EP0053704B1 - Cyclic esters, process for their preparation and their use as parfuming and flavouring agents; parfume and flavouring compositions containing them - Google Patents

Description

• worin R¹ C_1-4-Alkyl bedeutet und
• R² und R³ Wasserstoff oder Methyl darstellen, wobei aber nicht beide gleichzeitig Wasserstoff sind.

The invention relates to new fragrances and / or flavors. These are the compounds of the formula

• wherein R ^{1 is} C _1-4 alkyl and
• R ² and R ^{3 represent} hydrogen or methyl, but not both are hydrogen at the same time.

The formula I is intended to encompass all possible stereoisomers, defined by the relative position of the substituents on the C ₁ - are possible and C ₃ atom of I -, C. ₂

The radicals R ¹ can be straight-chain or branched. Methyl and isobutyl are preferred, and ethyl is particularly preferred.

The mixtures of compounds I with R ² = H and R ^{3 =} CH ₃ are preferred in combination with compounds I in which R ² = CH ₃ and R ³ = H are present. Preference is furthermore given to compounds I in which R ² = R ³ = CH _s .

The invention further relates to a process for the preparation of the compounds of formula I.

worin R¹, R² und R³ obige Bedeutung besitzen und eine der drei gestrichelt gezeichneten Linien eine zusätzliche Bindung darstellt, katalytisch hydriert.This process is characterized in that an ester of the formula

wherein R ¹ , R ² and R ^{3 have the} above meaning and one of the three dashed lines represents an additional bond, catalytically hydrogenated.

Suitable catalysts for this process are noble metal catalysts which e.g. Contain platinum, palladium, ruthenium or rhodium.

The hydrogenation can be carried out with or without the addition of solvents; inert solvents such as ethyl alcohol, methyl alcohol, cyclohexane etc. are preferred

The hydrogenation can be carried out at temperatures between e.g. 0 ° -100 ° C, especially between 15-30 ° C, as well as at normal pressure or higher pressures, e.g. 5-20 atm. (H.O. House, Modern Synthetic Reactions, N.A. Benjamin Inc., New York 1972.)

In the process according to the invention, I is obtained as a mixture of stereoisomers.

The separation of the isomer mixtures can, if desired, be carried out in a conventional manner, e.g. by means of preparative gas chromatography. The isomers of I do not differ fundamentally in their organoleptic properties, so that the isomer mixture in particular can be used for economic reasons.

The starting materials, the esters II, can be prepared by the known methods of preparing cyclogeranoyl derivatives, for example by cyclization of esters of the formula

Suitable cyclizing agents are inorganic and organic protonic acids such as sulfuric acid, phosphoric acid, methanesulfonic acid, formic acid, acetic acid or Lewis acids such as BF ₃ , SnCl ₄ , ZnCl ₂ .

The cyclization can be carried out with or without a solvent. Suitable solvents are inert solvents such as e.g. Hexane, benzene, nitromethane. The temperature is not critical (room temperature, or higher or lower temperatures).

The esters III are prepared, for example in the case of R ^{2 =} H, R ^{3 =} CH _3, expediently from the known 3,6-dimethyl-5-hepten-2-one. One can work, for example, according to Horner-Wittig (Wadsworth / Emmons modification, J. Amer. Chem. Soc. 83, 1733 [1961]): in the presence of an alkali hydride or alkali alcoholate as base, the ketone is mixed with a C _1-4 -Carb- alkoxy-methylene-diethylphosphonate implemented.

It is convenient to work in an aprotic solvent such as e.g. Benzene, toluene, dimethoxyethane. The reaction temperature is not critical. The temperature range of approx. 40-60 ° C is preferred, but it is also possible to work at a lower or higher temperature.

Höhere (R'=z.B. Propyl, Isobutyl) Ester der Formel I werden zweckmässigerweise aus einem Methyl- oder Äthylester der Formel III durch Umesterung, und zwar auf übliche Weise durch Erhitzen mit einem höheren Alkohol, z.B. Propanol oder Isobutanol, vorzugsweise unter alkalischen Bedingungen, hergestellt, wobei das gebildete Methanol bzw. Äthanol aus dem Reaktionsgemisch laufend abdestilliert werden kann.The following reaction scheme results for the preparation of the compounds of the formula I:

Higher (R '= for example propyl, isobutyl) esters of the formula I are expediently converted from a methyl or ethyl ester of the formula III by transesterification, in a conventional manner by heating with a higher alcohol, for example propanol or isobutanol, preferably under alkaline conditions, prepared, the methanol or ethanol formed can be continuously distilled off from the reaction mixture.

The compounds I have special organoleptic properties which make them particularly suitable as fragrances and / or flavors.

The invention accordingly also relates to the use of the compounds I as fragrances and / or flavorings.

The compounds of formula I, in particular the mixtures of compounds with R ^{2 =} hydrogen and R ³ = methyl in combination with compounds in which R2 = methyl and R ^{3 =} hydrogen, or the compounds with R ² = R ^{3 =} CH ₃ are suitable due to their natural scent, especially for the modification of known compositions.

The above-mentioned mixture of compounds of formula I with R ^{I =} ethyl is characterized by a strong, diffuse and very naturally warm top note in the direction of spicy, fruity and woody. In addition, a powdery-floral smell aspect is worth mentioning.

• - Naturprodukte wie Baum-Moos-Absolue, Basilikumöl, Bergamotteöl, Mandarineöl, Mastix-Absolue, Myrtenöl, Palmarosaöl, Patchouliöl, Petitgrainöl Paraguay, Wermutöl
• - Alkohole, wie Geraniol, Linalool, Nerol, Phenyläthylalkohol, Rhodinol, Zimtalkohol
• ― Aldehyde,wie Citral,Helionale®,α-Hexylzimt- aldehyd, Hydroxycitronellal, Lilial" (p-tert.Butyl- a-methyl-hydrozimtaldehyd), (p-tert. Butyl-a-methyl-dihydrozimtaldehyd), Methylnonylacetaldehyd
• ― Ketone, wie Allyljonon, α-Jonon, β-Jonon, Methyljonon
• - Ester, wie Allyl-phenoxyacetat, Benzyl-salicylat, Cinnamylpropinat, Dimethylbenzylcarbinyl-butyrat, Äthyl-acetoacetat, Linalylacetat, Methyl-dihydrojasmonat, Styrallylacetat, Vetiverylacetat
• ^- - Lactone, wie Cumarin
• - verschiedene, in der Parfümerie oft benützte Komponenten, wie Ambrettemoschus, Celestolid®, Galaxolid®, Indol, p-Menthan-8-thiol-3-on, Methyleugenol.

The esters I combine with numerous known fragrance ingredients of natural or synthetic origin, the range of natural raw materials comprising both light, medium and low volatile components, and that of synthetics can include representatives from practically all classes of substances, as follows from the following Compilation can be seen:

• - Natural products such as tree-moss absolute, basil oil, bergamot oil, mandarin oil, mastic absolute, myrtle oil, palmarosa oil, patchouli oil, petitgrain oil Paraguay, wormwood oil
• Alcohols such as geraniol, linalool, nerol, phenylethyl alcohol, rhodinol, cinnamon alcohol
• - Aldehydes, such as citral, Helionale®, α-hexylcinnamaldehyde, hydroxycitronellal, lilial "(p-tert-butyl-a-methyl-hydrocinnamaldehyde), (p-tert. Butyl-a-methyl-dihydrocinnamaldehyde), methylnonylacetaldehyde
• - Ketones, such as allyl ionone, α-ionone, β-ionone, methyl ionone
• - Esters, such as allyl phenoxyacetate, benzyl salicylate, cinnamyl propinate, dimethylbenzylcarbinyl butyrate, ethyl acetoacetate, linalyl acetate, methyl dihydrojasmonate, styrallyl acetate, vetiveryl acetate
• ^- - lactones such as coumarin
• - Various components often used in perfumery, such as ambrush musk, Celestolid®, Galaxolid®, indole, p-menthan-8-thiol-3-one, methyleugenol.

Also noteworthy is the way in which the compounds I round off and harmonize the olfactory notes of known compositions, but without dominating. For example, they underline the spicy and herbaceous notes in perfume bases with tea and green character, and in rose bases the sought-after character of the heavy, sweet and somewhat Bulgarian rose is underlined.

In fruit bases, e.g. of the apricot type, the mixtures mentioned above can be used successfully to achieve a velvety-soft, naturally sweet and rounded effect.

The compounds of the formula I (or their mixtures) can be used within wide limits, which can range, for example, from 0.1 (detergents) -30% (alcoholic solutions) in compositions, without these values being intended to represent limit values, however, since the experienced perfumers can achieve effects with even lower concentrations or can build up new complexes with even higher doses. The preferred concentrations are between 0.5 and 25%. The compositions produced with I can be used for all types of perfumed consumer goods (e.g. Eaux de Cologne, Eaux de Toilette, extras, lotions, creams, shampoos, soaps, ointments, powder, toothpastes, mouthwashes, deodorants, detergents, tobacco).

The compounds I (or their mixtures) can accordingly be used in the production of compositions and - as the above composition shows - using a wide range of known odorants or odorant mixtures. In the preparation of such compositions, the above-mentioned known fragrances or mixtures of fragrances can be used in a manner known to the perfumer, such as W.A. Poucher, Perfumes, Cosmetics, Soaps 2, 7th edition, Chapman and Hall, London 1974.

The new compounds of the formula or de Ren mixtures are also excellently suitable for use in fruit flavors of all kinds, but in particular also for flavoring tobacco.

As flavorings, the compounds I can be used, for example, to produce or improve, reinforce, increase or modify a wide variety of fruit flavors, e.g. Raspberry or apricot flavors can be used. Food (e.g. yogurt, confectionery), luxury foods (e.g. tea, tobacco) and drinks (e.g. lemonade) can be used as an area of application for these flavors.

The pronounced taste qualities of the compounds I (or their mixtures) enable their use as flavorings in low concentrations. A suitable dosage includes, for example, the range of 0.01 ppm - 100 ppm, preferably the range of 0.01 ppm - 20 ppm in the finished product, i.e. the flavored food, luxury food or drink.

When flavoring, for example, tobacco, the dosage can, however, also be higher and cover a larger range, for example the range of 1-1000 ppm, preferably 50-500 ppm.

The compounds can be mixed in a conventional manner with the constituents used for flavoring compositions or added to such flavors. The aromas used according to the invention are understood to mean flavoring compositions which can be diluted in a manner known per se or distributed in edible materials. They contain, for example, about 0.1-10, in particular 0.5-3,% by weight. They can be converted into the usual forms of use, such as solutions, pastes or powders, using methods known per se. The products can be spray dried, vacuum dried or lyophilized.

The known flavoring substances expediently used in the production of such flavors are either contained in the above compilation or can be found in the relevant literature, see e.g. J. Merory, Food Flavors, Composition, Manufacture and Use, Second Edition, The Avi Publishing Company, Inc., Westport, Conn. 1968, or G. Fenaroli, Fenaroli's Handbook of Flavor Ingredients, Second Edition, Volume 2, CRC-Press, Inc. Cleveland, Ohio 1975.

• Gummi arabicum, Tragant, Salze oder Brauereihefe, Alginate, Carrageen oder ähnliche Absorbentien; Indole, Maltol, Dienale, Gewürzoleoresine, Raucharomen; Gewürznelken, Diacetyl, Natriumcitrat; Mononatriumglutamat, Dinatrium- inosin-5'-monophosphat (IMP), Dinatriumgua- nosin-5-phosphat (GMP); oder spezielle Aromastoffe, Wasser- Äthanol, Propylenglykol, Glycerin.

The following carrier materials, thickeners, flavor enhancers, spices and auxiliary ingredients can be used to produce the usual forms of use:

• Gum arabic, tragacanth, salts or brewer's yeast, alginates, carrageenan or similar absorbents; Indoles, maltol, dienals, spice oleoresins, smoke flavors; Cloves, diacetyl, sodium citrate; Monosodium glutamate, disodium inosine 5'-monophosphate (IMP), disodium guanosine 5-phosphate (GMP); or special flavors, water-ethanol, propylene glycol, glycerin.

example 1

30 of an ester mixture consisting of around 20% ethyl, 2,3,6,6-tetramethyl-2-cyclohexene-1-carboxylate, around 14% c, t-2-ethylidene-6,6-dimethyl-cyclohexane-1-carboxylic acid ethyl ester and about 65% ethyl 2-ethyl-6,6-dimethyl-2-cyclohexene-1-carboxylate is dissolved in 300 ml absolute ethyl alcohol and hydrogenated with the addition of 600 mg palladium (10% on carbon) with good stirring under normal pressure. After 24 hours, 96.9% of the theoretical amount of hydrogen has been absorbed. The catalyst is filtered off through Celite, washed with a little ethanol and the solvent is distilled off on a rotary evaporator.

The crude product (29.8 g) is fractionally distilled in a high vacuum using a 10 cm Widmer column. 28 g (92.4% of theory) of a mixture with a boiling point of 42-55 ° C./0.05 mm Hg are obtained. According to the gas chromatogram [glass capillary column (50 mx 0.3 mm 1.D.) with Ucon HB 5100 as a stationary phase, 140 ° isothermal, helium flow 2.5 mf / min.], the following product composition essentially results: 41.8% cis-2-ethyl-6,6-dimethylcyclohexane-1-carboxylic acid - ethyl ester, 34.6 % trans-2-ethyl-6,6-dimethylcyclohexane-1-carboxylic acid ethyl ester and 19.6% 2,3,6,6-tetramethyl-cyclohexane-1-carboxylic acid ethyl ester (various stereoisomers, including approx. 4.1% 1 , 2 cis-2,3-trans-2,3,6,6-tetramethyl-1-cyclohexanecarboxylic acid ethyl ester and approx. 9.1% 1,2 trans-2,3-trans-2,3,6,6-tetramethyl -1-cyclo-hexanecarboxylic acid ethyl ester). The mixture of isomers was separated by means of preparative gas chromatography. The main peaks showed the following spectroscopic data:

The starting material is obtained as follows:

: 1,4708. Das Gemisch besteht aus 20% c,t-3,4,7-Trimethyl-2,6-octadiensäure-äthylester und 80% c,t-3-Äthyl-7-methyl-2,6-octadiensäure- äthylester.A solution of 30 g (0.214 mol) of a ketone mixture consisting of 20% 3.6- is added to a cooled solution of 5.8 g (0.252 g atom) sodium in 130 ml absolute ethanol at a temperature of 5―10 ° C. Dimethyl-5-hepten-2-one and 80% 7-methyl-6-octen-3-one and 62.4 g (0.278 mol) of phosphonoacetic acid triethyl ester in 130 ml of absolute toluene were added dropwise. The reaction mixture is then left at room temperature men and react overnight. The reaction mixture is poured onto ice water and extracted 3 times with hexane. The combined hexane solutions are washed neutral with saline, dried over sodium sulfate and evaporated. The crude product (43 g) is fractionally distilled in a high vacuum over a 10 cm Widmer column. 28.9 g (64.3%) of a mixture of boiling point: 58-61 ° C / 0.02 mm Hg are obtained;

: 1.4708. The mixture consists of 20% c, t-3,4,7-trimethyl-2,6-octadienoic acid ethyl ester and 80% c, t-3-ethyl-7-methyl-2,6-octadienoic acid ethyl ester.

Geruch:holzig, fruchtig-beerenartig,camphrig,an Eukalyptussamen erinnernd, aromatisch.228 ml of formic acid are cooled to 0-5 ° C. At this temperature, 12 ml of conc. Sulfuric acid was added and the mixture was then stirred for 1 hour. 24 g of the above ester mixture, consisting of 20% c, t-3,4,7-trimethyl-2,6-octadienoic acid ethyl ester and 80% c, t-3-ethyl-7- ethyl 2,6-octadienoate carefully added dropwise. When the addition is complete, the mixture is allowed to assume room temperature and is stirred at this temperature for a further hour. The reaction mixture is poured onto ice and extracted 3 times with hexane. The combined hexane solutions are washed neutral with water (1 time), with sodium bicarbonate solution (2 times) and finally with water (2 times), dried over sodium sulfate and evaporated. The crude product (22.5 g) is fractionally distilled in a 10 cm Widmer column under high vacuum. 17 g (70.8%) of an ester mixture consisting of about 20% of 2,3,6,6-tetramethyl-2-cyclohexene-1-carboxylic acid ethyl ester, 14% of c, t-2-ethylidene-6,6-dimethyl are obtained -cyclohexane-1-carboxylic acid ethyl ester and 65% 2-ethyl

Smell: woody, fruity-berry-like, camp-like, reminiscent of eucalyptus seeds, aromatic.

Example 3

5 g of an ester mixture consisting of approx. 90% 2-ethyl-6,6-dimethyl-2-cyclohexane-1-carboxylic acid ethyl ester (remainder: double bond isomers) is dissolved in 50 ml absolute ethyl alcohol and mixed with 100 mg palladium (10% on carbon) un-6,6-dimethyl-2-cyclohexene-1-carboxylic acid ethyl ester from the boiling point: 102 ° C / 6 mmHg;

: 1,4626.

: 1.4626.

Example 2

22.4 g (0.1 mol) of an ester mixture consisting of approx. 80% 2-ethyl-3,6,6-trimethyl-2-cyclohexane-1-carboxylic acid ethyl ester (remainder: double bond isomers) is dissolved in 250 ml absolute ethyl alcohol and with the addition of 800 mg palladium (10% on carbon) in an autoclave at 10 bar and 60 ° C for 24 hours. The catalyst is filtered off through Celite, washed with a little ethyl alcohol and the solvent is distilled off on a rotavapor.

: 1,4527. Im Kapillargaschromatogramm (50m × 0,31 mm i.D., Ucon HB 5100, 140°C isotherm, Heliumfluss 2,5 ml/Min. Splitverhältnis 1:30) sind 4 Peaks ersichtlich, mit folgenden prozentualen Anteilen am Gesamtgemisch (geordnet nach steigender Retentionszeit):

The crude product (21.8 g) is fractionally distilled over a 5 cm Widmer column under high vacuum. 18.0 g (79.6% of theory) of a mixture with a boiling point of 80-81 ° C./0.15 mm Hg are obtained.

: 1.4527. The capillary gas chromatogram (50m × 0.31mm iD, Ucon HB 5100, 140 ° C isothermal, helium flow 2.5ml / min. Split ratio 1:30) shows 4 peaks, with the following percentages of the total mixture (ordered according to increasing retention time) :

Peaks 1, 2, 3, 4 represent the 4 possible stereoisomers of ethyl 2-ethyl-3,6,6-trimethyl-cyclohexane-1-carboxylate.

• ¹H-NMR (360 MHz, CDCl₃):
  
  ter starkem Rühren bei Normaldruck und bei Raumtemperatur während 24 Stunden hydriert. Der Katalysator wird über Celite abfiltriert, mit wenig Äthylalkohol nachgewaschen und das Lösungsmittel am Rotavapor abdestilliert. Das Rohprodukt (4,9 g) wird im Kugelrohr destilliert. Man erhält 4,3 g (85,2% d.Th.) eines Gemisches vom Siedepunkt 65°C/0,08 mm Hg. Aus dem Kapillargaschromatogramm (50 m x 0,31 mm i.D. mit Ucon HB 5100, 140°C isotherm, Heliumfluss 2,5 ml/Min., Splitverhältnis 1:30) ergibt sich folgende Zusammensetzung: ca. 47% cis-2-Äthyl-6,6-dimethyl-1-cyclohexancarbonsäureäthylester und ca. 50% trans-2-Äthyl-6,6-dimethyl-1-cyclo- hexancarbonsäureäthylester (Spektroskopische Daten: siehe Beispiel 1 ).

The peak 1 product was separated by means of preparative gas chromatography and shows the following spectroscopic properties:

• ¹ H-NMR (360 MHz, CDCl ₃ ):
  
  ter vigorous stirring at normal pressure and at room temperature for 24 hours. The catalyst is filtered off through Celite, washed with a little ethyl alcohol and the solvent is distilled off on a rotavapor. The crude product (4.9 g) is distilled in a Kugelrohr. 4.3 g (85.2% of theory) of a mixture having a boiling point of 65 ° C./0.08 mm Hg are obtained. From the capillary gas chromatogram (50 mx 0.31 mm iD with Ucon HB 5100, 140 ° C isothermal, helium flow 2.5 ml / min., Split ratio 1:30), the following composition results: approx. 47% cis-2-ethyl-6,6-dimethyl-1-cyclohexanecarboxylic acid ethyl ester and approx. 50% trans-2-ethyl-6,6-dimethyl-1-cyclo-hexanecarboxylic acid ethyl ester (spectroscopic data: see Example 1).

Smell: very natural, in the direction of chamomile and tagetes.

Example 4

10 g of an ester mixture consisting of approximately 21% 2,3,6,6-tetramethyl-2-cyclohexene-1-carbonate isobutyl, approximately 12% c, t-2-ethylidene-6,6-dimethyl-cyclohexane-1 -carboxylic acid isobutyl ester and around 61% 2-ethyl-6,6-dimethyl-2-cyclohexene-1-carboxylic acid isobutyl ester are dissolved in 75 ml of absolute ethyl alcohol and with the addition of 300 mg palladium (5% on carbon) in an autoclave at 10 bar and hydrogenated at 50 ° C for 15 hours. The catalyst is filtered off through Celite, washed with a little ethyl alcohol and the solvent is distilled off on a rotary evaporator.

: 1,4510. Gemäss Gaschromatogramm [Glaskapillarsäule (50 m x 0,3 mm 1.D.) mit Ucon HB 5100 als stationärer Phase, 140°C isotherm, Heliumfluss 2,5 ml/Min.] ergibt sich im wesentlichen die folgende Produkte-Zusammensetzung: 55,1% cis-2-Äthyl-6,6-dimethyl-cyclohexan-1-carbonsäure-isobutylester, 31,2% trans-2-Äthyl-6,6-dimethyl-cyclohexan-1-carbonsäure-isobutylester und 13,7% 2,3,6,6-Tetramethyl-1-cyclohexancarbonsäure-isobutylester (verschiedene Stereoisomere). Geruch: blumig, etwas fettig, krautig.The crude product (9.9 g) is fractionally distilled in a high vacuum over a 5 cm Vigreux column. 8.2 g (85.4% of theory) of a mixture with a boiling point of 67-68 ° C./0.09 mg Hg are obtained;

: 1.4510. According to the gas chromatogram [glass capillary column (50 mx 0.3 mm 1.D.) with Ucon HB 5100 as stationary phase, 140 ° C isothermal, helium flow 2.5 ml / min.], The following product composition essentially results: 1% cis-2-ethyl-6,6-dimethyl-cyclohexane-1-carboxylic acid isobutyl ester, 31.2% trans-2-ethyl-6,6-dimethyl-cyclohexane-1-carboxylic acid isobutyl ester and 13.7% 2,3,6,6-tetramethyl-1-cyclohexanecarboxylic acid isobutyl ester (various stereoisomers). Smell: floral, slightly greasy, herbaceous.

• Zu einer Lösung von 140 mg Natrium in 101,3 g Isobutyl-alkohol wird eine Lösung von 27 g eines Gemisches bestehend aus rund 20% c,t-3,4,7-Trimethyl-2,6-octadiensäureäthylester und rund 80%c,t-3-Äthyl-7-methyl-2,6-octadiensäureäthyl- ester (Darstellung siehe Beispiel 1) in 135 g Cyclohexan zugetropft. Das Reaktionsgemisch wird zum Sieden erhitzt und dabei das Cyclohexan abdestilliert, wobei die abdestillierte Menge kontinuierlich aus einem Tropftrichter ersetzt wird (ca. 250 ml in 4 Stunden). Das Reaktionsgemisch wird mit Wasser (3x) neutralgewaschen, über Natriumsulfat getrocknet und eingedampft.

The starting material is obtained as follows:

• To a solution of 140 mg sodium in 101.3 g isobutyl alcohol, a solution of 27 g of a mixture consisting of around 20% c, t-3,4,7-trimethyl-2,6-octadienoic acid ethyl ester and around 80% c , t-3-ethyl-7-methyl-2,6-octadienoic acid ethyl ester (see example 1 for illustration) was added dropwise in 135 g of cyclohexane. The reaction mixture is heated to boiling and the cyclohexane is distilled off, the amount distilled off being continuously replaced from a dropping funnel (approx. 250 ml in 4 hours). The reaction mixture is washed neutral with water (3x), dried over sodium sulfate and evaporated.

: 1,4660. Das Gemisch besteht aus rund 20% c,t-3,4,7-Trimethyl-2,6-octadiensäure-isobu- tylester und rund 80% c,t-3-Äthyl-7-methyl-2,6-octadiensäure-isobutylester. Dieses Gemisch wird analog wie in Beispiel 1 beschrieben cyciisiert. Man erhält zu 68,9% ein Gemisch vom Siedepunkt 64-66°C/0,04mm Hg;

: 1,4608. Das Gemisch besteht aus rund 21% 2,3,6,6-Tetramethyl-2-cyclohexen-1-carbonsäure-isobutylester, rund 12% c, t-2-Äthyliden-6,6-dimethyl-cyclohexan-l-carbonsäure-isobutylester und rund 61% 2-Äthyl-6,6-dimethyl-2-cyclohexen-1-carbonsäure-isobutylester.The crude product (29.4 g) is fractionally distilled in a high vacuum over a 15 cm Widmer column. 27.5 g (70.9% of theory) of a mixture having a boiling point of 80-82 ° C./0.04 mm Hg are obtained;

: 1.4660. The mixture consists of around 20% c, t-3,4,7-trimethyl-2,6-octadienoic acid isobutyl ester and around 80% c, t-3-ethyl-7-methyl-2,6-octadienoic acid. isobutyl ester. This mixture is cyclized analogously to that described in Example 1. 68.9% of a mixture with a boiling point of 64-66 ° C./0.04 mm Hg is obtained;

: 1.4608. The mixture consists of around 21% 2,3,6,6-tetramethyl-2-cyclohexene-1-carboxylic acid isobutyl ester, around 12% c, t-2-ethylidene-6,6-dimethyl-cyclohexane-1-carboxylic acid. isobutyl ester and around 61% 2-ethyl-6,6-dimethyl-2-cyclohexene-1-carboxylic acid isobutyl ester.

In the following examples, “Mixture I” stands for the reaction product of Example 1.

Example 5

By adding 100 parts by weight of the mixture I, the composition receives significantly more diffusion and it becomes stronger. It also looks fresher, more spicy and sweeter and, subliminally, takes on a floral character in the direction of the rose.

If the composition is dissolved in ethyl alcohol and sensory tested in a concentration range usual for an eau de toilette, namely 5-10% by weight, the composition with the addition of the new mixture I shows an extraordinary diffusion even after several hours on the smell strip very warm appearance. This effect is very desirable, but rather unusual for a substance that is relatively volatile.

Example 6

The addition of 50 parts by weight of the mixture I to the above green base noticeably enhances the herbaceous-green and spicy aspects of the composition, which is particularly evident from the freshly dipped smell strips. The impression of the balanced shape, combined with floral-salicylar-like notes when you smell the stored fragrance strip, is very reminiscent of anthranilate fragrances. Both fresh and stored, the composition now looks stronger and has a greatly increased diffusion.

Example 7

By adding 100 parts by weight of the mixture I, the rose character of the original composition becomes significantly warmer and softer, and the diffusion increases. There is also a clear Damascon note. In the rear, the dominant musk character is slightly weakened and pleasantly rounded off.

Example 8

By adding 20 parts by weight of the mixture, the apple-like, weak green note of the basic composition and its musky note are advantageously changed to the desired apricot note. The composition becomes much more natural, harmonious, less rough. The influence of the addition is particularly noticeable in the rear, as elements of the composition that previously did not harmonize are now combined very harmoniously and at the same time the musk character, which is not desired here, is suppressed.

Example 9

The addition of 100 parts by weight of the mixture I produces a very pleasant fruity note on the freshly dipped fragrance strip, so that the new composition appears much warmer and softer without being intrusive. In the rear, unpleasant, soapy, annoying notes, especially of the aldehyde C ₁₂ -MNA, are advantageously covered.

Example 10

By adding Mixture I to the above apricot composition, its fruity note is significantly enhanced. The fruity note now appears fuller and more rounded, next to it is one velvety-soft note in appearance, reminiscent of fully ripe apricots.

Claims (13)

1. Compounds of the formula

wherein R¹ signifies C_1-4-alkyl and R² and R³ represent hydrogen or methyl, but in which both are not simultaneously hydrogen.

2. Compounds of formula I according to claim 1, wherein R² = R³ = methyl.

3. 2-Ethyl-3,6,6-trimethyl-cyclohexane-1-carboxylic acid ethyl ester,

4. 2,3,6,6-Tetramethyl-cyclohexane-1-carboxylic acid ethyl ester.

5. 2-Ethyl-6,6-dimethyl-cyclohexane-1-carboxylic acid ethyl ester. -

6. Mixtures of compounds of the formulae

wherein R¹ signifies C_1-4-alkyl.

7. Mixtures according to claim 6, characterized in that R¹ signifies ethyl.

8. Mixtures according to claim 6, characterized in that R¹ signifies isobutyl.

9. Odorant and/or flavouring substance compositions, characterized by a content of a compound of the formula

wherein R¹ signifies C_1-4-alkyl and R² and R³ represent hydrogen or methyl, but in which both are not simultaneously hydrogen.

10. Odorant and/or flavouring substance compositions, characterized by a content of a mixture according to claim 6, 7 or 8.

11. Process for the manufacture of compounds of the formula

wherein R¹ signifies C_1-4-alkyl and R² and R³ represent hydrogen or methyl, but in which both are not simultaneously hydrogen, characterized by catalytically hydrogenating an ester of the formula

wherein R¹, R² and R³ have the above significance and one of the three lines drawn dotwise represents an additional bond.

12. Use of compounds of the formula

wherein R¹ signifies C_1-4-alkyl and R² and R³ represent hydrogen or methyl, but in which both are not simultaneously hydrogen, as odorant and/or flavouring substances.

13. Use of mixtures according to claim 6, 7 or 8 as odorant and/or flavouring substances.