4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-3-en-1-ols, methods for their production and use as odorants

Abstract

The .beta.,.gamma.-unsaturated 2,2,3-trimethylcyclopent-3-enyl derivatives of formula I ##STR1## where R may be methyl, ethyl, propyl, isopropyl or butyl, the wavy line characterizes geometric isomers and the broken lines characterize stereoisomers. These compounds can be produced by reduction of the aldol condensation products of campholene aldehyde and aliphatic aldehydes using sodium borohydride at raised temperatures. The compounds can be used to individually or as a mixture with the relevant .alpha.,.beta.-unsaturated alcohols as odorants or as an ingredient of perfume oils for cosmetic and technical consumer goods.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to 4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-3-en-1-ols, to their method of production, and to their use as odorants.

2. Description of the Prior Art

Derivatives of campholene aldehyde (1), a product of rearrangement of .alpha.-pinene epoxide are known as aroma chemicals of the sandalwood type (Survey: E.-J. Brunke and E. Klein, in: Fragrance Chemistry, ed. E. Theimer, Academic Press, New York, N.Y. 1982, pp. 424-26). For instance, the .alpha.,.beta.-unsaturated aldehydes obtained by aldol condensation of camphene aldehyde (1) with acetone, propionic or butyraldehyde (catalyzed by alkali hydroxides or alcoholates), and the .alpha.,.beta.-unsaturated alcohols 2, 3 and 4, obtained from the above by subsequent reduction have already been described in DE-A1 No. 992 391 as aroma chemicals with sandalwood and musk notes. ##STR2##

U.S. Pat. No. 4,052,341 describes the aldol condensation of camphene aldehyde (1) with methyl ketone (catalyzed by alkali hydroxides) to the .alpha.,.beta.-unsaturated carbonyl compounds and their subsequent reduction to a mixture of the unsaturated secondary alcohols 5/6 and the saturated alcohols 7/8.

In U.S. Pat. No. 4,173,585, the aldol condensation of camphene aldehyde with various ketones using zinc acetate dihydrate is described. In contrast to the aldol condensations catalyzed with alkali hydroxides or alcoholates, it is not the uniform .alpha.,.beta.-unsaturated ketones that are produced in this patent but rather mixtures of .alpha.,.beta.- and .beta.,.gamma.-unsaturated ketones, which are present as (Z) and (E) isomers (9-12). ##STR3##

These mixtures are said to have fragrance notes of the ionone type (sweet, woody, green, melon-like, apricot-like, flowery, violet-like, ambrigris-like). The alcohol mixtures 14-16 obtained from the mixtures of the .alpha.,.beta.- and .beta.,.gamma.-unsaturated ketones by reduction are said to possess sandalwood, cedarwood, resiny and flowery notes. The individual isomers were not isolated. Nothing is known about the odorous properties of the individual isomers.

SUMMARY OF THE INVENTION

The present invention is directed to 4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-3-en-1-ols of general formula I: ##STR4## wherein R may be methyl, ethyl, propyl, isopropyl or butyl, the wavy line characterizes geometrical isomers and the broken lines characterize stereoisomers.

The compounds of formula I can be produced by reduction of the aldol condensation products of campholene aldehyde and aliphatic aldehydes using sodium borohydride at raised temperatures.

The compounds of formula I can be used individually or in a mixture with the relevant .alpha.,.beta.-unsaturated alcohols as odorants or as an ingredient of perfume oils for cosmetic and technical consumer goods.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the .sup.1 H-NMR spectrum of compound 22.

FIG. 2 shows the mass spectrum of the E isomer of compound 22.

FIG. 3 shows the mass spectrum of the Z isomer of compound 22.

FIG. 4 shows the mass spectrum of the E isomer of compound 4.

FIG. 5 shows the gas chromatogram of the reduction mixture from Example 1.

FIG. 6 shows the gas chromatogram of the reduction mixture from Example 2.

DETAILED DESCRIPTION OF THE INVENTION

We have now surprisingly found that the previously unknown .beta.,.gamma.-unsaturated alcohols of the general formula I possess characteristic woody-animal and soft-fruity odorous properties which differ substantially from the typical sandalwood or musk note of the .alpha.,.beta.-unsaturated alcohols 3 or 4.

The odorous properties of the compounds of the general formula I are of advantage for their use as odorants, especially when combined with the relevant .alpha.,.beta.-unsaturated alcohols of the same substitution.

.beta.,.gamma.-unsaturated alcohols of formula I can be prepared as shown in the following diagram and described below. ##STR5## For the production of the .beta.,.gamma.-unsaturated alcohols of the general formula I camphene aldehyde (1) was likewise taken as a basis, being condensed in the known manner with short-chained aliphatic aldehydes, whereby the .alpha.,.beta.-unsaturated aldehydes 17-20 were produced. Conditions for these aldol condensations have been described in DEA No. 1 922 391 and in U.S. Pat. No. 4,052,341, both of which are incorporated herein by reference. The reduction of the .alpha.,.beta.-unsaturated aldehydes 17 and 18 to the corresponding .alpha.,.beta.-unsaturated alcohols 3 and 4 can, according to DEA No. 1 922 391, incorporated herein by reference, be carried out with complex metal hydrides or in the presence of aluminum alcoholates according to the method of Meerwein-Pondorf.

We have now surprisingly found that when using complex hydrides, preferably sodium borohydride, in the presence of a basic medium, preferably soda lye, a partial deconjugation of the double bond from the .alpha.,.beta.- to the .beta.,.gamma.-position takes place. The equilibrium that is established is influenced not only by the temperature and the reaction time, but also by the reduction of the carbonyl group to the alcohol group (Example 1, Table 1). Temperatures of 10.degree.-80.degree. C., preferably 30.degree.-60.degree. C., are utilized. From the mixtures produced, the compounds of formula I can be isolated by separation methods that are in themselves known, preferably by distillation.

The structure specified for the new compounds of the general formula I can be proved by spectroscopic methods. In the .sup.1 H-NMR spectrum (FIG. 1) of the isolated alcohol 22 there appears in addition to the signal for the olefinic proton of the cyclopentane system a multiplet at .delta.=4.9-5.7 ppm (2 protons) which characterizes the .beta.,.gamma. double bond in the side chain. This position of the double bond of 22 is likewise indicated by a strong IR band at 968 cm.sup.-1 (disubstituted double bond). The mass-spectrometric fragmentation of 22 also matches the specified structure; the fragments specified for (E-22) (FIG. 2) also occur in a very similar form in the Z-configured 22 (FIG. 3). The most obvious mass-spectroscopic difference from the corresponding .alpha.,.beta.-unsaturated alcohols is the favorable .alpha.,.beta. bond fracture, which leads to a stronger fragment ion with m/z=135 (mass spectrum of 4; FIG. 4). In the case of allyl alcohols like 4, which was prepared from 18 by reduction with lithium aluminum hydride (in diethyl ether) the fragment with m/z=109 (cyclopentane system) resulting from allyl cleavage is much more pronounced than in the case of the corresponding .beta.,.gamma.-unsaturated alcohols (here: 22). Furthermore, in the case of the .beta.,.gamma.-unsaturated compounds a typical fragment ion with m/z=M.sup.+ -31 occurs (see FIG. 2) which shows distinctly less intensity in the corresponding .alpha.,.beta.-unsaturated alcohols (FIG. 4). A further proof of constitution is given by the selective hydration which led to the analogous compounds with a saturated side chain; these compounds have been described in DEC No. 2,827,957. The specified criteria prove the structure of the new compounds of formula I. When lithium aluminum hydride/ether (0.degree. C.) is used for reduction of the unsaturated aldehydes 17-20, deconjugation does not take place under customary reaction conditions.

The campholene aldehyde (1) can be produced from (+) or (-)-.alpha. pinene in an optically active form. Hence the C-1 side chain of compounds A can be of .alpha.- or .beta.-configuration. In .alpha.-position (branching of the side chain) the deconjugated alcohols of the formula A exhibit an additional chiral center. The alcohols A are thus present as diastereomers; the stated Z/E isomerism may also be present. The .beta.,.gamma.-unsaturated alcohols given here as (Z) or (E) isomers may therefore also be present with the same geometry as diastereomers.

The derivatives of our invention can be used to contribute sandalwood notes or woody undertones to perfume compositions, perfumed articles such as solid or liquid anionic, cationic, nonionic or zwitterionic detergents, fabric softener compositions, fabric softener articles, fabric optical brighteners and other fabric conditioners. As olfactory agents the campholenyl derivatives of our invention can be formulated into or used as components of a "perfumed composition".

The term "perfumed composition" is used herein to mean a mixture of organic compounds including for example, alcohols other than the campholenyl derivatives of our invention, aldehydes, ketones, nitriles, ethers, lactones and frequently hydrocarbons which are admixed so that the combined odors of the individual components produce a pleasant or desired fragrance. Such perfumed compositions usually contain: (a) the main note of the "bouquet" or foundation-stone of the composition; (b) modifiers which round off and accompany the main note; (c) fixatives which include odorous substances which lend a particular note to the perfume throughout all stages of evaporation, and substances which retard evaporation; and (d) top-notes which are usually low-boiling, fresh-smelling materials.

In perfume compositions the individual component will contribute its particular olfactory characteristics, but the overall effect of the perfume composition will be the sum of the effect of each ingredient. Thus, the individual compounds of this invention, or mixtures thereof, can be used to alter the aroma characteristics of a perfume composition, for example, by highlighting or moderating the olfactory reaction contributed by another ingredient in the compositions.

The amount of campholenyl derivatives of our invention which will be effective in perfume compositions depends upon many factors including the other ingredients, their amounts and the effects which are desired. It has been found that perfume compositions containing as little as 1% of the campholenyl of our invention or even less and perfume compositions containing as much as 70% of the campholenyl derivatives of our invention can be used to impart interesting sandalwood notes or woody undertones to perfumed articles, perfumed compositions and colognes. Such perfumed articles include fabric softener compositions, dryer-added fabric softeners, cosmetic powders, talcs and solid or liquid anionic, cationic, nonionic or zwitterionic detergents. The amount employed can range up to 70% and will depend on considerations of cost, nature of the end product and the effect desired on the finished product and particular fragrance sought.

Thus, the campholenyl derivatives of our invention can be used alone or in a perfumed composition as an olfactory component in solid or liquid anionic, cationic, nonionic or zwitterionic detergents (including soaps), space odorants and deodorants, perfumes, colognes, toilet waters, bath salts, hair preparations such as lacquers, brillantines, pomades and shampoos, cosmetic preparations such as creams, deodorants, hand lotions and sunscreens; powders such as talcs, dusting powders, face powder and the like. When used as an olfactory component of a perfumed article such as a solid or liquid cationic, nonionic, anionic or zwitterionic detergent or of a cosmetic powder, as little as 0.01% of one or more of the campholenyl derivatives of our invention will suffice to provide interesting sandalwood notes or woody undertones. Generally, no more than 0.8% of the campholenyl derivatives of our invention is required.

In addition, the perfume compositions of our invention can contain a vehicle or carrier for the campholenyl derivatives of our invention alone or with other ingredients. The vehicle can be a liquid such as an alcohol, such as ethanol, a glycol such as propylene glycol, or the like. The carrier can be an absorbent solid such as a gum, or components for encapsulating the composition as by coacervation.

The present invention will be further described by reference to the following non-limiting examples.

EXAMPLE 1

Reduction of 2-ethyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-2-en-al

A solution of 15 g (0.395 mol) sodium borohydride and 0.15 g sodium hydroxide was dropped within one hour at 60.degree. C. into a stirred solution of 275.5 g (1.25 mol) 2-ethyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-2-en-al (18 prepared analogously with U.S. Pat. No. 4,052,341) in 250 g methanol. The reaction solution was left for another 30 minutes at 60.degree. C. Then the methanol was distilled off. The residue was added to 200 g petrol ether (boiling point 50.degree.-70.degree. C.) and washed neutral with sodium chloride solution. The petrol ether was removed by distillation and the remaining raw product was fractionally distilled, a mixture of 2-ethyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-3-en-1-ol (22, E+Z isomer), 2-ethyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-butane-1-ol and 2-ethyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-2-en-1-ol (4, E+Z isomer) being obtained; the yield was 203 g (78%); boiling point 110.degree.-124.degree. C./2 Pa; gas chromatogram FIG. 5; mass spectrum for E-22 FIG. 2, for Z-22 FIG. 3, and for E-4 FIG. 4.

A small part of the aforementioned distilled alcohol mixture was fractionally distilled again on a 1 m spinning band column, an analytic sample of pure 2-ethyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-3-en-1-ol (22, E+Z isomer) being obtained: boiling point 111.degree.-113.degree. C./2 Pa; .sup.1 H-NMR spectrum FIG. 1. The reaction was performed analogously with the instructions given here at other temperatures and with other reaction times. The product mixtures were studies by gas chromatography (30 m DB WAX-30N; temperature program: 100.degree.-240.degree. C./min.). The results are shown in Table 1.

TABLE 1______________________________________Composition of the Reaction Products of 18deconjugated saturated conjugated alcohols ratioCondi- alcohols alcohol ratio conj./tions % Z % E (%) % Z % E E/Z deconj.______________________________________15.degree. C./5 1,95 2,13 2,17 6,10 87,64 14,37 22,98min30.degree. C./5 1,92 2,14 2,55 5,99 87,39 14,59 23,00min40.degree. C./5 2,30 2,44 3,04 6,16 86,06 13,97 19,46min60.degree. C./5 3,71 4,05 3,23 6,48 82,51 12,73 11,45min30.degree. C./1 4,03 4,44 3,57 6,96 81,01 11,64 10,3960.degree. C./1 7,95 9,12 2,68 7,98 72,27 9,06 4,70h10.degree. C./45 2,66 2,95 2,66 6,98 84,75 12,15 16,33mininverse______________________________________

EXAMPLE 2

Reduction of 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-2-en-al

A solution of 10 g (0.236 mol) sodium borohydride and 0.1 g sodium hydroxide in 33 g water was dropped within one hour at 60.degree. C. into a stirred solution of 153.6 (0.8 mol) 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-2-en-al (17, prepared analogously with U.S. Pat. No. 4,052,341) in 160 g methanol. The reaction solution was left for another 30 minutes at 60.degree. C. Then the methanol was distilled off. The residue was added to 150 g petrol either (boiling point 50.degree.-70.degree. C.) and washed neutral with a sodium chloride solution. The petrol ether was removed by distillation and the remaining raw product was fractionally distilled, a mixture of 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)-but-3-en-1-ol (21, E+Z isomer), 2-methyl-4-(2,2,3-trimethyl-cyclopent-3-en-1-yl)-butan-1-ol and 2-methyl-4-(2,2,3-trimethyl-cyclopent-3-en-1-yl)-but-2-en-1-ol (3, E+Z isomer) being obtained; the yield was 115 g (74%; boiling point 96.degree.-110.degree. C./1.5 mm; gas chromatogram FIG. 6.

The reaction was carried out analogously with the instructions given here at other temperatures and with other reaction times. The mixtures produced were studied by means of gas chromatography (30 m DB WAX-30N; temperature program 100.degree.-240.degree. C., 4.degree. C./min). The results are given in Table 2.

TABLE 2______________________________________Composition of the Reaction Products of 17deconjugated saturated conjugated alcohols ratioCondi- alcohols alcohol ratio conj./tions E+ Z (%) (%) % Z % E E/Z deconj.______________________________________30.degree. C./5 2,07 3,19 3,97 90,78 22,89 45,82min60.degree. C./5 4,79 3,91 4,41 86,90 19,70 19,04min30.degree. C./1 2,14 3,16 4,10 90,60 22,09 44,3460.degree. C./1 6,42 3,55 4,36 85,67 19,66 14,02h______________________________________

EXAMPLE 3

Mass-spectrometric Data of Compounds 3, 4 and 21-26

Compounds 3, 4 and 21-26 were analyzed by mass spectroscopy in a standard manner. The resulting data is shown in Table 3.

TABLE 3______________________________________m/z (%) m/z (%) m/z (%)______________________________________Z-2139 23 79 37 108 6441 57 83 31 109 2543 31 91 51 119 3655 63 93 100 121 8567 30 95 22 124 4869 37 105 38 135 3377 36 107 74 M.sup.+ : 194 6E-2141 43 79 32 108 5743 30 83 20 109 2255 56 91 44 119 3867 30 93 100 121 4569 34 105 28 124 3677 28 107 83 135 26 M.sup.+ : 194 1Z-339 21 79 40 107 5441 51 81 27 108 10043 53 84 41 109 6253 20 91 40 119 2955 36 93 87 121 5467 72 95 47 122 2577 27 105 32 161 28 M.sup.+ : 194 6E-339 24 79 64 108 10041 42 81 37 109 9543 45 91 62 119 2753 26 93 86 121 9655 31 94 23 122 4965 21 95 91 161 4567 84 105 33 179 2677 49 107 90 M.sup.+ : 194 12Z-2230 31 77 39 108 5939 17 79 46 109 4641 54 81 21 119 3143 22 83 41 121 10053 19 91 59 122 2155 45 93 82 133 1757 21 95 32 135 4465 16 105 45 138 3667 30 107 87 177 20 M.sup.+ : 208 4E-2229 15 69 45 108 7131 29 77 40 109 4239 19 79 41 119 3941 51 81 21 121 10043 20 83 36 122 2253 18 91 61 133 1855 44 93 89 135 4457 22 95 34 138 3965 16 105 46 177 2367 30 107 88 M.sup.+ : 208 5Z-441 39 79 31 107 4743 27 81 23 108 10055 29 91 26 109 5657 38 93 63 119 2167 45 95 33 121 4677 26 98 26 122 21 M.sup.+ : 208 5E-427 14 77 36 108 9829 28 79 52 109 9730 11 81 42 119 2939 23 82 15 121 10041 56 83 13 122 4343 49 91 45 123 1153 24 93 79 135 1855 45 94 16 161 1357 81 95 77 175 2765 15 98 15 177 1167 82 105 25 193 1569 18 107 80 M.sup.+ : 208 10Z-2331 28 83 41 109 4740 65 91 53 110 3143 29 93 71 119 4155 67 95 35 121 10067 35 105 35 122 2877 31 107 82 135 4779 39 108 73 152 3381 26 M.sup.+ : 222 8E-2331 25 83 44 109 6040 52 91 42 110 2743 29 93 96 119 4255 79 95 29 121 10067 33 105 42 135 5469 25 107 75 152 2977 29 108 77 191 2779 48 M.sup.+ : 222 10Z-2529 26 71 42 95 7439 26 77 38 105 2641 74 79 68 107 7643 49 81 35 108 8853 31 91 51 109 10055 45 93 76 121 9867 78 94 26 122 49 M.sup.+ : 222 10E-2539 22 77 27 107 3540 51 79 49 108 3843 54 81 30 109 10055 41 91 27 119 2457 22 93 65 121 4367 49 94 22 122 2269 22 95 76 189 2271 60 M.sup.+ : 222 8Z-2431 28 81 30 109 9241 72 83 57 112 3443 55 91 70 119 4955 98 93 89 121 10067 40 95 51 122 3069 47 105 57 133 3077 43 107 77 135 6279 45 108 87 M.sup.+ : 222 11E-2431 28 77 44 107 7439 26 79 50 108 8041 76 81 28 109 9843 46 83 52 112 3253 26 91 57 119 5055 100 93 85 121 9867 43 95 48 133 2669 44 105 57 135 63 M.sup.+ : 222 7Z-2641 37 81 19 108 10043 37 91 22 109 5255 33 93 61 112 1667 36 95 31 119 1869 19 105 18 121 4277 24 107 39 122 1779 30 M.sup.+ : 222 4E-2639 28 71 26 95 6841 68 77 40 107 7543 60 79 75 108 10053 28 81 39 109 9555 49 91 52 121 9367 65 93 83 122 4069 26 94 28 M.sup.+ : 222 6______________________________________

EXAMPLE 4

Perfume Base of the Sweet-Herby Type

______________________________________2,2-dimethyl-3-phenyl-propanol 50(muguet alcohol, DE PS 3 139 358)Oil of lavender, French 15Hyssop oil, Spanish 10Oak moss extract, 50% in dipropylene glycol 10Dihydromyrcene alcohol 5Oil of rosemary, Spanish 5Product from Example 2 (21 + 3) 5 100______________________________________

This base, which contains a relatively high proportion of the product from Example 2, has an attractive fresh and sweet-herby harmony with a distinct but soft woody note.

EXAMPLE 5

Perfume Base of the Woody-Spicy Type

______________________________________Mahogonate 150Vetiveryl acetate 100Muscogene 100Caryophyllenol 100Patchouli oil 502,2-dimethyl-5-phenyl propanol 50(muguet alcohol, DE PS 3 139 358)Musk ketone 30Oak moss extract, 50% 20Labdanum resinoid, 50% 20Myrrh resinoid 10Oil of pepper 5Nutmeg oil 5Cistus oil 5Eugenol 5 650______________________________________

This perfume base has a woody-spicy character with musk aspects. When 100 parts of compound 4 (DE OS No. 1 922 391) are added, a rounding out with simultaneous accentuation of sweetish-woody aspects is found. If 100 parts of compound 22 are added, the scent is more harmonious, with accentuation of the woody-animal aspects. The introduction of 100 parts of the product from Example 1 (22+4) yields a balanced composition with a sandalwood aspect.

EXAMPLE 6

A Perfume Oil of the Flowery Type

______________________________________ a b c______________________________________Citronellol 20 20 20Phenyl ethyl alcohol 170 170 170Indol, 50% in dipropylene glycol 5 5 5Isoeugenol 5 5 5Benzyl acetate 30 30 30Linalool 40 40 40Terpineol 240 240 2402,2-dimethyl-3-phenyl-propanol-1 200 200 200(muguet alcohol, DE PS 3 139 358)Cinnamic alcohol 40 40 40Citronellyl acetate 20 20 20Frambinone 15 15 151,4-dimethyl-8-hydroximino-bicyclo- 60 60 60[3.2.1 ]octane (DE PS 3 129 934)Hydroxycitronellal 25 25 25Compound 4 (DE OS 1 922 391) 20 -- --Compound 22 -- 20 --Product from example 1 (22 + 4) -- -- 20 890 890 890______________________________________

The mixture a has a well-balanced flowery scent of the type lily-of-the-valley/white lily. In mixture b, which contains the new compound 22 instead of allyl alcohol 4, an emphasis of the fresh note is found. Mixture c, in turn, has a harmonious flowery scent with a slight accentuation of woody aspects.

Claims

1. A compound having the formula I ##STR6## wherein R may be methyl, ethyl, propyl, isopropyl or butyl, the wavy line characterizes geometrical isomers and the broken lines characterize stereoisomers.

2. The compound of claim 1 wherein R is methyl.

3. The compound of claim 1 wherein R is ethyl.

4. The compound of claim 1 wherein R is propyl.

5. The compound of claim 1 wherein R is isopropyl.

6. A method for producing a compound as described in claim 1 which comprises:

(a) condensing campholene aldehyde and R--CH.sub.2 CHO, where R is defined as in claim 1, catalyzed by alkali hydroxides or alcoholates, and

(b) reducing in an alkaline environment the resulting .alpha.,.beta.-unsaturated aldehydes using sodium borohydride at temperatures of 10.degree.-80.degree. C.

7. The method of claim 6 wherein the temperature in step (b) is 30.degree.-60.degree. C.

8. A perfume composition containing as an active perfume ingredient an amount of at least one compound of formula I according to claim 1 sufficient to impart sandalwood notes or woody undertones thereto.

9. The perfume composition of claim 8 wherein said active perfume ingredient comprises two or more compounds of formula I.

10. An artificial essential oil of sandalwood notes or woody undertones, which comprises having added thereto an amount of at least one compound of formula I according to claim 1 sufficient to impart sandalwood notes or woody undertones thereto.

11. The artificial essential oil of claim 10 wherein two or more compounds of formula I are added.

12. A process for augmenting or enhancing the aroma of a perfume or cologne composition comprising the step of adding to a perfume or cologne base an aroma augmenting or enhancing quantity of a product containing at least one compound having the structure ##STR7## wherein R may be methyl, ethyl, propyl, isopropyl or butyl, the wavy line characterizes geometrical isomers and the borken lines characterize stereoisomers.

13. The process of claim 12 wherein said product comprises two or more compounds of formula I.

14. The method of claim 6 which further comprises the step of

(c) separating the compound from the resulting mixture by distillation.

15. The method of claim 14 wherein the temperature in step (b) is 30.degree.-60.degree. C.

16. A perfume composition containing as an active perfume ingredient an amount of a reduction mixture containing at least 1% of a compound of formula I according to claim 1 sufficient to impart sandalwood notes or woody undertones.

17. An artificial essential oil of sandalwood notes or woody undertones which comprises having added thereto an amount of a reduction mixture containing at least 1% of a compound of formula I according to claim 1 sufficient to impart sandalwood notes or woody undertones thereto.