WO1996039371A1

WO1996039371A1 - Aromatic carbonyl compounds

Info

Publication number: WO1996039371A1
Application number: PCT/EP1996/002282
Authority: WO
Inventors: Thomas Markert
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 1995-06-06
Filing date: 1996-05-28
Publication date: 1996-12-12
Also published as: DE19520556A1

Abstract

The invention concerns aromatic carbonyl compounds of formula (I) in which the groups R1-R3 independently of one another stand for hydrogen or an alkyl group with 1-4 carbon atoms; R4 stands for hydrogen or an alkyl group with 1-4 carbon atoms; and Ph stands for a phenyl group. These compounds are characterised by interesting aromas with wide diffusion and can be used as scents for example in cosmetic preparations, technical products or in alcohol-based perfumes.

Description

'Aromatic carbonyl compounds'

Field of the Invention

The invention relates to the use of special aromatic carbonyl compounds of the structure given below as fragrances.

State of the art

In the Journal of Chemical Society 1940. Pages 1266-1268, M.F. Carroll's manufacture of phenylhexenones. Cinnamon alcohol was reacted with acetoacetic ester in the presence of sodium acetate. Carroll isolated 4-phenyl-hex-5-en-2-one (synonym: 3-phenyl-1-hexen-5-one) in addition to cinnamon alcohol and cinnamon acetate. After fractional distillation, however, the latter compound was only isolated in a purity of 60%. A further increase in the purity of the ketone to 96% was achieved only by hydrolysis and permanganate oxidation of the by-products. The article by M.F. Carroll made no statements.

An alternative way of producing the phenylhexenone described by Carroll is described by IV Machinskaya, VA Barkhash, AT Prudchenko; Zhur. Obshchei Khim. 1960. (30), 2357-2362. Here, the ketone is prepared by Grignard reaction of l-bromo-3-acetoxy-l-phenyl-l-butene with vinyl magnesium bromide. In this publication, too, no information is given about the olfactory properties of the ketone. 4-Phenyl-5-hexen-2-one was also detected in the product mixture in the pyrolysis of 2,3-dihydrofuran (A. Accary, Y. Infarnet, J. Huet; CR Acad. Sei, Ser. C 275 , 1972 (1), pages 53-56). In this publication, too, there is no information about the olfactory characteristics of the ketone.

Many natural fragrances are available in completely inadequate amounts, measured according to need. For example, 5,000 kg of rose petals are required to obtain 1 kg of rose oil; the consequences are a very limited world annual production and a high price. It is therefore clear that the fragrance industry has a constant need for new fragrances with interesting fragrance notes in order to supplement the range of naturally available fragrances and to make the necessary adaptations to changing fashionable tastes, as well as the constantly increasing need for odor improvers for everyday products To cover needs such as cosmetics and cleaning agents.

It is therefore clear that the fragrance industry has a constant need for new fragrances with interesting fragrance notes, in order to supplement the range of naturally available fragrances and to make the necessary adaptations to changing fashionable tastes, as well as the constantly increasing need for odor improvers for everyday products ¬ Chen needs such as cosmetics and cleaning agents.

In addition, there is generally a constant need for synthetic odoriferous substances which can be produced cheaply and with constant quality and which have desired olfactory properties, ie which have pleasant odor profiles which are as close to nature as possible and of high quality and are of sufficient intensity and capable of To influence the scent of cosmetic and consumer goods advantageously. In other words, there is a constant need for connections which have characteristic new odor profiles with high adhesive strength, odor intensity and radiance. Description of the invention

It has now been found that the compounds of the general formula (I) meet the above requirements excellently in all respects and can advantageously be used as fragrances with differently nuanced odor notes with good adhesive strength. In particular, it has been found that the compounds of the formula (I) have an improved odor intensity over compounds of the prior art which are structurally close to them, i.e. develop their effect at lower concentrations.

The present invention relates to the use of aromatic carbonyl compounds of the general formula (I)

R ¹ -C0-CHR2-CH-CHR3-CH2R ⁴ (I)

I Ph

wherein

the radicals R to R3 independently of one another are hydrogen or an alkyl group having 1 to 4 carbon atoms,

the radical R ^{4 is} hydrogen or an alkyl group having 1 to 4 carbon atoms and

Ph is a phenyl group

mean as fragrances.

In a preferred embodiment of the invention, the radical R is methyl. In a further preferred embodiment, the radicals R2 and R3 are hydrogen. Again, those compounds are preferred in which R ^{4 is} hydrogen, methyl or ethyl. Of these latter compounds (I), 4-phenyl-hexan-2-one is very particularly preferred. It is characterized by an olfactory characteristic, in which fruity, floral as well as cinnamon and As ascone reminiscent notes dominate and excellent stability in recipes from cosmetics and perfumery.

The compounds (I) are prepared by known synthetic organic chemical methods. The compounds (I) are preferably produced in a 2-stage process. An aromatic and (olefinically) unsaturated carbonyl compound, the C = C double bond of which is subsequently selectively hydrogenated in a customary manner, is first produced in a first stage by means of the so-called Carroll reaction from the corresponding allyl alcohols (eg cinnamon alcohol) .

Carroll reaction in the context of the present invention means the conversion of allyl alcohols into gamma-delta-unsaturated ketones. In a first variant of the reaction, the allyl alcohol is converted into the corresponding allyl acetoacetate by reaction with acetoacetic ester, from which the alpha-allylacetoacetic acid is formed by [3,3] sigmatropic rearrangement (Claisen rearrangement) thermal decarboxylation gives the desired gamma-delta unsaturated ketone (I). The allyl acetoacetate can be used in bulk or formed in situ.

In a second variant of the Carroll reaction, which is exemplified in a review article by G.B. Bennett is addressed (see: Synthesis 1977, pages 589-606), the allyl alcohol is reacted with a vinyl ether or an alkoxyalkene. When using vinyl ethers, aldehydes (I) are formed, when using alkoxyalkenes, aldehydes (I) or ketones (I), depending on the nature of the alkoxyalkene used. For example, the reaction of cinnamon alcohol with 1-methoxypropene gives an aldehyde, the reaction of cinnamon alcohol with 2-methoxypropene gives a ketone. Acetals or allyl vinyl ethers can be assumed as intermediate compounds in these reactions.

In a preferred embodiment of the invention, allyl alcohols are reacted with 2-alkoxyalkenes, in particular 2-methoxypropene, in the Carroll reaction. The intermediate allyl vinyl ether can be isolated or subjected directly to the subsequent [3,3] sigmatropic rearrangement to the corresponding ketone (I) in situ.

In Scheme 1 below, the course of the Carroll reaction is sketched as an example for the reaction of cinnamon alcohol with 2-methoxypropene (for the experimental implementation of the reaction, reference is made to Example 1 below).

The invention therefore furthermore relates to a process for the preparation of the aromatic carbonyl compounds (I) by a Carroll reaction from the corresponding allyl alcohols, together with selective hydrogenation of the C CC double bond of the primary product obtained in the Carroll reaction. This is the variant in which the [3,3] sigmatropic rearrangement takes place via the allyl vinyl ether in the course of the Carroll reaction and in which the Allyl alcohol used at the beginning of the synthesis is reacted with a 2-alkoxyalkene, preferably since this type of preparation ensures a particularly high product purity and thus the desired high olfactory quality of the compounds (I) is ensured.

The compounds (I) in which R ¹ denotes a methyl group are distinguished by a floral, fruity odor which gains intensity through rose, gerani, iris and cinnamon aspects.

In perfume compositions, the compounds (I) reinforce the harmony and charisma and naturalness as well as the adhesion, the dosage being matched to the desired fragrance note, taking into account the other components of the composition.

The fact that the carbonyl compounds (I) have floral-fruity notes was not predictable and is therefore a further confirmation of the general experience that the olfactory properties of known fragrances do not allow any conclusive conclusions to be drawn about the properties of structurally related compounds, because neither the mechanism of fragrance perception and the influence of the chemical structure on fragrance perception have been sufficiently researched, so it cannot normally be predicted whether a change in the structure of known fragrances will change the olfactory properties and whether these changes will be assessed positively or negatively .

Because of their odor profile, the compounds of the formula (I) are particularly suitable for modifying and enhancing known compositions. Particularly to be emphasized is their extraordinary olfactory strength, which generally contributes to the refinement of the composition.

The compounds of formula (I) can be combined with numerous known fragrance ingredients, for example other fragrances of natural, synthetic or partially synthetic origin, essential oils and plant extracts. The range of natural fragrances can include both volatile and moderately volatile components and that of synthetic fragrances include representatives from practically all classes of substances. Examples are:

(a) Natural products such as tree moss absolute, basil oil, agricultural oils such as bergamot oil, mandarin oil, etc., mastic absolute, myrtle oil, pal arosa oil, patchouli oil, petitgrain oil, wormwood oil, myrrh oil, olibanum oil

(b) alcohols such as farnesol, geraniol, linalool, nerol, phenylethyl alcohol, rhodinol, cinnamon alcohol, Sandalore [3-methyl-5- (2.2.3-trimethylcyclopent-3-en-l-yl) pentan-2-ol] , Sandela [3-isocamphyl- (5) -cyclohexanol],

(c) aldehydes such as citral, HelionalR, α-hexylcinnamaldehyde, hydroxycitronellal, Lilial ^R [p-tert-butyl-α-methyldihydrocinnamaldehyde], methylnonyl acetaldehyde,

(d) ketones such as allyl ionone, α-ionone, β-ionone, isoraldein, methyl ionone,

(e) esters such as allylphenoxyacetate, benzyl salicylate, cinnamylpropionate, citronellylacetate, decyl acetate, dimethylbenzylcarbinylacetate, ethyllacetoacetate, hexenylisobutyrate, linalyl acetate, methyldihydrojasmonate, vetiveryl acetate, cyclylatyl cyclylhexyl

(f) lactones such as gamma-undecalactone, l-0xaspiro [4.4] nonan-2-one,

as well as various other components often used in perfumery such as musk and sandalwood fragrances, indole, p-menthan-8-thiol-3-one, methylleugenol, ambroxan.

Also noteworthy is the way in which the compounds of structure (I) round off and harmonize the olfactory notes of a wide range of known compositions, but without dominating in an unpleasant manner. 4-Phenyl-hexan-2-one is particularly noteworthy in this regard.

The compounds according to the invention contain centers of chirality, so that these compounds can exist in different spatial forms. In the context of conventional syntheses, the compounds according to the invention are obtained as mixtures of the corresponding isomers and are used as such as fragrances. The usable proportions of the compounds according to the invention or their mixtures in fragrance compositions range from 1 to 70 percent by weight, based on the mixture as a whole. Mixtures of the compounds (I) according to the invention and compositions of this type can be used both for perfuming cosmetic preparations such as lotions, creams, sha poos, soaps, ointments, powders, aerosols, toothpastes, mouthwashes, deodorants and in alcoholic perfumery (eg Eaux de Cologne, Eaux de Toilette, extras) can be used. There is also an application for perfuming technical products ¹ such as detergents and cleaning agents, fabric softeners and textile treatment agents. To perfume these various products, the compositions are added to them in an olfactory effective amount, in particular in a concentration of 0.05 to 2 percent by weight, based on the entire product. However, these values are not intended to represent any limit values, since the experienced perfumer can achieve effects with even lower concentrations or can build up new types of complexes with even higher doses.

The following examples are intended to explain the subject matter of the invention and are not to be interpreted as restrictive.

B e i s p e l e

I. Chemicals used

Cinnamon alcohol: 98% (Riedel de Haen)

Isopropenyl methyl ether: 2-methoxypropene, 92% (from Janssen) Cinnamaldehyde: 98% (from Fluka)

II. Production of aromatic and unsaturated carbonyl compounds by Carro11 reaction

Example 1; 4-phenyl-hex ~ 5-en-2-one

67 g (0.5 mol) of cinnamon alcohol, 43.2 g (0.6 mol) of isopropenyl methyl ether, 3 g of propionic acid and 150 g of toluene were weighed out in succession in a 500 ml steel autoclave. The system was flushed once with nitrogen and then heated to 190 ° C. for 7 hours (until complete conversion), with an inherent pressure of 10 bar. The mixture was then freed from the solvent on a rotary evaporator in vacuo and distilled overhead. 85 g of crude product were obtained, which were fractionally distilled on a rotating column. At bottom temperatures between 155 and 165 ° C and head temperatures of 128-130 ° C / 15 mbar, 72.3 g main run (this corresponds to 83% of theory) with a purity of 99.5% determined by gas chromatography was obtained. The IR spectrum (film on NaCl) shows 6 bands of medium strength in the range between 3060 and 2919 cm-1 and further bands at 1716, 1637, 1601, 1584, 1493, 1452, 1411, 1359, 1248, 1233, 1162, 1121 , 918, 753 and 702 CΠT.

III. Preparation of the compounds (I) by selective reduction of the primary Carro11 products

Example 2: 4-phenyl-hexan-2-one

Batch: 1) 68.8 g (0.4 mol) of 4-phenyl-5-hexen-2-one (from example 1)

2) 3.5 g palladium (5% on activated carbon)

3) 200 ml of ethanol, anhydrous. Execution:

The specified amounts of 4-phenyl-5-hexen-2-one, Pd / c and ethanol were introduced in succession into a 1 liter stirred autoclave and inerted with nitrogen. Then 10 bar of hydrogen were injected and the mixture was heated to 50 ° C. with stirring. The mixture was kept at this temperature and 10 bar of hydrogen for 7 hours, hydrogen being added from time to time. The conversion was then checked by gas chromatography. The reaction mixture was filtered and concentrated. The end product was freed of impurities by fractionation on a rotary belt column. The olfactory yield was 86% of theory. 60 g of 4-phenyl-2-hexanone were obtained.

Boiling point: 48 ° C / 0.07 mbar

GC purity: 99.8%

Description of smell: fruity, floral, cinnamon, damascone

After smell: cinnamon note, dusty-earthy

III. Composition example

Perfume concentrate for perfuming soap (floral-fresh fantasy composition):

Parts by weight

Phenylethanol 120

Cyclohexyl salicylate (from Henkel) 100

Lyra! (IFF) 100

Neobergamate forte (Fa. Quest) 80

Isopropyl myristate 50

Benzyl acetate 50

Floramat (Henkel) 50

Arova N (Hüls AG) 50

Hydroxycitrone11a1 50 lonon A 100 (from Haarmann & Reimer) 40

4-phenylbutan-2-ol 40

Ylang oil 40

Brahmanol (Dragoco) 30

Lilial (Givaudan-Roure) 30

Linalool oxide 20

Hedione (Firmich) 20

Hydratropaaldehyde 20

Evernyl (Givaudan-Roure) 10

Floropal (Dragoco) 10

Isoeugenol 10

Vetiver oil 10

Geranyl acetate 10

Linalyl acetate 10

Aldehyde 13-13 (Henkel) 10

Rose oxide 6

Oxanone (from Stepan) 2 delta-decalactone 2

970 If 20 parts of isopropyl myristate in the composition are replaced by 20 parts of 4-phenyl-hexan-2-one (according to Example 2), the result is that the mixture, instead of the original floral, fruity aromas of pear and apple reminiscent of the character experiences a shift in the aroma profile in the direction of a natural formulation with a geranium character. This gives the composition a character that can be described as perfume, which the comparison, i.e. the 4-phenyl-hexan-2-one-free composition, lacks.

Claims

Patent claims

1. Use of aromatic carbonyl compounds of the general formula (I)

R ¹ -CO-CHR2-CH-CHR3-CH ₂ R ⁴ (I) I

Ph

wherein

the radical R ^{4 is} hydrogen or an alkyl group having 1 to 4 carbon atoms and

Ph is a phenyl group

mean as fragrances.

2. Use according to claim 1, wherein the radical R * is methyl.

3. Use according to claim 1 or 2, wherein the radicals R2 and R3 are hydrogen.

4. Use according to any one of claims 1 to 3, wherein the radical R ⁴ denotes hydrogen, methyl or ethyl.

5. Fragrance compositions containing one or more aromatic carbonyl compounds (I) according to one of claims 1 to 4 in an amount of 1-70% by weight (based on the total composition).

6. Process for the preparation of aromatic carbonyl compounds of the general formula (I) R ¹ -C0-CHR2-CH-CHR3-CH2R ⁴ (I)

I.

Ph

wherein

the radicals R ¹ to R ³ independently of one another are hydrogen or an alkyl group having 1 to 4 carbon atoms,

the radical R ^{4 is} hydrogen or an alkyl group having 1 to 4 carbon atoms and

Ph is a phenyl group

mean by Carroll reaction from the corresponding allyl alcohols and selective hydrogenation of the olefinic C = C double bond of the primary product obtained in the Carroll reaction.

7. The method according to claim 6, wherein in the Carroll reaction the respective allyl alcohol is reacted with a 2-alkoxyalkene to give the corresponding allyl vinyl ether, which is then subjected to the [3,3] sigmatropic rearrangement.

8. The method according to claim 7, wherein in the Carroll reaction, cinnamon alcohol is used as the allyl alcohol and 2-methoxypropene is used as the 2-alkoxylalkene.