incorporation therein of one or more fragrance materials, eg in the form of a fragrance composition. Examples of such fragranced products are personal and household products including fabric washing powders, washing liquids, fabric softeners and other fabric care products; detergents and household cleaning, scouring and disinfection products; air fresheners, room sprays and pomanders; fine fragrances; soaps, bath and shower gels, shampoos, hair conditioners and other personal cleansing products; cosmetics such as creams, ointments, toilet waters, preshave, aftershave, skin and other lotions, talcum powders, body deodorants and antiperspirants etc. Fragrance compositions are also used in products that would normally have an unattractive or offensive odour, to mask this odour and produce an odour that is less unattractive or offensive. Products in this category include fuel odorants. The (generally pleasing) fragrance characteristics may be the main function of the product in to which the fragrance composition has been incorporated, as in the case of fine fragrances, or may be ancillary to the main function of the product, as, e. g., in the case of detergents, cleaning products and skin care products.

2,7-Octadiene nitrile has attractive fragrance characteristics. The odour type has been described as strong violet, green, citrus. The fragrance characteristics of 2,7-octadiene nitrile mean that it has potential application particularly in soaps, shower gels, shampoos, conditioners, air fresheners, fabric care fragrances and other personal cleansing products.

Other fragrance materials which can be advantageously combined with 2,7-octadiene nitrile in a fragrance composition are, for example, natural products such as extracts, essential oils, absolutes, resinoids, resins, concretes etc. and synthetic materials such as hydrocarbons, alcohols, aldehydes, ketones, ethers, acids, esters, acetals, ketals, nitriles, etc., including saturated and unsaturated compounds, aliphatic, carbocyclic and heterocyclic compounds.

Such fragrance materials are mentioned, for example, in S. Arctander,"Perfume and Flavor Chemicals" (Montclair, N. J., 1969), in S. Arctander"Perfume and Flavor Materials of Natural Origin" (Elizabeth, N. J., 1960) and in"Flavor and Fragrance materials-1991", Allured Publishing Co. Wheaton, Ill. USA.

Examples of fragrance materials which can be used in combination with 2,7-octadiene nitrile according to the invention include: geraniol, geranyl acetate, linalol, linalyl acetate, tetrahydrolinalol, citronellol, citronellyl acetate, dihydromyrcenol, dihydromyrcenyl acetate, tetrahydromyrcenol, terpineol, terpinyl acetate, nopol, nopyl acetate, 2- phenylethanol, 2-phenylethyl acetate, benzyl alcohol, benzyl acetate, benzyl salicylate, styrallyl acetate, benzyl benzoate, amyl salicylate, dimethylbenzylcarbinol, trichloromethylphenylcarbinyl acetate, p-tert-butylcyclohexyl acetate, isononyl acetate, vetiveryl acetate, vetiverol, a-hexylcinnamaldehyde, 2-methyl-3- (p-tert-butylphenyl)- propanal, 2-methyl-3- (p-isopropylphenyl) propanal, 3- (p-tert-butylphenyl) propanal, 2,4- dimethylcyclohex-3-enyl carboxaldehyde, tricyclodecenyl acetate, tricyclodecenyl propionate, 4- (4-hydroxy-4-methylpentyl)-3-cyclohexenecarboxaldehyde, 4- (4-methyl-3- pentenyl)-3-cyclohexenecarboxaldehyde, 4-acetoxy-3-pentyltetrahydropyran, 3- carboxymethyl-2-pentylcyclopentane, 2-n-heptylcyclopentanone, 3-methyl-2-pentyl-2- cyclopentenone, n-decanal, n-dodecanal, 9-decenol-1, phenoxyethyl isobutyrate, phenylacetaldehyde dimethylacetal, phenyl-acetaldehyde diethylacetal, geranyl nitrile, citronellyl nitrile, cedryl acetate, 3-isocamphylcyclohexanol, cedryl methyl ether, isolongifolanone, aubepine nitrile, aubepine, heliotropin, coumarin, eugenol, vanillin, diphenyl oxide, hydroxycitronellal, ionones, methylionones, isomethylionones, irones, cis- 3-hexenol and esters thereof, indan musks, tetralin musks, isochroman musks, macrocyclic ketones, macrolactone musks, ethylene brassylate.

Solvents which can be used for fragrance compositions which contain 2,7-octadiene nitrile according to the invention are, for example, ethanol, isopropanol, diethyleneglycol monoethyl ether, dipropyleneglycol, diethyl phthalate, triethyl citrate, isopropyl myristate etc.

The quantities in which 2,7-octadiene nitrile can be used in fragrance compositions or in fragranced products according to the invention may vary within wide limits and depend, inter alia, on the nature of the product, on the nature and quantity of the other components of the fragrance composition or fragranced product in which 2,7-octadiene nitrile is used and on the olfactive effect desired. It is, therefore, only possible to specify wide limits, which, however, provide sufficient information for the specialist in the art to be able to use 2,7-octadiene nitrile for his specific purpose. In fragrance compositions an amount of 0.01% by weight of the composition of 2,7-octadiene nitrile will generally have a perceptible olfactive effect. Preferably, the amount is at least 0.1%, more preferably at least 1.0%. Generally, the amount used in fragrance compositions will not exceed 80% by weight of the composition, although 2,7-octadiene nitrile is generally used in fragrance compositions according to the invention in amounts up to about 1.0 % by weight of the composition. The amount of 2,7-octadiene nitrile present in fragranced products according to the invention will generally be at least 10 ppm by weight of the product, preferably at least 100 ppm and more preferably at least 1000 ppm. However, levels of up to about 20% by weight may be used in particular cases, depending on the product to be perfumed.

2,7-Octadiene nitrile suitable for use in the invention can be prepared by any appropriate standard method for the production of nitriles. One suitable starting material is 2,7- octadien-1-ol which is commercially available or can be prepared by palladium catalysed coupling of two molecules of butadiene with one molecule of water. 2,7-Octadien-1-ol can be converted to the nitrile using any standard method for preparing nitriles. For example, 2,7-octadiene nitrile has been prepared in the laboratory by oxidation of 2,7-octadien-1-ol to 2,7-octadienal with pyridinium chlorochromate, conversion of the 2,7-octadienal to an oxime and subsequent dehydration of the oxime to 2,7-octadiene nitrile. This reaction scheme is illustrated below: Oh ou 2,7-octadien-1-ol 2,7-octadienal NOH 2,7-octadiene nitrile oxime The following, non-limiting, examples illustrate the preparation and use of 2,7-octadiene nitrile according to the invention.

EXAMPLE 1 Preparation of 2.7-octadiene nitrile.

Pyridinium chlorochromate (216 g, 1 mol) was placed in a 2 1 flask equipped with thermometer, condenser, stirrer and addition funnel. Dichloromethane (800 ml) was added and subsequently 2,7-octadien-1-ol (126g, 1 mol) was added dropwise with stirring over about 30 min. During addition, the heat of reaction was sufficient to heat the reactants to reflux. Stirring was continued for 30 min after addition stopped, the solvent was removed and the 2,7-octadien-1-al produced was purified by column chromatography (silica gel eluted with 1-10% diethyl ether in pentane).

2,7-octadien-1-al (6.2 g), hydroxylamine hydrochloride (3.5 g) and sodium acetate (8.2 g) were dissolved in 50 ml water and 100 ml ethanol in a flask fitted with a stirrer, condenser and thermometer. The solution was brought to reflux and the reflux was maintained for 2 hrs. After cooling to room temperature the solution was extracted with diethyl ether (2 x 100 ml), the organic layer was washed with water (2 x 50 ml) and dried over magnesium sulphate. The solvent was then removed by evaporation under vacuum.

The crude oxime (4.3 g) was placed in a flask equipped with a condenser with acetic anhydride (100 ml) and the mixture was refluxed for 2 hr. After cooling, the mixture was poured on to 500 ml ice/water and sodium hydrogen carbonate was added in portions until no more effervescence occurred and the pH of the mixture was between 8 and 9. The mixture was then extracted with diethyl ether (2 x 100 ml), the organic layer was washed with saturated sodium hydrogen carbonate solution (100 ml) and then with water (100 ml).

After drying over magnesium sulphate, the solvent was removed from the organic solution under vacuuni and the crude 2,7-octadiene nitrile was purified by column chromatography (silica gel eluted with 1-10% diethyl ether in pentane).

EXAMPLE 2 A typical fragrance composition including the novel compound of the invention is as follows: Ingredient % by weight Allyl heptanoate 3.80 Amberlyn Super PM 577 (Q) 0.80 Applinal (Q) 8.00 Calyxol (Q) 10.00 Cervolide (Q) 2.00 cis-3-Hexenol 1.60 Citrathal Concentrate TW (Q) 0.40 Cyclohexyl salicylate 3.80 Damascenone 0.60 2,7-octadiene nitrile (1 % in diethylphthalate (DPG)) 4.00 Dimethylphenylethyl carbinol 3.80 Ethyl 2,4-decadienoate 433 10 % DPG 0.40 Ethyl 2-methylbutyrate 1.20 Ethyl phenyl glycidate 0.20 Frutonile (Q) 0.60 Geranium bourbon pure 1.20 Geranyl acetate 3.80 Grapefruit oil pure 3.80 Herbanate (Q) 0.80 Hexyl isobutyrate 4.50 Isobutavan (Q) 0.20 Ligustral (Q) 0.80 Linalol 15.00 Dimethyl sulphide (0.1 % DEP) 0.20 Mandarin oil green 1.20 Methyl dihydrojasmonate Super (Q) 8.00 Neocaspirene CI (Q) 0.80 Phenoxanol (IFF) 5.80 Pivacyclene (Q) 11.50 Vetikol acetate (Dragoco) 1.20 The ingredients marked"Q"are identified by Trade Marks and are available from Quest International B. V. The ingredient marked"IFF"is identified by a Trade Mark and is available frorn International Flavours and Fragrances. The material marked"Dragoco"is identified by a Trade Mark and is available from Dragoco.

This fragrance composition is suitable for incorporation into products such as shower gels and bubble-baths.