Enrichment of Diastereoisomers in Magnolan

Abstract

The present invention relates to a distillation method for preparing a diastereomerically enriched fragrance mixture, a diastereomerically enriched fragrance mixture, and its use as a fragrance or in preparing a fragrance preparation. Furthermore, the present invention relates to the use of a diastereomerically enriched fragrance mixture in an organoleptically effective amount for mediating, modifying, or enhancing the floral aroma of a fragrance product or for preparing a fragrance product. Finally, the present invention also relates to a fragrance preparation and a fragrance product containing the diastereomerically enriched fragrance mixture.

Description

Technical Field

[0001] The present invention relates to a distillation process for preparing a diastereomerically enriched fragrance mixture having a floral aroma containing a compound of the general formula (A):

[0002]

[0003] The present invention also relates to a diastereoisomerically enriched fragrance mixture containing a compound of general formula (A) preparable by the process, and to its use as a fragrance or in the preparation of a fragrance preparation. Furthermore, the present invention relates to the use of a diastereoisomerically enriched fragrance mixture in an organoleptically effective amount for mediating (imparting), modifying, or enhancing the floral odor of a fragrance product, or for the preparation of the fragrance product itself. Finally, the present invention relates to a fragrance preparation and a fragrance product comprising the diastereoisomerically enriched fragrance mixture. Background Art

[0004] 4,4a,5,9b-tetrahydro-2,4-dimethylindeno[1,2-d][1,3]-dioxine is a popular flavor or fragrance with a predominantly transparent floral-green odor, reminiscent of magnolia, geranium, and grapefruit. The odor of this compound is often described as flowery-green and very complex. This is why this flavor or fragrance, commercially known as Magnolan (Symrise AG), is particularly used to create floral aromas.

[0005] Furthermore, Magnolan (Symrise AG) is extremely suitable for achieving specific floral notes in floral fragrance compositions and for achieving special odor effects in odor compositions containing dry and woody components.

[0006] Publication DE 1 793 310 describes 2,6-dialkyl-4,5-indan-1,3-dioxane compounds, methods for preparing these compounds, and their use as raw materials in perfume preparation and perfume products. It also discloses the preparation of 2,6-dimethyl-4,5-(1',2'-indan)-1,3-dioxane, which has an odor similar to that of Damascus rose. The product has two geometric isomers in a ratio of 1.8:1. This fragrance is particularly useful as a supplement or replacement for natural rose essence.

[0007] WO 2010 / 142815 A2 also discloses a fragrance mixture comprising Magnolia. The olfactory properties of the fragrance are described as "white flowers" (especially white magnolia), floral (safflower, peony, geranium) and "indole".

[0008] Although the well-established fragrance Magnolan (Symrise AG) has essentially excellent olfactory properties, this fragrance is often described as also having a rather disconcerting, industrial and plastic-like odor.

[0009] As described in DE 1 793 310, this is generally a product in which the diastereoisomers are present side by side in an almost equal distribution. Summary of the Invention

[0010] The present invention is therefore primarily based on the general aim of optimizing commercially available fragrances and eliminating interfering odors and thereby providing an intense, more harmonious and "cleaner" floral fragrance impression, and a corresponding process for preparing such optimized fragrances.

[0011] A gentle approach is of paramount importance in this context in order to reduce possible decomposition processes and potential side reactions, as well as interactions between these decomposition products or side reaction products, which could have further adverse effects on the olfactory properties of the product itself or of fragrance formulations and aroma products containing rich substances.

[0012] Although methods for preparing Magnolia are known, these methods often exhibit disadvantages in terms of isomeric purity, especially when the product is scaled up, i.e., prepared on a large scale (industrial): in this case, only low yields and selectivities, i.e., low purity, are generally observed. This can negatively affect the quality of the product, in particular its odor characteristics, as mentioned above.

[0013] Therefore, another object of the present invention is to provide a simple and mild preparation process which allows the preparation of optimized floral fragrances in a small number of steps, thereby providing the desired product in high yield and purity at a low cost.

[0014] Furthermore, an object relates to providing such a fragrance mixture, its use as fragrance and for the preparation of fragrance preparations and fragrance products, as well as fragrance preparations and fragrance products comprising such an optimized fragrance mixture.

[0015] Additional objects of the present invention relate to reducing or masking unpleasant odors and / or enhancing positive odor impressions, primarily harmonious, intense and "clean" floral fragrance impressions.

[0016] Another object relates to the gentle enrichment of isomers with positive odor properties and thus to a targeted influence on the odor without impairing or modifying the odor.

[0017] It is conceivable that the synthesis can, for example, begin with the use of optically active starting materials, i.e., starting materials whose stereoselectivity determines the stereoisomer of the product, or with separated diastereoisomers. However, such methods involve a large number of costly and complex presynthetic and purification steps to provide the separated enantiomers or diastereomers of the starting compound. In this regard, it is another object of the present invention to provide diastereomerically enriched magnolan products without the need to provide isomer-directed intermediates as starting or intermediate stages, or to provide a rapid and efficient method with a small number of process steps while ensuring high selectivity and minimizing decomposition reactions or side reactions that could adversely affect the odor characteristics.

[0018] According to the invention, the stated objects are solved by the subject matter of the independent claims. Further aspects and preferred designs of the invention emerge from the text of the dependent claims, the subsequent description and the examples.

[0019] A first subject (aspect) of the present invention relates to a distillation process for preparing a diastereomerically enriched fragrance mixture having a floral aroma containing a compound of general formula (A):

[0020]

[0021] The spice mixture comprises the following enantiomeric pairs which are diastereoisomers of each other:

[0022]

[0023] wherein the quantitative ratio of enantiomeric pair (I) to enantiomeric pair (II) is at least 10:1, and the quantitative ratio of enantiomeric pair (I) to (III) is at least 50:1, and wherein the process comprises the following distillation step:

[0024] (a) separating by distillation a crude product containing a compound of formula (A) in a first distillation step;

[0025] (b) subjecting the crude product to a subsequent fine distillation by one or more distillation steps to concentrate the enantiomeric pair (I) relative to the enantiomeric pairs (II) and (III), wherein the fine distillation comprises at least 15 separation stages.

[0026] The results show that fragrance mixtures with a lower content of isomer (III) have a better odor impression for magnolan fragrances. Furthermore, fragrance mixtures should contain a higher proportion of isomer (I) compared to isomer (II). This selective enrichment is surprising, as methods for selectively enriching enantiomeric pair (I) relative to enantiomeric pairs (II) or (III) were previously unknown and unpredictable. Such a high enrichment is particularly surprising. Furthermore, this enrichment is achieved using a process that is both cost-effective and efficient, and therefore process-wise advantageous.

[0027] In a second subject matter, the present invention comprises a diastereomerically enriched fragrance mixture containing a compound of general formula (A), wherein the compound of formula (A) comprises enantiomeric pairs of formulae (I), (II) and (III) which are diastereoisomers of each other, and wherein the quantitative ratio of enantiomeric pair (I) to enantiomeric pair (II) is at least 10:1, and the quantitative ratio of enantiomeric pair (I) to (III) is at least 50:1 (relative to the total mixture containing compounds of general formula (A), i.e. compounds (I), (II) and (III)).

[0028] A third subject of the present invention is the use of a diastereomerically enriched fragrance mixture as fragrance or for preparing fragrance formulations.

[0029] In a fourth aspect, the present invention relates to a fragrance formulation having a sensory effective amount of a diastereomerically enriched fragrance mixture.

[0030] Another subject of the invention is the use of a diastereomerically enriched fragrance mixture in an organoleptically effective amount for mediating, modifying or intensifying the floral aroma of a fragrance product or for preparing the fragrance product itself.

[0031] Finally, in another aspect, the present invention relates to a fragrance product comprising a diastereomerically enriched fragrance mixture, or a fragrance product comprising a fragrance formulation of the diastereomerically enriched fragrance mixture.

[0032] Surprisingly, within the scope of the present invention, it was found that, by means of the process described herein (preferably racemic), it is possible to obtain a diastereomerically enriched fragrance mixture having a more natural and intensely floral, rosy, warm, transparent and bright geranium scent that is perceived as less industrial and devoid of plastic smells than commercially available Magnolan. Furthermore, this scent is perceived as less green, more intensely rosy and less grapefruit-like than commercially available Magnolan.

[0033] Furthermore, the process described herein makes it possible to produce (preferably racemic) diastereomerically enriched fragrance mixtures in very high yields and excellent purity in just a few synthetic and process steps, distinguishing the process described herein as a highly efficient, highly selective, and reliable, i.e., reproducible, process. The intensely floral fragrances obtained in this manner allow for the preparation of improved fragrance compositions with a unique aroma and character, without the unpleasant smell of industrial and plastic components. Consequently, the substances, preparations, and products described herein are perceived as having a more floral and "cleaner" aroma.

[0034] These and other aspects of the present invention, as well as other features and advantages, will be readily apparent to those skilled in the art upon study of the detailed description and claims that follow. In this context, each feature from one aspect of the present invention may be inserted or interchanged with another aspect of the present invention. The examples included in this application illustrate the present invention but do not limit it.

[0035] Advantageous developments and variants of the invention are described in the dependent claims.

[0036] Unless otherwise indicated, all percentages are in weight %. Numerical examples given in the format "from x to y" include the aforementioned values. If multiple preferred numerical ranges are specified in this format, all ranges combining the different endpoints are also understood. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1a and 1b The first diastereoisomer enriched flavor mixture according to the present invention is shown 1 H-NMR spectrum (600 MHz, chloroform-d).

[0038] Figure 2 The first diastereoisomer enriched flavor mixture according to the present invention is shown 13 C-NMR spectrum (151 MHz, CDCl3).

[0039] Figure 3 Shown is a gas chromatography analysis of a second diastereomerically enriched fragrance mixture according to the present invention. DETAILED DESCRIPTION

[0040] In a first aspect, the present invention relates to a distillation process for preparing a (preferably racemic) diastereomerically enriched fragrance mixture having a floral aroma containing a compound of general formula (A):

[0041]

[0042] The spice mixture comprises the following enantiomeric pairs which are diastereoisomers of each other:

[0043]

[0044]

[0045] wherein the quantitative ratio of the enantiomeric pair (I) to the enantiomeric pair (II) is at least 10:1, and the quantitative ratio of the enantiomeric pair (I) to (III) is at least 50:1, and wherein the process comprises the following distillation step:

[0046] (a) separating by distillation a crude product containing a compound of formula (A) in a first distillation step;

[0047] (b) subjecting the crude product to a subsequent fine distillation by one or more distillation steps to concentrate the enantiomeric pair (I) in particular relative to the enantiomeric pair (II) and (III), wherein the fine distillation comprises at least 15 separation stages.

[0048] Those skilled in the art are aware that compounds of the general formula (A) are chiral compounds. Furthermore, they are familiar with the fact that these enantiomeric pairs are diastereomers of one another, while the enantiomers of an enantiomeric pair, as the name indicates, are enantiomers of one another, i.e., they appear as images and mirror images. Therefore, diastereomeric enrichment means producing an excess of one of these enantiomeric pairs (here, enantiomeric pair (I)) relative to the other enantiomeric pairs present in the fragrance mixture, here, the enantiomeric pairs (II) and (III) of formula (A).

[0049] Thus, the term "diastereomerically enriched" herein refers to the proportion of a diastereomer, i.e., a preferred enantiomeric pair, in a mixture of the compound under consideration, i.e., the other possible diastereomers of the general formula (A). The term "diastereomerically enriched" is understood herein to mean that the fragrance mixture obtainable within the scope of the process according to the invention has a significantly higher content of enantiomeric pair (I) relative to the diastereomeric pairs (II) and (III) than the Magnolan product obtainable by conventional methods and commercially available. Thus, the term "diastereomerically enriched" in the present invention describes the presence of a diastereomer, i.e., an enantiomeric pair, preferably enantiomeric pair (I), as defined above, in a proportion ranging from >50% to 100% by weight in a mixture of the other possible diastereomers. In particular, the term "diastereomerically enriched fragrance mixture" is to be understood as containing at least 80% to 99.9% by weight, preferably 90% to 99.8% by weight, particularly preferably 95% to 99.5% by weight of enantiomeric pair (I), including the enantiomers of formula (Ia) and (Ib), and a total of at most 20% by weight, preferably at most 10% by weight and particularly preferably 5% to 0.5% by weight of further enantiomeric pairs (II) and / or (III).

[0050] In the context of the present invention, the terms "compound of formula (I)" or "enantiomer pair of formula (I)" or "enantiomer pair (I)", "compound (I)" and "isomer (I)" are understood to mean the individual enantiomeric compounds of formula (I) and therefore the enantiomers (Ia) and (Ib) as well as all mixtures of these enantiomers in any mixing ratio. This means that the following description of "enantiomer pair (I)" applies both to the individual compounds of formula (I), and therefore to the enantiomers (Ia) and (Ib), and also to mixtures consisting of or comprising the enantiomers (Ia) and (Ib) in any mixing ratio. The same applies to the designations "enantiomer pair (II)" and "enantiomer pair (III)".

[0051] However, in this case, the enantiomers (Ia) and (Ib), (IIa) and (IIb), and (IIIa) and (IIIb) are preferably each included in one another, so that the enantiomer pairs (I), (II) and (III) are present in a racemic mixture of the respective enantiomers (Ia) and (Ib), (IIa) and (IIb), and (IIIa) and (IIIb), respectively. Therefore, another preferred embodiment relates to providing a racemic diastereoisomer-enriched fragrance mixture, wherein the enantiomer pairs (I), (II) and (III) are each present in racemic form, but in particular the enantiomer pair (I). Such racemic compounds and fragrance mixtures enriched thereby with racemic diastereoisomers exhibit particularly balanced and harmonious aromas.

[0052] The compounds of general formula (A) have the following names:

[0053] Enantiomeric pair (I):

[0054] Enantiomer (Ia):

[0055] (2S,4S,4aS,9bR)-2,4-Dimethyl-4,4a,5,9b-tetrahydroindeno[1,2-d][1,3]dioxin

[0056] Enantiomer (Ib):

[0057] (2R,4R,4aR,9bS)-2,4-Dimethyl-4,4a,5,9b-tetrahydroindeno[1,2-d][1,3]dioxin

[0058] Enantiomeric pair (II):

[0059] Enantiomer (IIa):

[0060] (2R,4R,4aS,9bR)-2,4-Dimethyl-4,4a,5,9b-tetrahydroindeno[1,2-d][1,3]dioxin

[0061] Enantiomer (IIb):

[0062] (2S,4S,4aR,9bS)-2,4-Dimethyl-4,4a,5,9b-tetrahydroindeno[1,2-d][1,3]dioxin

[0063] Enantiomeric pair (III):

[0064] Enantiomer (IIIa):

[0065] (2R,4S,4aS,9bR)-2,4-Dimethyl-4,4a,5,9b-tetrahydroindeno[1,2-d][1,3]dioxin

[0066] Enantiomer (IIIb):

[0067] (2S,4R,4aR,9bS)-2,4-Dimethyl-4,4a,5,9b-tetrahydroindeno[1,2-d][1,3]dioxin

[0068] The resulting (preferably racemic) diastereomerically enriched fragrance mixture comprising the compound of the general formula (1) comprises enantiomer pair (I) in a ratio of at least 10:1 relative to enantiomer pair (II) in the mixture. Preferably, the quantitative ratio of enantiomer pair (I) to enantiomer pair (II) in the mixture is at least 15:1, preferably at least 20:1, particularly preferably at least 50:1. It is also preferred that the quantitative ratio of the enantiomer pairs of these diastereomers to one another is at least 100:1.

[0069] As described in DE 1793310, 2,6-dialkyl-4,5-indano-1,3-dioxane comprises two main geometric isomers, which are present only in a ratio of 1.8:1. The Prins reaction is, for its part, a fundamentally nonselective process that generally results in the formation of nearly equal amounts of the enantiomeric pair.

[0070] It is indeed surprising within the scope of the present invention that one of these isomers, which are usually produced in an almost statistical distribution in the traditional Magnolan synthesis, is aromatically preferred. By the process described herein, the preferred isomer, isomer (I), can be significantly enriched in the resulting fragrance mixture relative to the second main isomer, thereby having a positive influence on the odor characteristics of the resulting fragrance.

[0071] Thus, by means of the present method, it is possible to enrich the enrichment mixture to a proportion of the preferred isomer to more than 95% by weight relative to the other isomers present, and thus to significantly enhance the positive odor components of the fragrance mixture. Furthermore, it was surprising that, in particular, the compounds of the enantiomeric pair (I) are responsible for the positive odor characteristics of the fragrance mixture, and that the above-mentioned isomer distribution allows the production of particularly intensely floral, "clean" and balanced odors, while the process described herein itself is highly selective, efficient and mild.

[0072] Therefore, a further embodiment of the process described herein is to provide a diastereomerically enriched fragrance mixture as described above, wherein the proportion of enantiomeric pair (I) in the fragrance mixture is at least 95% by weight, more preferably at least 97.5% by weight, and even more preferably at least 98.5% by weight relative to the sum of enantiomeric pairs (I), (II) and (III). Such fragrance mixtures have an extremely pleasant and intense floral odor, wherein no industrial or other negative odors are detected, i.e., a "clean" intense floral odor.

[0073] Therefore, a further design of the preparation process currently used involves providing a diastereomerically enriched fragrance mixture comprising at least 95% by weight of the (preferably racemic) enantiomeric pair (I), preferably 97.5% by weight and particularly preferably at least 98.5% by weight relative to the sum of the enantiomeric pairs (I), (II) and (III).

[0074] Such pure or highly enriched diastereoisomerically enriched magnolan-type fragrance mixtures have not been known to date. Furthermore, it must be emphasized that such fragrance mixtures have been found to have a particularly well-balanced and particularly natural warm and floral aroma. Furthermore, it should be emphasized that the process described here represents a highly selective process that is also particularly mild.

[0075] Furthermore, surprisingly, the racemic enantiomer pairs, in particular the racemic enantiomer pairs of formula (I), make a decisive contribution to a balanced, natural, floral, and intense odor. Thus, it was observed that fragrance mixtures comprising compounds of general formula (A), as described herein, and particularly those diastereomeric enriched with a higher proportion of the racemic enantiomer pair (I) relative to the enantiomer pairs (II) and / or (III), contribute to this particular odor: the resulting products were found to have a positive, optimized, natural, intensely floral, rosy, transparent, slightly warm, bright, and geranium odor, without any industrial or plastic nuances. In particular, the balanced, intense, exceptionally natural, and "clean" floral odor nuances are characteristic of the present fragrance mixtures, which nuances are attributable to the preferred diastereomeric enrichment of the racemic enantiomer pair (I) in the fragrance mixtures of the first aspect, and demonstrate the suitability of the present fragrance mixtures as fragrances or fragrance bases in a variety of complex fragrance formulations and aroma products.

[0076] Furthermore, the fragrance mixture obtained in this way, comprising the compound of the general formula (A), preferably comprises the enantiomeric pair (I) and (III) in a quantitative ratio of at least 50:1 to one another. Furthermore, it is preferred that the quantitative ratio between the enantiomeric pair (I) and (III) is at least 100:1; particularly preferred is at least 1000:1, and most preferred is a corresponding quantitative ratio of at least 1360:1.

[0077] Thus, at the same time, the fragrance components which are primarily responsible for the industrial and plastic odor impression can be significantly minimized, so that the fragrance mixture can be optimized accordingly.

[0078] Therefore, the fragrance mixture according to the present invention preferably has a significantly higher ratio of enantiomers (Ia) and (Ib) of the enantiomer pair (I) relative to the other diastereomers in the fragrance mixture, i.e., enantiomers (IIa) and (IIb) and (IIIa) and (IIIb) of the enantiomer pair (II) and (III).

[0079] Surprisingly, within the scope of the present invention, by means of the process described herein, it is thus possible to obtain a fragrance mixture enriched in the (preferably racemic) diastereomers of the enantiomeric pair (I), which has an intense, natural floral, rosy, generally slightly warm, transparent and bright geranium scent and is considered less industrial and devoid of a plastic-like odor (and is therefore considered "clean") compared to commercial Magnolan. Thus, the scent is more intense, more natural, more balanced, more floral and more "clean" than commercial Magnolan.

[0080] Process steps (a) and (b) of the distillation process for preparing a (preferably racemic) diastereomerically enriched fragrance mixture are explained further below.

[0081] The first step (a) of the distillation process described herein involves the distillative separation of a crude product comprising a compound of formula (A). In this case, the product subjected to the first distillation step is a crude magnolan product, preferably obtained from the synthesis of indene and paraldehyde. The provision of this product is described below. However, generally speaking, this is a magnolan product that has not undergone any additional purification steps and is present as a product directly in the reaction mixture after the reactants have reacted.

[0082] The primary distillation purpose of this first distillation step is to perform a crude distillation to separate solvent residues, catalyst residues and unreacted starting compounds or reactants from a fragrance mixture which has not been substantially enriched in diastereomers, comprising the compound of formula (A) or the enantiomeric pairs (I), (II) and (III). If necessary, this process step should also be carried out under reduced pressure.

[0083] Thus, based on the first distillation step of the process, it is first possible to provide a fragrance mixture in the form of a crude product by isolating a crude Magnolan product of sufficient chemical purity, and chemical interactions with other substances contained in the crude product, which could have a negative impact on the overall olfactory impression of the final diastereomerically enriched fragrance mixture, can be avoided.

[0084] The crude product comprising the compound of general formula (A) has, for example after crude distillation, a chemical purity of at least 80%, preferably at least 90%.

[0085] After this first distillation step, the process described herein for preparing a diastereomerically enriched fragrance mixture comprises a further distillation step comprising a fine distillation of the crude product of the compound of formula (A). The fine distillation is carried out by one or more distillation steps to concentrate the enantiomeric pair (I), wherein the fine distillation comprises at least 15 separation stages. However, preferably, the fine distillation comprises at least 18 separation stages, and most preferably comprises at least 20 separation stages.

[0086] Magnolan of formula (A) obtainable by conventional synthesis generally has a composition in which the isomers (I) and (II) are distributed almost statistically relative to one another, but with a maximum distribution ratio of 2:1.

[0087] Thus, the distillation process according to the invention carried out in accordance with steps (a) and (b) also allows the preparation of diastereomerically enriched flavor mixtures by selective fine distillation from substantially diastereomerically enriched starting compounds which have substantially no significant enantiomeric or diastereomeric excess of one or more geometric isomers contained therein.

[0088] Preferably, a crude distillation pretreatment (preliminary run) is performed before a subsequent fine distillation. In this way, even higher (diastereoisomer) purities and yields can be achieved.

[0089] Furthermore, the method described here is highly suitable for the large-scale preparation of fragrance mixtures, thus fully meeting the needs of the perfume industry. Of particular importance is the consistent quality of the product from batch to batch, which can be ensured using current processes. The method is particularly selective, requires only a few steps, and is extremely gentle, effectively preventing any decomposition or side reactions. Therefore, the method described here is a particularly efficient method.

[0090] In particular, an enrichment of the enantiomeric pair (I) to more than 95% by weight relative to the sum of the enantiomeric pairs (I), (II) and (III) in the resulting fragrance mixture is possible.

[0091] This enrichment is surprising since, to date, there has been no known nor expected selective enrichment of enantiomeric pair (I) over enantiomeric pairs (II) or (III).

[0092] In another preferred embodiment, the present invention relates to a process for preparing a diastereomerically enriched spice mixture as described above, which further comprises, before the distillation steps (crude distillation and fine distillation):

[0093] - providing paraldehyde or acetaldehyde of the general formula (IV),

[0094]

[0095] as well as

[0096] - reaction with an indene of general formula (V) in a solvent under acidic catalysis,

[0097]

[0098] wherein the reaction of paraldehyde or acetaldehyde with indene occurs at a temperature below 10°C; and

[0099] - A crude product comprising a compound of general formula (A) is obtained.

[0100] Thus, this preferred embodiment describes the synthesis of a crude Magnolan product which can be subjected to the distillation process of the first aspect and preferably can be subjected to the distillation process of the first aspect.

[0101] In a further development of the synthesis, the reaction of the compounds of the general formulae (IV) and (V) is carried out under acid catalysis, preferably in the presence of dilute sulfuric acid in toluene.

[0102] Basically, the mechanism of the synthesis conforms to the essential features of the so-called classical Prins reaction, i.e., the acid-catalyzed carbonyl-ene reaction, a form of cycloaddition that describes the electrophilic addition of aldehydes or ketones to alkenes or alkynes.

[0103] Therefore, the process described herein also involves providing the crude product (2,4,4a,9b)-2,4-dimethyl-(4,4a,5,9b)-tetrahydroindeno[1,2d][1,3]dioxin via the classical Prins reaction under optimized process conditions.

[0104] According to the method according to the invention of the first aspect, the reaction of converting the compound of formula (IV) and formula (V) into the crude product of general formula (A) is carried out preferably in the duration of about 5 hours. In addition, it is preferred that the acid catalysis is carried out by reacting in an emulsion consisting of dilute sulfuric acid and toluene.

[0105] Very high chemical purities and yields are already achieved with this process for the crude product (which has not yet been enriched in diastereomers).

[0106] Preferably, no other substances such as antioxidants, iodine, enzymes or other salts are involved in the conversion (reaction).

[0107] Therefore, the reaction step of the reactants is not selective for the individual enantiomers or diastereomers of the compound of general formula (A). Therefore, the crude product of formula (A) is usually a mixture of essentially statistically distributed amounts of the individual geometric isomers, i.e. the enantiomeric pairs (I), (II) and (III) are almost statistically distributed in the crude product of general formula (A).

[0108] In this case, the predominantly formed enantiomers and (preferably racemic) diastereomers can be described by formula (Ia), (Ib), (IIa), (IIb), (IIIa) or (IIIb) or (I), (II) and (III), respectively.

[0109] In this case, it was discovered that the enantiomers (I), (II), and (III), which are diastereoisomers of one another, have different odor profiles. Thus, the odor of enantiomer pair (I) can be described as floral, rosy, transparent, bright, and geranium-like, while the odor of enantiomer pair (II) is floral, green, somewhat industrial, and grapefruit-like, and is weaker than that of enantiomer pair (I). Furthermore, it was surprisingly discovered that enantiomer pair (III) has a floral, industrial, unclean, and plastic odor. This odor profile of enantiomer pair (III) has now been identified and described for the first time within the scope of the present invention.

[0110] Furthermore, it has been shown that isomer (I) is the most odoriferous of the three identified diastereoisomers, and therefore the selective enrichment of diastereoisomers of fragrance mixtures with geometrical isomers preferring the racemic enantiomeric pair (I) is particularly desirable, and there is a need for an efficient and selective method for specifically enriching the isomers of the enantiomeric pair (I) in fragrance mixtures to be prepared.

[0111] At the same time, with regard to the odor characteristics that are considered to be negative, the proportion of the enantiomeric pair (III) is therefore preferably reduced. In this case, it is particularly interesting if the number ratio of the enantiomeric pair (I) and (III) is at least 50:1.

[0112] It is further preferred that, simultaneously or independently thereof, the quantitative ratio of enantiomeric pair (I) to enantiomeric pair (II) is at least 10:1.

[0113] Surprisingly, it has been found that when the enantiomeric pairs (I), (II) and (III) of the diastereoisomers are present in these ratios, corresponding fragrance mixtures can achieve particularly intense bright, warmer, more natural and more transparent floral fragrances or floral odors with a special balance.

[0114] However, standard methods for separating enantiomers or diastereomers or pairs of enantiomers typically involve many intermediate steps, such as providing specific reactants for enzyme-controlled targeting of a given (predetermined) stereoisomer or geometry. Furthermore, such methods are typically neither mild nor particularly efficient or selective.

[0115] However, the method described herein for providing a (preferably racemic) diastereomerically enriched fragrance mixture comprising a compound of formula (A) and enantiomeric pairs (I), (II), and (III) successfully enriches enantiomeric pair (I) relative to its diastereoisomers in such a way that the resulting product emits a positive and optimized, natural, intensely floral, rosy, transparent, slightly warm, bright, and geranium-like aroma. In particular, the high intensity, cleanliness, and naturalness of the aroma make the present fragrance mixture an excellent fragrance / fragrance blend or fragrance base for further use in the preparation of fragrance preparations and aromatic products with natural and intense floral aromas. Together with reduced industrial, unclean, and plastic odor nuances, this results in an excellent fragrance mixture with a unique, balanced, intense, and "clean" floral aroma that can be perfectly integrated into complex perfume creations. These odor nuances can be achieved with fragrance mixtures having enantiomeric pairs (I), (II), and (III) in the ratios described herein. A certain proportion of the enantiomeric pair (II) in a fragrance mixture also contributes to a more intensely floral, greener, and therefore more natural floral fragrance component. Natural nuances are particularly interesting in the perfume industry. Thus, due to their particularly intensely floral, balanced, and surprisingly "clean" scent, the fragrance mixture described above can provide the perfume industry with a fragrance component that is particularly suitable as a natural floral odor component in various preparations and products.

[0116] Furthermore, a highly selective, simple and mild preparation method has now been developed which allows the preparation of an optimized, intensely floral fragrance in a small number of steps and thus provides it in a cost-effective, extremely pure and high-yield manner.

[0117] At the same time, the process described here allows efficient and highly selective diastereomeric enrichment of the enantiomeric pair (I) based on the synthesis of the crude product in high yield and high product purity by means of the classical Prins reaction.

[0118] Furthermore, it has been discovered that using the methods described herein, fragrance mixtures having a floral, rosy, transparent, bright, and geranium-like aroma can be prepared. The diastereomerically enriched fragrance mixtures prepared in this manner are free of any industrial or plastic odors. The grapefruit odor also recedes significantly into the base notes, resulting in fragrance mixtures having a substantially brighter, more intense, and more natural floral aroma than the commercially available Magnolan product.

[0119] In a further preferred alternative, the process described herein for preparing diastereomerically enriched flavor mixtures according to the first aspect is performed such that the fine distillation of the distillation process takes place in a continuous process.

[0120] This continuous process allows for the elimination of intermediate steps, such as refilling or cooling and heating equipment, and is therefore more economical than batch processes and ensures a constant, i.e., consistent, product quality. Accordingly, the present method is also suitable for the preparation of the described fragrance mixtures on an industrial scale, thus allowing the high-quality preparation of over 180 kg of diastereomerically enriched fragrance mixtures with excellent flavor properties and high purity.

[0121] In another preferred embodiment, the fine distillation step for preparing the diastereomerically enriched fragrance mixture according to the distillation process of the first aspect of the invention is carried out at a reflux ratio of at least 5:1. Preferably, the reflux ratio is at least 7:1, preferably at least 10:1, in order to achieve a particularly high ratio of enantiomeric pair (I) relative to enantiomeric pairs (II) and (III) and to minimize odor components described as negative and industrial or plastic odors while highlighting a strong floral and positive odor impression.

[0122] Within the scope of the present invention, it was surprisingly found that such a reflux ratio in combination with the parameters described above leads to a particularly efficient and strong diastereomeric enrichment of the enantiomeric pair (I) in the fragrance mixtures described herein.

[0123] Furthermore, in the method according to the first aspect of the present invention, the fine distillation of the distillation method is preferably carried out at a temperature of 120°C to 150°C, but the head (top) temperature is preferably between 125°C and 145°C, particularly preferably between 135°C and 140°C.

[0124] This enables efficient and highly selective enrichment of the preferred diastereomer, ie the enantiomeric pair (I), and ensures the reproducibility of the desired odor.

[0125] In a further preferred embodiment, the fine distillation of the distillation process according to the invention for preparing a diastereomerically enriched flavor mixture is carried out under a reduced pressure of about 1 mbar to 100 mbar, preferably under a reduced pressure of about 1 mbar to 50 mbar, particularly preferably under a reduced pressure of about 1 mbar to 10 mbar, even more preferably under a reduced pressure of 10 mbar.

[0126] As described herein, such a method allows for a particularly efficient and gentle enrichment of the enantiomeric pair (I). In this context, a particularly gentle enrichment is very important, since it reduces undesirable decompositions. In the context of the present invention, a gentler enrichment therefore means that both the heat- and pressure-related loads during the diastereoisomer enrichment are lower, and the diastereoisomer-enriched fragrance mixture produced thereby does not suffer from negative heat- or pressure-related damages, which could manifest themselves in changes in product properties such as color, odor and stability, by decomposition or by the formation of decomposition products and by-products. Such decomposition products and by-products could interact adversely with the fragrance / fragrance mixture and thus reduce the overall product quality, for example by producing unpleasant side odors, distorting or adversely affecting the characteristic odor impression of the fragrance or fragrance mixture, or even adversely affecting the stability of the fragrance and fragrance mixture or of the preparations and products containing the fragrance and fragrance mixture.

[0127] Furthermore, the present invention relates to a process for the preparation of a diastereomerically enriched fragrance mixture according to the first aspect, wherein the first crude distillation step (a) describes a thin-layer distillation.

[0128] The method of the present invention is therefore particularly suitable for efficiently producing highly diastereomerically enriched pure spices, flavors, or flavor mixtures with an optimized, particularly intense, balanced, and natural floral aroma in high yields through a combination of gentle and selective preparation under mild conditions. Temperature-sensitive substances, such as many spices and / or flavorings, are typically only briefly heated to high temperatures to counteract undesirable thermal decomposition processes. Conventional distillation methods often subject the components to be distilled to prolonged thermal stress, which negatively impacts the yield and quality of the resulting product. Therefore, efficient distillation processes with high selectivity, i.e., high separation performance and simultaneously short residence times, are particularly preferred for enrichment. Since the thin-film evaporator of the present invention is preferably operated under vacuum, the method described herein allows for the use of lower temperatures and is therefore suitable for particularly gentle separation of the crude products described herein. Overall, the method of the present invention is therefore a very gentle method that reduces undesirable decomposition caused by heat and pressure, and by means of this method, crude products can be separated efficiently and gently with very high purity and yield, i.e., with excellent product quality.

[0129] Furthermore, another preferred design of the process for preparing the diastereomerically enriched flavor mixture of the first aspect described herein involves a thin film distillation comprising two stages:

[0130] - separating the solvent under a reduced pressure of about 1 mbar to 400 mbar, preferably under a reduced pressure of about 100 mbar to 300 mbar, particularly preferably under a reduced pressure of about 150 mbar to 250 mbar, even more preferably under a reduced pressure of about 200 mbar; and

[0131] - extracting the crude product comprising the compound of general formula (A) under reduced pressure of about 0 to 100 mbar, preferably about 0 to 10 mbar, particularly preferably about 0 to 5 mbar, even more preferably about 1 mbar.

[0132] Furthermore, in a particularly preferred embodiment of the process, the first stage of the thin film distillation is carried out at a shell temperature of 120°C to 200°C, preferably at a temperature of 150°C to 180°C, more preferably at a temperature of 160°C to 175°C, particularly preferably at a shell temperature of about 165°C, and the second stage of the thin film distillation is carried out at a shell (jacket) temperature of 150°C to 250°C, preferably at a temperature of 180°C to 210°C, more preferably at a temperature of 185°C to 200°C, particularly preferably at a temperature of about 190°C.

[0133] This allows for gentler and more efficient extraction of the crude Magnolan product in terms of purity and yield.

[0134] In a second subject matter, the present invention comprises (preferably racemic) diastereomerically enriched fragrance mixtures containing compounds of (A):

[0135]

[0136] Wherein the compounds of formula (A) include the following enantiomeric pairs of formula (I), (II) and (III) which are diastereoisomers of each other:

[0137]

[0138]

[0139] The number ratio of the enantiomeric pair (I) to the enantiomeric pair (II) is at least 10:1, and the number ratio of the enantiomeric pair (I) to (III) is at least 50:1.

[0140] The diastereoisomerically enriched fragrance mixture of the second aspect (preferably racemic) comprising a compound of general formula (A) comprises, in this case, enantiomer pair (I) in a ratio of at least 10:1 relative to enantiomer pair (II) in the mixture. Preferably, the quantitative ratio of enantiomer pair (I) to enantiomer pair (II) in the mixture is at least 15:1, more preferably at least 20:1, and particularly preferably at least 50:1. It is further preferred that the quantitative ratio of the enantiomer pairs of these diastereoisomers to each other is at least 100:1.

[0141] Furthermore, the (preferably racemic) diastereoisomerically enriched fragrance mixture of the second aspect of the present invention comprising a compound of formula (A) preferably comprises enantiomeric pairs (I) and (III) in a quantitative ratio of at least 50:1 to each other. Further preferably, the quantitative ratio between enantiomeric pairs (I) and (III) is at least 100:1; more preferably at least 1000:1, and most preferably at least 1360:1.

[0142] The diastereomerically enriched fragrance mixture that can be prepared by the process of the first aspect has an intensely floral, natural, rosy, transparent and bright geranium scent that is perceived as less industrial and free of plastic smell and therefore "cleaner" than commercially available Magnolan.

[0143] Therefore, fragrance mixtures of the general formula (A) enriched in diastereomers having a higher ratio of enantiomer pair (I) relative to enantiomer pair (II) and / or (III) are advantageous within the meaning of the present invention. Particularly preferred are fragrance mixtures having a ratio of enantiomer pair (I) to enantiomer pair (II) of at least 10:1 and a ratio of enantiomer pair (I) to enantiomer pair (III) of at least 50:1. Such fragrance mixtures have a more intensely floral, natural, "clean," rosy, transparent, and bright geranium fragrance. Furthermore, the quantitative ratios defined above are preferred.

[0144] In another preferred embodiment, the diastereomerically enriched fragrance mixture preferably contains more than 95% by weight of enantiomeric pair (I) in the fragrance mixture (relative to all enantiomeric pairs in the fragrance mixture), which results in a significant emphasis on the positive aroma components of the fragrance mixture. In addition, such fragrance mixtures have a very pleasant and intense floral and natural aroma profile, without any industrial or otherwise negatively perceived aromas.

[0145] Therefore, a further development of the present diastereomerically enriched fragrance mixtures relates to fragrance mixtures containing at least 95% by weight (relative to all enantiomeric pairs) of the (preferably racemic) enantiomeric pair (I). Preferably, the proportion of enantiomeric pair (I) relative to the sum of the enantiomeric pairs (I), (II) and (III) of the fragrance mixture according to the invention is at least 97.5% by weight, and more preferably at least 98.5% by weight, so that a particularly intense floral, "clean" and natural odor impression can be achieved.

[0146] Furthermore, diastereomerically enriched fragrance mixtures exhibit high purity and can be provided in very high yields.

[0147] Accordingly, in another preferred design, the present invention relates to a diastereomerically enriched fragrance mixture according to the second aspect, wherein the fragrance mixture comprises an overall chemical purity of at least 96.5% by weight, but preferably at least 98.5% by weight, most preferably at least 99.0% by weight, of the enantiomeric pairs (I), (II) and (III).

[0148] Such flavor mixtures have excellent secondary properties, such as high stability.

[0149] In another alternative design, the remainder of the diastereomerically enriched fragrance mixture constitutes other impurities, however, the fragrance mixture according to the invention contains less than 3.0% by weight, in particular less than 2.0% by weight, preferably at most or less than 1.5% by weight, most preferably at most 1.0% by weight of such impurities, based on the total mass of the fragrance mixture.

[0150] The diastereomerically enriched fragrance mixtures are suitable for use as additives to fragrances or fragrance formulations. Other uses are the use of these diastereomerically enriched fragrance mixtures in consumer products containing these compounds and mixtures.

[0151] In a third aspect, the present invention relates to the use of a diastereomerically enriched fragrance mixture as a fragrance or for preparing a fragrance preparation. Thus, the present invention relates to the use of the fragrance mixture according to the invention as a fragrance, in particular having an optimized, intense, bright, natural, and transparent floral aroma, or for preparing a fragrance preparation, in particular a fragrance preparation having such an optimized floral aroma.

[0152] As stated above, a further subject of the present invention is therefore a fragrance preparation having a sensory effective amount of a diastereomerically enriched fragrance mixture.

[0153] Within the scope of the present invention, fragrance preparations are mixtures of various substances produced from corresponding substances according to a recipe and a prescribed method. Such preparations are specially prepared and used to mediate, modify or enhance a desired odor impression that is generally considered pleasant or otherwise positive.

[0154] A fragrance preparation according to the invention, particularly in the form of a perfume oil, preferably having an optimized floral scent as described herein, consists of or includes a diastereomerically enriched fragrance mixture according to the invention, as defined above, and one, two, three, four, five, six, seven, eight, nine, ten, or more additional fragrances. In this way, particularly interesting, intense, and natural floral scents can be easily created, without the industrial or plastic-like odors characteristic of most magnolan-based fragrance preparations to date. The fragrance mixture according to the invention can be used as a single substance or in combination with numerous other fragrances in a wide variety of products to create or produce a unique odor impression.

[0155] Fragrances and / or flavorings suitable as further fragrances or flavorings for the fragrance preparations according to the invention in the sense of the above definition can be found, for example, in S. Arctander, "Perfume and Flavor Materials", Volumes 1 and 2, Montclair, NJ 1969, self-published, or in K. Bauer et al., "Common Fragrance and Flavor Materials", 4th edition, Wiley-VCH, Weinheim 2001.

[0156] Particular mention is made of: extracts of natural raw materials, such as essential oils, extracts, absolutes, resins, resinoids, balsams, tinctures, such as amber tincture; amla oil; angelica seed oil; angelica root oil; anise oil Valerian oil; basil oil; moss absolute; bay oil; artemisia oil; benzyl resin; bergamot oil; beeswax absolute; birch tar; bitter almond oil; savory oil Buco leaf oil Kabrova Oil Juniper berry oil; calamus oil; camphor oil; cananga oil; cardamom oil; cascarilla oil; cinnamon oil; cassia absolute; castoreum absolute; cedar leaf oil; cedarwood oil (cedar oil); labdanum oil; citronella oil; lemon oil; copaiba balsam; copaiba balsam oil; coriander oil; costus root oil; cumin oil; cypress oil; davana oil; dill weed oil; dill seed oil; perfume absolute; oakmoss absolute; olive oil; tarragon oil; lemon eucalyptus oil; eucalyptus oil; cumin oil; spruce needle oil; galbanum oil; galbanum Geranium oil; Grapefruit oil; Guaiac wood oil; Guru balm; Guru balm; Immortelle absolute; Immortelle oil; Ginger oil; Orris root absolute; Orris root oil; Jasmine absolute; Calamus oil; Chamomile oil blue; Roman chamomile oil; Carrot seed oil; Cascarilla oil; Pine needle oil; Curly mint oil (Spearmint oil); Cumin oil; Labdanum oil; Labdanum absolute; Labdanum resin; Lavender absolute; Lavender oil; Lavender absolute; Lavender oil; Lemongrass oil; Lovage oil; Pear berry distillate Oil; pressed pear berry oil; camphor oil (agarwood oil); litsea cubeba oil; bay leaf oil; nutmeg oil Marjoram oil; mandarin orange oil; maso bark oil; mimosa absolute; musk seed oil; musk tincture; sage oil; nutmeg seed oil Myrrh Absolute; Myrrh Oil; Myrtle Oil; Clove Leaf Oil; Clove Flower Oil; Neroli Oil; Frankincense Absolute; Frankincense Oil; Parsnip Root Oil; Neroli Absolute; Orange Oil; Oregano Oil; Palmarosa Oil; Patchouli Oil; Perilla Oil; Peru Balsam Oil; Parsley Leaf Oil; Parsley Seed Oil; Petitgrain Oil; Peppermint Oil; Allspice Oil; Pine Oil; Polyol Oil; Rose Absolute; Rosewood Oil; Rose Oil; Rosemary Oil; Dalmatian Sage Oil; Spanish Sage Oil; Sandalwood Oil; Celery Seed Oil; Purple Flower Oil; Anise Oil; Styrax Oil; Marigold Oil; Pine Needle Oil Tea tree oil; turpentine oil; thyme oil; tolu balsam; tonka bean essence; tuberose absolute; vanilla extract; violet leaf absolute; verbena oil; vetiver oil; juniper berry oil; wine yeast oil; wormwood oil; wintergreen oil; ylang-ylang oil; hyssop oil; civet absolute; cinnamon leaf oil; cassia bark oil and their fractions or isolated components;

[0157] Single fragrances from the hydrocarbon group, such as 3-carene; α-pinene; β-pinene; α-terpinene; γ-terpinene; p-cymene; bisabolene; camphene; caryophyllene; cedrene; farnesene; limonene; longifolene; myrcene; ocimene; valencia tangerine; (E,Z)-1,3,5-undecatriene; styrene; diphenylmethane;

[0158] Aliphatic alcohols, such as hexanol; octanol; 3-octanol; 2,6-dimethylheptanol; 2-methyl-2-heptanol; 2-methyl-2-octanol; (E)-2-hexenol; 1-octen-3-ol; a mixture of 3,4,5,6,6-pentamethyl-3 / 4-hepten-2-ol and 3,5,6,6-tetramethyl-4-methyleneheptan-2-ol; (E,Z)-2,6-nonadienol; 3,7-dimethyl-7-methoxyoctan-2-ol; 9-decanol; 10-undecanol; 4-methyl-3-decen-5-ol;

[0159] Fatty aldehydes and their acetals, such as hexanal; heptanal; octanal; nonanal; decanal; undecanal; dodecanal; 2-methyloctanal; 2-methylnonanal; (E)-2-hexenal; (Z)-4-heptanal; 2,6-dimethyl-5-heptanal; 10-undecenal; (E)-4-decenal; 2-dodecenal; 2,6,10-trimethyl-9-undecenal; 2,6,10-trimethyl-5,9-undecadienal; heptanal diethyl acetal Aldehydes; 1,1-dimethoxy-2,2,5-trimethyl-4-hexene; citronelloloxyacetaldehyde; 1-(1-methoxy-propyloxy)-(E / Z)-3-hexene; aliphatic ketones and their oximes, such as 2-heptanone; 2-octanone; 3-octanone; 2-nonanone; 5-methyl-3-heptanone; 5-methyl-3-heptanone oxime; 2,4,4,7-tetramethyl-6-octen-3-one; 6-methyl-5-hepten-2-one;

[0160] Aliphatic sulfur-containing compounds, such as 3-methylthio-hexanol; 3-methylthiohexyl acetate; 3-mercaptohexanol; 3-mercaptoacetate; 3-mercaptohexylbutyrate; 3-acetylthiohexyl acetate; 1-menthene-8-thiol;

[0161] Aliphatic nitriles, such as 2-nonenenitrile; 2-undecenenitrile; 2-tridecenenitrile; 3,12-tridecadienenitrile; 3,7-dimethyl-2,6-octadienenitrile; 3,7-dimethyl-6-octanonitrile;

[0162] Fatty carboxylic acids and their esters, such as (E)- and (Z)-3-hexenylcarboxylate; ethyl acetoacetate; isoamyl acetate; 3,5,5-trimethylhexyl acetate; 3-methyl-2-butene acetate; (E)-2-hexene acetate; (E) and (Z)-3-hexene acetate; octyl acetate; 3-octyl acetate; 1-octen-3-yl acetate; ethyl butyrate; butyl butyrate; isoamyl butyrate; hexyl butyrate; ( E) and (Z)-3-hexenyl isobutyrate; hexyl crotonate; ethyl isovalerate; ethyl 2-methylvalerate; ethyl hexanoate; allyl hexanoate; ethyl heptanoate; allyl heptanoate; ethyl octanoate; ethyl (E,Z)-2,4-decadienoate; methyl 2-octanoate; methyl 2-nonanoate; allyl 2-isopentyloxyacetate; methyl 3,7-dimethyl-2,6-octadienoate; 4-methyl-2-pentyl crotonate;

[0163] Acyclic terpene alcohols, such as geraniol; nerol; lavandinol; nerolidol; farnesol; tetrahydrolinalool; tetrahydrogeraniol; 2,6-dimethyl-7-octen-2-ol; 2,6-dimethyloctan-2-ol; 2-methyl-6-methylene-7-octen-2-ol; 2,6-dimethyl-5,7-octadiene-2-ol -ol; 2,6-dimethyl-3,5-octadien-2-ol; 3,7-dimethyl-4,6-octadien-3-ol; 3,7-dimethyl-1,5,7-octatrien-3-ol; 2,6-dimethyl-2,5,7-octatrien-1-ol; and their formates, acetates, propionates, isobutyrates, butyrates, isovalerates, valerates, hexanoates, crotonates, tiglates and 3-methyl-2-butenoic acid salts;

[0164] Acyclic terpene aldehydes and ketones, such as citronellal; 7-methoxy-3,7-dimethyloctanal; 2,6,10-trimethyl-9-undecenal; geranylacetone; and the dimethyl and diethyl acetals of geranial and neral;

[0165] Cyclic terpene alcohols, such as menthol; isopulegol; alpha-terpineol; terpineol-4; menthan-8-ol; menthan-1-ol; menthan-7-ol; borneol; isoborneol; linalool oxide; nopol; cedarol; ambroxol; vetiverol; guaiacol; and their formates, acetates, propionates, isobutyrates, butyrates, isovalerates, valerates, hexanoates, crotonates, tiglic acid salts and 3-methyl-2-butenoate salts;

[0166] Cyclic terpenoid aldehydes and ketones, such as menthone; isomenthone; 8-mercaptomenthan-3-one; carvone; camphor; aniseed ketone; α-ionone; β-ionone; α-n-methylionone; β-n-methylionone; α-isomethylionone; β-isomethylionone; α-ferric ionone; β-damascena ketone; 1-(2,4,4-trimethyl-2-cyclohexen-1-yl)-2-buten-1-one; 1,3,4,6,7,8a-hexahydro-1,1,5,5-tetramethyl -2H-2,4a-Methane-8-(5H)-naphthalene-1-one; 2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-butenal; Nootkaton; Dihydronootkaton; 4,6,8-Meganostachystigmatrien-3-one; α-sinensal; β-sinensal; Acetylated cedar oil (methylcedrylketone);

[0167] Cyclic alcohols, such as 4-tert-butylcyclohexanol; 3,3,5-trimethylcyclohexanol; 3-isooctylcyclohexanol; 2,6,9-trimethyl-Z2,Z5,E9-cyclododecatrien-1-ol; 2-isobutyl-4-methyltetrahydro-2H-pyran-4-ol;

[0168] Aliphatic cyclic alcohols, such as α,3,3-trimethylcyclohexylmethanol; 1-(4-isopropylcyclohexyl)ethanol; 2-methyl-4-(2,2,3-trimethyl-3-cyclopent-1-yl)butanol; 2-methyl-4-(2,2,3-trimethyl-3-cyclopent-1-yl)-2-buten-1-ol; 3-methyl-5-(2,2,3-trimethyl-3-cyclopent-1-yl)pentan-2-ol; 3-methyl-5-(2,2,3-trimethyl-3-cyclopent-1-yl)-4-penten-2-ol; 3,3-dimethyl-5-(2,2,3-trimethyl-3-cyclopent-1-yl)-4-penten-2-ol; 1-(2,2,6-trimethylcyclohexyl)pentan-3-ol; 1-(2,2,6-trimethylcyclohexyl)hexan-3-ol;

[0169] Cyclic and cycloaliphatic ethers (alicyclic ethers), such as eucalyptol; cedaryl methyl ether; cyclododecyl methyl ether; 1,1-dimethoxycyclododecane; (ethoxymethoxy)-cyclododecane; α-cedarene oxide; 3a,6,6,9a-tetramethyldodecahydronaphthalene[2,1b]furan; 3a-ethyl-6,6,9a-trimethyldodecahydronaphthalene[2,1b]furan; 1,5,9-trimethyl-13-oxabicyclo(oxabicyclo)[10.1.0]tridecyl-4,8-diene; rose oxide; 2-(2,4-dimethyl-3-cyclohexen-1-yl)-5-methyl-5-(1-methylpropyl)-1,3-dioxane;

[0170] Cyclic ketones and macrocyclic ketones, such as 4-tert-butylcyclohexanone; 2,2,5-trimethyl-5-pentylcyclopentanone; 2-heptylcyclopentanone; 2-pentylcyclopentanone; 2-hydroxy-3-methyl-2-cyclopenten-1-one; 3-methyl-cis-2-penten-1-yl-2-cyclopenten-1-one; 3-methyl-2-pentyl-2-cyclopenten-1-one; 3-methyl-4-cyclopentadienone; 3-methyl-5-cyclopentadienone; 3-methylcyclopentadienone 3-Methylcyclopentadecanon; 4-(1-ethoxyvinyl)-3,3,5,5-tetramethylcyclohexanone; 4-tert-pentylcyclohexanone; 5-cyclohexadecene-1-one; 6,7-dihydro-1,1,2,3,3-pentamethyl-4(5H)indanone; 8-cyclohexadecene-1-one; 9-cycloheptadecene-1-one; cyclopentadecanone; cyclohexadecanone;

[0171] Aliphatic cyclic aldehydes, such as 2-methyl-4-(2,2,6-trimethyl-cyclohexen-1-yl)-2-butenal; 4-(4-hydroxy-4-methylpentyl)-3-cyclohexenecarboxaldehyde; 4-(4-methyl-3-penten-1-yl)-3-cyclohexenecarboxaldehyde;

[0172] Aliphatic cyclic ketones, such as 1-(3,3-dimethylcyclohexyl)-4-penten-1-one; 2,2-dimethyl-1-(2,4-dimethyl-3-cyclohexen-1-yl)-1-propanone; 1-(5,5-dimethyl-1-cyclohexen-1-yl)-4-penten-1-one; 2,3,8,8-tetramethyl-1,2,3,4,5,6,7,8-octahydro-2-naphthylmethyl ketone; methyl-2,6,10-trimethyl-2,5,9-cyclododecantrienyl ketone; tert-butyl (2,4-dimethyl-3-cyclohexen-1-yl) ketone;

[0173] Esters of cyclic alcohols, such as 2-tert-butylcyclohexyl acetate; 4-tert-butylcyclohexyl acetate; 2-tert-amylcyclohexyl acetate; 4-tert-amylcyclohexyl acetate; 3,3,5-trimethylcyclohexyl acetate; decahydro-2-naphthyl acetate; 2-cyclopentylcyclopentyl crotonate; 3-pentyltetrahydro-2H-pyran-4-yl acetate; decahydro-2,5,5,8a-tetramethyl-2-naphthyl acetate ; 4,7-Methano-3a,4,5,6,7,7a hexahydro-5 and 6-indenyl acetate; 4,7-Methano-3a,4,5,6,7,7a hexahydro-5 and 6-indenyl propionate; 4,7-Methano-3a,4,5,6,7,7a hexahydro-5 and 6-indenyl isobutyrate; 4,7-Methano-octahydro-5 and 6-indenyl acetate;

[0174] Esters of cycloaliphatic alcohols, such as 1-cyclohexylethyl crotonate;

[0175] Esters of cycloaliphatic (alicyclic) carboxylic acids, such as allyl-3-cyclohexyl propionate; allylcyclohexyloxyacetate; cis- and trans-methyldihydrojasmonate; cis- and trans-methyl jasmonate; methyl 2-hexyl-3-oxocyclopentanecarboxylate; ethyl 2-ethyl-6,6-dimethyl-2-cyclohexenecarboxylate; ethyl 2,3,6,6-tetramethyl-2-cyclohexenecarboxylate; ethyl 2-methyl-1,3-dioxolane-2-acetate; fatty alcohols, such as benzyl alcohol; 1-phenylethanol ; 3-phenylpropanol; 2-phenylpropanol; 2-phenoxyethanol; 2,2-dimethyl-3-phenylpropanol; 2,2-dimethyl-3-(3-methylphenyl)propanol; 1,1-dimethyl-2-phenylethanol; 1,1-dimethyl-3-phenylpropanol; 1-ethyl-1-methyl-3-phenylpropanol; 2-methyl-5-phenylpentanol; 3-methyl-5-phenylpentanol; 3-phenyl-2-propen-1-ol; 4-methoxybenzyl alcohol; 1-(4-isopropylphenyl)ethanol;

[0176] Esters of fatty alcohols and fatty carboxylic acids, such as benzyl acetate; benzyl propionate; benzyl isobutyrate; benzyl isovalerate; ethyl 2-phenylethyl acetate; 2-phenylethyl propionate; 2-phenylethyl isobutyrate; 2-phenylethyl isovalerate; ethyl 1-phenylethyl acetate; α-trichloromethylbenzyl acetate; α,α-dimethylphenylethyl acetate; α,α-dimethylphenylethyl butyrate; cinnamyl acetate; 2-phenoxyethyl isobutyrate; 4-methoxybenzyl acetate;

[0177] Aliphatic ethers, such as 2-phenylethyl methyl ether; 2-phenylethyl isopentyl ether; 2-phenylethyl-1-ethoxyethyl ether; phenylacetaldehyde dimethyl acetal; phenylacetaldehyde diethyl acetal; propionaldehyde dimethyl acetal hydrate; phenylacetaldehyde glycerol acetal; 2,4,6-trimethyl-4-phenyl-1,3-dioxane; aromatic and aliphatic aldehydes, such as benzaldehyde; phenylacetaldehyde; 3-phenylpropanol; propionaldehyde hydrate; 4-methylbenzaldehyde; 4-methylphenylacetaldehyde; 3-(4-ethylphenyl)-2,2-dimethylpropane; 2-methyl-3-(4-isopropylphenyl)-1,3-dioxane 2-Methyl-3-(4-isobutylphenyl)propanal; 3-(4-tert-butylphenyl)propanal; Cinnamaldehyde; α-Butylcinnamaldehyde; α-Hexylcinnamaldehyde; 3-Methyl-5-phenylpentanal; 4-Methoxybenzaldehyde; 4-Hydroxy-3-methoxybenzaldehyde; 4-Hydroxy-3-ethoxybenzaldehyde; 3,4-Methylenedioxybenzaldehyde; 3,4-Dimethoxybenzaldehyde; 2-Methyl-3-(4-methoxyphenyl)propanal; 2-Methyl-3-(4-methylenedioxyphenyl)propanal; 2-Methyl-3-(4-methylenedioxyphenyl)propanal;

[0178] Aromatic and aliphatic ketones, such as acetophenone; 4-methylacetophenone; 4-methoxyacetophenone; 4-tert-butyl-2,6-dimethylacetophenone; 4-phenyl-2-butanone; 4-(4-hydroxyphenyl)-2-butanone; 1-(2-naphthyl)ethanol; 2-benzofuranethanone; (3-methyl-2-benzofuranethanone); benzophenone; 1,1,2,3,3,6-hexamethyl-5-indanylmethylketone; 6-tert-butyl-1,1-dimethyl-4-indanylmethylketone; 1-[2,3-dihydro-1,1,2,6-tetramethyl-3-(1-methylethyl)-1H-5-indenyl]ethanone; 5',6',7',8'-tetrahydro-3',5',5',6',8',8'-hexamethyl-2-naphthylacetonone;

[0179] Aromatic and aliphatic carboxylic acids and their esters, such as benzoic acid; phenylacetic acid; methyl benzoate; ethyl benzoate; hexyl benzoate; benzyl benzoate; methyl phenylacetate; ethyl phenylacetate; geranyl phenylacetate; phenylethyl phenylacetate; methyl cinnamate; ethyl cinnamate; benzyl cinnamate; phenylethyl cinnamate; cinnamyl cinnamate; allylphenoxyacetate; methyl salicylate; hexyl salicylate; cyclohexyl salicylate; cis-3-hexenyl salicylate; benzyl salicylate; phenylethyl salicylate; methyl 2,4-dihydroxy-3,6-dimethylbenzoate; ethyl 3-phenylglycidate; ethyl 3-methyl-3-phenylglycidate;

[0180] Nitrogen-containing aromatic compounds, such as 2,4,6-trinitro-1,3-dimethyl-5-tert-butylbenzene; 3,5-dinitro-2,6-dimethyl-4-tert-butylacetophenone; cinnamic acid nitrile; 3-methyl-5-phenyl-2-pentenenitrile; 3-methyl-5-phenylpentenenitrile; methyl anthranilate; methyl N-methyl anthranilate; the Schiff base of methyl anthranilate with 7-hydroxy-3,7-dimethyloctanal, 2-methyl-3-(4-tert-butyl-phenyl)propanal, or 2,4-dimethyl-3-cyclohexenecarboxaldehyde; 6-isopropylquinoline; 6-isobutylquinoline; 6-sec-butylquinoline; 2-(3-phenylpropyl)pyridine; indole; skatole; 2-methoxy-3-isopropylpyrazine; 2-isobutyl-3-methoxypyrazine;

[0181] Phenols, phenyl ethers and phenyl esters, such as estragol; anethol; eugenylmethylether; isoeugenol; isoeugenylmethylether; thymol; carvacrol; diphenyl ether; β-naphthylmethyl ether; β-naphthylethyl ether; β-naphthylisobutyl ether; 1,4-dimethoxybenzene; eugenyl acetate; 2-methoxy-4-methylphenol; 2-ethoxy-5-(1-propenyl)phenol; p-cresolphenylacetate;

[0182] Heterocyclic compounds, such as 2,5-dimethyl-4-hydroxy-2H-furan-3-one; 2-ethyl-4-hydroxy-5-methyl-2H-furan-3-one; 3-hydroxy-2-methyl-4H-pyran-4-one; 2-ethyl-3-hydroxy-4H-pyran-4-one;

[0183] Lactones, such as 1,4-octanolactone; 3-methyl-1,4-octanolactone; 1,4-nonanolactone; 1,4-decanolactone; 8-decene-1,4-lactone; 1,4-undecanolactone; 1,4-dodecanolactone; 1,5-decanolactone; 1,5-dodecanolactone; 4-methyl-1,4-decanolactone; 1,15-pentadecanolactone; 1,16-hexadecanolactone; 9-hexadecene-1,16-lactone; 10-oxa-1,16-hexadecanolactone; 11-oxa-1,16-hexadecanolactone; 12-oxa-1,16-hexadecanolactone; ethylene-1,12-dodecanedioate; ethylene-1,13-tridecanedioate; 2,3-dihydrocoumarin; octahydrocoumarin.

[0184] In the fragrance preparations according to the invention, in particular perfume oils, the amount of the diastereomerically enriched fragrance mixture, as defined above, is in the range of 0.0001% to 40% by weight, based on the total weight of the fragrance preparation, preferably in the range of 0.001% to 25% by weight, and particularly preferably in the range of 0.0001% to 10% or 5% by weight relative to the total weight of the fragrance preparation.

[0185] In addition to being used as liquids in solutions or emulsions, the fragrance mixtures according to the invention or fragrance preparations containing them, such as perfume oils, can be adsorbed on solids or (micro)encapsulated in carriers. These formulations ensure both a fine distribution of the fragrance in the product and controlled release during use. Such solids can be porous inorganic materials such as light sulfates, silica gels, zeolites, gypsum, clays, clay granules, and aerated concrete, or organic materials such as wood, cellulose-based materials, sugars, or plastics such as polyvinyl chloride, polyvinyl acetate, or polyurethane.

[0186] The encapsulated product may be, for example, a spray-dried inclusion compound or an extruded product.

[0187] In the context of the present invention, "organoleptically effective amount" means that the fragrance or diastereoisomerically enriched fragrance mixture is present in a sufficient amount so that the resulting product, upon use, is recognizable by the organoleptic properties of the fragrance or the fragrance mixture according to the invention. Thus, an organoleptically effective amount is that portion of the fragrance mixture according to the invention which is sufficient to produce the desired effect, for example, to highlight or emphasize a pleasant and optimized floral aroma and / or a masking effect.

[0188] Furthermore, the present invention relates to the use of a diastereomerically enriched fragrance mixture according to one of the aforementioned aspects in an organoleptically effective amount for mediating, modifying or enhancing the floral aroma of a fragrance product or for preparing a fragrance product. In this context, enhancement means highlighting or emphasizing a particular aroma, in particular an optimized, intense, naturally "clean" floral-type aroma or taste as described herein.

[0189] Since floral fragrances, i.e., those with "clean" floral aromas, are particularly preferred and in demand in the perfume industry, the fragrances and fragrance preparations described herein, containing diastereomerically enriched fragrance mixtures, are particularly well-suited for such applications. In this context, industrial-style odors or those reminiscent of plastic are often perceived as negative and therefore disturbing. Since the present fragrance mixtures can be prepared simply in a few steps, simultaneously with high yield and high purity, fragrance mixtures can be prepared that do not have these perceived negative odors and are therefore suitable for many applications, particularly for mediating, modifying, or enhancing strong, bright, and "clean" floral aromas.

[0190] In this context, “clean” is understood as a scent that does not have odor characteristics that are industrial, reminiscent of plastic, or otherwise considered negative, distracting from floral scents, and considered unnatural.

[0191] The spices or spice blends and preparations described herein exhibit a noticeable enhancement of strong, natural and "clean" floral aromas, even at low doses.

[0192] Surprisingly, it was observed that the fragrance mixtures described herein have excellent stability and can therefore be well incorporated into a wide range of product formulations. Thus, the fragrance mixtures are particularly suitable for preparing a wide range of fragrance products, such as shampoos, creams, soaps, deodorants and detergents.

[0193] The present invention therefore ultimately relates to a fragrance product comprising a diastereomerically enriched fragrance mixture as described above or the corresponding fragrance preparations in concentrated form, solution form or other modified form for the production of consumer products or fragrance products in the sense of the present invention, such as perfume extracts, perfumes, eau de toilette, shaving water, cologne, pre-shave products, splash cologne and fragranced refreshing wipes, as well as acidic, alkaline and neutral cleaners for perfumery, such as floor cleaners, window glass cleaners, dishwashing detergents, bathroom and sanitary cleaners, detergents, solid and liquid toilet cleaners, powdered and foaming carpet cleaners, liquid detergents, powdered detergents, laundry pretreaters such as bleaches, soaking agents and stain removers, laundry fabric softeners, soaps, detergent tablets, disinfectants, surface disinfectants and liquid , air conditioners in gel form or with a fixed carrier, aerosol sprays, waxes and polishes such as furniture polish, floor wax, shoe polish as well as body care products such as solid and liquid soaps, shower gels, shampoos, shaving soaps, shaving foams, bath oils, cosmetic emulsions of the water-in-oil, oil-in-water and water-in-oil-in-water types such as skin creams and lotions, face creams and lotions, sunscreen creams and lotions, after-sun creams and lotions, hand creams and lotions, foot creams and lotions, hair removal creams and lotions, aftershave creams and lotions, tanning creams and lotions and hair care products such as hair sprays, hair waxes, hair lotions, conditioners, permanent and semi-permanent hair dyes and hair shaping agents such as cold perms and hair straighteners, hair tonics, hair creams and lotions, deodorants and antiperspirants such as underarm sprays, roll-ons, deodorant sticks, deodorants or decorative cosmetic products.

[0194] The present invention therefore ultimately also relates to a fragrance product comprising a diastereomerically enriched fragrance mixture as described above, or a corresponding fragrance formulation comprising the same.

[0195] Example

[0196] The present invention is described in more detail below by way of examples.

[0197] Diastereomerically enriched fragrance mixtures were prepared according to the methods described herein:

[0198] First, an emulsion of dilute sulfuric acid and toluene was added to a reaction vessel. Then, the reactants, paraldehyde and indene, were added at 5°C and stirred for 5 hours. The reaction product was then washed three times with water and the organic phase was distilled off.

[0199] According to step (a) of the process described herein, the reaction product thus obtained is fed to a thin-film evaporator. In a first stage of thin-film distillation, any solvent residues and unreacted reactants are removed from the crude product at 200 mbar and a housing (jacket) temperature of 165°C. The purified crude product is then extracted by distillation at 1 mbar and a housing (jacket) temperature of 190°C (second stage of thin-film distillation).

[0200] The crude product obtained in this way was then subjected to a fine distillation (step (b)). For this purpose, the crude product was distilled in a continuous process in a distillation apparatus using Sulzer BX as packing material over 20 separation stages. In this case, the reflux ratio was approximately 10:1, the head temperature was approximately 138°C to 139°C, and the distillation was carried out under a reduced pressure of approximately 10 mbar.

[0201] The product obtained in this manner has the following enantiomeric pairs in the following quantitative ratios: the quantitative ratio of enantiomeric pair (I) to enantiomeric pair (II) in the resulting fragrance mixture is 96.894 to 0.577, while the quantitative ratio of enantiomeric pair (I) to enantiomeric pair (III) is 96.894 to 0.047. Thus, the proportion of enantiomeric pair (I) in the resulting fragrance mixture relative to the total amount of compounds of formula (A), i.e., relative to the sum of enantiomeric pairs (I), (II), and (III), is at least 95% by weight, and has a corresponding diastereomeric purity. In this case, the chemical purity, i.e., the total amount of all diastereomers of formula (A) relative to the sum of all other impurities, is 97.5 to 2.5.

[0202] In a second example using the same method, the ratio of enantiomeric pairs (I) to (II) to (III) was 97.971:0.979:0.072. In this case, the ratio of enantiomeric pair (I) to the sum of enantiomeric pairs (I), (II) and (III) exceeded 95% by weight. In addition, the chemical purity of the obtained product exceeded 98.5% by weight, i.e., it contained less than 1% by weight of impurities (see Figure 3 ).

[0203] analyze:

[0204] Gas chromatography analysis of the first example revealed a composition corresponding to 96.894% by weight of enantiomeric pair (I), 0.577% by weight of enantiomeric pair (II), and 0.047% by weight of enantiomeric pair (III). In the second example, a composition corresponding to the following ratios was detected: 97.971% enantiomeric pair (I), 0.979% enantiomeric pair (II), and 0.072% enantiomeric pair (III).

[0205] The corresponding values ​​were determined using a Thermo Fisher Scientific brand gas chromatograph (TRACE1300 series) using polyethylene glycol as the column material.

[0206] The corresponding NMR measurements for the first example and the gas chromatography analysis for the second example are given.

[0207] Nuclear magnetic resonance (NMR) data for the first example:

[0208] H-NMR: 7.38m(1H), 7.25m(2H), 7.21m(1H), 5.46d, J=6.60(1H), 4.75q, J=5.09(1H), 3.32dq, J=10.38, 6.13(1H), 2.92dd d,J=15.89,6.52,1.25(1H),2.49d,J=16.00(1H),2.40dt,J=10.44,6.58(1H),1.35d,J=5.11(3H),1.27d,J=6.15(3H).

[0209] Furthermore, the resulting fragrance mixture had no measurable rotation values, so it can be inferred that the enantiomers of the respective enantiomeric pairs exist in racemic form with respect to each other, ie enantiomeric pairs (I), (II) and (III) are each racemic.

[0210] Comparative Example:

[0211] Although isomers (I) and (II) are present in a ratio of at least 10:1, a comparative example shows that, under otherwise identical distillation conditions, a change in reflux ratio of 1:1 and head temperature of about 141°C to 142°C has resulted in a fragrance mixture in which the ratio of enantiomeric pair (I) to enantiomeric pair (II) is only 1:2 to 2:1.

[0212] Thus, by clever choice of the distillation conditions, diastereoisomerically enriched fragrance mixtures according to the invention having a preferential and optimized floral aroma can be provided.

[0213] Odor Description:

[0214] To determine the olfactory properties, enantiomer pairs (I), (II), and (III) were obtained by chromatographic separation and their odor was evaluated by a panel of eight subjects. The enantiomer pairs had the following odor characteristics: the odor of enantiomer pair (I) could be described as floral, rosy, transparent, bright, and geranium-like, while the odor of enantiomer pair (II) was floral, green, somewhat industrial, and grapefruit-like, and was weaker than that of enantiomer pair (I). In contrast, enantiomer pair (III) had a substantially floral, industrial, unclean, and plastic odor.

[0215] The results of the olfactory properties test are shown in Table 1 below:

[0216] Table 1:

[0217]

[0218] As can be seen from Table 1, the enantiomeric pair (III) prepared in the comparative example and the commercially available Magnolan have a strong plastic odor. In contrast, the isomer mixture according to the present invention according to claim 1 has a significantly lower plastic odor and a brighter rose odor. Thus, the odor of the commercially available Magnolan can be improved.

[0219] In both cases, the aroma of the exemplary total racemic product according to the invention, i.e., the fragrance mixture according to the invention, can be described as slightly warm, intense, and naturally floral, rosy, transparent, bright, and geranium-like, while the comparative fragrance mixture, which has a different enantiomeric composition than the one described here, is characterized by the odor characteristics of the enantiomeric pair (II) and / or (III), thus having a slightly industrial grapefruit odor and, compared to the enantiomeric pair (I), a weaker, i.e., less intense, unclean, and overall less floral odor impression, some of which even have a strongly industrial or even plastic-reminiscent and unclean odor. Therefore, the purified product according to the invention is preferred.

[0220] Commercially available Magnolan products, such as the Magnolan or crude Magnolan products prepared in the Comparative Examples, also have a slightly industrial and plastic odor and can therefore be described as floral, green, slightly rosy, slightly industrial, and grapefruit and plastic.

[0221] In contrast, the diastereomerically enriched fragrance mixtures of the first and second aspects obtained from the process, as described herein, have an extremely strong bright, balanced, natural, "clean" floral, rosy, transparent, slightly warm and geranium fragrance that is generally considered to be more pleasant, balanced and "clean" than the above products and has no industrial or plastic smell.

[0222] Thus, using the method described herein, an efficient, simple and gentle distillation method can be demonstrated for the effective and gentle distillative enrichment of enantiomer pair (I), and for providing diastereomer-enriched fragrance mixtures containing compounds of general formula (A) in high purity and high yield according to the first and second aspects. It is particularly surprising that, in the fragrance mixture according to the invention, enantiomer pair (I) is enriched to more than 95% by weight relative to the sum of enantiomer pairs (I), (II) and (III), thereby effectively optimizing the resulting odor impression.

Claims

1. A distillation process for preparing a diastereoisomer-enriched spice mixture containing a compound of general formula (A): The spice mixture comprises the following enantiomeric pairs which are diastereoisomers of each other: Enantiomer pair (I): Enantiomer pair (II): Enantiomer pair (III): wherein the quantitative ratio of the enantiomeric pair (I) to the enantiomeric pair (II) is at least 10:1; wherein the quantitative ratio of the enantiomeric pair (I) to (III) is at least 50:1; and The method comprises the following distillation steps: (a) separating by distillation a crude product containing a compound of formula (A) in a first distillation step; (b) subjecting the crude product to a subsequent fine distillation by one or more distillation steps to concentrate the enantiomeric pair (I) relative to the enantiomeric pairs (II) and (III), wherein the fine distillation comprises at least 15 separation stages, and The fine distillation of the distillation method described therein is carried out in a continuous process.

2. The method for preparing a diastereomerically enriched spice mixture according to claim 1, further comprising, before the distillation step: - providing paraldehyde or acetaldehyde of formula (IV); as well as - reaction with an indene of general formula (V) in a solvent under acid catalysis, wherein the reaction of paraldehyde with indene occurs at a temperature below 10°C; and - A crude product containing the compound of general formula (A) is obtained.

3. The process for preparing a diastereomerically enriched fragrance mixture according to any one of claims 1 to 2, characterized in that The fine distillation of the distillation process has a reflux ratio of at least 5:

1.

4. The process for preparing a diastereomerically enriched fragrance mixture according to any one of claims 1 to 2, characterized in that The fine distillation of the distillation process is carried out at a temperature of 120°C to 150°C.

5. The process for preparing a diastereomerically enriched flavor mixture according to any one of claims 1 to 2, characterized in that The fine distillation of the distillation process is carried out under reduced pressure of 1 to 100 mbar.

6. The process for preparing a diastereomerically enriched flavor mixture according to any one of claims 1 to 2, characterized in that The first distillation step is thin layer distillation.

7. The method for preparing a diastereoisomerically enriched spice mixture according to claim 6, characterized in that The thin layer distillation comprises two stages: - separation of the solvent under reduced pressure of 1 mbar to 400 mbar; and - extracting the crude product containing the compound of general formula (A) under reduced pressure of 0 to 100 mbar.

8. The process for preparing a diastereomerically enriched flavor mixture according to claim 6, characterized in that The first stage of the thin-layer distillation is carried out at a shell temperature of 120°C to 200°C, and the second stage of the thin-film distillation is carried out at a shell temperature of 150°C to 250°C.

9. A diastereoisomerically enriched fragrance mixture comprising a compound of formula (A): Wherein the compounds of formula (A) include the following enantiomeric pairs of formula (I), (II) and (III) which are diastereoisomers of each other: Enantiomer pair (I): Enantiomer pair (II): Enantiomer pair (III): wherein the quantitative ratio of enantiomeric pair (I) to enantiomeric pair (II) is at least 10:1; and wherein the quantitative ratio of the enantiomeric pair (I) to (III) is at least 50:

1.

10. The diastereomerically enriched spice mixture according to claim 9, characterized in that The fragrance mixture comprises in total at least 96.5% by weight of the enantiomeric pairs (I), (II) and (III).

11. Use of a diastereomerically enriched fragrance mixture according to any one of the preceding claims 9 or 10 as a fragrance or for preparing a fragrance formulation.

12. A fragrance formulation comprising a sensory effective amount of the diastereomerically enriched fragrance mixture according to any one of the preceding claims 9 or 10.

13. Use of the diastereomerically enriched fragrance mixture according to any one of the preceding claims 9 or 10 in an organoleptically effective amount for mediating, modifying or enhancing the floral aroma of a fragrance product or for preparing a fragrance product.

14. A fragrance product comprising the diastereomerically enriched fragrance mixture according to claim 9 or 10 or the fragrance preparation according to claim 11 or 12.

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