PERFUME COMPOSITION AND PERFUMED PRODUCTS WHICH CONTAIN ONE OR MORE O-ALKOXYPHENOLS AS PERFUME COMPONENT

Abstract: Parfume compositions and perfumed products characterized by a content of one or more fragrances which have the characteristic odour of vanilla and correspond to the formula wherein R₁ or R₂ represents a hydrogen atom and the other symbol an ethyl or propyl group and R₃ represents a methyl or ethyl group.

Description: The invention relates to perfume compositions which contain one or more o-alkoxyphenols as perfume component and to products perfumed with one or more of these compounds or with the said compositions. The odour character of vanilla is highly valued in perfumery and is therefore important from an economic point of view. To impart this odour character to a perfume composition or to a product to be perfumed, use is normally made of vanillin, ethylvanillin or a combina­ tion of the two. These compounds are, however, not stable in an alkaline medium such as soap. If perfumes contain­ ing vanillin or ethylvanillin are used in toilet soap, after a short time a deviation in odour and a strong brown discoloration therefore occur and after some time the vanilla character has completely disappeared. There is therefore a requirement for fragrances which both have an odour of vanilla and are chemically stable. Surprisingly, it has now been found that alkyl- substituted o-alkoxyphenols with the formula wherein R₁ or R₂ represents a hydrogen atom and the other symbol an ethyl or propyl group and R₃ represents a methyl or ethyl group, are valuable fragrances with a characteristic odour of vanilla. Various alkyl-substituted alkoxyphenols are known as a fragrance and/or flavouring. Thus, in "Perfume and Flavor Chemicals" S. Arctander names 4-methylguaiacol (No. 705), 4-propylguaiacol (No. 944), ortho-ethoxyphenol (No. 1136), 4-ethylguaiacol (No. 1251) and 5-propyl-2-ethoxyphenol (No. 2704). These compounds are in general characterised by spicy (clove/eugenol), phenolic and leathery or smokey odour notes, in some cases also by a vanilla-like note. A number of these compounds are therefore used in flavour compositions to supplement the taste of vanillin in synthetic vanilla flavours. None of them can, however, impart to a perfume composition a perfect odour of vanilla which is free of all types of annoying subsidiary notes. They are therefore unsuitable as substitutes for vanillin. The Dutch Patent Application No. 72.09426 states that 2-propoxyphenol is suitable for imparting a smoke taste to foodstuffs. The Dutch Patent Application No. 72.13842 states that substituted phenols are used in the perfume and flavour industry and that there is therefore a need for vinylguaiacol without specifying in more detail for what purpose this compound and other compounds named in the application are used. Finally, in the Dutch Patent Application No. 75.04532 a number of 2-alkoxy-4-butenyl- and methylpro­ penylphenols are described with flowery (carnation-like) fragrances with leathery, oak-moss and smoky and in some cases also vanilla-like notes. This state of the prior art, however, gives no cause for any supposition that precisely the compounds according to the present application would be particu­ larly suitable for imparting the fragrance characteristic of natural vanilla to perfume compositions. The compounds according to the invention may be prepared according to methods described in the literature for these and similar compounds. Thus, for example, the synthesis of 2-ethoxy-4-methylphenol by catalytic reduc­ tion of ethylvanillin is described by C.H. Shunk et al. in J. Am. Chem. Soc. 82 (1960), page 5917. A similar method of synthesis is described by G.R. Clemo et al. in J. Chem. Soc. 1952, page 3844 et seq.. Starting from isoethylvanillin (S. Arctander No. 1364), 2-ethoxy-5-methylphenol can be obtained in the same manner. The above-named compounds, as well as the corresponding 2-propoxy compounds, can also be prepared by alkylation of 4-methylcatechol with the aid of an ethyl or propyl halide or another conventional alkylating agent. By this method a mixture of 2-ethoxy-4-methyl- and 2-ethoxy-5-methylphenol or 2-propoxy-4-methyl- and 2-propoxy-5-methylphenol is obtained. By means of a Wittig reaction and starting from 3,4- dihydroxybenzaldehyde, 3,4-dihydroxystyrene can be pre­ pared which can subsequently be converted into 4-ethyl­ catechol by catalytic reduction. This compound can be alkylated as mentioned above to form a mixture of 2-ethoxy- 4-ethyl- and 2-ethoxy-5-ethylphenol or 2-propoxy-4-ethyl- and 2-propoxy-5-ethylphenol. In addition 2-ethoxy-4- ethyl- and 2-ethoxy-5-ethylphenol can be prepared by sub­ jecting ethylvanillin or isoethylvanillin to a Wittig reaction and to a catalytic reduction as described above for 3,4-dihydroxybenzaldehyde. Variations in the above-named synthesis routes, as well as various other routes not named, are obvious to the expert in the field of organic chemistry synthesis methods. The mixtures of isomers obtained by some of the above-named synthesis methods can be separated in a con­ ventional manner, for example by means of chromatographic techniques, into the two components. The compounds according to the invention are powerful fragrances with a characteristic odour of vanilla. They are also distinguished by their high chemical stabi­ lity, especially in alkali medium such as soap, and are therefore very suitable for use in perfumes and products in which the conventional vanilla fragrances are not usable or only usable to a very limited extent. Especi­ ally the compounds in which both R₃ and R₁ or R₂ repre­ sent an ethyl group are characterised by their pleasant odour of vanilla which even exceeds the odour of vanillin in naturalness. Although the odours of the two isomers in the mix­ tures obtained by some synthesis methods are not entirely identical, separation of the isomers is in many cases not necessary or even undesirable because precisely the mixtures are often very suitable for imparting a perfect vanilla note to a perfume composition. In this connection the term "perfume composition" means a mixture of fragrances and optionally auxiliary sub­ stances, if desired, dissolved in a suitable solvent or mixed with a powdery substrate which is used to impart the desired odour to the skin and/or all types of pro­ ducts. Examples of such products are: soaps, detergents, air fresheners, room sprays, pomanders, candles, cosmetics such as creams, ointments, toilet waters, pre- and after­ shave lotions, talcum powders, hair care agents, body deodorants and antiperspirants. Fragrances and mixtures of fragrances which can be used in combination with the compounds according to the invention for the production of perfume compositions are for example: natural products such as essential oils, absolutes, resinoids, resins, concretes etc., but also synthetic fragrances such as hydrocarbons, alcohols, aldehydes, ketones, ethers, acids, esters, acetals, ketals, nitriles etc., including saturated and unsaturated com­ pounds, aliphatic, carbocyclic and heterocyclic compounds. Examples of fragrances which can be used in combination with the compounds according to the invention are: gera­ niol, geranyl acetate, linalool, linalyl acetate, tetra­ hydrolinalool, citronellol, citronnellyl acetate, dihydro­ myrcenol, 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-butylcyclo­ hexyl acetate, isononyl acetate, vetiveryl acetate, veti­ verol, α-hexylcinnamaldehyde, 2-methyl-3-(p-tert-butyl phenyl)propanal, 2-methyl-3-(p-isopropylphenyl)propanal, 3-(p-tert-butylphenyl)propanal, tricylcodecenyl acetate, tricyclodecenyl propionate, 4-(4-hydroxy-4-methylpentyl)- 3-cyclohexanecarbaldehyde, 4-(4-methyl-3-pentenyl)-3- cyclohexenecarbaldehyde, 4-acetoxy-3-pentyltetrahydro­ pyran, 3-carboxymethyl-2-pentylcyclopentane, 2-n-heptylcyclopentanone, 3-methyl-2-pentyl-2-cyclopenten­ one, n-decanal, n-dodecanal, 9-decenol-1, phenoxyethyl isobutyrate, phenylacetaldehyde, dimethylacetal, phenyl­ acetaldehyde diethylacetal, geranylnitrile, citronellyl­ nitrile, cedryl acetate, 3-isocamphylcyclohexanol, cedryl methyl ether, isolongifolanone, aubepine nitrile, aubepine, heliotropine, coumarin, eugenol, vanillin, diphenyl oxide, hydroxycitronellal, ionones, methylionones, isomethylion­ ones, irones, cis-3-hexenol and esters thereof, indan musks tetralin musks, isochroman musks, macrocyclic ketones, macrolactone musks, ethylene brassylate, and aromatic nitromusks. Auxiliary substances and solvents which can be used in perfume compositions which contain compounds according to the invention are, for example: ethanol, iso­ propanol, diethyleneglycol monoethyl ether, diethyl phthalate, etc. The quantities in which the compounds according to the invention can be used in perfume oompositions or products to be perfumed can vary within wide limits and depend inter alia on the nature of the product in which the fragrance is used, on the nature and quantity of the other components in the perfume composition and on the odiferous effect aimed at. It is therefore only possible to specify very rough limits which, however, provide the expert with sufficent information to be able to use the compounds according to the invention independently. In most cases a quantity of only 10 ppm in a perfume composition will already be sufficient to achieve a clearly per­ ceptable odiferous effect. On the other hand, to achieve special odiferous effects, it is possible to use quanti­ ties of 25% by weight or even more in a composition. In products perfumed by means of perfume compositions these concentrations are porportionally lower, depending on the quantity of composition used in the product. The following examples serve only to illustrate the preparation and use of the compounds according to the invention. The invention is, however, not limited thereto. Example I Preparation of a mixture of 2-ethoxy-4-methyl- and 2- ethoxy-5-methylphenol 1.05 mole equivalents of diethylsulphate were slowly added dropwise to a solution of 1.0 mole of 4- methylcatechol in 420 g of 10% sodium hydroxide solution (1.05 mole equivalents of NaOH) at 50°C The reaction mixture was then stirred for a further 2 hours at 50-60°C. After cooling the reaction mixture was acidified and then extracted with ether. The ether solution was concentrated by evaporation and the residue distilled under reduced pressure, an approximately 1:1 mixture of 2-ethoxy-4-methyl and -5- methylphenol being obtained with a yield of 80%. Boiling point: 76-77°C/40 Pa; n = 1.5237. The mixture had a pleasant and very natural odour of vanilla. Example II Preparation of 2-ethoxy-4-ethylphenol A suspension of methyltriphenylphosphonium brom­ ide (1.15 mole) and potassium tert-butylate (1.33 moles) in 1 litre toluene was stirred for 1 hour at room tempera­ ture. 1.0 mole of ethylvanillin was added to the ylide thus formed. The reaction mixture was stirred for a fur­ ther hour and then washed with dilute hydrochloric acid. The solution was concentrated by evaporation and the residue distilled under reduced pressure. In this way 2-ethoxy-4-vinylphenol was obtained with a yield of 55%. Boiling point: 75°C/15 Pa. This was dissolved in 400 ml of ethanol, 1 g of 5% Pd/C hydrogenating catalyst was added and the reaction mixture was hydrogenated at 400 kPa until the theoreti­ cal quantity of H₂ had been absorbed. After the cata­ lyst had been filtered off, the reaction mixture was con­ centrated by evporation. The residue was distilled under reduced pressure, 2-ethoxy-4-ethylphenol being obtained with a yield of 95%. Boiling point: 60°C/20 Pa. The compound had a pleasant, somewhat sweetly spicy odour of vanilla. Example III A soap perfume for white soap was prepared accor­ ding to the following recipe: absolute of jasmine, synthetic 110 parts by weight α-hexylcinnam aldehyde 90 parts by weight 5-acetyl-3-isopropyl-1,1,2,6-tetra­ methylindan 90 parts by weight absolute of lily of the valley, synthetic 80 parts by weight 4-tert-butylcyclohexyl acetate 75 parts by weight benzyl salicylate 70 parts by weight bergamot oil, synthetic 65 parts by weight rose oil, synthetic 50 parts by weight 3-(4-tert-butylphenyl)propanal 50 parts by weight linalool 50 parts by weight 4-(4-hydroxy-4-methylpentyl)cyclo­ hexene-3-carbaldehyde 45 parts by weight -phenylethyl amyl ether 30 parts by weight styrallyl propionate 25 parts by weight lavandin oil 20 parts by weight absolute of mousse d'abre, colour­ less 15 parts by weight undecylenealdehyde 10 parts by weight amber grease oxide* 10 parts by weight galbanum oil, synthetic 5 parts by weight -undecalactone 5 parts by weight decanal 5 parts by weight 2-ethoxy-4-ethylphenol 60 parts by weight Total 1000 parts by weight Example IV A cream perfume was prepared according to the following recipe: β-phenolethanol 130 parts by weight absolute of lily of the valley, synthetic 125 parts by weight acetylcedrene 100 parts by weight 5-acetyl-3-isopropyl-1,1,2,6- tetramethylindan 100 parts by weight benzyl salicylate 80 parts by weight citronellol 70 parts by weight 3-(4-tert-butylphenyl)propanal 65 parts by weight bergamot oil, synthetic 50 parts by weight linalool 50 parts by weight 3-isocamphylcyclohexanol 50 parts by weight absolute of jasmine, synthetic 30 parts by weight 2-heptylcyclopentanone 30 parts by weight α-terpineol 25 parts by weight mandarin oil, Italian 20 parts by weight absolute of mimosa* 20 parts by weight undecylene aldehyde* 10 parts by weight cis-3-hexenyl salicylate 10 parts by weight rose oxide* 10 parts by weight* -decalactone 5 parts by weight phenol mixture obtained according to Example I 20 parts by weight Total1000 parts by weight * 10% solution in dipropyleneglycol Example V Two types of vanilla-perfumed toilet soap were prepared by mixing 1 kg of white soap grains twice in a pelleting machine with 10 g of 2-ethoxy-4-methylphenol and 10 g of vanillin respectively. The white soap flakes obtained in this manner were pressed into pieces of toilet soap in the conventional manner. The two types of fresh toilet soap had a pleasant odour of vanilla, it being striking that the soap perfumed with 2-ethoxy-4-methylphenol had a much stronger odour than the soap perfumed with vanillin. Both types of soap were kept unpacked at room temperature and exposed to daylight. Even after a few days the soap perfumed with vanillin exhibited a marked brown discoloration and a deviation in odour was perceptible. After a few weeks this soap was discoloured dark brown not only on the surface, but right through. The odour of vanilla had completely disappeared and had been replaced by a faint, somewhat phenolic odour. On the other hand, the soap perfumed with 2- ethoxy-4-methylphenol was still hardly discoloured even after half a year (somewhat cream-coloured on the surface and still white inside), while the strength of the odour had somewhat diminished but was not changed in character.

Claims: 1. Perfume composition and perfumed product, charac­ terised by a content of one or more compounds with the formula wherein one of the symbols R₁ or R₂ represents a hydro­ gen atom and the other an ethyl or propyl group and R₃ represents a methyl or ethyl group. 2. Perfume composition and perfumed product according to Claim 1, characterised by a content of one or both compounds with the formula wherein one of the symbols R₁ or R₂ represents a hydro­ gen atom and the other an ethyl group and R₃ represents an ethyl group. 3. Perfume composition according to Claim 1 or 2, characterised by a content of at least 10 ppm of one or more of the compounds with the formula wherein R₁, R₂ and R₃ have the meanings stated in Claim 1 or 2. 4. Use of a perfume composition according to one or more of the Claims 1-3, or of one or more compounds with the formula wherein R₁, R₂ and R₃ have the meanings stated in Claim 1 or 2, for the perfuming of products.

Inventors: BROEKHOF, NICOLAAS LEONARDUS JOHANNA MARIA, VAN DER WEERDT, ANTONIUS JOHANNES ALBERTUS
Applicants: NAARDEN INTERNATIONAL N.V.
Application year: 1985
Main classification: C11B9
IPC codes: C11D9, A61K8, A61Q13, C11B9