3-acyl-oxazolidin-5-one properfumes

Abstract

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Description

[0001]Firmenich SA 3-ACYL-OXAZOLIDIN-5-ONE PROPERFUMES Technical Field The present invention relates to compounds of formula (I) as properfume compounds. In particular, the present invention relates to a method to release an aldehyde or a ketone of formula (II), by exposing the compound of formula (I) to a trace of water. Moreover, the present invention relates to a perfuming composition and a perfumed consumer product comprising at least one compound of formula (I). Background The perfume industry has a particular interest for compositions or additives which are capable of prolonging or enhancing the perfuming effect of at least one perfuming ingredient for a certain period of time. It is particularly desirable to obtain long-lasting properties for standard perfumery raw materials which are too volatile or have a poor substantivity by themselves, or which are only deposited in a small amount onto the surface of the final application. Furthermore, some of the perfumery ingredients are unstable and need to be protected against slow degradation prior to their use. Long-lasting perfumes are desirable for various applications, as for example fine or functional perfumery or cosmetic preparations. The washing and softening of textiles are particular fields in which there is a constant need to enable the effect of active substances, in particular perfumes, or perfuming compositions, to be effective for a certain period of time after washing, softening and drying. Indeed, many active substances which are particularly suitable for this type of application are known to lack tenacity on laundry, or do not remain on the laundry when rinsed, with the result that their perfuming effect is experienced only briefly and not very intensely. Given the importance of this type of application in the perfume industry, research in this field has been sustained, in particular with the aim of finding new, and more effective solutions to the aforementioned problems. Furthermore, consumers increasingly demand eco-friendly and sustainable solutions for the aforementioned problems. This implies that compositions or additives used to prolong or enhance the perfuming effect must be biocompatible and biodegradable. Furthermore, substrates and building blocks that serve to improve the long-lastingness of perfumery materials or other active compounds should be derived from natural sources, consisting of renewable carbon. Derivatives of naturally occurring amino acids are examples for suitable substrates or building blocks in this context. Firmenich SA Some hydrolytically cleavable, amino acid-derived properfumes are known. For example, WO 2008 / 142591 reports 1,3-diaza-4-oxo-heterocyclic derivatives (imidazolidin-4- ones) to deliver active aldehydes or ketones. US 6,861,402 relates to the use of aldehyde- and ketone- releasing properfume accords comprising heterocyclic profragrances, beta-amino profragrances and / or orthoester proaccords. Among the heterocyclic profragrances, oxazolidines, and in particular oxazolidine-4- carboxylates, are described as the preferred aldehyde- or ketone-releasing structures. To achieve an enhanced fragrance benefit to fine fragrances, personal care and hygiene articles, fragrance delivery systems composed of at least two of the oxazolidine profragrances, beta-amino profragrances and / or orthoester proaccords are used. A particular challenge of properfumes releasing active compounds by hydrolysis (e.g. when being exposed to humidity in ambient air) is that these properfumes are expected to be sufficiently labile to efficiently release the fragrance in the target application. For this reason, they typically have a limited shelf-life (storage) stability when they are formulated into aqueous consumer articles, such as typical body and homecare products. On the other hand, hydrolytically cleavable properfumes that have a very high storage stability in aqueous media might be inefficient in releasing the fragrance in application. It is therefore not evident to provide properfumes that are highly performant in application and at the same time display a high storage stability in water-based consumer products. It has now surprisingly been found that 3-acyl-oxazolidin-5-one derivatives of formula (I) according to the present invention are particularly suitable as properfumes. They release active compounds in application by slow hydrolysis, while being reasonably stable during storage in water-based consumer articles. Furthermore, they may be efficiently prepared from readily available, even preferably naturally occurring, starting materials, and they allow the release of an aldehyde or ketone compound of formula (II). Detailed description Olfaction is a complex and dynamic process and controlling the release profile of volatile fragrance compounds may maximize the impact of fragrance formulations and enrich the sensorial experience. Properfumes, such as the compounds of the present invention, add a dimension of control and long-lastingness to the release profile of highly volatile perfumery raw materials (PRMs), such as aldehydes or ketones representing an important group of compounds in the perfumery field. Firmenich SA Without intending to be limited to any particular theory, the compounds of the present invention may achieve their effect on the olfactive properties of a perfuming composition by tethering the PRM to a molecular anchor and requiring a specific reaction mechanism under certain environmental conditions to release the volatile PRM from this anchor. In the present invention, the release of PRMs is prompted by hydrolysis when the properfume is exposed to humidity in ambient air. A first object of the present invention is a method to release from a precursor compound of formula (I), an aldehyde or a ketone of formula (II) wherein R1is a hydrogen atom or a C1to C18hydrocarbon group, optionally comprising one or more O or S atoms, R is a C4to C22hydrocarbon group, optionally comprising one or more O or S atoms, and R and R1, when taken together, form a C5-16hydrocarbon group, optionally comprising one or more O or S atoms, wherein the precursor compound comprises a compound of formula in the form of any one of its stereoisomers or a mixture thereof, and wherein R and R1are as defined herein-above, R2is a hydrogen atom or a C1to C18hydrocarbon group, optionally comprising one or more N, O or S atoms, R3is a hydrogen atom or a C1to C4alkyl or alkenyl group, R4is a C1to C18hydrocarbon group, optionally comprising one or more N, O or S atoms, Firmenich SA R2and R3, when taken together, form a double bond, substituted with one or two hydrogen atoms or one or two C1to C12hydrocarbon groups, and R3and R4, when taken together, form a five-, six-or seven-membered lactam or a five- or six- membered cyclic carbamate. According to any one of the embodiments of the invention, the aldehyde or ketone of formula (II) is an active compound. The terms “active compound”, “active volatile compound”, “active volatile aldehyde or ketone” or the similar, are understood as compounds being capable of bringing a benefit or effect into its surrounding environment. In particular, the “active compound” is selected from the group consisting of a perfuming ingredient, flavoring ingredient, malodor counteracting ingredient, antimicrobial ingredient and insect repellent or attractant ingredient. Therefore, to be considered as an “active compound” the compound has to possess at least one property which renders it useful as a perfuming ingredient, as a malodor counteracting ingredient, as a flavoring ingredient, as an antimicrobial ingredient and / or as an insect repellent or attractant. The term “perfuming ingredient” is understood as a compound which is used as an active ingredient in perfuming preparations or compositions in order to impart a hedonic effect. In other words, a compound to be considered as being a perfuming ingredient, must be recognized by a skilled person in the art of perfumery as being able to impart or modify in a positive or pleasant way the odor of a composition, and not just as having an odor. The perfuming ingredient may impart an additional benefit beyond that of modifying or imparting an odor, such as long-lasting, blooming, malodor counteraction, antimicrobial effect, antiviral effect, microbial stability, or pest control. The term “flavoring ingredient” is understood as being capable of imparting a taste sensation to the taster’s pallet. The term “malodor counteracting ingredient” is understood as being capable of reducing the perception of malodor, i.e. of an odor that is unpleasant or offensive to the human nose. The term “antimicrobial ingredient” is understood as being capable of killing microorganisms or reducing or preventing their growth and / or accumulation and include antibacterial, antibiotic, antifungal, antiviral and antiparasitic ingredients. The term “insect attractant or repellent” is understood as a compound having a positive or negative effect on insects. Examples of insect attractant or repellent ingredients can be found in reference texts or in other works of a similar nature as for example: A. M. El-Sayed, 2024, The Pherobase: Database of Pheromones and Semiochemicals (https: / / www.pherobase.com). Firmenich SA According to the above and below mentioned embodiments of the invention, the method according to the present invention is particularly useful when the active compound is a perfuming ingredient, i.e. a perfuming aldehyde or ketone. A “perfuming aldehyde or ketone” is a perfuming ingredient as defined above comprising at least one ketone or aldehyde functional group. The perfuming aldehydes or ketones can be of natural or synthetic origin. Many of these perfuming aldehydes or ketones are in any case listed in reference texts such as the book by S. Arctander, Perfume and Flavor Chemicals, 1969, Montclair, New Jersey, USA, or its more recent versions, or in other works of a similar nature, as well as in the abundant patent literature in the field of perfumery. Herein described, the terms “perfuming aldehyde or ketone” are also referred to as “perfuming compounds”. Practically, the invention is carried out exactly in the same manner, independent of the exact properties of the active aldehyde or ketone. Therefore, it is understood that, even if the invention will be further illustrated herein below with a specific reference to “perfuming compounds”, the below embodiments are also applicable to other active aldehydes or ketones (i.e. it is possible to replace the expression “perfuming” with “flavoring”, “malodor counteracting”, “antibacterial”, “antimicrobial”, “insect attractant” or with “insect repellent” for instance). The term “optionally” is understood that a certain group optionally comprising or to be optionally substituted can or cannot comprise heteroatom or can or cannot be substituted with a certain functional group. The term “one or more” is understood as being substituted with 1 to 9, preferably 1 to 7, preferably 1 to 5, preferably 1 to 3 and more preferably 1 to 2 of a certain functional group. Unless specified otherwise, all percentages refer to percent by weight, based on the total weight of the referenced composition. The terms “alkyl” and “alkenyl” are understood as comprising branched, alicyclic and linear alkyl and alkenyl groups. The terms “alkenyl”, “cycloalkenyl” and “heterocycloalkenyl” are understood as comprising 1, 2 or 3 olefinic double bonds, preferably 1 or 2 olefinic double bonds, provided that the cycloalkenyl group is not an aryl group. The terms “cycloalkyl”, “cycloalkenyl”, “heterocycloalkyl” and “heterocycloalkenyl” are understood as comprising a monocyclic or fused, spiro and / or bridged bicyclic or tricyclic cycloalkyl, cycloalkenyl, heterocycloalkyl and heterocycloalkenyl groups, preferably monocyclic cycloalkyl, cycloalkenyl, heterocycloalkyl and heterocycloalkenyl groups. The term “alkoxy” is understood Firmenich SA as an -OR’ group wherein R’ is a linear, branched or cyclic alkyl group. The term “C1-4 carboxylic ester group” is understood as -OC(=O)R’’ or -C(=O)O-R’’ wherein R’’ is a linear branched or cyclic alkyl group. The term “aryl” is understood as comprising any group comprising at least one aromatic group such as phenyl, indenyl, indanyl, benzodioxolyl, dihydrobenzodioxinyl, tetrahydronaphthalenyl or naphthalenyl group. It is understood that by “… hydrocarbon group ...” it is meant that said group consists of hydrogen and carbon atoms and can be in the form of an aliphatic hydrocarbon, i.e. linear or branched saturated hydrocarbon (e.g. alkyl group), a linear or branched unsaturated hydrocarbon (e.g. alkenyl or alkynyl group), a saturated cyclic hydrocarbon (e.g. cycloalkyl) or an unsaturated cyclic hydrocarbon (e.g. cycloalkenyl or cycloalkynyl), or can be in the form of an aromatic hydrocarbon, i.e. aryl group, or can also be in the form of a mixture of said type of groups, e.g. a specific group may comprise a linear alkyl, a branched alkenyl (e.g. having one or more carbon-carbon double bonds), a (poly)cycloalkyl and an aryl moiety, unless a specific limitation to only one type is mentioned. Similarly, in all the embodiments of the invention, when a group is mentioned as being in the form of more than one type of topology (e.g. linear, cyclic or branched) and / or being saturated or unsaturated (e.g. alkyl, aromatic or alkenyl), it is also meant a group which may comprise moieties having any one of said topologies or being saturated or unsaturated, as explained above. Similarly, in all the embodiments of the invention, when a group is mentioned as being in the form of one type of saturation or unsaturation, (e.g. alkyl), it is meant that said group can be in any type of topology (e.g. linear, cyclic or branched) or having several moieties with various topologies. It is understood that with the term “… a hydrocarbon group, optionally comprising one or more oxygen atoms…” it is meant that said hydrocarbon group optionally comprises one, two, three or more oxygen atoms in a form of alcohol, ketone, aldehyde, ether, ester, carboxylic acid, carbonate groups. These groups can either substitute a hydrogen atom of the hydrocarbon group and thus be laterally attached to said hydrocarbon, or substitute a carbon atom (if chemically possible) of the hydrocarbon group and thus be inserted into the hydrocarbon chain. For example, a -CH2-CH2-CHOH-CH2- group represents a C4hydrocarbon group comprising an alcohol group (substitution of a hydrogen atom), i.e. a C4hydrocarbon comprising an oxygen atom; a -CH2-CH2-COO-CH2-CH2CH2-CH2- group represents a C7hydrocarbon group comprising one ester group (substitution of carbon atoms / insertion into the hydrocarbon chain), i.e. a C7hydrocarbon comprising two oxygen atoms and, similarly, a -CH2-CH2-O-CH2-CH2- Firmenich SA O-CH2-CH2- group represents a C6 hydrocarbon group comprising two ether groups, i.e. a C6 hydrocarbon comprising two oxygen atoms. For the sake of clarity, by the expression “any one of its stereoisomers or a mixture thereof”, or the similar, it is meant the normal meaning understood by a person skilled in the art, i.e. that the compound of formula (I) can be a pure enantiomer or diastereomer. In other words, the compound of formula (I) may possess several stereocenters and each of said stereocenter can have two different stereochemistries (e.g. R or S). The compound of formula (I) may even be in the form of a pure enantiomer or in the form of a mixture of enantiomers or diastereoisomers. The compound of formula (I) can be in a racemic form or scalemic form. Therefore, the compound of formula (I) can be one stereoisomer or in the form of a composition of matter comprising, or consisting of, various stereoisomers. According to any of the above embodiments, the compound of formula (I) is a C11-C70compound, preferably a C12-C40compound, even more preferably a C15-C36compound. According to any of the above embodiments, R contains at least 5 carbon atoms, preferably at least 6 carbon atoms, more preferably at least 7 carbon atoms, even more preferably at least 8 carbon atoms. According to any of the above embodiments, R is not a phenyl group, optionally substituted with alkyl groups or alkoxy groups, or a naphthyl group. According to any of the above embodiments, R and R1do not comprise a double bond in conjugation with the carbonyl function of formula (I) or adjacent to the N-C-O carbon of the oxazolidinone moiety of formula (II), respectively. According to any of the above embodiments, R is C4to C20hydrocarbon group, optionally comprising one or more O atoms. Particularly, R is C4to C18hydrocarbon group, optionally comprising one or more O atoms. Particularly, R is a C4to C15hydrocarbon group, optionally comprising one or more O atoms. In a particular embodiment, R is a C4to C15alkyl or alkenyl group, optionally substituted with one or more hydroxy groups, or a C8to C16aralkyl group, preferably a C2-6alkyl group substituted with a C6-10aryl group, C7to C12cycloalkylalkyl group, preferably a C2-6alkyl group Firmenich SA substituted with a C5-6 cycloalkyl group, C7 to C12 cycloalkenylalkyl group, preferably a C2-6 alkyl group substituted with a C5-6cycloalkenyl group, each optionally and independently substituted with one or more C1to C4alkyl groups. In a particular embodiment, R is a linear or branched C4to C15alkyl or alkenyl group or a C8to C12aralkyl, preferably a C2-6alkyl group substituted with a C6aryl group, C8-12cyclohexylalkyl group, preferably a C2-6alkyl group substituted with a cyclohexyl group, or a C8-12cyclohexenylalkyl group, preferably a C2-6alkyl group substituted with a cyclohexenyl group, each optionally and independently substituted with one or more linear or branched C1to C4alkyl groups. In a particular embodiment, R is a linear or branched C4to C15alkyl group or a C8to C12 phenylalkyl, preferably a C2-6 alkyl group substituted with a phenyl group, C8-12 cyclohexylalkyl group, preferably a C2-6alkyl group substituted with a cyclohexyl group, or a C8-12cyclohexenylalkyl group, preferably a C2-6alkyl group substituted with a cyclohexenyl group, each optionally and independently substituted with one or more linear or branched C1to C4alkyl groups. In a particular embodiment, R is a linear or branched C5to C12alkyl group or a C8to C12phenylalkyl, preferably a C2-6alkyl group substituted with a phenyl group, C8-12cyclohexylalkyl group, preferably a C2-6alkyl group substituted with a cyclohexyl group, or a C8-12cyclohexenylalkyl group, preferably a C2-6alkyl group substituted with a cyclohexenyl group, each optionally and independently substituted with one or more linear or branched C1to C4 alkyl groups. According to any of the above embodiments, R is either one of formula (i) or (ii) wherein R5is a C3to C18hydrocarbon group, optionally comprising one or more O or S atoms, R6and R7, each independently, is a hydrogen atom or a C1to C18hydrocarbon group, R8is a methyl or ethyl group, R1and R5, when taken together, form a cyclic C5to C14hydrocarbon group, optionally comprising one or two O atoms, and Firmenich SA R5and R6, when taken together, form a cyclic alkyl or alkenyl group. In a particular embodiment, R is of formula (i). In certain embodiments when R is of formula (i), R is of formula (iii) wherein R9, R10, R11and R12each independently, are a hydrogen atom or a methyl group, R13is a C1to C10hydrocarbon group, R9and R13, when taken together form a cyclohexenyl group, R11and R13when taken together form a cyclohexenyl or a phenyl group, optionally substituted with one or several C1to C8hydrocarbon groups. According to any of the above embodiments, R1is a hydrogen atom or a C1to C18hydrocarbon group, optionally comprising one or more O or S atoms. In a particular embodiment, R1is a hydrogen atom or a C1to C18hydrocarbon group, optionally substituted with one or more O or S atoms. In a particular embodiment, R1is a hydrogen atom or a C1to C18hydrocarbon group, optionally substituted with one or more O atoms, preferably optionally substituted with one O atom. In a particular embodiment, R1is a hydrogen atom or a linear or branched C1to C4alkyl group. In a particular embodiment, R1is a hydrogen atom or a methyl group. According to any of the above embodiments, R and R1, when taken together, form a C5-16cycloalkyl or C5-16cycloalkenyl group wherein the double bond is not conjugated with the ketone functional group, a C4-14heterocycloalkyl or C4-14heterocycloalkenyl group wherein the double bond is not conjugated with the ketone functional group, each optionally substituted with one or more of a C1-15alkyl, C1-15alkoxy, C3-15cycloalkyl, C5-15cycloalkenyl, C6-10aryl and / or C6-10aryloxy group, each optionally substituted with one or more of a C1-8alkyl, C1-8alkoxy and / or C1-4carboxylic ester group, Firmenich SA In a particular embodiment, R and R1, when taken together, form a C5-16 cycloalkyl or C5-16cycloalkenyl group wherein the double bond is not conjugated with the ketone functional group, each optionally substituted with one or more of a C1-15alkyl group, preferably a C1-5alkyl group, even more preferably a methyl group. In a particular embodiment, R and R1, when taken together, form a C5-6cycloalkyl or C5-6cycloalkenyl group wherein the double bond is not conjugated with the ketone functional group, each optionally substituted with one or more of a C1-15alkyl group, preferably a C1-5alkyl group, even more preferably a methyl group. In certain embodiments in which the double bond is not conjugated with the ketone functional group, compounds of formula (II) are contemplated. According to any of the above embodiments, R2is a hydrogen atom, a phenyl group, a benzyl group, a cyclohexyl group or a C1to C10alkyl group optionally substituted by an amide, a guanidine, a thiol, a primary amine (i.e. NH2), a C1to C3thioether, preferably a SCH3, a phenyl, a hydroxyphenyl, a carboxylic acid, a hydroxy or a C4to C8heterocycloalkenyl group, wherein the heteroatom is one or two nitrogen atoms, such as an imidazolyl or an indolyl group. In a particular embodiment, R2is a hydrogen atom, a phenyl group, a cyclohexyl group or a residue derived from an amino acid of formula R2CH(NH2)COOH, and in particular of a natural α-amino acid, such as S-alanine (R2= CH3), S-arginine [R2= (CH2)3NHC(NH)(NH2)], S-asparagine (R2= CH2CONH2), R-cysteine (R2= CH2SH), S-glutamine [R2= (CH2)2CONH2], glycine (R2= H), S-histidine [R2= CH2(C3N2H3)], S-isoleucine [R5= C(CH3)CH2CH3], S- leucine [R5= CH2CH(CH3)2], S-lysine [R5= (CH2)4NH2], S-methionine [R2= (CH2)2SCH3], S- phenylalanine (R2= CH2C6H5), S-serine (R2= CH2OH), S-threonine [R2= CH(OH)CH3], S- tryptophane [R2= CH2(C8H6N)], S-tyrosine (R2= CH2C6H4OH), S-valine [R2= CH(CH3)2], S- aspartic acid (R2= CH2COOH), and S-glutamic acid [R2= (CH2)2COOH], or of an artificial α- amino acid selected from the group of norleucine [R2= (CH2)3CH3], norvaline [R2= (CH2)2CH3], 2-phenylglycine (R2= C6H5), ornithine [R2= (CH2)3NH2], homoalanine (R2= CH2CH3), homocysteine [R2= (CH2)2SH], and homoserine [R2= (CH2)2OH]. In a particular embodiment, R2is a hydrogen atom, a 2-(methylthio)ethyl group, a phenyl group, a benzyl group, a cyclohexyl group or a linear or branched C1to C10linear or branched alkyl group, preferably a hydrogen atom, a 2-(methylthio)ethyl group or a linear or branched C1to C6alkyl group. Firmenich SA In an embodiment, R2is a hydrogen atom, a methyl group, an ethyl group, isopropyl group, an isobutyl group, a 2-(methylthio)ethyl group, or a benzyl group. In a particular embodiment, R2is a hydrogen atom, a methyl group, an isopropyl group, an isobutyl group, a 2-(methylthio)ethyl group or a benzyl group. In a particular embodiment, R2is a hydrogen atom, a methyl group, or an isobutyl group. According to any of the above embodiments, R3is a hydrogen atom. According to any of the above embodiments, R2and R3, when taken together, form a double bond, substituted with one hydrogen atom and one C1to C8alkyl or C6to C10aryl group. In a particular embodiment, R2and R3, when taken together, form a double bond, substituted with one hydrogen atom and one linear or branched C1to C4alkyl or C6aryl group. In a particular embodiment, R2and R3, when taken together, form a double bond, substituted with one hydrogen atom and one phenyl group. According to any of the above embodiments, R4is a phenyl group, a benzyl group or a C1to C18alkyl, alkenyl or cycloalkyl group, C1to C6alkylamino group, C1to C6alkoxy group, phenyloxy group or a benzyloxy group. In a particular embodiment, R4is a benzyl group or a linear or branched C1to C12alkyl or alkenyl group, preferably a C1to C8alkyl or alkenyl group. In a particular embodiment, R4is a benzyl group or a linear or branched C1 to C12 alkyl group, preferably a linear or branched C1to C8alkyl group. According to any of the above embodiments, R3and R4, when taken together, form a C4to C5lactam group (cyclic amide). According to any of the above embodiments, R5is a C3to C17hydrocarbon group, optionally comprising one or more O or S atoms. In a particular embodiment, R5is a C3to C17hydrocarbon group, optionally substituted with one or more O atoms. In a particular embodiment, R5is a C3to C14alkyl or alkenyl group, optionally substituted with one or more hydroxy groups. In a particular embodiment, R5is a C3to C14alkyl or alkenyl group. Firmenich SA According to any embodiment, R1and R5, when taken together, form a cyclic C5to C14hydrocarbon group, optionally comprising one or two O atoms. In a particular embodiment, R1and R5, when taken together, form a cyclic C5to C14cycloalkyl or C5to C14cycloalkenyl group wherein the double bond is not conjugated with the ketone functional group, each optionally substituted with one or more of a C1to C15alkyl group, preferably a C1-5alkyl group, even more preferably a methyl group. In a particular embodiment, R1and R5, when taken together, form a C5to C6cycloalkyl or C5to C6cycloalkenyl group wherein the double bond is not conjugated with the ketone functional group, each optionally substituted with one or more of a C1to C15alkyl group, preferably a C1 to C5 alkyl group, even more preferably a methyl group. In certain embodiments in which the double bond is not conjugated with the ketone functional group, compounds of formula (II) are contemplated. According to any of the above embodiments, R6is a hydrogen atom or a C1to C14hydrocarbon group. In a particular embodiment, R6is a hydrogen atom or a linear or branched C1to C4alkyl or alkenyl group. In a particular embodiment, R6is a hydrogen atom or a linear or branched C1to C4alkyl group. According to any of the above embodiments, R5and R6, when taken together, form a C5to C6cycloalkyl or cycloalkenyl group, optionally substituted with one or more C1to C4alkyl groups. In a particular embodiment, R5and R6, when taken together, form a C5to C6cycloalkyl group, optionally substituted with one or more C1to C4alkyl groups. According to any of the above embodiments, R7is a hydrogen atom or a C1to C14hydrocarbon group. In a particular embodiment, R7is a hydrogen atom or a linear or branched C1to C4alkyl or alkenyl group. In a particular embodiment, R7is a hydrogen atom or a linear or branched C1to C4alkyl group. Firmenich SA In a particular embodiment, R7is a hydrogen atom. According to any of the above embodiments, R8is a methyl group. In a particular embodiment, the compound of formula (I) is 3-(undecan-2-yl)dihydro- 1H,3H-pyrrolo[1,2-c]oxazole-1,5(6H)-dione, 3-acetyl-4-isobutyl-2-(undecan-2-yl)oxazolidin- 5-one, 3-benzoyl-2-(undecan-2-yl)oxazolidin-5-one, 3-benzoyl-4-isobutyl-2-(undecan-2- yl)oxazolidin-5-one, 3-acetyl-2-(undecan-2-yl)oxazolidin-5-one, 3-acetyl-4-phenyl-2- (undecan-2-yl)oxazolidin-5-one, 3-acetyl-4-benzylidene-2-(undecan-2-yl)oxazolidin-5-one, 3- (2-phenylacetyl)-2-(undecan-2-yl)oxazolidin-5-one, 3-octanoyl-2-(undecan-2-yl)oxazolidin-5- one, 4-methyl-3-octanoyl-2-(undecan-2-yl)oxazolidin-5-one, 4-isopropyl-3-octanoyl-2- (undecan-2-yl)oxazolidin-5-one, 4-benzyl-3-octanoyl-2-(undecan-2-yl)oxazolidin-5-one, 2- nonyl-3-octanoyloxazolidin-5-one, 3-octanoyl-2-pentyloxazolidin-5-one, 3-octanoyl-2- phenethyloxazolidin-5-one, 2-(4-(tert-butyl)phenethyl)-3-octanoyloxazolidin-5-one, 2-(non-3- en-1-yl)-3-octanoyloxazolidin-5-one, 3-octanoyl-2-(undec-3-en-1-yl)oxazolidin-5-one, 3- octanoyl-2-(2-phenylpropyl)oxazolidin-5-one, 3-octanoyl-2-(1-(p-tolyl)propan-2- yl)oxazolidine-5-one, 2-(2-(4,4-dimethylcyclohex-1-en-1-yl)ethyl)-3-octanoyloxazolidin-5- one, 2-(4,8-dimethylnon-3-en-1-yl)-3-octanoyloxazolidin-5-one, 2-(6-methylhept-5-en-2-yl)- 3-octanoyloxazolidin-5-one, 3-butyryl-2-(undecane-2-yl)oxazolidine-5-one, 3-butyryl-2-(2- (4,4-dimethylcyclohex-1-en-1-yl)ethyl)oxazolidin-5-one, 3-butyryl-2-(2,4-dimethylcyclohex- 3-en-1-yl)oxazolidin-5-one, 3-butyryl-2-(dec-9-en-1-yl)oxazolidin-5-one, 3-butyryl-2-(4,8- dimethylnon-3-en-1-yl)oxazolidin-5-one, 3-butyryl-2-(6-methylhept-5-en-2-yl)oxazolidin-5- one, 3-isobutyryl-2-(undecane-2-yl)oxazolidine-5-one, 3-pivaloyl-2-(undecane-2- yl)oxazolidine-5-one, 2-(2-(4,4-dimethylcyclohex-1-en-1-yl)ethyl)-3-(2- phenylacetyl)oxazolidin-5-one, 3-(2-phenylacetyl)-2-(undec-3-en-1-yl)oxazolidin-5-one, 2-(3- methyl-4-(4-methylphenyl)but-3-en-1-yl)-3-(2-phenylacetyl)oxazolidin-5-one, 2-(2-(1,1- and 3,3-dimethyl-2,3-dihydro-1H-inden-5- and 4-yl)ethyl)-3-(2-phenylacetyl)oxazolidin-5-one, 2- (2-(3-isopropylphenyl)propyl)-3-(2-phenylacetyl)oxazolidin-5-one, 2-nonyl-3-(2- phenylacetyl)oxazolidin-5-one, 2-(6-methylhept-5-en-2-yl)-3-(2-phenylacetyl)oxazolidin-5- one, 2-(4,8-dimethylnon-3-en-1-yl)-3-(2-phenylacetyl)oxazolidin-5-one, benzyl 5-oxo-2- (undecan-2-yl)oxazolidine-3-carboxylate, 2-(4-methoxyphenyl)-5-oxooxazolidine-3- carboxylate, 2-(5-cyclohexyl-4-methylpent-4-en-2-yl)-5-oxooxazolidine-3-carboxylate, 3-(2- phenoxyacetyl)-2-(undecane-2-yl)oxazolidine-5-one, 3-acetyl-4-methyl-2-(undecan-2- Firmenich SA yl)oxazolidin-5-one, 3-butyryl-4-methyl-2-(undecan-2-yl)oxazolidin-5-one, 4-methyl-3- octanoyl-2-(undec-3-en-1-yl)oxazolidin-5-one, 3-acetyl-4-isobutyl-2-phenethyloxazolidin-5- one, 3-acetyl-4-isobutyl-2-(non-3-en-1-yl)oxazolidin-5-one, 3-acetyl-4-benzyl-2-(undecan-2- yl)oxazolidin-5-one, 3-acetyl-4-(2-(methylthio)ethyl)-2-(undecan-2-yl)oxazolidin-5-one or 3- acetyl-4-isopropyl-2-(undecan-2-yl)oxazolidin-5-one or a mixture thereof. According to any of the above embodiments, the aldehyde or ketone of formula (II) is a fragrance aldehyde or ketone. According to any of the embodiments, the compounds of formula (I) are non-volatile and essentially odorless. Non-volatile and essentially odorless compounds are advantageously characterized by a vapor pressure below 2.0 Pa, as obtained by calculation using the software EPIwin v. 3.10 (2000, available at the US Environmental Protection Agency). Preferably, said vapor pressure is below 0.2 Pa, or even more preferably below 0.02 Pa. According to any of the embodiments, the compound of formula (II) is advantageously characterized by a vapor pressure between 200 and 0.1 Pa, as obtained by calculation using the software EPIwin v. 3.10 (2000, available at the US Environmental Protection Agency). According to another embodiment, said vapor pressure is preferably between 150 and 0.2 Pa, even more preferably between 100 and 0.3 Pa, most preferably between 47 and 0.4 Pa. In a particular embodiment, the compound of formula (II) wherein R1is a hydrogen atom; i.e. an aldehyde of formula RCHO, may be selected from the group consisting of benzaldehyde, 3-(1,3-benzodioxol-5-yl)-2-methylpropanal, 3-butoxybenzaldehyde, 5- cyclohexyl-2,4-dimethylpent-4-enal (Muguissimo®, origin: Firmenich SA, Geneva, Switzerland), decanal, 4,7-decadienal, 4-decenal, 8-decenal, 9-decenal, 3-(6,6-dimethyl- bicyclo[3.1.1]hept-2-en-2-yl)propanal, 2,4-dimethylcyclohex-3-ene-1-carbaldehyde (Triplal®, origin: International Flavors & Fragrances, New York, USA), 3,5-dimethyl-3-cyclohexene-1- carbaldehyde, 3-(4,4-dimethylcyclohex-1-enyl)propanal (Tillenal®, origin: Firmenich SA, Geneva, Switzerland), 5,9-dimethyl-4,8-decadienal, 4,8-dimethyl-4,9-decadienal, 5,9- dimethyldec-4-enal, 3-(1,1- or 3,3-dimethyl-2,3-dihydro-1H-inden-4- or 5-yl)propanal (Hivernal®Neo, origin: Firmenich SA, Geneva, Switzerland), 2,6-dimethyl-5-heptenal (Melonal), 3,7-dimethyloctanal, 3,7-dimethyl-6-octenal (Citronellal), (3,7-dimethyl-6- octenyl)acetaldehyde, 2-((3,7-dimethyloct-6-en-1-yl)oxy)acetaldehyde, dodecanal, 3- Firmenich SA dodecenal, 4-dodecenal, 3-ethoxy-4-hydroxybenzaldehyde (Ethyl vanillin), 4-ethyl benzaldehyde, 2-hydroxybenzaldehyde, 9-hydroxy-5,9-dimethyl-4-decenal (Mahonial®, origin: Givaudan-Roure SA., Vernier, Switzerland), 7-hydroxy-3,7-dimethyloctanal (hydroxycitronellal), 4- and 3-(4-hydroxy-4-methylpentyl)-3-cyclohexene-1-carbaldehyde (Lyral®, origin: International Flavors and Fragrances, New York, USA), 3-(4-isobutyl-2- methylphenyl)propanal (Nympheal®, origin: Givaudan-Roure SA., Vernier, Switzerland), 3-(4- isobutylphenyl)propanal, 4-isopropylbenzaldehyde (Cuminaldehyde), 3-(4-isopropylcyclohex- 1-en-1-yl)-2-methylpropanal, 3-(4-isopropylcyclohex-1-en-1-yl)propanal, 8-isopropyl-6- methylbicyclo[2.2.2]oct-5-ene-2-carbaldehyde, 3-(3-isopropylphenyl)butanal (Florhydral®, origin: Givaudan-Roure SA., Vernier, Switzerland), 3-(4-isopropylphenyl)-2-methylpropanal (Cyclamen aldehyde), 2-(4-isopropylphenyl)propanal, 4-methoxybenzaldehyde (Anisaldehyde), 6-methoxy-2,6-dimethylheptanal (Methoxymelonal), 3-methoxy-4- hydroxybenzaldehyde (Vanillin), 3-(4-methoxyphenyl)-2-methylpropanal, 8(9)-methoxy- tricyclo[5.2.1.0.(2,6)]decane-3(4)-carbaldehyde (Scentenal®, origin: Firmenich SA, Geneva, Switzerland), 4-methylbenzaldehyde, 3-(4-methyl-3-cyclohexen-1-yl)butanal (Liminal®, origin: Firmenich SA, Geneva, Switzerland), 2-methyldecanal, 2-(4- methylenecyclohexyl)propanal, 4-methyl-5-(4-methylphenyl)pent-4-enal (Mimosal®, origin: Firmenich SA, Geneva, Switzerland), 2-methyl-3-(4-methylphenyl)propanal, 3- and 4-(4- methyl-3-pentenyl)-3-cyclohexene-1-carbaldehyde (Empetal, origin: Givaudan-Roure SA., Vernier, Switzerland), (4-methylphenyl)acetaldehyde, 3-methyl-5-phenylpentanal (Phenexal®, origin: Firmenich SA, Geneva, Switzerland), 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1- yl)pent-4-enal, 2-methylundecanal, nonanal, 3-nonenal, 6-nonenal, 8-nonenal, 4-(octahydro- 5H-4,7-methanoinden-5-ylidene)butanal, octanal, phenoxyacetaldehyde, phenylacetaldehyde, 3-phenylbutanal (Trifernal®, origin: Firmenich SA, Geneva, Switzerland), 2-phenylpropanal (Hydratropaldehyde), 3-phenylpropanal, 3-(4-tert-butylphenyl)-2-methylpropanal (Lilial®, origin: Givaudan-Roure SA, Vernier, Switzerland), 3-(4-tert-butylphenyl)propanal (Bourgeonal®, origin: Quest International, Naarden, Netherlands), tricyclo[5.2.1.0(2,6)]decane- 4-carbaldehyde, exo-tricyclo[5.2.1.0(2,6)]decane-8exo-carbaldehyde (Vertral®, origin: Symrise, Holzminden, Germany), trideca-4,7-dienal, 2,6,6-trimethyl-bicyclo[3.1.1]heptane-3- carbaldehyde (Formyl pinane), 2,4,6- and 3,5,6-trimethyl-3-cyclohexene-1-carbaldehyde, 2,2,3-trimethyl-3-cyclopentene-1-acetaldehyde (Campholenic aldehyde), 6-(2,2,3- trimethylcyclo-3-pentenyl)-4-hexenal, 2,5,6-trimethyl-4-heptenal, 3,5,5-trimethylhexanal, 2,6,10-trimethyl-9-undecenal, undecanal, 10-undecenal or 9-undecenal and their mixtures such Firmenich SA as Intreleven aldehyde (origin: International Flavors & Fragrances, New York, USA) and Aldehyde Supra (origin: Firmenich SA, Geneva, Switzerland); wherein the underlined compounds represent, in a preferred embodiment of the invention, particularly useful aldehydes. In a particular embodiment, the compound of formula (II) wherein R1is not a hydrogen atom; i.e. a ketone of formula (R1)(R)C=O, may be selected from the group consisting of 4- (1,3-benzodioxol-5-yl)-2-butanone, (4E / Z,8E / Z)-cyclododeca-4,8-dien-1-one, cyclopentadecanone, (Z)-cyclopentadec-4-en-1-one, (Z)-cycloheptadec-9-en-1-one, 1-(3,5- diisopropylphenyl)ethan-1-one, 1-(3,3-dimethylcyclohexyl)ethan-1-one, 1-[2,6-dimethyl-4-(2- methyl-2-propanyl)phenyl]ethanone, 4,7-dimethyl-6-octen-3-one, 2,6-dimethyl-7-octen-4-one (Dihydrotagetone), 4-(1,1-dimethylpropyl)cyclohexan-1-one (Orivone®, origin: International Flavors & Fragrances, New York, USA), (5-E / Z)-6,10-dimethylundeca-5,9-dien-2-one, 2- ethyl-4,4-dimethylcyclohexan-1-one, 4-ethyl-8-methyloctahydronaphthalen-1(2H)-one, 1-(4- ethylphenyl)ethan-1-one, 1-(3-ethyl-1,1,3,6-tetramethyl-2,3-dihydro-1H-inden-5-yl)ethanone, 2-heptylcyclopentan-1-one, 4,4a,6,7,8,8a-hexahydro-1,4-methanonaphthalen-5(1H)-one, 1- (1,1,2,3,3,6-hexamethyl-2,3-dihydro-1H-inden-5-yl)ethanone (Phantolid®, origin: PFW Aroma Chemicals, Barnevald, The Netherlands), 1-(3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydro-2- naphthalenyl)ethan-1-one (Fixolide®, origin: Givaudan SA, Vernier, Switzerland), 2-(5-hexen- 1-yl)cyclopentan-1-one, 4-(4-hydroxyphenyl)-2-butanone (Raspberry ketone), 1-isopropyl-4- methylbicyclo[3.1.0]hexan-3-one, 5-isopropyl-2-methylcyclohexan-1-one, 2-isopropyl-5- methylcyclohexan-1-one (Menthone), 1-(5-isopropyl-2-methylcyclohex-2-en-1-yl)propan-1- one, 1-(3-isopropyl-1,1,2,6-tetramethyl-5-indanyl)ethan-1-one, 4-(4-methoxyphenyl)-2- butanone, 1-(4-methoxyphenyl)ethan-1-one (Acetanisole, origin: Givaudan SA, Vernier, Switzerland), 1-(2-methoxyphenyl)propan-1-one, 7-methyl-2H-benzo[b][1,4]dioxepin-3(4H)- one, 2-(2-(4-methylcyclohex-3-en-1-yl)propyl)cyclopentan-1-one, 3-methylcyclopentadecan- 1-one, 3-methylcyclopentadec-4-en-1-one, 3-methylcyclopentadec-5-en-1-one, 5-methyl-3- heptanone, 6-methyl-5-hepten-2-one, 7-methyloctahydro-1,4-methanonaphthalen-6(2H)-one, methyl (Z)-2-(3-oxo-2-(pent-2-en-1-yl)cyclopentyl)acetate (Methyl jasmonate), methyl 2-(3- oxo-2-pentylcyclopentyl)acetate (Hedione®, origin: Firmenich SA, Geneva, Switzerland), 3- methyl-1-phenylbutan-1-one, 1-(4-methylphenyl)ethan-1-one, 2-methyl-1-phenylpropan-1- one, 1-(4-methylphenyl)propan-1-one, 1-[4-(2-methyl-2-propanyl)phenyl]ethan-1-one, 2-(1- methylpropyl)cyclohexan-1-one, 2-nonanone, 4-nonanone, 1-(octahydro-2,3,8,8-tetramethyl- 2-naphthalenyl)-1-ethanone (isomeric mixture, Iso E Super®, origin: International Flavors & Firmenich SA Fragrances, New York, USA), 2-octanone, 3-octanone, 2-pentadecanone, 2-pentylcyclopentan- 1-one (Delphone, origin: Firmenich SA, Geneva, Switzerland), 1-phenylbutan-1-one, 4-phenyl- 2-butanone, 1-phenylethan-1-one (Acetophenone), 1-phenylhexan-1-one, 1-phenylpentan-1- one, 1-phenyl-4-penten-1-one (Lavonax, origin: International Flavors & Fragrances, New York, USA), 1-phenylpropan-1-one (Propiophenone), 7-propyl-2H-benzo[b][1,4]dioxepin-3(4H)- one, 2-(tert-butyl)cyclohexan-1-one, 4-(tert-butyl)cyclohexan-1-one, 1-(6-tert-butyl-1,1- dimethyl-4-indanyl)-1-ethanone (Crysolide, Givaudan SA, Vernier, Switzerland), 1-(5,6,7,8- tetrahydro-2-naphthalenyl)ethan-1-one (Florantone®, origin: Takasago Corporation, Tokyo, Japan), 3,6,8,8-tetramethylhexahydro-1H-3a,7-methanoazulen-5(4H)-one, 1,1,5,5- tetramethylhexahydro-2H-2,4a-methanonaphthalen-8(5H)-one (iso-Longifolanone), 2,4a,8,8- tetramethyloctahydrocyclopropa[d]naphthalen-3(1H)-one (Thujopsan-4-one), 2,2,7,9- tetramethylspiro[5.5]undec-7-en-1-one, 2-tridecanone, 1,3,3-trimethylbicyclo[2.2.1]heptan-2- one, 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one, 2,2,4-trimethylbicyclo[3.1.1]heptan-3-one, 2,6,6-trimethylcycloheptan-1-one, 2,2,6-trimethylcyclohexan-1-one, 4-(2,6,6- trimethylcyclohex-2-en-1-yl)butan-2-one (Dihydro-alpha-ionone), 4-(2,6,6-trimethylcyclohex- 1-en-1-yl)butan-2-one (Dihydro-beta-ionone), 2,2,5-trimethyl-5-pentylcyclopentan-1-one, 2- undecanone and 5-undecanone; wherein the underlined compounds represent, in a preferred embodiment of the invention, particularly useful ketones. According to any one of the above embodiments, the aldehyde or ketone of formula (II) is released from the precursor compound of formula (I) via hydrolysis; i.e. by exposing the precursor compound of formula (I) to a trace of water. For the sake of clarity, by the expression “trace of water”, or the like, it is meant the normal meaning understood by a person skilled in the art, i.e. small amounts of residual water on the target surface (cotton after the washing) as well as a minimum of humidity in the air, typically 20% of humidity, preferably 30%, even more preferably 50%, most preferably >60%. The hydrolysis occurs at room temperature, under air and atmospheric pressure and in the absence of a catalyst. Without being bound by theory, it is also possible that, in addition to aqueous hydrolysis, the precursor compound of formula (I) can be hydrolyzed enzymatically to release the aldehyde or ketone of formula (II), e.g. by enzymes provided from bacteria, bacterial spores and / or other (micro-)organisms. Due to their natural occurrence, these enzymes might already be present on surfaces onto which the precursor has been deposited, or they might be intentionally brought to the target surface. The present invention also relates to a microcapsule comprising at least one compound Firmenich SA of formula (I). In one embodiment, the at least one compound of formula (I) is encapsulated in a core-shell microcapsule wherein the at least one compound of formula (I) is contained in the core surrounded by the shell. In one embodiment, the shell of the microcapsule protects the compound of formula (I) from the environment, e.g. from water. The shell is made of material which is able to release the at least one compound of formula (I) and / or the compound of formula (II). In one embodiment, the shell is made of material which is able to release the compound of formula (I) and / or the compound of formula (II) upon breakage of the shell and / or by diffusion through the shell. A person skilled in the art is well aware of processes to prepare said microcapsules. So, a microcapsule comprising at least one compound of formula (I) is one object of the present invention. In a preferred embodiment, encapsulation of a compound of formula (I) may provide an environment within the capsule wherein all, or a portion of the compound of formula (I) may decompose, thereby releasing the individual aldehyde or ketone of formula (II) into the capsule. In a preferred embodiment, the shell of the microcapsule may act as a permeability barrier, preventing the leakage of the individual aldehyde or a ketone of formula (II) from the capsule. According to a particular embodiment, the shell of the microcapsule comprises a material selected from the group consisting of polyurea, polyurethane, polyamide, polyester, poly(meth)acrylate (i.e. polyacrylate and / or polymethacrylate), polysiloxane, polycarbonate, polysulfonamide, polymers of urea and formaldehyde, melamine and formaldehyde, melamine and urea, or melamine and glyoxal and mixtures thereof. The shell can also be hybrid, namely organic-inorganic, such as a hybrid shell composed of at least two types of inorganic particles that are cross-linked, or yet a shell resulting from the hydrolysis and condensation reaction of a polyalkoxysilane macro-monomeric composition. According to a particular embodiment, the core-shell microcapsule(s) can be also derived by using different or more than one encapsulation method. In a preferred embodiment, the shell of the microcapsules may be, each independently, selected from the group of aminoplast, polyamide, polyester, polyurea and polyurethane shells and mixtures thereof. In a particular embodiment, the shell of the microcapsules comprises an aminoplast copolymer, such as melamine-formaldehyde or urea-formaldehyde or cross-linked melamine formaldehyde or melamine glyoxal. In a particular embodiment, the shell of the microcapsules is polyurea-based made from, for example but not limited to isocyanate-based monomers and amine-containing crosslinkers Firmenich SA such as guanidine carbonate and / or guanazole. Certain polyurea microcapsules comprise a polyurea wall which is the reaction product of the polymerization between at least one polyisocyanate comprising at least two isocyanate functional groups and at least one reactant selected from the group consisting of an amine (for example a water-soluble guanidine salt and guanidine); a colloidal stabilizer or emulsifier; and an encapsulated perfume. However, the use of an amine can be omitted. In a particular embodiment, the colloidal stabilizer includes an aqueous solution of between 0.1% and 0.4% of polyvinyl alcohol, between 0.6% and 1% of a cationic copolymer of vinylpyrrolidone and of a quaternized vinylimidazol (all percentages being defined by weight relative to the total weight of the colloidal stabilizer). In a particular embodiment, the emulsifier is an anionic or amphiphilic biopolymer, which may be for example chosen from the group consisting of Gum Arabic, soy protein, gelatin, sodium caseinate and mixtures thereof. In a particular embodiment, the shell of the microcapsules is polyurethane-based made from, for example but not limited to polyisocyanate and polyols, polyamide, polyester, etc. In a particular embodiment, the microcapsules have a polymeric shell resulting from complex coacervation wherein the shell is possibly cross-linked. In a particular embodiment of the core-shell microcapsules, the core-shell microcapsules comprise an oil-based core comprising a hydrophobic active, preferably at least one compound of formula (I), and a composite shell comprising a first material and a second material, wherein the first material and the second material are different, the first material is a coacervate, the second material is a polymeric material. In a particular embodiment, the weight ratio between the first material and the second material is comprised between 50:50 and 99.9:0.1. In a particular embodiment, the coacervate comprises a first polyelectrolyte, preferably selected among proteins (such as gelatin), polypeptides or polysaccharides (such as chitosan), most preferably gelatin and a second polyelectrolyte, preferably alginate salts, cellulose derivatives, guar gum, pectinate salts, carrageenan, polyacrylic and methacrylic acid or xanthan gum, or yet plant gums such as acacia gum (Gum Arabic), most preferably Gum Arabic. The first coacervate material can be hardened chemically using a suitable cross-linker such as glutaraldehyde, glyoxal, formaldehyde, tannic acid or genipin or can be hardened enzymatically using an enzyme such as transglutaminase. The second polymeric material can be selected from the group consisting of polyurea, polyurethane, polyamide, polyester, polyacrylate, polysiloxane, polycarbonate, Firmenich SA polysulfonamide, polymers of urea and formaldehyde, melamine and formaldehyde, melamine and urea, or melamine and glyoxal and mixtures thereof, preferably polyurea and / or polyurethane. The second material is preferably present in an amount less than 3% w / w, preferably less than 1% w / w based on the total weight of the microcapsule slurry. The preparation of an aqueous dispersion / slurry of core-shell microcapsules is well known by a skilled person in the art. In a particular embodiment, the microcapsule wall material may comprise any suitable resin and especially including melamine, glyoxal, polyurea, polyurethane, polyamide, polyester, etc. Suitable resins include the reaction product of an aldehyde and an amine, suitable aldehydes include formaldehyde and glyoxal. Suitable amines include melamine, urea, benzoguanamine, glycoluril, and mixtures thereof. Suitable melamines include, methylol melamine, methylated methylol melamine, imino melamine and mixtures thereof. Suitable ureas include, dimethylol urea, methylated dimethylol urea, urea-resorcinol, and mixtures thereof. Suitable materials for making may be obtained from one or more of the following companies Solutia Inc. (St Louis, Missouri U.S.A.), Cytec Industries (West Paterson, New Jersey U.S.A.), Sigma-Aldrich (St. Louis, Missouri U.S.A.). In a particular embodiment of the core-shell microcapsules, the core-shell microcapsule comprises - an oil-based core comprising a hydrophobic active, preferably comprising at least one compound of formula (I), - optionally an inner shell made of a polymerized polyfunctional monomer; - a biopolymer shell comprising a protein, wherein at least one protein is cross- linked. According to a particular embodiment, the protein is chosen from the group consisting of milk proteins, caseinate salts such as sodium caseinate or calcium caseinate, casein, whey protein, hydrolyzed proteins, gelatins, gluten, pea protein, soy protein, silk protein and mixtures thereof, preferably sodium caseinate. According to a particular embodiment, the protein comprises sodium caseinate and a globular protein, preferably chosen from the group consisting of whey protein, beta- lactoglobulin, ovalbumine, bovine serum albumin, vegetable proteins, and mixtures thereof. The protein is preferably a mixture of sodium caseinate and whey protein. According to a particular embodiment, the biopolymer shell comprises a crosslinked protein chosen from the group consisting of sodium caseinate and / or whey protein. According to a particular embodiment, the microcapsule slurry comprises at least one Firmenich SA microcapsule made of: - an oil-based core comprising the hydrophobic active, preferably comprising at least one compound of formula (I); - an inner shell made of a polymerized polyfunctional monomer; preferably a polyisocyanate having at least two isocyanate functional groups - a biopolymer shell comprising a protein, wherein at least one protein is cross- linked; wherein the protein contains preferably a mixture comprising sodium caseinate and a globular protein, preferably whey protein. - optionally at least an outer mineral layer. According to an embodiment, sodium caseinate and / or whey protein is (are) cross-linked protein(s). The weight ratio between sodium caseinate and whey protein is preferably comprised between 0.01 and 100, preferably between 0.1 and 10, more preferably between 0.2 and 5. In a particular embodiment, the microcapsule is a one-shell aminoplast core-shell microcapsule obtainable by a process comprising the steps of: 1) admixing a perfume oil with at least a polyisocyanate having at least two isocyanate functional groups to form an oil phase; 2) dispersing or dissolving into water an aminoplast resin and optionally a stabilizer to form a water phase; 3) preparing an oil-in-water dispersion, wherein the mean droplet size is comprised between 1 and 100 microns, by admixing the oil phase and the water phase; 4) performing a curing step to form the wall of said microcapsule; and 5) optionally drying the final dispersion to obtain the dried core-shell microcapsule. In a particular embodiment, the core-shell microcapsule is a formaldehyde-free capsule. A typical process for the preparation of an aminoplast formaldehyde-free microcapsule slurry comprises the steps of 1) preparing an oligomeric composition comprising the reaction product of, or obtainable by reacting together: a. a polyamine component in the form of melamine or of a mixture of melamine and at least one C1-C4compound comprising two NH2functional groups; b. an aldehyde component in the form of a mixture of glyoxal, a C4-62,2- dialkoxy-ethanal and optionally a glyoxalate, said mixture having a molar ratio glyoxal / C4-6 Firmenich SA 2,2-dialkoxy-ethanal comprised between 1 / 1 and 10 / 1; and c. a protic acid catalyst; 2) preparing an oil-in-water dispersion, wherein the droplet size is comprised between 1 and 600 microns, and comprising: a. an oil; b. a water medium: c. at least an oligomeric composition as obtained in step 1; d. at least a cross-linker selected amongst: i. C4-C12aromatic or aliphatic di- or tri-isocyanates and their biurets, triurets, trimmers, trimethylol propane-adduct and mixtures thereof; and / or ii. a di- or tri-oxiran compounds of formula: Q-(oxiran-2-ylmethyl)m wherein m stands for 2 or 3 and Q represents a C2-C6group optionally comprising from 2 to 6 nitrogen and / or oxygen atoms; e. optionally a C1-C4compound comprising two NH2functional groups; 3) heating the dispersion; and 4) cooling the dispersion. The above process is described in more detail in WO 2013 / 068255. In a particular embodiment of the core-shell microcapsules, the core-shell microcapsule is a polyamide core-shell polyamide microcapsule comprising: - an oil based core comprising an hydrophobic active, preferably comprising at least one compound of formula (I), and - a polyamide shell comprising or being obtainable from: • an acyl chloride, • a first amino compound, and • a second amino compound. According to a particular embodiment, the polyamide core-shell microcapsule comprises: an oil-based core comprising a hydrophobic active, preferably comprising at least one compound of formula (I), and a polyamide shell comprising or being obtainable from: • an acyl chloride, preferably in an amount comprised between 5 and 98%, preferably between 20 and 98%, more preferably between 30 and 85% w / w, Firmenich SA • a first amino compound, preferably in an amount comprised between 1% and 50% w / w, preferably between 7 and 40% w / w; • a second amino compound, preferably in an amount comprised between 1% and 50% w / w, preferably between 2 and 25% w / w, • a stabilizer, preferably a biopolymer, preferably in an amount comprised between 0 and 90%, preferably between 0.1 and 75%, more preferably between 1 and 70%. According to a particular embodiment, the polyamide core-shell microcapsule comprises: - an oil-based core comprising a hydrophobic active, preferably comprising at least one compound of formula (I), and - a polyamide shell comprising or being obtainable from: • an acyl chloride, • a first amino-compound being an amino-acid, preferably chosen from the group consisting of L-Lysine, L-Arginine, L-Histidine, L-Tryptophane and / or mixture thereof. • a second amino compound chosen from the group consisting of ethylene diamine, diethylene triamine, cystamine and / or mixture thereof, and • a biopolymer chosen from the group consisting of casein, sodium caseinate, bovin serum albumin, whey protein, and / or mixture thereof. The first amino-compound can be different from the second amino-compound. Typically, a process for preparing a polyamide-based micrcoapsule includes the following steps: a) dissolving at least one acyl chloride in a hydrophobic material, preferably a perfume to form an oil phase; b) dispersing the oil phase obtained in step a) into a water phase comprising a first amino compound to form an oil-in water emulsion; c) performing a curing step to form polyamide microcapsules in the form of a slurry; wherein a stabilizer is added in the oil phase and / or in the water phase, and wherein at least a second amino-compound is added in the water phase before the formation of the oil-in-water emulsion and / or in the oil-in water emulsion obtained after step b). In a particular embodiment, the shell of the microcapsule is polyurea-or polyurethane- based. Examples of processes for the preparation of polyurea and polyureathane-based microcapsule slurries are for instance described in WO 2007 / 004166, EP 2300146, and EP 2579976. Typically, a process for the preparation of polyurea or polyurethane-based Firmenich SA microcapsule slurries includes the following steps: a) dissolving at least one polyisocyanate having at least two isocyanate groups in an oil to form an oil phase; b) preparing an aqueous solution of an emulsifier or colloidal stabilizer to form a water phase; c) adding the oil phase to the water phase to form an oil-in-water dispersion, wherein the mean droplet size is comprised between 1 and 500 µm, preferably between 5 and 50 µm; and d) applying conditions sufficient to induce interfacial polymerization and form microcapsules in form of a slurry. In a particular embodiment, the microcapsules can be in form of a powder, which in particular may be obtained by submitting the microcapsule slurry to a drying step, like spray- drying, to provide the microcapsules as such, i.e. in a powdery form. It is understood that any standard method known by a person skilled in the art to perform such drying is also applicable. In particular, the slurry may be spray-dried, preferably in the presence of a polymeric carrier material such as polyvinyl acetate, polyvinyl alcohol, dextrins, natural or modified starch, gum Arabic, vegetable gums, pectins, xanthans, alginates, carrageenans or cellulose derivatives to provide microcapsules in a powder form. However, one may also cite other drying methods such as extrusion, plating, spray granulation, the fluidized bed process, or even drying at room temperature using materials (carriers, desiccants) that meet specific criteria as disclosed in WO 2017 / 134179. In another aspect, the present invention relates to a method to confer, enhance, improve or modify the odor properties of a perfuming composition, the air surrounding the perfuming composition, a surface or a perfumed article, comprising adding to the composition, the air, or article, or contacting or treating the surface with an effective amount of at least one compound of formula (I) as defined above. The term “surface”, as used herein may refer to a user’s skin, hair, a textile, or hard surface, on to which, a perfume composition comprising or containing the at least one compound of formula (I) is applied. In another aspect, the present invention relates to a method for intensifying or prolonging the diffusion effect of the characteristic fragrance of an aldehyde or a ketone of formula (II) as defined above, on a surface or the air surrounding the perfuming composition, wherein the surface, or the air is treated with at least one compound (I) as defined above, or Firmenich SA with a composition or article containing at least one compound (I), under conditions susceptible of allowing the release of a an aldehyde or a ketone of formula (II) over time. Another object of the present invention is the use of the above-described compounds of formula (I) as delivery system to release perfuming compounds; i.e. use of a compound of formula (I) as defined above as perfuming ingredient to provide a long-lasting odor / effect. In other words, it concerns a method to confer, enhance, improve or modify the odor properties of a perfuming composition, the air surrounding the perfuming composition, a surface or a perfumed article, which method comprises adding to said composition, or article, or contacting or treating the surface with an effective amount of at least one compound of formula (I) as defined above. By “use of an invention’s compound” it has to be understood here also the use of any composition containing said compounds and which can be advantageously employed in perfumery industry as active ingredients. The term “surface”, as used herein may refer to a user’s skin, hair, a textile, or hard surface, on to which, a perfume composition comprising or containing the at least one compound of formula (I) is applied. For sake of clarity, a long-lasting effect is typically achieved if, after a certain time, e.g. after several hours or days, a given compound emits higher amounts of an odor into the environment than a reference compound. Whether a long-lasting odor effect is achieved can be verified by demonstrating that a given compound emits at a given time point higher headspace concentrations of a perfuming ingredient into the environment than an equimolar amount of the corresponding ingredient (reference), or by comparing the odor intensity that a given compound emits at a given time point with respect to a comparable amount of the reference in an olfactive panel evaluation. Said compositions, which in fact can be advantageously employed as perfuming ingredient, are also an object of the present invention. Therefore, another object of the present invention is a perfuming composition comprising: i) as perfuming ingredient, at least one of the invention’s compounds of formula (I) as defined above; ii) at least one ingredient selected from the group consisting of a perfumery carrier and a perfumery base; and iii) optionally at least one perfumery adjuvant. By “perfumery carrier” it is meant here a material which is practically neutral from a Firmenich SA perfumery point of view, i.e. that does not significantly alter the organoleptic properties of perfuming ingredients. Said carrier may be a liquid or a solid. As liquid carrier one may cite, as non-limiting examples, an emulsifying system, i.e. a solvent and a surfactant system, or a solvent commonly used in perfumery. A detailed description of the nature and type of solvents commonly used in perfumery cannot be exhaustive. However, one can cite as non-limiting examples, solvents such as butylene or propylene glycol, glycerol, dipropyleneglycol and its monoether, 1,2,3-propanetriyl triacetate, dimethyl glutarate, dimethyl adipate 1,3-diacetyloxypropan-2-yl acetate, diethyl phthalate, isopropyl myristate, Abalyn®(rosin resins, available from Eastman), benzyl benzoate, benzyl alcohol, 2-(2-ethoxyethoxy)-1-ethano, tri-ethyl citrate or mixtures thereof, which are the most commonly used or also naturally derived solvents like glycerol or various vegetable oils such as palm oil, sunflower oil or linseed oil. For the compositions which comprise both a perfumery carrier and a perfumery base, other suitable perfumery carriers than those previously specified, can be also ethanol, water / ethanol mixtures, limonene or other terpenes, isoparaffins such as those known under the trademark Isopar (origin: Exxon Chemical) or glycol ethers and glycol ether esters such as those known under the trademark Dowanol (origin: Dow Chemical Company), or hydrogenated castor oils such as those known under the trademark Cremophor RH 40 (origin: BASF). Solid carrier is meant to designate a material to which the perfuming composition or some element of the perfuming composition can be chemically or physically bound. In general, such solid carriers are employed either to stabilize the composition, or to control the rate of evaporation of the compositions or of some ingredients. Solid carriers are of current use in the art and a person skilled in the art knows how to reach the desired effect. However, by way of non-limiting example of solid carriers, one may cite absorbing gums or polymers or inorganic material, such as porous polymers, cyclodextrins, dextrins, maltodextrins, wood-based materials, organic or inorganic gels, clays, gypsum, talc or zeolites. As other non-limiting examples of solid carriers, one may cite encapsulating materials. Examples of such materials may comprise wall-forming and plasticizing materials, such as glucose syrups, natural or modified starches, hydrocolloids, cellulose derivatives, polyvinyl acetates, polyvinylalcohols, proteins or pectins, plant gums such as acacia gum (Gum Arabic), urea, sodium chloride, sodium sulfate, sodium carbonate, sodium bicarbonate, calcium carbonate, magnesium sulfate, calcium sulfate, magnesium oxide, zinc oxide, titanium dioxide, calcium chloride, potassium chloride, magnesium chloride, zinc chloride, carbohydrates, Firmenich SA saccharides such as sucrose, mono-, di-, tri- and polysaccharides and derivatives such as chitosan, starch, cellulose, carboxymethyl methylcellulose, methylcellulose, hydroxyethyl cellulose, ethyl cellulose, propyl cellulose, polyols / sugar alcohols such as sorbitol, maltitol, xylitol, erythritol and isomalt, polyethylene glycol (PEG), polyvinyl pyrrolidin (PVP), polyvinyl alcohol, acrylamides, acrylates, polyacrylic acid and related structures, maleic anhydride copolymers, amine-functional polymers, vinyl ethers, styrenes, polystyrenesulfonates, vinyl acids, ethylene glycol-propylene glycol block copolymers, pectins, xanthanes, alginates, carragenans, citric acid or any water soluble solid acid, fatty alcohols or fatty acids and mixtures thereof, or yet the materials cited in reference texts such as H. Scherz, Hydrokolloide: Stabilisatoren, Dickungs- und Geliermittel in Lebensmitteln, Band 2 der Schriftenreihe Lebensmittelchemie, Lebensmittelqualität, Behr's Verlag GmbH & Co., Hamburg, 1996. The encapsulation is a well-known process to a person skilled in the art, and may be performed, for instance, by using techniques such as spray-drying, agglomeration or yet extrusion; or consists of a coating encapsulation, including coacervation and complex coacervation techniques. As non-limiting examples of solid carriers, one may cite in particular the core-shell capsules with resins of aminoplast, polyamide, polyester, polyurea or polyurethane type or a mixture thereof (all of said resins are well known to a person skilled in the art) using techniques like phase separation process induced by polymerization, interfacial polymerization, coacervation or altogether (all of said techniques have been described in the prior art), optionally in the presence of a polymeric stabilizer or of a cationic copolymer. Resins may be produced by the polycondensation of an aldehyde (e.g. formaldehyde, 2,2-dimethoxyethanal, glyoxal, glyoxylic acid or glycolaldehyde and mixtures thereof) with an amine such as urea, benzoguanamine, glycouryl, melamine, methylol melamine, methylated methylol melamine, guanazole and the like, as well as mixtures thereof. Alternatively, one may use preformed resins alkylolated polyamines such as those commercially available under the trademark Urac®(origin: Cytec Technology Corp.), Cymel®(origin: Cytec Technology Corp.), Urecoll®or Luracoll®(origin: BASF). Other resins are those produced by the polycondensation of an a polyol, like glycerol, and a polyisocyanate, like a trimer of hexamethylene diisocyanate, a trimer of isophorone diisocyanate or xylene diisocyanate or a Biuret of hexamethylene diisocyanate or a trimer of xylene diisocyanate with trimethylolpropane (known with the tradename of Takenate®, origin: Mitsui Chemicals), among which a trimer of xylene diisocyanate with trimethylolpropane and Firmenich SA a Biuret of hexamethylene diisocyanate are preferred. Some of the seminal literature related to the encapsulation of perfumes by polycondensation of amino resins, namely melamine-based resins with aldehydes includes articles such as those published by K. Dietrich et al. Acta Polymerica, 1989, Vol.40, pages 243, 325 and 683, as well as 1990, Vol. 41, page 91. Such articles already describe the various parameters affecting the preparation of such core-shell microcapsules following prior art methods that are also further detailed and exemplified in the patent literature. US 4'396'670, to the Wiggins Teape Group Limited, is a pertinent early example of the latter. Since then, many other authors have enriched the literature in this field and it would be impossible to cover all published developments here, but the general knowledge in encapsulation technology is very significant. More recent publications of pertinence, which disclose suitable uses of such microcapsules, are represented for example by the article of K. Bruyninckx and M. Dusselier, ACS Sustainable Chemistry & Engineering, 2019, Vol.7, pages 8041-8054. By “perfumery base” what is meant here is a composition comprising at least one perfuming co-ingredient. The perfuming co-ingredient is not a compound according to the invention. Moreover, by the term “perfuming co-ingredient” is meant a perfuming ingredient as defined above. The nature and type of the perfuming co-ingredients present in the base do not warrant a more detailed description here, which in any case would not be exhaustive, the skilled person being able to select them on the basis of general knowledge and according to intended use or application and the desired organoleptic effect. In general terms, these perfuming co-ingredients belong to chemical classes as varied as alcohols, lactones, aldehydes, ketones, esters, ethers, acetates, nitriles, thiols, terpene hydrocarbons, nitrogenous or sulfurous heterocyclic compounds and essential oils, and the perfuming co-ingredients can be of natural or synthetic origin. In particular, one may cite perfuming co-ingredients which are commonly used in perfume formulations, such as: - Aldehydic ingredients: decanal, dodecanal, 2-methylundecanal, 10-undecenal, octanal, nonanal and / or nonenal; - Aromatic-herbal ingredients: eucalyptus oil, camphor, eucalyptol, 5- methyltricyclo[6.2.1.02,7]undecan-4-one, 1-methoxy-3-hexanethiol, 2-ethyl-4,4- dimethyl-1,3-oxathiane, 2,2,7 / 8,9 / 10-tetramethylspiro[5.5]undec-8-en-1-one, menthol and / or alpha-pinene; - Balsamic ingredients: ethylvanillin and / or vanillin; Firmenich SA - Citrus ingredients: dihydromyrcenol, citral, orange oil, linalyl acetate, citronellyl nitrile, orange terpenes, limonene, 1-p-menthen-8-yl acetate and / or 1,4(8)-p-menthadiene; - Floral ingredients: methyl dihydrojasmonate, linalool, citronellol, phenylethanol, 3-(4- tert-butylphenyl)-2-methylpropanal, benzyl acetate, benzyl salicylate, tetrahydro-2- isobutyl-4-methyl-4(2H)-pyranol, beta ionone, (E)-3-methyl-4-(2,6,6-trimethyl-2- cyclohexen-1-yl)-3-buten-2-one, (1E)-1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-1-penten- 3-one, (2E)-1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-2-buten-1-one, (2E)-1-[2,6,6- trimethyl-3-cyclohexen-1-yl]-2-buten-1-one, (2E)-1-(2,6,6-trimethyl-1-cyclohexen-1- yl)-2-buten-1-one, 2,5-dimethyl-2-indanmethanol, 2,6,6-trimethyl-3-cyclohexene-1- carboxylate, 3-(4,4-dimethyl-1-cyclohexen-1-yl)propanal, hexyl salicylate, 3,7-dimethyl- 1,6-nonadien-3-ol, 3-(4-isopropylphenyl)-2-methylpropanal, verdyl acetate, geraniol, p- menth-1-en-8-ol, 4-(1,1-dimethylethyl)-1-cyclohexyle acetate, 1,1-dimethyl-2- phenylethyl acetate, 4-cyclohexyl-2-methyl-2-butanol, amyl salicylate , high cis methyl dihydrojasmonate, 3-methyl-5-phenyl-1-pentanol, verdyl proprionate, geranyl acetate, tetrahydro linalool, cis-7-p-menthanol, propyl (S)-2-(1,1-dimethylpropoxy)propanoate, 2,2,2-trichloro-1-phenylethyl acetate, 4 / 3-(4-hydroxy-4-methylpentyl)-3-cyclohexene-1- carbaldehyde, 8-decen-5-olide, 4-phenyl-2-butanone, isononyle acetate, 4-(1,1- dimethylethyl)-1-cyclohexyl acetate, verdyl isobutyrate and / or mixture of methylionone isomers; - Fruity ingredients: gamma-undecalactone, 2,2,5-trimethyl-5-pentylcyclopentanone, 2- methyl-4-propyl-1,3-oxathiane, 4-decanolide, ethyl 2-methyl-pentanoate, hexyl acetate, ethyl 2-methylbutanoate, gamma-nonalactone, allyl heptanoate, 2-phenoxyethyl isobutyrate, ethyl 2-methyl-1,3-dioxolane-2-acetate, 3-(3,3 / 1,1-dimethyl-5- indanyl)propanal, diethyl 1,4-cyclohexanedicarboxylate, 3-methyl-2-hexen-1-yl acetate, oct-2-en-4-one, 4-(4-hydroxyphenyl)-2-butanone, 1-[3,3-dimethylcyclohexyl]ethyl [3- ethyl-2-oxiranyl]acetate and / or diethyl 1,4-cyclohexane dicarboxylate; - Green ingredients: 2-methyl-3-hexanone (E)-oxime, 2,4-dimethyl-3-cyclohexene-1- carbaldehyde, 2-tert-butyl-1-cyclohexyl acetate, styrallyl acetate, allyl (2- methylbutoxy)acetate, 4-methyl-3-decen-5-ol, diphenyl ether, (Z)-3-hexen-1-ol and / or 1- (5,5-dimethyl-1-cyclohexen-1-yl)-4-penten-1-one; - Musk ingredients: 1,4-dioxa-5,17-cycloheptadecanedione, (Z)-4-cyclopentadecen-1-one, 3-methylcyclopentadecanone, 1-oxa-12-cyclohexadecen-2-one, 1-oxa-13- cyclohexadecen-2-one, (9Z)-9-cycloheptadecen-1-one, 2-{1S)-1-[(1R)-3,3- Firmenich SA dimethylcyclohexyl]ethoxy}-2-oxoethyl propionate 3-methyl-5-cyclopentadecen-1-one, 4,6,6,7,8,8-hexamethyl-1,3,4,6,7,8-hexahydrocyclopenta[g]isochromene, (1S,1'R)-2-[1- (3',3'-dimethyl-1'-cyclohexyl)ethoxy]-2-methylpropyl propanoate, oxacyclohexadecan- 2-oneand / or (1S,1'R)-[1-(3',3'-dimethyl-1'-cyclohexyl)ethoxycarbonyl]methyl propanoate; - Woody ingredients: 1-[(1RS,6SR)-2,2,6-trimethylcyclohexyl]-3-hexanol, 3,3-dimethyl- 5-[(1R)-2,2,3-trimethyl-3-cyclopenten-1-yl]-4-penten-2-ol, 3,4'-dimethylspiro[oxirane- 2,9'-tricyclo[6.2.1.02,7]undec[4]ene, (1-ethoxyethoxy)cyclododecane, 2,2,9,11- tetramethylspiro[5.5]undec-8-en-1-yl acetate, 1-(octahydro-2,3,8,8-tetramethyl-2- naphtalenyl)-1-ethanone, patchouli oil, terpenes fractions of patchouli oil, Clearwood®, (1'R,E)-2-ethyl-4-(2',2',3'-trimethyl-3'-cyclopenten-1'-yl)-2-buten-1-ol, 2-ethyl-4-(2,2,3- trimethyl-3-cyclopenten-1-yl)-2-buten-1-ol, methyl cedryl ketone, 5-(2,2,3-trimethyl-3- cyclopentenyl)-3-methylpentan-2-ol, 1-(2,3,8,8-tetramethyl-1,2,3,4,6,7,8,8a- octahydronaphthalen-2-yl)ethan-1-one and / or isobornyl acetate; - Other ingredients (e.g. amber, powdery spicy or watery): dodecahydro-3a,6,6,9a- tetramethyl-naphtho[2,1-b]furan and any of its stereoisomers, heliotropin, anisic aldehyde, eugenol, cinnamic aldehyde, clove oil, 3-(1,3-benzodioxol-5-yl)-2- methylpropanal, 7-methyl-2H-1,5-benzodioxepin-3(4H)-one, 2,5,5-trimethyl- 1,2,3,4,4a,5,6,7-octahydro-2-naphthalenol, 1-phenylvinyl acetate, 6-methyl-7-oxa-1- thia-4-azaspiro[4.4]nonan and / or 3-(3-isopropyl-1-phenyl)butanal. A composition according to the invention may not be limited to the above-mentioned perfuming co-ingredients, and many other of these co-ingredients are in any case listed in reference texts such as the book by S. Arctander, Perfume and Flavor Chemicals, 1969, Montclair, New Jersey, USA, or its more recent versions, or in other works of a similar nature, as well as in the abundant patent literature in the field of perfumery. It is also understood that said co-ingredients may also be compounds known to release in a controlled manner various types of perfuming ingredients also known as properfumes or profragrances. Non-limiting examples of suitable properfumes may include 4-(dodecylthio)-4-(2,6,6-trimethyl-2- cyclohexen-1-yl)-2-butanone, 4-(dodecylthio)-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2- butanone, 3-(dodecylthio)-1-(2,6,6-trimethyl-3-cyclohexen-1-yl)-1-butanone, 3- (dodecylsulfonyl)-1-(2,6,6-trimethylcyclohex-3-en-1-yl)butan-1-one, a linear polysiloxane co- polymer of (3-mercaptopropyl)(methyl)dimethoxysilane, typically comprising at least one 2- (3-((2-methyl-3-oxo-5-(prop-1-en-2-yl)cyclohexyl)thio)propyl side chain; 3-(dodecylthio)-1- Firmenich SA (6-ethyl-2,6-dimethylcyclohex-3-en-1-yl)butan-1-one, 2-(dodecylthio)octan-4-one, 2- (dodecylsulfonyl)octan-4-one, 4-oxooctan-2-yl dodecanoate, 2-phenylethyl oxo(phenyl)acetate, 3,7-dimethylocta-2,6-dien-1-yl oxo(phenyl)acetate, (Z)-hex-3-en-1-yl oxo(phenyl)acetate, 3,7-dimethyl-2,6-octadien-1-yl hexadecanoate, bis(3,7-dimethylocta-2,6- dien-1-yl) succinate, (2E,6Z)- nona-2,6-dien-1-yl tetradecanoate, (2E,6Z)-nona-2,6-dien-1-yl dodecanoate, (2E,6Z)-nona-2,6-dien-1-yl hexadecanoate, (2-((2-methylundec-1-en-1- yl)oxy)ethyl)benzene, 1-methoxy-4-(3-methyl-4-phenethoxybut-3-en-1-yl)benzene, (3- methyl-4-phenethoxybut-3-en-1-yl)benzene, 1-(((Z)-hex-3-en-1-yl)oxy)-2-methylundec-1- ene, (2-((2-methylundec-1-en-1-yl)oxy)ethoxy)benzene, 2-methyl-1-(octan-3-yloxy)undec-1- ene, 1-methoxy-4-(1-phenethoxyprop-1-en-2-yl)benzene, 1-methyl-4-(1-phenethoxyprop-1- en-2-yl)benzene, (2-phenethoxyvinyl)benzene, (2-((2- pentylcyclopentylidene)methoxy)ethyl)benzene, 4-allyl-2-methoxy-1-((2-methoxy-2- phenylvinyl)oxy)benzene, (2-((2-heptylcyclopentylidene)methoxy)ethyl)benzene, 1-methoxy- 4-(1-phenethoxyprop-1-en-2-yl)benzene, (2-((2-methyl-4-(2,6,6-trimethylcyclohex-1-en-1- yl)but-1-en-1-yl)oxy)ethyl)benzene, 1-methoxy-4-(2-methyl-3-phenethoxyallyl)benzene, (2- ((2-isopropyl-5-methylcyclohexylidene)methoxy)ethyl)benzene, 1-isopropyl-4-methyl-2-((2- pentylcyclopentylidene)methoxy)benzene, 2-methoxy-1-((2- pentylcyclopentylidene)methoxy)-4-propylbenzene, 3-methoxy-4-((2-methoxy-2- phenylvinyl)oxy)benzaldehyde, 1-isopropyl-2-((2-methoxy-2-phenylvinyl)oxy)-4- methylbenzene, 4-((2-(hexyloxy)-2-phenylvinyl)oxy)-3-methoxybenzaldehyde, 3-methyl-5- phenylpentyl hexadecanoate, 3-(dodecylthio)-2-methyl-1-(2,6,6-trimethylcyclohex-3-en-1- yl)butan-1-one, 3,5-bis(1-(4-isopropylphenyl)propan-2-yl)dihydro-1H,3H,5H-oxazolo[3,4- c]oxazole, 3,5-di(undecan-2-yl)dihydro-1H,3H,5H-oxazolo[3,4-c]oxazole, 3,5-bis(2,4- dimethylcyclohex-3-en-1-yl)dihydro-1H,3H,5H-oxazolo[3,4-c]oxazole, ethyl 2-acetyl-4- methyltridec-2-enoate, dec-9-en-1-yl (E)-3-(2-hydroxyphenyl)acrylate, 4-(dodecylthio)-4- methylpentan-2-one, methyl or ethyl N,S-bis(4-oxo-4-(2,6,6-trimethylcyclohex-3-en-1- yl)butan-2-yl)-L-cysteinate, 1-butoxy-3-((1E,4Z)-hepta-1,4-dien-1-yl)benzene, 2-methoxy-4- ((1E,4Z)-hepta-1,4-dien-1-yl)phenol, 2-ethoxy-4-((1E,4Z)-hepta-1,4-dien-1-yl)phenol, 1- methoxy-4-(3-phenylprop-1-en-1-yl)benzene or a mixture thereof. In a particular embodiment, the perfuming composition according to the invention comprises a perfumery adjuvant. The term “perfumery adjuvant” is understood as an ingredient capable of imparting additional added benefit such as a color, a particular light resistance, chemical stability, etc. A Firmenich SA detailed description of the nature and type of adjuvant commonly used in perfuming bases cannot be exhaustive, but it has to be mentioned that the ingredients are well known to a person skilled in the art. However, one may cite as specific non-limiting examples the following: viscosity agents (e.g. surfactants, thickeners, gelling and / or rheology modifiers), stabilizing agents (e.g. preservatives, antioxidants, heat / light and or buffers or chelating agents, such as BHT), coloring agents (e.g. dyes and / or pigments), preservatives (e.g. antibacterial or antimicrobial or antifungal or anti-irritant agents), abrasives, skin cooling agents, fixatives, insect repellants, ointments, vitamins and mixture thereof. By “fixative” also called “modulator”, it is understood here an agent having the capacity to affect the manner in which the odor, and in particular the evaporation rate and intensity, of the compositions incorporating said modulator can be perceived by an observer or user thereof, over time, as compared to the same perception in the absence of the modulator. In particular, the modulator allows prolonging the time during which their fragrance is perceived. Non-limiting examples of suitable modulators may include methyl glucoside polyol; ethyl glucoside polyol; propyl glucoside polyol; isocetyl alcohol; PPG-3 myristyl ether; neopentyl glycol diethylhexanoate; sucrose laurate; sucrose dilaurate, sucrose myristate, sucrose palmitate, sucrose stearate, sucrose distearate, sucrose tristearate, hyaluronic acid disaccharide sodium salt, sodium hyaluronate, propylene glycol propyl ether; dicetyl ether; polyglycerin-4 ethers; isoceteth-5; isoceteth-7, isoceteth-10; isoceteth-12; isoceteth-15; isoceteth-20; isoceteth-25; isoceteth-30; disodium lauroamphodipropionate; hexaethylene glycol monododecyl ether; and their mixtures; neopentyl glycol diisononanoate; cetearyl ethylhexanoate; panthenol ethyl ether, DL-panthenol, n-hexadecyl n-nonanoate, noctadecyl n-nonanoate, cyclodextrin, and a combination thereof. At most 20% by weight, based on the total weight of the perfuming composition, of the modulator may be incorporated into the perfumed consumer product. It is understood that a person skilled in the art is perfectly able to design optimal formulations for the desired effect by admixing the above-mentioned components of a perfuming composition, simply by applying the standard knowledge of the art as well as by trial-and-error methodologies. An invention’s composition consisting of at least one compound of formula (I) and at least one perfumery carrier consists of a particular embodiment of the invention as well as a perfuming composition comprising at least one compound of formula (I), at least one perfumery carrier, at least one perfumery base, and optionally at least one perfumery adjuvant. Firmenich SA According to a particular embodiment, the compositions mentioned above, comprise more than one compound of formula (I) and enable the perfumer to prepare accords or perfumes possessing the odor tonality of various compounds of the invention, creating thus new building block for creation purposes. For the sake of clarity, it is also understood that any mixture resulting directly from a chemical synthesis, e.g. a reaction medium without an adequate purification, in which the compound of the invention would be involved as a starting, intermediate or end-product could not be considered as a perfuming composition according to the invention as far as said mixture does not provide the inventive compound in a suitable form for perfumery. Thus, unpurified reaction mixtures are generally excluded from the present invention unless otherwise specified. The invention’s compound can also be advantageously used in all the fields of modern perfumery, i.e. fine or functional perfumery, to positively impart or modify the odor of a consumer product into which said compound (I) is added. Consequently, another object of the present invention consists of a perfumed consumer product comprising, as a perfuming ingredient, at least one compound of formula (I), as defined above. The invention’s compound can be added as such or as part of an invention’s perfuming composition. For the sake of clarity, it has to be mentioned that the term “perfumed consumer product” is understood as a consumer product, which is expected to deliver at least a pleasant perfuming effect to the surface to which it is applied (e.g. skin, hair, textile, or hard surface). In other words, a perfumed consumer product according to the invention is a perfumed consumer product, which comprises the inventive compound or perfuming composition, as well as optionally additional benefit agents, corresponding to the desired consumer product, e.g. a conditioner, a detergent or an air freshener, and an olfactorily effective amount of the perfuming composition according to the invention. For the sake of clarity, the perfuming consumer product is a non-edible product. The nature and type of the constituents of the perfuming consumer product do not warrant a more detailed description here, which in any case would not be exhaustive, the skilled person being able to select them on the basis of his general knowledge and according to the nature and the desired effect of the product. In a particular embodiment, the perfumed consumer product is a perfume, a fabric care product, a body-care product, a cosmetic preparation, a skin-care product, an air care product or a home care product. Firmenich SA Non-limiting examples of suitable perfumed consumer products include a perfume, such as a fine perfume, a splash or an eau de parfum, a cologne or a shave or after-shave lotion; a fabric care product, such as a liquid or solid detergent optionally in the form of a pod or tablet, a fabric softener, a fabric rinse, a liquid or solid scent booster, a dryer sheet, a fabric refresher, an ironing water, a paper, a bleach, a carpet cleaner, a curtain-care product; a body-care product, such as a hair care product (e.g. a shampoo, a leave-on or rinse-off hair conditioner, a coloring preparation or a hair spray, a color-care product, a hair shaping product, a dental care product), a disinfectant, an intimate care product; a cosmetic preparation (e.g. a skin cream or lotion, a vanishing cream or a deodorant or antiperspirant (e.g. a spray or roll on), a hair remover, a nail product, a skin cleansing, a makeup); or a skin-care product (e.g. a soap, a shower or bath mousse, oil or gel, or a hygiene product or a foot / hand care product); an air care product, such as an air freshener or a “ready to use” powdered air freshener which can be used in the home space (rooms, refrigerators, cupboards, shoes or car) and / or in a public space (halls, hotels, malls, etc..); or a home care product, such as a mold remover, a furniture care product, a wipe, a dish detergent or a hard-surface (e.g. a floor, bath, sanitary or a window-cleaning) detergent; a leather care product; a car care product, such as a car air-freshener, a polish, a wax or a plastic cleaner. Particularly, the perfumed consumer product may be a fabric care product, such as a liquid or solid detergent, a fabric softener, a liquid or solid scent booster, a dryer sheet, a fabric refresher, an ironing water, a hair care product (e.g. a shampoo, a leave-on or rinse-off hair conditioner), a disinfectant, an air care product, such as an air freshener, or a hard-surface detergent. More particularly, the perfumed consumer product may be a fabric care product, such as a liquid or solid detergent, a fabric softener, a liquid or solid scent booster, a dryer sheet, a fabric refresher, an ironing water, an air care product, such as an air freshener, or a hard-surface detergent. According to a particular embodiment, the invention’s perfumed consumer product is in the form of a personal care, a home care or fabric care consumer product comprising ingredients that are common in personal, home or fabric care consumer products, in particular shower gels, shampoos, soaps, fabric detergents or softeners and all-purpose cleaners. The main functional constituents of perfumed consumer products are surfactants and / or softener components capable of cleaning and / or softening fabrics and / or textiles of varied nature, such as clothes, curtain fabrics, carpets and furniture fabrics, etc., or other home surfaces, skin or hair, and typically used in a large amount of water or water-based solvents. These are therefore formulations wherein the amount of water is typically comprised between 50 and 99% by Firmenich SA weight of the perfumed consumer product with the exception of soaps or solid detergents, wherein the amount of water is at most 20%. A more detailed description of such fabric cleaning and / or softening formulations is not warranted here, many descriptions of current liquid formulations can be found in the cleaner / fabric softener’s patent and other pertinent literature, such as for example the textbook of Louis Ho Tan Tai, “Détergents et Produits de Soins Corporels, Chapters 1 to 7 in particular, Dunod, Paris, 1999, or any other similar and / or more recent textbooks pertaining to the art of liquid softener and all-purpose cleaners formulations. A patent publication, WO 2010 / 105873, is also cited by way of example, in as much as it describes typical current ingredients, other than perfumes, of such liquid products, particularly on pages 9 to 21. Of course, many other examples of liquid cleaner and / or fabric softener formulations can be found in the literature. Any such liquid formulations, namely liquid fabric cleaners or conditioners and / or all-purpose cleaners, can be used in the here-described compositions. Other examples of fabric detergents or softener compositions into which the compounds of the invention can be incorporated are described in WO 97 / 34986 or in US patents 4,137,180 and 5,236,615 or EP 799885. Other typical detergent and softening compositions which can be used are described in works such as Ullmann's Encyclopedia of Industrial Chemistry, Vol.20, Wiley-VCH, Weinheim, p.355-540 (2012); Flick, Advanced Cleaning Product Formulations, Noye Publication, Park Ridge, New Jersey (1989); Showell, in Surfactant Science Series, Vol. 71: Powdered Detergents, Marcel Dekker, New York (1988); Proceedings of the World Conference on Detergents (4th, 1998, Montreux, Switzerland), AOCS print. According to a particular embodiment of the invention, the invention’s perfumed consumer product may be a liquid fabric softener comprising at least one compound of formula (I) and a fabric softener active base in amount comprised between 85 and 100% by weight, based on the total weight of the perfumed consumer product. The main constituent of the fabric softener active base is water or water-based solvents. The fabric softener active base may comprise dialkyl quaternary ammonium salts, dialkyl ester quaternary ammonium salts, Hamburg esterquat, triethanolamine quat, silicones and mixtures thereof. Optionally, component a) of the composition may further comprise a viscosity modifier in an amount comprised between 0.05 and 1% by weight, based on the total weight of the liquid base; preferably chosen from the group consisting of calcium chloride. According to a particular embodiment of the invention, the invention’s consumer product is an all-purpose cleaner comprising at least one compound of formula (I) and an all- Firmenich SA purpose cleaner active base in amount comprised between 85 and 100% by weight, based on the total weight of the consumer product. The main constituent of the all-purpose cleaner active base is water or water-based solvents. The all-purpose active base may comprise linear alkylbenzene sulfonates (LAS) in an amount comprised between 0 and 4%, preferably 1 and 2%, nonionic surfactant in an amount comprised between 0 and 8%, preferably 2 and 4% and acid such as citric acid in an amount comprised between 0.1 and 0.5%. According to a particular embodiment of the invention, the invention’s consumer product is a liquid detergent comprising at least one compound of formula (I) and liquid detergent active base in amount comprised between 85 and 100% by weight, based on the total weight of the consumer product. The main constituent of the liquid detergent active base is water or water-based solvents. The liquid detergent active base may comprise anionic surfactants such as alkylbenzenesulfonates (ABS), linear alkylbenzene sulfonates (LAS), secondary alkyl sulfonates (SAS), primary alcohol sulfates (PAS), lauryl ether sulfates (LES), sodium lauryl ether sulfates (SLES), methyl ester sulfonates (MES); nonionic surfactants such as alkyl amines, alkanolamides, fatty alcohol ethoxylates (FAE), ethylene oxide (EO) and propylene oxide (PO) copolymers, amine oxides, alkyl polyglucosides, alkyl polyglucosamides; or mixtures thereof. According to a particular embodiment of the invention, the invention’s consumer product is a solid detergent comprising at least one compound of formula (I) and a solid detergent active base in amount comprised between 85 and 100% by weight, based on the total weight of the consumer product. The solid detergent active base may comprise at least one surfactant chosen from the group consisting of anionic, nonionic, cationic, zwitterionic surfactant and mixtures thereof. The surfactant in the solid detergent active base is preferably chosen from the group consisting of linear alkene benzene sulfonates (LABS), sodium laureth sulfate, sodium lauryl ether sulfates (SLES), sodium lauryl sulfate (SLS), alpha olefin sulfonates (AOS), methyl ester sulfonates (MES), alkyl polyglycosides (APG), primary alcohol ethoxylates and in particular lauryl alcohol ethoxylates (LAE), primary alcohol sulfonates (PAS), soap and mixtures thereof. The solid detergent active base may comprise a further component, commonly used in powder detergent consumer product, selected from the group consisting of bleaching agents such as EDTA (tetraacetylethylenediamine); buffering agent; builders such as zeolites, sodium carbonate or mixture thereof; soil release or soil suspension polymers; granulated enzyme particles such as cellulase, lipase, protease, mannanase, pectinase or mixtures thereof; corrosion inhibitor; antifoaming; sud suppressing agents; dyes; fillers such Firmenich SA as sodium silicate, sodium sulfate or mixture thereof; source of hydrogen peroxide such as sodium percarbonate or sodium perborate; and mixtures thereof. The proportions in which the perfuming composition according to the invention can be incorporated into the various aforementioned articles or compositions vary within a wide range of values. These values are dependent upon the nature of the article or product to be perfumed and on the desired olfactory effect as well as the nature of the co-ingredients in a given composition when the compounds according to the invention are mixed with perfuming co- ingredients, solvents or additives commonly used in the art. For example, in the case of perfuming compositions, typical concentrations are in the order of 0.001 % to 10 % by weight, or even more, of the compounds of the invention based on the weight of the composition into which they are incorporated. In the case of perfumed consumer products, typical concentrations are in the order of 0.0001 % to 1 % by weight, or even more, preferably between 0.05 % to 0.8 %, even more preferably between 0.1 % and 0.5 % of the compounds of the invention based on the weight of the consumer product into which they are incorporated. Another aspect of the invention concerns the use of a perfuming composition according to the invention for improving, enhancing, conferring and / or modifying the fragrance impression and / or fragrance intensity of a consumer product. Another aspect of the invention concerns a method for improving, enhancing, conferring and / or modifying the fragrance impression and / or fragrance intensity of a consumer product, comprising the step of adding the perfuming composition according to the invention to a consumer product. Moreover, the present invention relates to a compound of formula (I). So, another object of the invention is a compound of formula (Ia) or (Ib) in the form of any one of its stereoisomers or a mixture thereof, and wherein Firmenich SA R1, R6and R7, each independently, is a hydrogen atom or a C1 to C18 hydrocarbon group, optionally comprising one or more O or S atoms, R2is a hydrogen atom or a C1to C18hydrocarbon group, optionally comprising one or more N, O or S atoms, R3is a hydrogen atom or a C1to C4alkyl or alkenyl group, R4is a C1to C18hydrocarbon group, optionally comprising one or more N, O or S atoms, R5is a C3to C18hydrocarbon group, optionally comprising one or more O or S atoms, R8is methyl or ethyl, R1and R5, when taken together, form a cyclic C5to C14hydrocarbon group, optionally comprising one or two O atoms, R2and R3, when taken together, form a double bond, substituted with one or two hydrogen atoms or one or two C1to C12hydrocarbon groups, R3and R4, when taken together, form a five-, six-or seven-membered lactam or a five- or six- membered cyclic carbamate, R5and R6, when taken together, form a cyclic alkyl or alkenyl group, with the proviso that benzyl (1-(2,4-dibenzyl-5-oxooxazolidin-3-yl)-3-methyl-1-oxobutan-2- yl)carbamate, 2-(2-oxo-2-(2-oxo-1-oxa-4-azaspiro[4.5]decan-4-yl)ethyl)isoindoline-1,3-dione, benzyl 2-nonyl-5-oxooxazolidine-3-carboxylate, 2,4-dibenzyl-3-(3- methylbutanoyl)oxazolidin-5-one and benzyl 4-allyl-5-oxo-2-pentyloxazolidine-3-carboxylate are excluded. In an embodiment, the compound of formula (Ia) is a compound of formula (Ic) in the form of any one of its stereoisomers or a mixture thereof, and wherein R9, R10, R11and R12each independently, are a hydrogen atom or a methyl group, R13is a C1to C10hydrocarbon group, R9and R13, when taken together form a cyclohexenyl group, Firmenich SA R11and R13when taken together form a cyclohexenyl or a phenyl group, optionally substituted with one or several C1to C8hydrocarbon groups. Any of the definitions and embodiments, in particular any of the definitions of R and R1-R13, as described for the compound of formula (I) and (II) herein-above apply to the compounds of formula (Ia), (Ib) and (Ic) mutatis mutandis. In a particular embodiment, R2is a hydrogen atom, a phenyl group, a benzyl group, a cyclohexyl group or a C1to C10alkyl group optionally substituted by an amide, a guanidine, a thiol, a primary amine (i.e. NH2), a C1to C3thioether, preferably a SCH3group, a phenyl, a hydroxyphenyl, a carboxylic acid, a hydroxy or a C4 to C8 heterocycloalkenyl group, wherein the heteroatom is one or two nitrogen atoms, such as an imidazolyl or an indolyl group. In a particular embodiment, R2is a hydrogen atom, a phenyl group, a cyclohexyl group or a residue derived from an amino acid of formula R2CH(NH2)COOH, and in particular of a natural α-amino acid, such as S-alanine (R2= CH3), S-arginine [R2= (CH2)3NHC(NH)(NH2)], S-asparagine (R2= CH2CONH2), R-cysteine (R2= CH2SH), S-glutamine [R2= (CH2)2CONH2], glycine (R2= H), S-histidine [R2= CH2(C3N2H3)], S-isoleucine [R5= C(CH3)CH2CH3], S- leucine [R5= CH2CH(CH3)2], S-lysine [R5= (CH2)4NH2], S-methionine [R2= (CH2)2SCH3], S- phenylalanine (R2= CH2C6H5), S-serine (R2= CH2OH), S-threonine [R2= CH(OH)CH3], S- tryptophane [R2= CH2(C8H6N)], S-tyrosine (R2= CH2C6H4OH), S-valine [R2= CH(CH3)2], S- aspartic acid (R2= CH2COOH), and S-glutamic acid [R2= (CH2)2COOH], or of an artificial α- amino acid selected from the group of norleucine [R2= (CH2)3CH3], norvaline [R2= (CH2)2CH3], 2-phenylglycine (R2= C6H5), ornithine [R2= (CH2)3NH2], homoalanine (R2= CH2CH3), homocysteine [R2= (CH2)2SH], and homoserine [R2= (CH2)2OH]. In a particular embodiment, R3is a hydrogen atom. In a particular embodiment R4is a phenyl group, a benzyl group, a C1to C18alkyl, alkenyl or cycloalkyl group, a C1to C6alkoxy group or a benzyloxy group. In a particular embodiment, R4is a benzyl group or a C1to C18alkyl, alkenyl or cycloalkyl group. Firmenich SA In a particular embodiment, R3and R4taken together form a C4 to C5 lactam group (cyclic amide). In a particular embodiment, the compound of formula (Ia), (Ib) or (Ic) is 3-(undecan-2- yl)dihydro-1H,3H-pyrrolo[1,2-c]oxazole-1,5(6H)-dione, 3-acetyl-4-isobutyl-2-(undecan-2- yl)oxazolidin-5-one, 3-benzoyl-2-(undecan-2-yl)oxazolidin-5-one, 3-benzoyl-4-isobutyl-2- (undecan-2-yl)oxazolidin-5-one, 3-acetyl-2-(undecan-2-yl)oxazolidin-5-one, 3-acetyl-4- phenyl-2-(undecan-2-yl)oxazolidin-5-one, 3-acetyl-4-benzylidene-2-(undecan-2- yl)oxazolidin-5-one, 3-(2-phenylacetyl)-2-(undecan-2-yl)oxazolidin-5-one, 3-octanoyl-2- (undecan-2-yl)oxazolidin-5-one, 4-methyl-3-octanoyl-2-(undecan-2-yl)oxazolidin-5-one, 4- isopropyl-3-octanoyl-2-(undecan-2-yl)oxazolidin-5-one, 4-benzyl-3-octanoyl-2-(undecan-2- yl)oxazolidin-5-one, 2-nonyl-3-octanoyloxazolidin-5-one, 3-octanoyl-2-pentyloxazolidin-5- one, 3-octanoyl-2-phenethyloxazolidin-5-one, 2-(4-(tert-butyl)phenethyl)-3- octanoyloxazolidin-5-one, 2-(non-3-en-1-yl)-3-octanoyloxazolidin-5-one, 3-octanoyl-2- (undec-3-en-1-yl)oxazolidin-5-one, 3-octanoyl-2-(2-phenylpropyl)oxazolidin-5-one, 3- octanoyl-2-(1-(p-tolyl)propan-2-yl)oxazolidine-5-one, 2-(2-(4,4-dimethylcyclohex-1-en-1- yl)ethyl)-3-octanoyloxazolidin-5-one, 2-(4,8-dimethylnon-3-en-1-yl)-3-octanoyloxazolidin-5- one, 2-(6-methylhept-5-en-2-yl)-3-octanoyloxazolidin-5-one, 3-butyryl-2-(undecane-2- yl)oxazolidine-5-one, 3-butyryl-2-(2-(4,4-dimethylcyclohex-1-en-1-yl)ethyl)oxazolidin-5-one, 3-butyryl-2-(2,4-dimethylcyclohex-3-en-1-yl)oxazolidin-5-one, 3-butyryl-2-(dec-9-en-1- yl)oxazolidin-5-one, 3-butyryl-2-(4,8-dimethylnon-3-en-1-yl)oxazolidin-5-one, 3-butyryl-2- (6-methylhept-5-en-2-yl)oxazolidin-5-one, 3-isobutyryl-2-(undecane-2-yl)oxazolidine-5-one, 3-pivaloyl-2-(undecane-2-yl)oxazolidine-5-one, 2-(2-(4,4-dimethylcyclohex-1-en-1-yl)ethyl)- 3-(2-phenylacetyl)oxazolidin-5-one, 3-(2-phenylacetyl)-2-(undec-3-en-1-yl)oxazolidin-5-one, 2-(3-methyl-4-(4-methylphenyl)but-3-en-1-yl)-3-(2-phenylacetyl)oxazolidin-5-one, 2-(2-(1,1- and 3,3-dimethyl-2,3-dihydro-1H-inden-5- and 4-yl)ethyl)-3-(2-phenylacetyl)oxazolidin-5- one, 2-(2-(3-isopropylphenyl)propyl)-3-(2-phenylacetyl)oxazolidin-5-one, 2-nonyl-3-(2- phenylacetyl)oxazolidin-5-one, 2-(6-methylhept-5-en-2-yl)-3-(2-phenylacetyl)oxazolidin-5- one, 2-(4,8-dimethylnon-3-en-1-yl)-3-(2-phenylacetyl)oxazolidin-5-one, benzyl 5-oxo-2- (undecan-2-yl)oxazolidine-3-carboxylate, 2-(4-methoxyphenyl)-5-oxooxazolidine-3- carboxylate, 2-(5-cyclohexyl-4-methylpent-4-en-2-yl)-5-oxooxazolidine-3-carboxylate, 3-(2- phenoxyacetyl)-2-(undecane-2-yl)oxazolidine-5-one, 3-acetyl-4-methyl-2-(undecan-2- yl)oxazolidin-5-one, 3-butyryl-4-methyl-2-(undecan-2-yl)oxazolidin-5-one, 4-methyl-3- Firmenich SA octanoyl-2-(undec-3-en-1-yl)oxazolidin-5-one, 3-acetyl-4-isobutyl-2-phenethyloxazolidin-5- one, 3-acetyl-4-isobutyl-2-(non-3-en-1-yl)oxazolidin-5-one, 3-acetyl-4-benzyl-2-(undecan-2- yl)oxazolidin-5-one, 3-acetyl-4-(2-(methylthio)ethyl)-2-(undecan-2-yl)oxazolidin-5-one or 3- acetyl-4-isopropyl-2-(undecan-2-yl)oxazolidin-5-one or a mixture thereof. In a further aspect, the present invention also relates to the use of precursor compounds of formula (I) as described herein-above for releasing an aldehyde or a ketone of formula (II) as described herein-above. In a further aspect, the present invention relates to the use of at least one compound of formula (I) as defined above to confer, enhance, improve or modify the odor properties of a perfuming composition, the air surrounding the perfuming composition, a surface, or of a perfumed article, comprising adding to the composition or article or contacting or treating the surface with an effective amount of at least one compound of formula (I) as defined above. The term “surface”, as used herein may refer to a user’s skin, hair, a textile, or hard surface, on to which, a perfume composition comprising or containing the at least one compound of formula (I) is applied. In a further aspect, the present invention relates to the use of at least one compound of formula (I) as defined above for intensifying or prolonging the diffusion effect, and / or perception of the characteristic fragrance of an aldehyde or a ketone of formula (II) as defined above, on a surface, wherein the surface is treated with at least one compound of formula (I) as defined above, or with a composition or article containing the at least one compound of formula (I), under conditions susceptible of allowing the release of the aldehyde or a ketone of formula (II) over time. The compounds of formula (I) can be prepared according to standard methods known in the art as described herein-below. Examples The invention will now be described in further detail by way of the following examples, wherein the abbreviations have the usual meaning in the art, the temperatures are indicated in degrees centigrade (°C). Reactions were carried out in standard glassware under N2. Commercially available reagents and solvents were used without further purification. If not specified otherwise, NMR spectra were acquired in CDCl3at room temperature using either a Bruker Avance III spectrometer operating at 400 MHz (1H) and 100 MHz (13C), a Bruker Firmenich SA Avance III 500 operating at 500 MHz (1H) and 125.8 MHz (13C) or a Bruker Avance III 600 cryoprobe operating at 600 MHz (1H) and 150.9 MHz (13C). Spectra were internally referenced relative to tetramethyl silane (0.0 ppm).1H-NMR chemical shifts (^^^are expressed in ppm, coupling constants (J) are indicated in Hz with the following multiplicities: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; br., broad signal (indicating unresolved couplings).13C-NMR chemical shifts (^^ are expressed in ppm, signals marked with an asterisk (*) have been tentatively assigned. Although specific conformations or configurations are indicated for some of the compounds, this is not meant to limit the use of these compounds to the isomers described. According to the invention, all possible conformation or configuration isomers are expected to have a similar effect. For many of the 3-acyl-oxazolidine-5-ones, the NMR spectra showed minor signals that are attributed to slow conformational interconversions in solution. In the1H NMR spectra, these minor signals were broadened but readily apparent for the heterocyclic ring protons. The minor signals resulting from this dynamic process are reported for the1H NMR spectra but, unless otherwise indicated, are not reported for the13C NMR spectra. In some cases NMR spectra were recorded at elevated temperature (as indicated). Preparation of comparative compounds A-D Synthesis of (±)-1-octanoyl-2-(undecan-2-yl)imidazolidin-4-one (Compound A) Step 1. Triethylamine (TEA, 11.25 g, 15.5 mL, 110.1 mmol) and (±)-2-methylundecanal (8.46 g, 45.9 mmol) were added to a suspension of glycinamide hydrochloride (11.28 g, 100.0 mmol) in methanol (100 mL). The mixture was heated under reflux for 96 h. After cooling to room temperature, the suspension was filtered, and the filtrate concentrated under reduced pressure. Then demineralized water (50 mL) was added to the residue, and the mixture extracted with ethyl acetate (EtOAc, 100 mL). The aqueous phase was re-extracted with ethyl acetate (100 mL) and the combined organic phases were washed with distilled water (50 mL) and a saturated aqueous solution of NaCl (50 mL), dried (Na2SO4), filtered and concentrated to give 11.42 g of a brown oil. Column chromatography (SiO2, n-heptane / EtOAc 7:3, then EtOAc and EtOAc / ethanol 1:1) gave 8.38 g (76%) of (±)-2-(undecan-2-yl)imidazolidin-4-one as a mixture of two diastereoisomers (ca.1:1). Firmenich SA1H NMR (CDCl3, 500 MHz): δ 0.88 (t, J=6.9 Hz, 3H), 0.93 and 0.94 (d, J=6.8 and 6.7 Hz, 3H), 1.05–1.65 (m, 17H), 2.04 (br. s, 1H), 3.44 (s, 2H), 4.47 and 5.51 (d, J=5.6 and 5.1 Hz, 1H), 7.63 and 7.71 (s, 1H).13C NMR (CDCl3, 125.8 MHz): δ 13.76 and 14.21 (CH3), 14.12 (CH3), 22.69 (CH2), 26.95 and 26.95 (CH2), 29.33 (CH2), 29.59 and 29.60 (2 CH2), 29.81 (CH2), 31.69 and 31.77 (CH2), 31.90 (CH2), 38.77 and 39.07 (CH), 49.33 and 49.39 (CH2), 75.91 and 76.23 (CH), 177.45 and 177.61 (C). Step 2. Octanoyl chloride (1.3 mL, 1.23 g, 7.5 mmol) was added dropwise during 5 min to an ice-cold solution (0–2°C) of (±)-2-(undecan-2-yl)imidazolidin-4-one (1.20 g, 5.0 mmol) and TEA (0.73 mL, 5.2 mmol) in dichloromethane (25 mL). The reaction mixture was left warming to room temperature and stirred for 3 h. The solvent was removed, and the residue was taken up in ethyl acetate (100 mL) and washed with an aqueous solution of NaHCO3(50 mL). The aqueous layer was re-extracted with ethyl acetate (100 mL) and washed with an aqueous solution of NaCl (50 mL). The combined organic phases were dried (Na2SO4), filtered and concentrated. Column chromatography (SiO2, n-heptane / EtOAc 1:1) afforded 0.80 g (44%) of isomer 1 of the target compound and 0.72 g (39%) of isomer 2 of the target compound. Isomer 1 was assigned as (±)-(RS)-1-octanoyl-2-((RS)-undecan-2-yl)imidazolidin-4-one, isomer 2 as (±)-(RS)-1-octanoyl-2-((SR)-undecan-2-yl)imidazolidin-4-one.1H NMR (CDCl3, 500 MHz, isomer 1): δ 0.76 (d, J=6.8 Hz, 3H), 0.88 (t, J=6.9 Hz, 6H), 1.08– 1.18 (m, 1H), 1.20–1.47 (m, 23H), 1.59–1.77 (m, 2H), 2.18–2.29 (m, 2H), 2.30–2.41 (m, 1H), 3.94–4.06 (m, 2H), 5.38–5.43 (m, 1H), 7.43 (br. s, 1H).13C NMR (CDCl3, 125.8 MHz, isomer 1): δ 11.61 (CH3), 14.07 (CH3), 14.12 (CH3), 22.61 (CH2), 22.69 (CH2), 24.49 (CH2), 27.22 (CH2), 29.06 (CH2), 29.26 (CH2), 29.34 (CH2), 29.55 (CH2), 29.56 (CH2), 29.70 (CH2), 31.68 (CH2), 31.90 (CH2), 32.46 (CH2), 34.86 (CH2), 35.54 (CH), 49.13 (CH2), 73.74 (CH), 170.80 (C), 171.28 (C).1H NMR (CDCl3, 500 MHz, isomer 2): δ 0.88 (t, J=6.8 Hz, 3H), 0.88 (t, J=6.9 Hz, 3H), 0.94 (d, J=7.1 Hz, 3H), 0.98–1.10 (m, 1H), 1.12–1.43 (m, 23H), 1.59–1.73 (m, 2H), 2.18–2.35 (m, 3H), 3.94–4.07 (m, 2H), 5.34–5.39 (m, 1H), 7.46 (br. s, 1H).13C NMR (CDCl3, 125.8 MHz, isomer 2): δ 14.07(CH3), 14.11 (CH3), 15.13 (CH3), 22.62 (CH2), 22.68 (CH2), 24.57 (CH2), 27.02 (CH2), 28.51 (CH2), 29.08 (CH2), 29.25 (CH2), 29.34 (CH2), 29.59 (CH2), 29.62 (CH2), 29.90 (CH2), 31.70 (CH2), 31.91 (CH2), 34.89 (CH2), 35.92 (CH), 49.33 (CH2), 74.69 (CH), 170.79 (C), 171.47 (C). Firmenich SA Synthesis of ethyl (±)-(4S)-3-acetyl-2-(undecan-2-yl)oxazolidine-4-carboxylate (Compound B) Step 1. (±)-2-Methylundecanal (1.84 g, 10.0 mmol) was added to a solution of ethyl L-serinate hydrochloride (3.39 g, 20.0 mmol) and TEA (3.0 mL, 22.0 mmol) in ethanol (50 mL). Then MgSO4(2.00 g) was added and the mixture heated under reflux (80°C) for 17 h. After cooling to room temperature, the solvent was removed under reduced pressure. Then demineralized water (50 mL) was added to the residue, and the mixture extracted with EtOAc (2x 100 mL). The combined organic phases were washed with a saturated aqueous solution of NaCl (2x 50 mL), dried (Na2SO4), filtered and concentrated. Bulb-to-bulb distillation (120°C, 0.68 mbar) gave 2.68 g (89%) of ethyl (±)-(4S)-2-(undecan-2-yl)oxazolidine-4-carboxylate as a mixture of four diastereoisomers (ca.34:33:17:16).1H NMR (CDCl3, 500 MHz, major isomers): δ 0.88 (t, J=6.9 Hz, 3H), 1.00 (dd, J=6.7, 1.3 Hz, 3H), 1.17–1.46 (m, 18H), 1.47–1.69 (m, 1H), 1.69–1.82 (m, 1H), 2.63 (br. s, 1H), 3.72–3.80 (m, 1H), 3.86–3.95 (m, 2H), 4.18 (d, J=5.8 Hz, 1H), 4.18–4.29 (m, 2H).13C NMR (CDCl3, 125.8 MHz, major isomers): δ 14.12 (CH3), 14.17 (CH3), 14.60 and 14.74 (CH3), 22.69 (CH2), 26.95 and 27.03 (CH2), 29.34 (CH2), 29.62 (2 CH2), 29.85 and 29.86 (CH2), 31.91 (CH2), 32.65 and 32.78 (CH2), 36.39 and 36.48 (CH), 59.64 and 59.69 (CH), 61.63 (CH2), 68.16 and 68.19 (CH2), 96.99 and 97.01 (CH), 172.52 and 172.54 (C).1H NMR (CDCl3, 500 MHz, minor isomers): δ 0.88 (t, J=6.9 Hz, 3H), 0.94 (dd, J=6.7, 1.3 Hz, 3H), 1.17–1.46 (m, 18H), 1.47–1.69 (m, 2H), 2.63 (br. s, 1H), 3.67–3.73 (m, 1H), 3.94–4.01 (m, 1H), 4.11 (dt, J=8.0, 4.5 Hz, 1H), 4.18–4.29 (m, 2H), 4.39–4.43 (m, 1H).13C NMR (CDCl3, 125.8 MHz, minor isomers): δ 14.12 (CH3), 14.20 (CH3), 14.42 and 14.73 (CH3), 22.69 (CH2), 26.97 and 27.05 (CH2), 29.34 (CH2), 29.62 (2 CH2), 29.90 (CH2), 31.91 (CH2), 32.39 and 32.58 (CH2), 37.18 and 37.26 (CH), 59.21 and 59.23 (CH), 61.35 (CH2), 68.22 and 68.26 (CH2), 96.36 and 96.48 (CH), 172.70 (C). Step 2. Iodine (38 mg, 0.15 mmol) was added to ethyl (±)-(4S)-2-(undecan-2-yl)oxazolidine-4- carboxylate (0.45 g, 1.5 mmol) in acetyl acetate (1.50 g, 15.0 mmol). After stirring at room temperature for 2 h, a saturated aqueous solution of NaHCO3(25 mL) and EtOAc (15 mL) were added. The reaction mixture was stirred at room temperature for 30 min. The organic phase was decanted and the aqueous phase extracted with EtOAc (25 mL). The combined organic phases were washed with a saturated aqueous solution of NaCl, dried (Na2SO4), filtered and Firmenich SA concentrated. After addition of a saturated aqueous solution of NaHCO3 (25 mL) and n-pentane (25 mL), the mixture was stirred at room temperature for 1 h. Then the organic phase was decanted and the aqueous phase extracted with n-pentane (25 mL). The combined organic phases were washed with a saturated aqueous solution of NaCl, dried (Na2SO4), filtered and concentrated to yield 0.41 g of the crude compound. Column chromatography (SiO2, n- heptane / EtOAc 70:30) gave 0.20 g (29%) of the target compound as a mixture of diastereoisomers (ca.33:31:21:15).1H NMR (CDCl3, 500 MHz, major isomers): δ 0.80 and 0.97 (d, J=6.7 and 7.0 Hz, 3H), 0.88 (t, J=6.9 Hz, 3H), 1.00–1.73 (m, 19H), 2.10–2.16 (m, 3H), 1.98–2.10 (m, 0.5H), 2.22–2.32 (m, 0.5H), 4.00–4.31 (m, 3H), 4.31–4.36 (m, 0.5H), 4.38–4.47 (m, 1.5H), 5.20 and 5.25 (d, J=3.8 and 5.4 Hz, 1H).13C NMR (CDCl3, 125.8 MHz, major isomers): δ 12.21 and 15.11 (CH3), 14.12 (CH3), 22.69 (CH2), 23.17 and 23.42 (CH3), 27.01 and 27.38 (CH2), 29.35, 29.62, 29.65, 29.75, 29.88 and 30.00 (4 CH2), 31.91 (CH2), 32.68 (CH2), 34.70 and 35.32 (CH), 59.22 and 59.36 (CH), 62.04 (CH2), 68.20 and 68.45 (CH2), 94.33 and 94.74 (CH), 169.94 (C), 169.05 and 169.74 (C).1H NMR (CDCl3, 500 MHz, minor isomers): δ 0.88 (t, J=6.9 Hz, 3H), 0.85–0.91 and 0.93–0.97 (m, 3H), 1.00–1.73 (m, 19H), 1.76–1.94 (m, 1H), 2.10–2.16 (m, 3H), 4.00–4.31 (m, 4H), 4.82– 4.90 (m, 1H), 5.02 and 5.04 (d, J=8.3 and 6.4 Hz, 1H).13C NMR (CDCl3, 125.8 MHz, minor isomers): δ 13.22 and 15.55 (CH3), 14.12 (CH3), 22.69 (CH2), 22.75 (CH3), 26.75 and 27.38 (CH2), 29.35, 29.62, 29.65, 29.75, 29.88 and 30.00 (4 CH2), 31.09 and 32.81 (CH2), 31.91 (CH2), 36.34 and 36.84 (CH), 56.95 and 57.48 (CH), 61.58 (CH2), 66.99 and 67.48 (CH2), 94.39 and 95.05 (CH), 169.98 (C), 170.07 and 170.38 (C). Synthesis of ethyl (±)-(4S)-3-isopropyl-2-(undecan-2-yl)oxazolidine-4-carboxylate (Compound C) Step 1. TEA (3.5 mL, 25 mmol), potassium acetate (2.45 g, 25 mmol) and acetone (3.3 mL, 45 mmol) were consecutively added to ethyl L-serinate hydrochloride (4.24 g, 25.0 mmol) in dichloromethane (80 mL). The suspension was cooled on an ice bath to 0°C before sodium triacetoxyboranuide (NaBH(OAc)3, 6.55 g, 30 mmol) was added in small portions during 30 min. After stirring at 0°C for 1 h, the ice bath was removed and the reaction mixture left stirring at room temperature for 22 h. After carefully adding a saturated aqueous solution of NaHCO3(50 mL) the reaction mixture was stirred at room temperature for 30 min. Then the phases were Firmenich SA separated and the aqueous phase extracted with dichloromethane (2x 25 mL). The combined organic phases were dried (Na2SO4), filtered and concentrated to yield 3.25 g (74%) of ethyl (S)-3-(hydroxy)-2-(isopropylamino)propanoate (ethyl isopropyl-L-serinate).1H NMR (CDCl3, 600 MHz): δ 1.05 (d, J= 6.2 Hz, 3H), 1.10 (d, J=6.6 Hz, 3H), 1.29 (t, J=7.1, 3H), 2.83 (hept., J=6.2 Hz, 1H), 2.90 (br. s, 2H), 3.44 (dd, J=6.6, 4.6 Hz, 1H), 3.55 (dd, J=10.4, 6.9 Hz, 1H), 3.77 (dd, J=10.8, 4.6 Hz, 1H), 4.21 (q, J=7.1 Hz, 2H).13C NMR (CDCl3, 150.9 MHz): δ 14.23 (CH3), 22.43 (CH3), 23.51 (CH3), 47.63 (CH), 60.24 (CH), 61.25 (CH2), 62.84 (CH2), 173.57 (C). Step 2. (±)-2-Methylundecanal (0.46 g, 2.5 mmol) and p-toluenesulfonic acid monohydrate (21.5 mg, 0.1 mmol) were added to a solution of ethyl isopropyl-L-serinate (0.44 g, 2.5 mmol) in toluene (12.5 mL). The reaction mixture was heated under reflux with constant removal of water for 16 h. After cooling to room temperature, ethyl acetate (50 mL) was added, and the reaction mixture was washed with a saturated aqueous solution of NaCl (2x, 25 mL). The aqueous phases were re-extracted with ethyl acetate (50 mL) and the combined organic layers dried (Na2SO4), filtered and concentrated. Bulb-to-bulb distillation (0.68 mbar, 100°C) to remove remaining 2-methylundecanal afforded 0.68 g (80%) of the target compound as a mixture of diastereoisomers (ca.54:46).1H NMR (CDCl3, 500 MHz): δ 0.84–0.93 (m, 6H), 1.02 (2 d, J=6.4 Hz, 3H), 1.09 (2 d, J= 6.7Hz, 3H), 0.97–1.12 (m, 1H), 1.13–1.44 (m, 17H), 1.47–1.76 (m, 2H), 2.93–3.04 (m, 1H), 3.69–3.76 (m, 1H), 3.90 and 3.93 (t, J=8.2 Hz, 1H), 4.03 and 4.07 (dd, J=8.3, 4.8 Hz and J=8.3, 4.5 Hz, 1H), 4.10–4.22 (m, 2H), 4.24 and 4.27 (d, J=7.1 and 5.4 Hz, 1H).13C NMR (CDCl3, 125.8 MHz): δ 14.13 (CH3), 14.16 (CH3), 13.74 and 15.65 (CH3), 17.69 and 17.88 (CH3), 21.68 and 21.87 (CH3), 22.70 (CH2), 27.19 and 27.37 (CH2), 29.37 (CH2), 29.66 and 29.68 (CH2), 29.70 (CH2), 30.00 and 30.04 (CH2), 31.93 (CH2), 31.44 and 33.00 (CH2), 37.06 (CH), 51.67 and 52.40 (CH), 59.75 and 59.90 (CH), 60.74 (CH2), 67.78 and 68.12 (CH2), 99.14 and 99.83 (CH), 173.95 and 174.01 (C). Synthesis of ethyl (±)-(4S)-2-(2,4-dimethylcyclohex-3-en-1-yl)-3-isopropyloxazolidine-4- carboxylate (Compound D) (±)-2,4-Dimethylcyclohex-3-enecarbaldehyde (mixture of two isomers, ca.40:60, 1.58 g, 11.4 mmol) and p-toluenesulfonic acid monohydrate (0.10 g, 0.6 mmol) were added to a solution of Firmenich SA ethyl isopropyl-L-serinate (2.00 g, 11.4 mmol) in toluene (50 mL). The reaction mixture was heated under reflux with constant removal of water (Dean-Stark apparatus) for 16 h. After cooling to room temperature, ethyl acetate (150 mL) was added, and the reaction mixture was washed with a saturated aqueous solution of NaCl (2x, 100 mL). The aqueous phases were re- extracted with ethyl acetate (150 mL) and the combined organic layers dried (Na2SO4), filtered and concentrated. Bulb-to-bulb distillation (0.5 mbar, 100°C) to remove remaining 2,4- dimethylcyclohex-3-enecarbaldehyde afforded 2.48 g (74%) of the target compound as a mixture of isomers (ca.43:37:11:9).1H NMR (CDCl3, 500 MHz, major isomers): δ 0.98–1.06 (m, 6H), 1.08 and 1.11 (d, J=6.7 Hz, 3H), 1.27 (2 t, J=7.2 Hz, 3H), 1.30–1.40 (m, 1H), 1.40–1.55 (m, 1H), 1.64 (s, 3H), 1.71–2.03 (m, 3H), 2.12–2.28 (m, 1 H), 2.97 and 3.03 (quint., J=6.7 Hz, 1H), 3.70–3.81 (m, 1H), 3.89– 3.99 (m, 1H), 4.00–4.10 (m, 1H), 4.10–4.22 (m, 2H), 4.47 and 4.55 (d, J=7.4 and 6.1 Hz, 1 H), 5.17–5.23 (m, 1H).13C NMR (CDCl3, 125.8 MHz, major isomers): δ 14.16 and 14.18 (CH3), 17.28 and 18.38 (CH3), 20.95 and 21.90 (CH3), 21.70 and 21.98 (CH3), 20.21 and 22.70 (CH2), 23.63 and 23.65 (CH3), 28.49 and 28.63 (CH2), 31.35 and 31.75 (CH), 42.87 and 43.10 (CH), 52.10 and 53.02 (CH), 59.30 and 60.29 (CH), 60.77 and 60.79 (CH2), 67.42 and 68.13 (CH2), 95.36 and 98.44 (CH), 127.05 and 127.36 (CH), 132.75 and 133.25 (C), 173.92 and 174.04 (C).1H NMR (CDCl3, 500 MHz, minor isomers): δ 0.89 and 0.92 (d, J=7.1 Hz, 3H), 0.98–1.13 (m, 6H), 1.25 and 1.26 (t, J=7.1 Hz, 3H), 1.60–1.71 (m, 4H), 1.71–2.03 (m, 2H), 2.20–2.42 (m, 1H), 3.07–2.98 and 3.10 (m and quint., J=6.6 Hz, 1H), 3.70–3.81 (m, 1H), 3.89–3.99 (m, 1H), 4.00– 4.10 (m, 1H), 4.10–4.22 (m, 2H), 4.42 and 4.45 (d, J=7.4 and 10.3 Hz, 1H), 5.33–5.38 (m, 1H), 2H not assigned.13C NMR (CDCl3, 125.8 MHz, minor isomers): δ 14.12 and 14.20* (CH3), 15.15 and 16.15 (CH3), 17.21 and 19.21 (CH3), 21.22 and 22.51 (CH3), 18.66 and 19.84 (CH2), 23.49 and 23.52 (CH3), 30.76 and 30.81 (CH2), 29.78 and 31.06 (CH), 40.14 and 40.69 (CH), 52.71 and 53.55 (CH), 60.80 and 60.81 (CH2), 58.38 and 60.94 (CH), 67.02 and 67.64 (CH2), 97.61 and 99.21 (CH), 127.75 and 127.99 (CH), 132.83 and 132.93 (C), 174.09 and 174.10 (C). Firmenich SA Example 1 Preparation of compounds according to formula (I) Synthesis of (±)-3-octanoyl-2-pentyloxazolidin-5-one (Compound 1) General procedure to prepare 3-octanoyloxazolidin-5-ones: In a typical procedure, the aldehyde (35 mmol), acetic anhydride (7.2 g, 70.6 mmol) and N-octanoylglycine (7.1 g, 35 mmol) were added to 250 mL of dichloromethane. N-octanoylglycine was prepared using a literature procedure: W. D. Jones, Journal of the Chemical Society, Perkin Transactions 1, 1981, pages 344-348. The turbid mixture was stirred well to disperse the undissolved N- octanoylglycine and 1.1 g (0.33 equiv.) of concentrated sulfuric acid was added. The progress of the reaction was monitored by gas chromatography (GC) or thin layer chromatography. After 4-72 h, sodium carbonate (2-3 equiv.) was added, and the mixture stirred for 30 min. The reaction mixture was filtered and concentrated. The crude product was dissolved in ethyl ether and the solution washed with sat. Na2CO3(aq.). The organic phase was collected, and the aqueous phase was washed twice with diethyl ether (Et2O). The organic phases were combined, dried over MgSO4, filtered, and the solvent removed under reduced pressure. The crude product that was either distilled or subjected to column chromatography (SiO2, hexane / EtOAc 80:20) to afford the pure product. Following the general procedure and starting from hexanal, the title compound was isolated by bulb-to-bulb distillation (oven temperature 165-170°C, 12 mtorr) in 51% yield as pale-yellow oil.1H NMR (CDCl3, 400 MHz): δ 0.88 (t, J=6.8 Hz, 6H), 1.11-1.54 (m, 14H), 1.56-1.72 (m, 2H), 1.72-1.91 (m, 1H), 1.91-2.14 (m, 1H), 2.14-2.38 (m, 2H), 3.86 (br. d, J=18.5 Hz, 0.2H), 4.09 (d, J=16.6 Hz, 0.8H), 4.20 (d, J=16.6 Hz, 0.8H), 4.46 (br. d, J=18.5 Hz, 0.2H), 5.76 (br. s, 0.2H), 5.98 (dd, J=6.3, 2.2 Hz, 0.8H).13C NMR (CDCl3, 100 MHz): δ 13.9 (CH3), 14.1 (CH3), 22.5 (CH2), 22.6 (CH2), 22.7 (CH2), 24.3 (CH2), 29.0 (CH2), 29.2 (CH2), 31.2 (CH2), 31.7 (CH2), 34.2 (CH2), 35.0 (CH2), 45.3 (CH2), 91.0 (CH), 169.2 (C), 170.8 (C). Firmenich SA Synthesis of (±)-2-nonyl-3-octanoyloxazolidin-5-one (Compound 2) Following the general procedure described for Compound 1 and starting from decanal, the title compound was isolated by column chromatography in 49% yield as pale-yellow oil.1H NMR (CDCl3, 400 MHz): δ 0.879 and 0.884 (overlapping t, J=7.0 Hz, 6H), 1.18-1.50 (m, 22H), 1.59-1.72 (m, 2H), 1.72-1.86 (m, 1H), 1.92-2.06 (m, 1H), 2.14-2.37 (m, 2H), 3.85 (br. d, J=18.5 Hz, 0.2H), 4.09 (d, J=16.5 Hz, 0.8H), 4.20 (d, J=16.6 Hz, 0.8H), 4.45 (br. d, J=18.5 Hz, 0.2H), 5.85 (br. s, 0.2H), 5.97 (dd, J=6.3, 2.2 Hz, 0.8H).13C NMR (CDCl3, 100 MHz): δ 14.0 (CH3), 14.1 (CH3), 22.6 (CH2), 22.7 (CH2), 23.0 (CH2), 24.3 (CH2), 29.0 (CH2), 29.1 (CH2), 29.2 (CH2), 29.3 (CH2), 29.5 (CH2), 31.7 (CH2), 31.9 (CH2), 34.2 (CH2), 35.0 (CH2), 45.4 (CH2), 91.0 (CH), 169.2 (C), 170.7 (C). Synthesis of (±)-2-(4-(tert-butyl)phenethyl)-3-octanoyloxazolidin-5-one (Compound 3) Following the general procedure described for Compound 1 and starting from 3-(4-tert- butylphenyl)propanal (Bourgeonal®), the title compound was isolated by column chromatography in 44% yield as a white solid.1H NMR (CDCl3, 400 MHz): δ 0.88 (t, J=6.7 Hz, 3H), 1.18-1.37 (m, 17H), 1.53-1.69 (m, 2H), 2.01-2.25 (m, 3H), 2.30-2.44 (m, 1H), 2.71 (t, J=7.9 Hz, 2H), 3.87 (br. d, J=18.5 Hz, 0.2H), 3.96 (d, J=16.5 Hz, 0.8H), 4.13 (d, J=16.6 Hz, 0.8H), 4.46 (br. d, J=18.5 Hz, 0.2H), 5.77 (br. s, 0.2H), 6.00 (dd, J=6.3, 2.2 Hz, 0.8H), 7.13 (d, J=8.1 Hz, 2H), 7.30 (d, J=8.1 Hz, 2H).13C NMR (CDCl3, 100 MHz): δ 14.1 (CH3), 22.6 (CH2), 24.2 (CH2), 24.7 (CH2), 28.6 (CH2), 29.0 (CH2), 29.2 (CH2), 31.4 (CH3), 31.6 (CH2), 34.4 (C), 34.9 (CH2), 45.2 (CH2), 90.3 (CH), 125.4 (CH), 127.9 (CH), 136.8 (C), 149.1 (C), 169.0 (C), 170.7 (C). Synthesis of (±)-3-octanoyl-2-phenethyloxazolidin-5-one (Compound 4) Following the general procedure described for Compound 1 and starting from 3- phenylpropanal, the title compound was isolated by column chromatography in 41% yield as a white solid.1H NMR (CDCl3, 400 MHz): δ 0.88 (t, J=6.9 Hz, 3H), 1.19-1.38 (m, 8H), 1.55-1.68 (m, 2H), 2.02-2.25 (m, 3H), 2.29-2.45 (m, 1H), 2.73 (t, J=7.8 Hz, 2H), 3.86 (br. d, J=18.5 Hz, 0.2H), Firmenich SA 3.97 (d, J=16.6 Hz, 0.8H), 14.3 (d, J=16.5 Hz, 0.8H), 4.45 (br. d, J=18.5 Hz, 0.2H), 5.76 (br. s, 0.2H), 5.98 (dd, J=6.3, 2.2 Hz, 0.8H), 7.14-7.23 (m, 2H), 7.23-7.35 (m, 3H).13C NMR (CDCl3, 100 MHz): δ 14.1 (CH3), 22.6 (CH2), 24.1 (CH2), 29.0 (CH2), 29.1 (CH2), 29.3 (CH2), 31.6 (CH2), 34.9 (CH2), 35.1 (CH2), 45.2 (CH2), 90.2 (CH), 126.3 (CH), 128.3 (CH), 128.5 (CH), 140.0 (C), 169.0 (C), 170.7 (C). Synthesis of (±)-3-octanoyl-2-(undecan-2-yl)oxazolidin-5-one (Compound 5) Following the general procedure described for Compound 1 and starting from (±)-2- methylundecanal and 1.4 g H2SO4, the title compound was isolated by column chromatography in 72% yield as pale-yellow oil as a mixture of two diastereoisomers (ca.50:50).1H NMR (CDCl3, 400 MHz): δ 0.82 (d, J=6.7 Hz, 1.5H), 0.88 (t, J=6.5 Hz, 6H), 1.00 (d, J=6.9 Hz, 1.5H), 1.04-1.57 (m, 24H), 1.57-1.79 (m, 2H), 2.11-2.39 (m, 3H), 3.78-3.92 (br. m, 0.2H), 4.08 (d, J=16.5 Hz, 0.8H), 4.20 (d, J=16.5 Hz, 0.8H), 4.38-4.54 (br. m, 0.2H), 5.71 (br. s, 0.1H), 5.79 (br. s, 0.1H), 5.92 (d, J=2.4 Hz, 0.4H), 5.95 (d, J=2.0 Hz, 0.4H).13C NMR (CDCl3, 100 MHz): δ 11.5 (CH3), 14.06 (CH3), 14.12 (CH3), 14.5 (CH3), 22.6 (CH2), 22.7 (CH2), 24.3 (CH2), 24.4 (CH2), 26.9 (CH2), 27.0 (CH2), 28.5 (CH2), 29.0 (CH2), 29.2 (CH2), 29.3 (CH2), 29.6 (CH2), 29.7 (CH2), 29.8 (CH2), 31.7 (CH2), 31.9 (CH2), 35.136.6 (CH), 37.2 (CH), 46.1 (CH2), 46.2 (CH2), 93.6 (CH), 94.4 (CH), 169.4 (C), 170.9 (C), 171.2 (C). Synthesis of (±)-(E)-2-(non-3-en-1-yl)-3-octanoyloxazolidin-5-one (Compound 6) Following the general procedure described for Compound 1 and starting from N- octanoylglycine (5.71 g, 28.4 mmol), (E)-4-decenal (4.0 g, 25.9 mmol), acetic anhydride (15.9 g, 156 mmol) and H2SO4(1.27 g, 13.0 mmol), 2.56 g (29%) of the title compound was isolated by column chromatography as a pale-yellow oil.1H NMR (CDCl3, 600 MHz): δ 0.88 (t, J=7.3 Hz, 3H), 0.885 (t, J=6.9 Hz, 3H), 1.20-1.39 (m, 14H), 1.61-1.73 (m, 2H), 1.82-1.92 (m, 1H), 1.92-2.04 (m, 2H), 2.04-2.14 (m, 2H), 2.14-2.31 (m, 3H), 3.85 (d, J=18.3 Hz, 0.2H), 4.07 (d, J=16.5 Hz, 0.8H), 4.18 (d, J=16.5 Hz, 0.8H), 4.46 (d, J=18.3 Hz, 0.2H), 5.37 (dt, J=15.3, 6.0 Hz, 1H), 5.47 (dt, J=15.3, 6.6 Hz, 1H), 5.84 (br. s, 0.2H), 5.99 (br. d, J=5.8 Hz, 0.8H). Firmenich SA13C NMR (CDCl3, 150.9 MHz): δ 14.0 (CH3, 2 C), 22.5 (CH2), 22.6 (CH2), 24.2 (CH2), 26.2 (CH2), 29.0 (CH2), 29.1 (CH2), 29.2 (CH2), 31.4 (CH2), 31.7 (CH2), 32.5 (CH2), 33.7 (CH2), 35.0 (CH2), 45.3 (CH2), 90.5 (CH), 127.7 (CH), 132.0 (CH), 169.0 (C), 170.7 (C). Synthesis of (±)-(Z)-2-(non-3-en-1-yl)-3-octanoyloxazolidin-5-one (Compound 7) Following the general procedure described for Compound 1 and starting from N- octanoylglycine (4.28 g, 21.3 mmol), (Z)-4-decenal (3.0 g, 19.4 mmol), acetic anhydride (11.9 g, 117 mmol) and H2SO4(0.96 g, 9.76 mmol), 2.0 g (30%) of the title compound was isolated by silica gel flash chromatography as a colorless oil.1H NMR (CDCl3, 500 MHz): δ 0.90 (t, J=6.9 Hz, 6H), 1.20-1.42 (m, 14H), 1.61-1.73 (m, 2H), 1.81-1.95 (m, 1H), 1.98-2.07 (m, 2H), 2.07-2.35 (m, 5H), 3.87 (d, J=18.4 Hz, 0.2H), 4.10 (d, J=16.4 Hz, 0.8H), 4.19 (d, J=16.4 Hz, 0.8H), 4.47 (d, J=18.4 Hz, 0.2H), 5.30-5.37 (m, 1H), 5.40-5.47 (m, 0.8H), 5.47-5.57 (br. m, 0.2H), 5.83 (br. s, 0.2H), 5.99 (br. d, J=6.3 Hz, 0.8H).13C NMR (CDCl3, 125.8 MHz): δ 14.0 (CH3, 2 C), 21.1 (CH2), 22.5 (CH2), 22.6 (CH2), 24.2 (CH2), 27.2 (CH2), 29.0 (CH2), 29.2 (CH2), 29.3 (CH2), 31.5 (CH2), 31.6 (CH2), 33.9 (CH2), 35.0 (CH2), 45.3 (CH2), 90.5 (CH), 127.1 (CH), 131.7 (CH), 169.0 (C), 170.7 (C). Synthesis of (±)-(Z)-3-octanoyl-2-(undec-3-en-1-yl)oxazolidin-5-one (Compound 8) Following the general procedure described for Compound 1 and starting from N- octanoylglycine (2.77 g, 13.7 mmol), (Z)-4-dodecenal (2.48 g, 13.6 mmol), acetic anhydride (4.2 g, 41.2 mmol) and H2SO4(0.62 g, 6.3 mmol), 3.0 g (61%) of the title compound was isolated by silica gel flash chromatography as a colorless oil.1H NMR (CDCl3, 500 MHz): δ 0.88 (t, J=6.4 Hz, 6H), 1.20-1.44 (m, 18H), 1.60-1.73 (m, 2H), 1.74-1.93 (m, 1H), 1.93-2.06 (m, 2H), 2.06-2.32 (m, 5H), 3.85 (d, J=18.4 Hz, 0.2H), 4.08 (d, J=16.5 Hz, 0.8H), 4.18 (d, J=16.5 Hz, 0.8H), 4.46 (d, J=18.4 Hz, 0.2H), 5.28-5.36 (m, 1H), 5.38-5.46 (m, 0.8H), 5.46-5.55 (br. m, 0.2H), 5.83 (br. s, 0.2H), 5.98 (br. d, J=5.9 Hz, 0.8H).13C NMR (CDCl3, 125.8 MHz): δ 14.0 (CH3), 14.1 (CH3), 21.1 (CH2), 22.6 (CH2), 22.7 (CH2), 24.2 (CH2), 27.2 (CH2), 29.0 (CH2), 29.2 (CH2), 29.3 (CH2), 29.6 (CH2, 2C), 31.6 (CH2), 31.9 (CH2), 33.9 (CH2), 35.0 (CH2), 45.3 (CH2), 90.5 (CH), 127.1 (CH), 131.7 (CH), 169.0 (C), 170.7 (C). Firmenich SA Synthesis of (±)-3-octanoyl-2-(2-phenylpropyl)oxazolidin-5-one (Compound 9) Following the general procedure described for Compound 1 and starting from N- octanoylglycine (3.0 g, 14.9 mmol), 3-phenylbutanal (Trifernal®, 2.21 g, 14.9 mmol), acetic anhydride (6.0 g, 58.8 mmol), ethyl acetate (150 mL, instead of dichloromethane) and H2SO4(0.62 g, 6.3 mmol), 2.9 g (58%) of the title compound was isolated by silica gel flash chromatography as a pale-yellow oil as a mixture of two diastereoisomers (ca.60:40).1H NMR (CDCl3, 500 MHz): δ 0.88 and 0.89 (overlapping t, J=6.9 Hz, 3H), 1.09-1.41 (m, 11H), 1.42-1.57 (m, 1H), 1.57-1.73 (m, 1H), 1.73-1.97 (m, 1.2H), 1.98-2.28 (m, 2H), 2.37-2.47 (m, 0.4H), 2.47-2.57 (m, 0.4H), 2.88-3.06 (m, 1H), 3.44 (d, J=16.5 Hz, 0.4H), 3.83 (d, J=18.4 Hz, 0.2H), 3.89 (d, J=16.5 Hz, 0.4H), 4.06 (AB q, J=16.5 Hz, 0.8H), 4.45 (br. d, J=18.5 Hz, 0.2H), 5.76 (br. s, 0.2H), 5.98 (dd, J=6.3, 2.2 Hz, 0.8H), 7.14-7.23 (m, 2H), 7.24-7.35 (m, 3H).13C NMR (CDCl3, 125.8 MHz): δ 14.1 (CH3), 22.59 (CH2), 22.6 (CH2), 23.3 (CH3), 23.6 (CH3), 23.8 (CH2), 24.1 (CH2), 29.0 (CH2), 29.1 (CH2), 31.6 (CH2), 34.4 (CH), 34.6 (CH2), 34.9 (CH2), 35.6 (CH), 40.1 (CH2), 41.7 (CH2), 44.9 (CH2), 45.0 (CH2), 89.4 (CH), 89.8 (CH), 126.4 (CH), 126.6 (CH), 126.7 (CH), 127.1 (CH), 128.6 (CH), 128.7 (CH), 144.5 (C), 145.9 (C), 168.9 (C), 169.1 (C), 170.5 (C), 170.6 (C). Synthesis of (±)-3-octanoyl-2-(1-(p-tolyl)propan-2-yl)oxazolidine-5-one (Compound 10) Following the general procedure described for Compound 1 and starting from N- octanoylglycine (3.00 g, 14.9 mmol), 2-methyl-3-(4-methylphenyl)propanal (3.84 g, 14.9 mmol), acetic anhydride (6.0 g, 58.8 mmol), ethyl acetate (150 mL, instead of dichloromethane) and H2SO4(0.58 g, 5.91 mmol), 2.25 g (44%) of the title compound was isolated by silica gel flash chromatography as a pale-yellow oil as a mixture of two diastereoisomers.1H NMR (CDCl3, 500 MHz): δ 0.81 (d, J=6.7 Hz, 1.5H), 0.85 – 0.90 (m, 3H), 0.97 (d, J=6.5 Hz, 0.5H), 1.01 (d, J=7Hz, 1H), 1.20 – 1.35 (m, 8H), 1.50 – 1.70 (m, 2H), 1.85 – 1.95 (m, 0.5H), 2.05 – 2.15 (m, 0.4H), 2.15 – 2.25 (m, 1.1H), 2.30 – 2.35 (m, 3H), 2.41 (dd, J=13.6 and 8.2 Hz, 0.4H), 2.56 (dd, J=13.3 and 8.5 Hz, 0.5H), 2.60 – 2.80 (m, 2.1H), 3.72 (d, J=16.5 Hz, 0.3H), 3.87 (d, J=18.5 Hz, 0.1H), 4.00 – 4.25 (m, 1.5H), 4.39 (d, J=18.5Hz, 0.1H), 5.62 (br. s, 0.1H), 5.90 (d, J=19.5 Hz, 0.9H), 7.02 (d, J=7.9Hz, 0.7H), 7.05 – 7.15 (m, 3.3H).13C NMR (CDCl3, 125 MHz): δ 11.26 (CH3), 14.06 (CH3), 14.07 (CH3), 14.12 (CH3), 15.60 (CH3), 20.98 (CH), 21.01 (CH), 22.59 (CH2), 22.60 (CH2), 24.12 (CH2), 24.23 (CH2), 29.00 Firmenich SA (CH2), 29.04 (CH2), 29.15 (CH2), 29.20 (CH2), 31.63 (CH2), 31.68 (CH2), 34.94 (CH2), 34.99 (CH2), 35.05 (CH2), 37.81 (CH), 37.89 (CH2), 38.04 (CH), 38.69 (CH2), 45.84 (CH2), 45.99 (CH2), 60.82 (CH2), 62.08 (CH2), 92.84 (CH), 93.92 (CH), 128.62 (CH), 128.79 (CH), 128.90 (CH), 129.08 (CH), 129.18 (CH), 129.49 (CH), 135.73 (C), 135.79 (C), 135.86 (C), 136.02 (C), 169.21 (C), 169.25 (C), 170.83 (C), 171.05 (C). Synthesis of (±)-2-(2-(4,4-dimethylcyclohex-1-en-1-yl)ethyl)-3-octanoyloxazolidin-5-one (Compound 11) Following the general procedure described for Compound 1 and starting from N- octanoylglycine (4.07 g, 20.2 mmol), 3-(4,4-dimethylcyclohexen-1-yl)propanal (Tillenal®, 3.50 g, 21.1 mmol), acetic anhydride (6.0 mL, 63.9 mmol), ethyl acetate (134 mL, instead of dichloromethane) and H2SO4(0.54 mL, 10.1 mmol), 4.48 g (63%) of the title compound was isolated by silica gel flash chromatography as a pale-yellow oil.1H NMR (CDCl3, 500 MHz): δ 0.85 – 0.90 (m, 9H), 1.25 – 1.40 (m, 10H), 1.66 (quint, J=6.7 Hz, 2H), 1.76 (br., 2H), 1.80 – 2.00 (m, 3H), 2.05 – 2.10 (m, 2H), 2.50 – 2.30 (m, 3H), 3.86 (d, J=18.3 Hz, 0.2H), 4.09 (d, J=16.5 Hz, 0.8H), 4.18 (d, J=16.5 Hz, 0.8H), 4.47 (d, J=18.3 Hz, 0.2H), 5.35 – 5.45 (m, 1H), 5.84 (br., 0.2H), 5.97 (d, J=5.4 Hz, 0.8H).13C NMR (CDCl3, 125 MHz): δ 14.06 (CH3), 22.59 (CH2), 24.25 (CH2), 25.94 (CH2), 28.08 (CH3), 28.27 (CH3), 28.45 (C), 29.02 (CH2), 29.17 (CH2), 30.94 (CH2), 31.64 (CH2), 32.15 (CH2), 35.02 (CH2), 35.60 (CH2), 39.26 (CH2), 45.32 (CH2), 90.68 (CH), 121.19 (CH), 134.16 (C), 169.06 (C), 170.67 (C). Synthesis of (±)-2-((E / Z)-4,8-dimethylnon-3-en-1-yl)-3-octanoyloxazolidin-5-one (Compound 12) Following the general procedure described for Compound 1 and starting from N- octanoylglycine (3.03 g, 15.1 mmol), (E / Z)-5,9-dimethyldec-4-enal (2.83 g, 15.5 mmol), acetic anhydride (4.5 mL, 47.9 mmol), ethyl acetate (100 mL, instead of dichloromethane) and H2SO4(0.40 mL, 7.50 mmol), 3.32 g (60%) of the title compound was isolated by silica gel flash chromatography as a pale-yellow oil as a mixture of diastereomers (ca.56:44)1H NMR: (CDCl3, 500 MHz): δ 0.85 – 0.90 (m, 9H), 1.05 – 1.60 (m, 2H), 1.25 – 1.40 (m, 10H), 1.45 – 1.55 (m,1H), 1.55 – 1.70 (m, 5H), 1.75 – 1.90 (m, 1H), 1.90 – 2.00 (m, 2H), 2.00 – 2.30 Firmenich SA (m, 5H), 3.84 (d, J=18.4 Hz, 0.2H), 4.06 (dd, J=16.5 and 2.8 Hz, 0.8H), 4.17 (d, J=16.5 Hz, 0.8H), 4.46 (d, J=18.4 Hz, 0.2H), 5.08 (t, J=5.6 Hz, 1H), 5.8 (br.s, 0.2H), 5.98 (d, J=6.0 Hz, 0.8H).13C NMR: (CDCl3, 125 MHz): δ 14.06 (CH3), 15.95 (CH3), 21.57 (CH2), 21.68 (CH2), 22.60 (CH2), 22.61 (CH3), 22.63 (CH3), 23.38 (CH3), 24.26 (CH2), 25.67 (CH2), 25.69 (CH2), 27.88 (CH), 27.91 (CH), 29.03 (CH2), 29.20 (CH2), 31.65 (CH2), 31.94 (CH2), 33.93 (CH2), 34.13 (CH2), 35.01 (CH2), 38.62 (CH2), 38.81 (CH2), 39.88 (CH2), 45.30 (CH2), 90.61 (CH), 90.64 (CH), 121.78 (CH), 122.56 (CH), 137.18 (C), 137.35 (C), 169.05 (C), 169.08 (C), 170.62 (C). Synthesis of (±)-2-(6-methylhept-5-en-2-yl)-3-octanoyloxazolidin-5-one (Compound 13) General procedure to prepare oxazolidinones through amino acid sodium salts: Step 1. Following a literature procedure (see: A. B. Hughes, B. E. Sleebs, Synthetic Communications, 2009, Vol.39, pages 48–60) the corresponding amino acid (20.0 g, 266 mmol) was dissolved in 1 M sodium hydroxide solution (aq., 266 mL). The solvent was removed, and the white solid was dried under high vacuum overnight. The sodium salt of the amino acid was used without further purification. Step 2. The amino acid sodium salt (6.40 g, 65.9 mmol) and aldehyde (73.8 mmol) were suspended in dichloromethane (DCM, 88 mL). The mixture was refluxed overnight, azeotropically removing water using an inverse Dean-Stark trap. The heterogenous mixture was cooled to room temperature or on an ice bath and the acyl chloride (67.4 mmol) was added dropwise. The mixture was then refluxed again until the reaction was completed. The mixture was cooled to room temperature, diluted with EtOAc and extracted with either saturated Na2CO3(aq.) or NaHCO3(aq.). The organic layer was collected and washed two additional times. The organic layer was dried over Na2SO4, filtered, and the solvent of the filtrate was removed. The crude oil was purified by column chromatography. Following the general procedure and starting with glycine sodium salt (6.40 g, 65.9 mmol), 2,6- dimethyl-5-hepten-1-al (Melonal, 10.3 g, 73.8 mmol), and octanoyl chloride (11.5 mL, 67.4 mmol), 6.91 g (32 %, yellow oil) of the title compound was obtained as a mixture of two diastereomers (ca.71:29). Firmenich SA1H NMR (CDCl3, 600 MHz): δ 0.83 (d, J=6.9 Hz, 1.8H), 0.88 (t, J=7.1 Hz, 3.5H), 1.02 (d, J=6.9 Hz, 0.7H), 1.05 – 1.20 (m, 0.3H), 1.25 – 1.40 (m, 9H), 1.41 (br., 0.2H), 1.50 – 1.75 (m, 8.5H), 1.92 (sept, J=7.2 Hz, 0.3H), 1.95 – 2.15 (m, 1.8H), 2.15 – 2.35 (m, 2.9H), 3.86 (d, J=18.4 Hz, 0.2H), 4.09 (d, J=16.5 Hz, 0.8H), 4.19 (d¸ J=16.5 Hz, 0.8H), 4.44 (d, J=18.4 Hz, 0.2H), 5.03 (t, J=6.8 Hz, 0.3H), 5.10 (t, J=6.8 Hz, 0.7H), 5.71 (br.s, 0.1H), 5.78 (br.s, 0.2H), 5.93 (d, J=2.2 Hz, 0.2H), 5.96 (d, J=1.7 Hz, 0.5H).13C NMR (CDCl3, 150 MHz): δ 11.39 (CH3), 14.06 (CH3), 14.37 (CH3), 17.70 (CH3), 22.60 (CH2), 24.33 (CH2), 24.42 (CH2), 25.24 (CH2), 25.45 (CH2), 25.71 (CH3), 25.72 (CH3), 29.03 (CH2), 29.18 (CH2), 31.65 (CH2), 31.91 (CH2), 35.11 (CH2), 36.38 (CH), 36.85 (CH), 46.07 (CH2), 46.24 (CH2), 93.61 (CH), 94.38 (CH), 123.70 (CH), 132.10 (C), 169.31 (C), 170.96(C), 171.25 (C). Synthesis of (±)-3-butyryl-2-(undecane-2-yl)oxazolidine-5-one (Compound 14) General procedure to prepare 3-butyryloxazolidin-5-ones: Step 1. In a round bottom flask, glycine (15.0 g, 200 mmol) was dissolved in an aqueous solution of NaOH (2N, 100 mL). The colorless solution was placed in an ice bath and butyric anhydride (30.96 g, 200 mmol) was added dropwise. Reaction mixture was allowed to stir for an additional 30 min on ice before warming to room temperature and stirring for an additional 2.5 h. The pH of the reaction mixture was adjusted to 2 using HCl (1 M, aq.). The mixture was then extracted with ethyl acetate and aqueous phase was washed 2 additional times. The organic layers were combined, dried over MgSO4, filtered, and the solvent of the filtrate was removed under reduce pressure. The white solid was washed twice with hexanes to yield butyrylglycine (24.0 g, 83%).1H NMR (DMSO-d6, 500 MHz): δ 12.47 (s, 1H), 8.11 (t, J=5.9 Hz, 1H), 3.73 (d, J=5.9 Hz, 2H), 2.10 (t, J=7.4 Hz, 2H), 1.52 (sext., J=7.4 Hz, 2H), 0.86 (t, J=7.4 Hz, 3H).13C NMR (DMSO-d6, 125 MHz): δ 172.45 (C), 171.41 (C), 40.48 (CH2), 36.96 (CH2), 18.57 (CH2), 13.51 (CH3). Step 2. In a round bottom flask, butyrylglycine (2.00 g, 13.8 mmol), aldehyde (16.3 mmol), and acetic anhydride (5.00 g, 50.0 mmol) were suspended EtOAc (50 mL). The mixture was stirred vigorously as concentrated sulfuric acid (0.40 g, 4.08 mmol) was added. The reaction mixture was stirred at room temperature overnight. Solid Na2CO3(2.0 eq.) was added to neutralize the reaction causing it to become cloudy. The mixture was diluted with Et2O and extracted with sat. Firmenich SA Na2CO3 (aq). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over MgSO4, filtered, and the solvent of the filtrate was removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 – 20% EtOAc in Hexanes). Following the general procedure and starting from (±)-2-methylundecanal (3.00 g), 2.50 g (58%, colorless oil) of the title compound was collected as a mixture of two diastereomers (ca. 71:29).1H NMR (CDCl3, 500 MHz): δ 0.82 (d, J=6.9 Hz, 1.7H), 0.88 (t, J=7.1 Hz, 3.5H), 0.95 – 1.05 (m, 3.8H), 1.05 – 1.50 (m, 16H), 1.70 (sext., J=7.4 Hz, 2H), 2.15 – 2.30 (m, 3H), 3.85 – 3.90 (m, 0.2H), 4.09 (d, J=16.5 Hz, 0.8H), 4.19 (d, J=16.5 Hz, 0.8H), 4.40 – 4.50 (m, 0.2H), 5.79 (brs, 0.1H), 5.95 (dd, J=14.2 and 1.7 Hz, 0.9H).13C NMR (CDCl3, 125 MHz): δ 11.45 (CH3), 13.74 (CH3), 14.12 (CH3), 14.51 (CH3), 17.79 (CH2), 17.87 (CH2), 22.69 (CH2), 26.84 (CH2), 27.01 (CH2), 29.32 (CH2), 29.53 (CH2), 29.56 (CH2), 29.68 (CH2), 29.74 (CH2), 31.89 (CH2), 36.62 (CH), 36.94 (CH2), 37.17 (CH), 46.06 (CH2), 46.21 (CH2), 93.63 (CH), 94.43 (CH), 169.32 (C), 170.74 (C), 171.02 (C). Synthesis of (±)-3-butyryl-2-(2-(4,4-dimethylcyclohex-1-en-1-yl)ethyl)oxazolidin-5-one (Compound 15) Following the general procedure described for Compound 14 and starting from N- butyrylglycine (3.0 g, 20.7 mmol), Tillenal®(4.06 g, 24.4 mmol), acetic anhydride (7.50 g, 73.5 mmol) and H2SO4(0.60 g, 6.1 mmol), 2.83 g (46%, pale-yellow oil) of the title compound was obtained.1H NMR (CDCl3, 500 MHz): δ 0.88 (s, 6H), 0.98 (t, J=7.4 Hz, 3H), 1.30 – 1.41 (m, 2H), 1.70 (sext., J=7.4 Hz, 2H), 1.74 – 2.30 (m, 10H), 3.86 (d, J=18.4 Hz, 0.2H), 4.09 (d, J=16.5 Hz, 0.8H), 4.18 (d, J=16.5 Hz, 0.8H), 4.47 (d, J=18.4 Hz, 0.2H), 5.37 (s, 0.8H), 5.40 (br. s, 0.2H), 5.84 (br. s, 0.2H), 5.97 (dd, J=17.3, 1.8 Hz, 0.8H).13C NMR (CDCl3, 125.8 MHz): δ 13.75 (CH3), 17.72 (CH2), 25.94 (CH2), 28.07 (CH3), 28.27 (CH3), 28.45 (C), 30.95 (CH2), 32.17 (CH2), 35.60 (CH2), 36.86 (CH2), 39.25 (CH2), 45.30 (CH2), 90.68 (CH), 121.21 (CH), 134.15 (C), 169.05 (C), 170.49 (C). Firmenich SA Synthesis of (±)-3-butyryl-2-(2,4-dimethylcyclohex-3-en-1-yl)oxazolidin-5-one (Compound 16) Following the general procedure described for Compound 14 and starting from N- butyrylglycine (3.0 g, 20.7 mmol), 2,4-dimethylcyclohex-3-ene-1-carbaldehyde (Triplal®, 3.37 g, 24.4 mmol), acetic anhydride (7.50 g, 73.5 mmol) and conc. H2SO4(0.60 g, 6.1 mmol), 2.2 g (40%, yellow oil) of the title compound was obtained as a mixture of diastereoisomers.1H NMR (CDCl3, 500 MHz): δ 0.94-1.14 (m, 6H), 1.30-1.43 (m, 0.5H), 1.43-1.52 (m, 0.5H), 1.52-1.67 (m, 4H), 1.67-1.77 (m, 2H), 1.77-1.88 (m, 0.5H), 1.88-2.04 (m, 2H), 2.14-2.35 (m, 2.5H), 2.35-2.52 (m, 1H), 3.73 (br. d, J=16.6 Hz, 0.1H), 3.84-4.57 (m, 1.8H), 4.70 (br. d, J=16.6 Hz, 0.1H), 5.08-5.28 (m, 0.2H), 5.36 (s, 0.8H), 5.73 (br. s, 0.1H), 5.87 (br. s, 0.1H), 6.03, 6.13, 6.15, 6.22 (all s, 0.8H).13C NMR (CDCl3, 125.8 MHz): δ 13.69 (CH3), 13.77 (CH3), 15.21 (CH3), 16.58 (CH2), 16.61 (CH3), 17.71 (CH2), 17.83 (CH2), 18.00 (CH2), 19.35 (CH2), 19.74 (CH3), 20.14 (CH2), 20.55 (CH3), 23.27 (CH3), 23.30 (CH3), 23.32 (CH3), 29.13 (CH2), 29.54 (CH2), 30.09 (CH2), 30.11 (CH2), 30.94 (CH), 31.22 (CH), 36.67 (CH2), 36.92 (CH2), 37.01 (CH2), 41.64 (CH), 43.38 (CH), 44.10 (CH), 45.29 (CH2), 45.77 (CH2), 46.08 (CH2), 91.18 (CH), 91.59 (CH), 92.84 (CH), 126.52 (CH), 127.03 (CH), 127.08 (CH), 132.31 (C), 132.62 (C), 132.81 (C), 169.35 (C), 169.66 (C), 171.03 (C), 172.00 (C), 174.83 (C). Synthesis of (±)-3-butyryl-2-(dec-9-en-1-yl)oxazolidin-5-one (Compound 17) Following the general procedure described for Compound 14 and starting from N- butyrylglycine (3.00 g, 20.7 mmol), undec-10-enal (3.52 g, 20.9 mmol), acetic anhydride (6.52 g, 63.9 mmol), and conc. H2SO4(1.01 g, 10.3 mmol), 3.97 g (65%, yellow oil) of the title compound was obtained.1H NMR (CDCl3, 500 MHz): δ 0.98 (t, J=7.4 Hz, 3H), 1.25 – 1.45 (m, 12H), 1.65 – 1.95 (m, 3H), 1.95 – 2.05 (m, 3H), 2.15 – 2.30 (m, 2H), 3.85 (d, J=18.3 Hz, 0.2H), 4.09 (d, J=16.5 Hz, 0.8H), 4.19 (d, J=16.5 Hz, 0.8H), 4.46 (d, J=18.3 Hz, 0.2H), 4.92 (d, J=10.1 Hz, 1H), 4.99 (dd, J=17.1 and 1.6 Hz, 1H), 5.75 – 5.85 (m, 1H), 5.98 (d, J=4.5 Hz, 1H).13C NMR (CDCl3, 125 MHz): δ 13.73 (CH3), 17.75 (CH2), 22.97 (CH2), 28.87 (CH2), 29.03 (CH2), 29.29 (CH2), 29.35 (CH2), 33.78 (CH2), 34.21 (CH2), 36.83 (CH2), 45.32 (CH2), 90.98 (CH), 114.16 (CH2), 139.17 (CH), 169.13 (C), 170.54 (C). Firmenich SA Synthesis of (±)-3-butyryl-2-((E / Z)-4,8-dimethylnon-3-en-1-yl)oxazolidin-5-one (Compound 18) Following the general procedure described for Compound 14 and starting from N- butyrylglycine (3.00 g, 20.7 mmol), (E / Z)-5,9-dimethyldec-4-enal (3.83 g, 21.0 mmol), acetic anhydride (6.52 g, 63.9 mmol), and conc. H2SO4(1.01 g, 10.3 mmol), 3.19 g (50%, yellow oil) of the title compound was obtained.1H-NMR (CDCl3, 500 MHz): δ 0.87 (dd, J=6.6 and 4.1 Hz, 6H), 0.99 (t, J=7.4 Hz, 3H), 1.05 – 1.20 (m, 2H), 1.30 – 1.40 (m, 2H), 1.45 – 1.55 (m, 1H), 1.55- 1.65 (m, 3H), 1.65 – 1.75 (m, 3H), 1.75 – 1.90 (m, 1H), 1.90 – 2.00 (m, 2H), 2.05 – 2.30 (m, 4H), 3.85 (d, J=18.2 Hz, 0.1H), 4.07 (d, J=16.5 Hz, 0.9H), 4.18 (d, J=16.5 Hz, 0.9H), 4.47 (d, J=18.2 Hz, 0.1H), 5.09 (t, J=6.7 Hz, 1H), 5.82 (br., 0.2H), 5.98 (d, J=6.2 Hz, 0.8H).13C-NMR (CDCl3, 125 MHz): δ 13.73 (CH3), 17.46 (CH2), 22.97 (CH2), 28.87 (CH2), 29.00 (CH2), 29.29 (CH2), 29.35 (CH2), 33.78 (CH2), 34.21 (CH2), 36.83 (CH2), 45.32 (CH2), 90.98 (CH), 114.16 (CH2), 139.17 (CH), 169.13 (C), 170.53 (C). Synthesis of (±)-3-butyryl-2-(6-methylhept-5-en-2-yl)oxazolidin-5-one (Compound 19) Following the general procedure described for Compound 13 and starting with glycine sodium salt (3.06 g, 31.5 mmol), Melonal (4.92 g, 35.1 mmol), and butyryl chloride (3.3 mL, 31.9 mmol), 4.25 g (50%, yellow oil) of the title compound was obtained as a mixture of two diastereomers (ca.71:29).1H-NMR (CDCl3, 500 MHz): δ 0.83 (d, J=7.0 Hz, 1.7H), 0.91 (d, J=6.2 Hz, 0.6H), 0.98 (td, J=7.4 and 1.1 Hz, 3H), 1.02 (d, J=7.0 Hz, 0.7H), 1.05 – 1.20 (m, 0.4H), 1.25 – 1.45 (m, 0.9H), 1.50 – 1.65 (m, 3.7H), 1.65 – 1.75 (m, 5H), 1.92 (sept, J=7.5 Hz, 0.3H), 1.95 – 2.15 (m, 1.9H), 2.15 – 2.30 (m, 2.8H), 3.87 (d, J=18.3 Hz, 0.2H), 4.09 (d, J=16.5 Hz, 0.8H), 4.19 (d¸ J=16.5 Hz, 0.8H), 4.44 (d, J=18.3 Hz, 0.2H), 5.02 (t, J=7.0 Hz, 0.3H), 5.10 (t, J=7.0 Hz, 0.7H), 5.72 (br.s, 0.01H), 5.79 (br.s, 0.09H), 5.93 (d, J=2.4 Hz, 0.3H), 5.97 (d, J=2.0 Hz, 0.6H).13C-NMR (CDCl3, 125 MHz): δ 11.38 (CH3), 13.71 (CH3), 13.75 (CH3), 14.37 (CH3), 17.69 (CH3), 17.80 (CH2), 17.88 (CH2), 25.21 (CH2), 25.44 (CH2), 25.70 (CH), 25.72 (CH), 28.70 (CH2), 31.91 (CH2), 36.38 (CH), 36.83 (CH), 36.95 (CH2), 46.06 (CH2), 46.22 (CH2), 93.61 (CH), 94.27 (CH), 123.70 (CH), 132.10 (C), 132.25 (C), 169.32 (C), 170.78 (C), 171.06 (C). Firmenich SA Synthesis of (±)-3-isobutyryl-2-(undecane-2-yl)oxazolidine-5-one (Compound 20) General procedure to prepare 3-isobutyryloxazolidin-5-ones: Step 1. In a round bottom flask, glycine (5.00 g, 66.6 mmol) was dissolved in water (15 mL). To the colorless solution, isobutyric anhydride (21.1 g, 133 mmol) was added in one portion. The reaction was heated to 100 °C and stirred for 4 hours. The volatiles were removed under reduce pressure to afford 2- (2-methylpropanoylamino)acetic acid which was used without further purification.1H NMR (DMSO-d6, 500 MHz): δ 1.01 (d, J=6.9 Hz, 6H), 2.42 (sept., J=6.9 Hz, 1H), 3.71 (d, J=5.9 Hz, 2H), 8.04 (t, J=5.9 Hz, 1H), 12.46 (br. s, 1H).13C NMR (DMSO-d6, 125 MHz): δ 19.34 (CH3), 33.65 (CH), 40.38 (CH2), 171.39 (C), 176.39 (C). Step 2. In a round bottom flask, 2-(2-methylpropanoylamino)acetic acid (3.03 g, 20.9 mmol), aldehyde (20.9 mmol), and acetic anhydride (5.9 mL, 62 mmol) were suspended EtOAc (150 mL). The mixture was stirred vigorously as concentrated sulfuric acid (0.57 mL, 10.3 mmol) was added. The reaction mixture was stirred at room temperature for 2 days. Solid Na2CO3(2.0 eq.) was added to neutralize the reaction causing it to become cloudy. The mixture was diluted with Et2O and extracted with sat. Na2CO3(aq). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over MgSO4, filtered, and the solvent of the filtrate was removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 – 20% EtOAc in Hexanes). Following the general procedure and starting from (±)-2-methylundecanal (3.85 g, 20.9 mmol), 3.87 g (60%, light yellow oil) of the title compound was collected as a mixture of two diastereomers (ca.70:30).1H NMR (CDCl3, 500 MHz): δ 0.81 (d, J=6.8 Hz, 2H), 0.88 (td, J=7.1 and 1.6 Hz, 3H), 1.00 (d, J=6.8 Hz, 1H), 1.16 (d, J=6.6 Hz, 2.6H), 1.18 (d, J=6.9Hz, 3.4H), 1.20 – 1.35 (m, 14H), 1.35 – 1.45 (m, 1H), 1.45 – 1.55 (m, 1H), 2.17 (br., 0.3H), 2.27 (br., 0.7H), 2.45 – 2.55 (m, 1H), 3.86 (d, J=16.2 Hz, 0.2H), 4.12 (d, J=15.5 Hz, 0.8H), 4.24 (d, J=16.5 Hz, 0.8H), 4.43 (d, J=16.2 Hz, 0.2H), 5.81 (br. s, 0.1H), 5.95 (d, J=17.7 Hz, 0.9H).13C NMR (CDCl3, 125 MHz): δ 11.44 (CH3), 14.11 (CH3), 14.12 (CH3), 18.07 (CH3), 19.20 (CH3), 19.32 (CH3), 22.68 (CH2), 22.69 (CH2), 26.78 (CH2), 26.99 (CH2), 29.30 (CH2), 29.32 (CH2), 29.51 (CH2), 29.54 (CH2), 29.55 (CH2), 29.66 (CH2), 29.69 (CH2), 31.88 (CH2), 31.90 Firmenich SA (CH2), 33.23 (CH), 36.47 (CH), 37.06 (CH), 45.87 (CH2), 46.02 (CH2), 93.56 (CH), 94.39 (CH), 169.40 (C), 174.83 (C), 175.10 (C). Synthesis of (±)-3-pivaloyl-2-(undecane-2-yl)oxazolidine-5-one (Compound 21) Following the general procedure using the amino acid sodium salt as seen for Compound 19 and starting with glycine sodium salt (3.07 g, 31.6 mmol), (±)-2-methylundecanal (5.90 g, 32.0 mmol), and pivaloyl chloride (4.0 mL, 32.5 mmol), 5.06 g (49%, yellow solid) of the title compound was obtained as a mixture of two diastereomers (ca.67:33).1H NMR (CDCl3, 500 MHz): δ 0.80 (d, J=6.9 Hz, 2H), 0.88 (t, J=6.6 Hz, 3H), 1.00 (d, J=7.0 Hz, 1H), 1.05 – 1.50 (m, 25H), 2.10 – 2.20 (m, 0.3H), 2.20 – 2.30 (m, 0.7H), 4.20 (dd, J=16.5 and 6.0 Hz, 1H), 4.42 (d, J=16.5 Hz, 1H), 6.02 (dd, J = 20.9 and 2.1 Hz, 1H).13C NMR (CDCl3, 125 MHz): δ 11.46 (CH3), 14.11 (CH3), 14.12 (CH3), 14.57 (CH3), 22.67 (CH2), 22.69 (CH2), 26.77 (CH2), 26.97 (CH3), 27.01 (CH2), 27.04 (CH3), 27.06 (CH3), 28.44 (CH2), 29.31 (CH2), 29.33 (CH2), 29.49 (CH2), 29.53 (CH2), 29.54 (CH2), 29.70 (CH2), 29.71 (CH2), 31.89 (CH2), 31.90 (CH2), 32.09 (CH2), 36.24 (CH), 36.65 (CH), 39.30 (C), 39.34 (C), 47.05 (CH2), 47.17 (CH2), 94.64 (CH), 95.59 (CH), 169.92 (C), 169.93 (C), 175.71 (C), 175.95 (C). Synthesis of (±)-3-(2-phenylacetyl)-2-(undecan-2-yl)oxazolidin-5-one (Compound 22) General procedure to prepare 3-(2-phenylacetyl)oxazolidin-5-ones: A mixture of (2- phenylacetyl)glycine (2.46 g, 12.5 mmol), the aldehyde (12.5 mmol) and para-toluenesulfonic acid monohydrate (0.10 g, 0.6 mmol) in toluene (50 mL) was heated under reflux with continuous removal of water (Dean-Stark apparatus) for 20 h. After cooling to room temperature the mixture was poured into EtOAc (100 mL) and washed with a saturated aqueous solution of NaHCO3(50 mL). The aqueous phase was extracted with EtOAc (100 mL, 1–2x) and the organic phases were washed with a saturated aqueous solution of NaHCO3(50 mL, optionally, 1x) and with a saturated aqueous solution of NaCl (50 mL, 1–2x). The organic phases were dried (Na2SO4), filtered and concentrated to give the crude compound. Following the general procedure, and starting from (±)-2-methylundecanal (2.30 g), 4.37 g of the crude product were obtained. Column chromatography (SiO2, n-heptane / EtOAc 9:1, then Firmenich SA 8:2) afforded 1.84 g (41%) of the title compound as a mixture of two diastereoisomers (ca. 61:39).1H NMR (CDCl3, 500 MHz, major isomer): δ 0.74 (d, J=6.7 Hz, 3H), 0.90 (t, J=6.9 Hz, 3H), 1.15–1.55 (m, 16H), 2.26–2.37 (m, 1H), 3.65 (d, J=15.1 Hz, 1H), 3.72 (d, J=15.1 Hz, 1H), 3.95 (d, J=16.3 Hz, 1H), 4.17 (d, J=16.3 Hz, 1H), 5.99 (d, J=1.9 Hz, 1H), 7.24–7.29 (m, 2H), 7.29– 7.34 (m, 1H), 7.34–7.41 (m, 2H).13C NMR (CDCl3, 125.8 MHz, major isomer): δ 11.39 (CH3), 14.13 (CH3), 22.69 (CH2), 26.99 (CH2), 29.32 (CH2), 29.52 (CH2), 29.55 (CH2), 29.67 (CH2), 31.88 (CH2), 31.90 (CH2), 36.41 (CH), 42.93 (CH2), 46.08 (CH2), 93.69 (CH), 127.58 (CH), 128.83 (CH), 129.10 (CH), 132.74 (C), 168.70 (C), 169.10 (C).1H NMR (CDCl3, 500 MHz, minor isomer): δ 0.89 (t, J=6.9 Hz, 3H), 0.98 (d, J=7.1 Hz, 3H), 0.94–1.42 (m, 16H), 2.15–2.25 (m, 1H), 3.63 (d, J=15.1 Hz, 1H), 3.71 (d, J=15.1 Hz, 1H), 3.90 (d, J=16.7 Hz, 1H), 4.15 (d, J=16.7 Hz, 1H), 5.92 (d, J=5.6 Hz, 1H), 7.22–7.27 (m, 2H), 7.27– 7.32 (m, 1H), 7.32–7.38 (m, 2H).13C NMR (CDCl3, 125.8 MHz, minor isomer): δ 14.13 (CH3), 14.49 (CH3), 22.70 (CH2), 26.86 (CH2), 28.23 (CH2), 29.31 (CH2), 29.55 (CH2), 29.58 (CH2), 29.76 (CH2), 31.91 (CH2), 36.93 (CH), 42.99 (CH2), 46.25 (CH2), 94.54 (CH), 127.58 (CH), 128.79 (CH), 129.09 (CH), 132.79 (C), 168.97 (C), 169.11 (C). Synthesis of (±)-2-(2-(4,4-dimethylcyclohex-1-en-1-yl)ethyl)-3-(2-phenylacetyl)oxazolidin-5- one (Compound 23) Following the general procedure described for Compound 22, and starting from Tillenal®(2.16 g), 3.25 g of the crude product were obtained. Column chromatography (SiO2, n-heptane / EtOAc 9:1, then 8:2) afforded 1.49 g (35%) of the title compound, containing some remaining EtOAc.1H NMR (CDCl3, 500 MHz): δ 0.87 (s, 3H), 0.88 (s, 3H), 1.30–1.40 (m, 2H), 1.72–1.79 (m, 2H), 1.80–1.91 (m, 2H), 1.91–2.12 (m, 3H), 2.14–2.24 (m, 1H), 3.62 (d, J=15.1 Hz, 1H), 3.67 (d, J=15.1 Hz, 1H), 3.95 (d, J=16.3 Hz, 1H), 4.15 (d, J=16.5 Hz, 1H), 5.29–5.36 (m, 1H), 5.95– 6.01 (m, 1H), 7.22–7.39 (m, 5H).13C NMR (CDCl3, 125.8 MHz): δ 168.80 (C), 168.42(C), 134.07 (C), 132.69 (C), 129.10 (CH), 128.83 (CH), 127.57 (CH), 121.26 (CH), 90.77 (CH), 45.37 (CH2), 42.77 (CH2), 39.24 (CH2), 35.58 (CH2), 31.88 (CH2), 30.77 (CH2), 28.44 (C), 28.22 (CH3), 28.11 (CH3), 25.91 (CH2). Firmenich SA Synthesis of (±)-(Z)-3-(2-phenylacetyl)-2-(undec-3-en-1-yl)oxazolidin-5-one (Compound 24) Following the general procedure described for Compound 22, and starting from (2- phenylacetyl)glycine (2.96 g, 15.0 mmol), (Z)-4-dodecenal (2.77 g, 15.0 mmol) and para- toluenesulfonic acid monohydrate (0.12 g, 0.7 mmol), 4.60 g of the crude product were obtained. Column chromatography (SiO2, n-heptane / EtOAc 9:1, then 8:2) afforded 2.37 g (44%) of the title compound.1H NMR (CDCl3, 500 MHz): δ 0.88 (t, J=7.1 Hz, 3H), 1.20–1.37 (m, 10H), 1.79–1.90 (m, 1H), 1.91–2.03 (m, 2H), 2.03–2.17 (m, 3H), 3.61 (d, J=15.1 Hz, 1H), 3.67 (d, J=15.1 Hz, 1H), 3.94 (d, J=16.7 Hz, 1H), 4.15 (d, J=16.7 Hz, 1H), 5.24–5.32 (m, 1H), 5.33–5.43 (m, 1H), 5.96–6.01 (m, 1H), 7.22–7.27 (m, 2H), 7.27–7.32 (m, 1H), 7.37–7.32 (m, 2H).13C NMR (CDCl3, 125.8 MHz): δ 14.12 (CH3), 20.94 (CH2), 22.66 (CH2), 27.19 (CH2), 29.22 (CH2), 29.24 (CH2), 29.58 (CH2), 31.85 (CH2), 33.58 (CH2), 42.77 (CH2), 45.33 (CH2), 90.62 (CH), 127.00 (CH), 127.58 (CH), 128.84 (CH), 129.09 (CH), 131.72 (CH), 132.64 (C), 168.44 (C), 168.79 (C). Synthesis of (±)-(E)-2-(3-methyl-4-(4-methylphenyl)but-3-en-1-yl)-3-(2- phenylacetyl)oxazolidin-5-one (Compound 25) Following the general procedure described for Compound 22, and starting from (2- phenylacetyl)glycine (2.96 g, 15.0 mmol), (E)-4-methyl-5-(4-methylphenyl)pent-4-enal (Mimosal®, 2.94 g, 15.0 mmol) and para-toluenesulfonic acid monohydrate (0.12 g, 0.7 mmol), 5.20 g of the crude product were obtained. Column chromatography (SiO2, n-heptane / EtOAc 9:1, then 8:2) afforded 2.84 g (52%) of the title compound.1H NMR (CDCl3, 500 MHz): δ 1.83 (d, J=1.3 Hz, 3H), 1.94–2.06 (m, 1H), 2.17–2.35 (m, 3H), 2.33 (s, 3H), 3.61 (d, J=15.1 Hz, 1H), 3.67 (d, J=15.1 Hz, 1H), 3.98 (d, J=16.3 Hz, 1H), 4.15 (d, J=16.3 Hz, 1H), 6.03 (br. dd, J=6.4, 1.9 Hz, 1H), 6.20 (s, 1H), 7.07–7.15 (m, 4H), 7.22–7.39 (m, 5H).13C NMR (CDCl3, 125.8 MHz): δ 17.49 (CH3), 21.13 (CH3), 31.82 (CH2), 34.00 (CH2), 42.79 (CH2), 45.42 (CH2), 90.61 (CH), 125.95 (CH), 128.67 (CH), 128.79 (CH), 128.86 (CH), 129.01 (CH), 129.12 (CH), 132.63 (C), 135.02 (C), 135.80 (C), 135.89 (C), 168.55 (C), 168.69 (C). Firmenich SA Synthesis of (±)-2-(2-(1,1- and 3,3-dimethyl-2,3-dihydro-1H-inden-5- and 4-yl)ethyl)-3-(2- phenylacetyl)oxazolidin-5-one (Compound 26) Following the general procedure described for Compound 22, and starting from (2- phenylacetyl)glycine (2.96 g, 15.0 mmol), 3-(1,1- and 3,3-dimethyl-2,3-dihydro-1H-inden-4- and 5-yl)propanal (Hivernal®Neo, mixture of three isomers (ca.49:41:10), 3.08 g, 15.0 mmol) and para-toluenesulfonic acid monohydrate (0.12 g, 0.7 mmol), 5.26 g of the crude product were obtained. Column chromatography (SiO2, n-heptane / EtOAc 9:1, then 8:2) afforded 3.32 g (59%) of the title compound as a mixture of three isomers (ca. 48:41:11), containing some remaining n-heptane.1H NMR (CDCl3, 500 MHz, major isomers): δ 1.23 and 1.24 (s, 6H), 1.90 (t, J=7.2 Hz, 2 H), 2.02–2.17 (m, 1H), 2.31–2.42 (m, 1H), 2.57–2.73 (m, 2H), 2.75–2.91 (m, 2H), 3.51–3.66 (m, 2H), 3.88 and 3.91 (d, J=16.3 and 16.7 Hz, 1H), 4.12 and 4.13 (d, J=16.7 and 16.3 Hz, 1H), 5.98–6.04 (m, 1H), 6.90–7.15 (m, 3H), 7.20–7.38 (m, 5H).13C NMR (CDCl3, 125.8 MHz, major isomers): δ 28.56, 28.59 and 28.62 (CH3), 28.99 and 29.18 (CH2), 29.66 and 29.95 (CH2), 35.26 and 35.49 (CH2), 41.50 and 41.57 (CH2), 42.69 and 42.71 (CH2), 43.62 and 43.89 (C), 45.27 and 45.29 (CH2), 90.47 and 90.57 (CH), 121.98 and 122.00 (CH), 124.45 and 124.51 (CH), 126.23 and 126.44 (CH), 128.81 (CH), 127.58 (CH), 129.10 (CH), 132.64 (CH), 137.77 and 137.97 (C), 140.82 and 143.23 (C), 150.71 and 153.01 (C), 168.45 (C), 168.78 (C). Synthesis of (±)-2-(2-(3-isopropylphenyl)propyl)-3-(2-phenylacetyl)oxazolidin-5-one (Compound 27) Following the general procedure described for Compound 22, and starting from (2- phenylacetyl)glycine (2.96 g, 15.0 mmol), 3-(3-isopropylphenyl)butanal (Florhydral®, 2.94 g, 15.0 mmol) and para-toluenesulfonic acid monohydrate (0.12 g, 0.7 mmol), 4.91 g of the crude product were obtained. Column chromatography (SiO2, n-heptane / EtOAc 8:2, then 7:3) afforded 3.28 g (60%) of the title compound as a mixture of two diastereoisomers (ca.54:46), containing some remaining EtOAc.1H NMR (DMSO-d6, 500 MHz, 45°C): δ 1.15–1.30 (m, 9H), 1.87–1.99, 2.03–2.21 and 2.24– 2.34 (br. m, 2H), 2.77–2.91 (m, 2H), 3.41 and 3.52–3.67 (d and br. m, J=15.7 Hz, 2H), 4.02 Firmenich SA 4.21 and 4.44 (br. dd, J=16.3 Hz, 2H), 5.54 and 5.94 (dd and br. m, J=8.7, 2.6 Hz, 1H), 6.97– 7.11 (m, 3H), 7.16–7.34 (m, 6H).13C NMR (DMSO-d6, 125.8 MHz, 45°C): δ 21.71 and 23.34 (br., CH3), 23.74, 23.78, 23.79 and 23.83 (CH3), 33.35 (CH), 34.28 and 35.05 (CH), 40.76 (CH2), 40.51 and 40.93 (CH2), 44.93 (CH2), 88.70 and 88.86 (br., CH), 123.84, 123.94 and 124.17 (br., CH), 124.76 and 124.99 (CH), 126.48 and 126.50 (CH), 128.10 and 128.15 (CH), 128.27 and 128.32 (CH), 129.38 and 129.43 (CH), 134.33 and 134.42 (br., C), 145.10 and 146.34 (br., C), 148.41 (br., C), 168.25 and 168.50 (br., C), 169.70 and 169.79 (C). Synthesis of (±)-2-nonyl-3-(2-phenylacetyl)oxazolidin-5-one (Compound 28) Following the general procedure described for Compound 22, and starting from decanal (1.97 g), 3.54 g of the crude product were obtained. Repetitive column chromatography (SiO2, n- heptane / EtOAc 9:1, then 8:2) afforded 2.05 g (50%) of the title compound.1H NMR (CDCl3, 600 MHz): δ 0.88 (t, J=7.1 Hz, 3H), 1.19–1.44 (m, 14H), 1.72–1.82 (m, 1H), 1.95–2.05 (m, 1H), 3.62 (d, J=15.0 Hz, 1H), 3.67 (d, J=15.0 Hz, 1H), 3.94 (d, J=16.6 Hz, 1H), 4.15 (d, J=16.6 Hz, 1H), 5.95–6.01 (m, 1H), 7.22–7.27 (m, 2H), 7.27–7.32 (m, 1H), 7.32–7.38 (m, 2H).13C NMR (CDCl3, 150.9 MHz): δ 14.11 (CH3), 22.67 (CH2), 22.78 (CH2), 29.02 (CH2), 29.24 (CH2), 29.40 (2 CH2), 31.84 (CH2), 33.90 (CH2), 42.74 (CH2), 45.36 (CH2), 91.05 (CH), 127.55 (CH), 128.82 (CH), 129.07 (CH), 132.73 (C), 168.42 (C), 168.91 (C). Synthesis of (±)-2-(6-methylhept-5-en-2-yl)-3-(2-phenylacetyl)oxazolidin-5-one (Compound 29) Following the general procedure described for Compound 13, and starting with glycine sodium salt (4.85 g, 50.0 mmol), Melonal (7.72 g, 55.0 mmol), and phenylacetyl chloride (8.70 g, 55.0 mmol), 13.91 g of the crude product were obtained. Column chromatography (SiO2, n- heptane / EtOAc 9:1, then 8:2) afforded 6.95 g (44%) of the title compound as a mixture of two diastereoisomers (ca.73:27), containing some remaining n-heptane.1H NMR (CDCl3, 600 MHz, major isomer): δ 0.74 (d, J=6.6 Hz, 3H), 1.21–1.35 (m, 1H), 1.47– 1.56 (m, 1H), 1.60 (s, 3H), 1.68 (s, 3H), 1.96–2.16 (m, 2H), 2.27–2.36 (m, 1H), 3.63 (d, J=15.0 Firmenich SA Hz, 1H), 3.70 (d, J=15.0 Hz, 1H), 3.92 (d, J=16.6 Hz, 1H), 4.15 (d, J=16.6 Hz, 1H), 5.06–5.11 (m, 1H), 5.97 (d, J=1.9 Hz, 1H), 7.21–7.38 (m, 5H).13C NMR (CDCl3, 150.9 MHz, major isomer): δ 11.21 (CH3), 17.70 (CH3), 25.42 (CH2), 25.72 (CH3), 31.89 (CH2), 36.15 (CH), 42.93 (CH2), 46.07 (CH2), 93.65 (CH), 123.65 (CH), 127.58 (CH), 128.83 (CH), 129.10 (CH), 132.14 (C), 132.73 (C), 168.71 (C), 169.07 (C).1H NMR (CDCl3, 600 MHz, minor isomer): δ 1.00 (d, J=6.9 Hz, 3H), 1.02–1.22 (m, 2H), 1.58 (s, 3H), 1.68 (s, 3H), 1.83–1.92 (m, 1H), 1.96–2.16 (m, 1H), 2.18–2.27 (m, 1H), 3.63 (d, J=15.0 Hz, 1H), 3.71 (d, J=15.0 Hz, 1H), 3.90 (d, J=16.6 Hz, 1H), 4.15 (d, J=16.6 Hz, 1H), 4.95–5.01 (m, 1H), 5.93 (d, J=2.3 Hz, 1H), 7.21–7.38 (m, 5H).13C NMR (CDCl3, 150.9 MHz, minor isomer): δ 14.32 (CH3), 17.70 (CH3), 25.16 (CH2), 25.72 (CH3), 28.43 (CH2), 36.59 (CH), 42.96 (CH2), 46.25 (CH2), 94.49 (CH), 123.65 (CH), 127.58 (CH), 128.79 (CH), 129.10 (CH), 132.19 (C), 132.78 (C), 169.00 (C), 169.06 (C). Synthesis of (±)-3-benzoyl-2-(undecan-2-yl)oxazolidin-5-one (Compound 30) A suspension of benzoyl glycine (hippuric acid, 3.29 g, 18.0 mmol), (±)-2-methylundecanal (2.84 g, 15.0 mmol) and acetic anhydride (5.8 mL, 60.0 mmol) in EtOAc (150 mL) was stirred at room temperature for 5 min before sulfuric acid (98%, 0.53 mL, 9.8 mmol) was added dropwise during 1 h. The reaction mixture was stirred at room temperature for 20 h. Then anhydrous Na2CO3(7.2 g) was added in small portions and the mixture stirred at room temperature for 15 min. After addition of EtOAc (100 mL), the reaction mixture was washed with a saturated aqueous solution of NaHCO3(50 mL). The aqueous phase was reextracted with EtOAc (100 mL) and the organic phases were washed with a saturated solution of NaCl (50 mL). The combined organic phases were dried (Na2SO4), concentrated, taken up in cold acetone (12 mL) and put into the freezer. After warming to room temperature, the mixture was filtered and washed with a minimum of cold acetone. The filtrate was concentrated to afford 5.43 g of the crude compound. Column chromatography (SiO2, n-heptane / EtOAc 9:1, then 8:2) yielded 1.72 g (33%) of the title compound as a mixture of two diastereoisomers (ca.60:40).1H NMR (DMSO-d6, 600 MHz, 45°C): δ 0.84 and 0.86 (t, J=7.2 Hz, 3H), 0.90 (br. m, 1.5H), 0.96 (d, J=7.0 Hz, 1.5H), 1.01–1.60 (m, 14H), 1.94–2.15 (br. m, 2H), 4.00–4.13 (m, 1H), 4.50– 4.65 (m, 1H), 6.04–6.10 (m, 1H), 7.45–7.51 (m, 2H), 7.51–7.56 (m, 1H), 7.61–7.67 (m, 2H).13C NMR (DMSO-d6, 150.9 MHz, 45°C): δ 13.80 and 13.82 (CH3), 11.94 and 14.15 (CH3), 21.98 and 21.99 (CH2), 26.19 and 26.22 (CH2), 28.58, 28.59, 28.82, 28.86, 28.88, 28.92 and Firmenich SA 28.98 (4 CH2), 31.19, 31.20 and 31.32 (2 CH2), 36.62 and 37.19 (CH), 47.56 and 47.88 (br., CH2), 92.31 and 92.78 (CH), 127.60 and 127.74 (CH), 128.31 and 128.33 (CH), 130.97 and 131.07 (CH), 134.48 and 134.56 (C), 168.70 and 169.17 (br., C), 169.93 and 169.95 (C). Synthesis of (±)-3-acetyl-2-(undecan-2-yl)oxazolidin-5-one (Compound 31) A suspension of 2-acetamidoacetic acid (2.16 g, 18.3 mmol), (±)-2-methylundecanal (2.84 g, 15.0 mmol) and acetic anhydride (5.50 mL, 57.0 mmol) in EtOAc (150 mL) was stirred at room temperature for 5 min. Then sulfuric acid (96%, 0.53 mL, 9.5 mmol) was added dropwise during 1 h and the reaction mixture stirred at room temperature for 23 h. After adding Na2CO3(7.20 g) in small portions and stirring for 15 min, a saturated aqueous solution of NaHCO3 (50 mL) was added. Then the reaction mixture was poured into EtOAc (100 mL) and diluted with water (20–30 mL). The aqueous phase was extracted with EtOAc (100 mL) and the organic phases washed with a saturated aqueous solution of NaCl (50 mL). The combined organic phases were dried (Na2SO4) and concentrated to afford 4.03 g of the crude compound. The product was taken up in a saturated aqueous solution of NaHCO3(50 mL) and stirred for 15 min. After addition of a saturated aqueous solution of NaCl (25 mL), the mixture was extracted with EtOAc (100 mL). The aqueous phases were reextracted with EtOAc (100 mL) and the combined organic phases washed with a saturated aqueous solution of NaCl (50 mL), dried (Na2SO4) and concentrated to give 3.85 g of product, 2.85 g of which were suspended in n-heptane / EtOAc 8:2, filtered and concentrated. Column chromatography (SiO2, n-heptane / EtOAc 8:2, then 7:3) yielded 1.21 g (38%) of the title compound as a mixture of two diastereoisomers (ca.70:30).1H NMR (DMSO-d6, 500 MHz, 48°C, major isomer): δ 0.76 (br. d, J=6.4 Hz, 3H), 0.86 (t, J=6.9 Hz, 3H), 1.10–1.50 (m, 16H), 2.00 (s, 3H), 2.05–2.16 (br. m, 1H), 4.20–4.44 (m, 2H), 5.77 (br. s, 1H).13C NMR (DMSO-d6, 125.8 MHz, 48°C, major isomer): δ 11.31 (CH3), 13.80 (CH3), 21.99 (CH2), 22.40 (br, CH3), 26.33 (CH2), 28.59 (CH2), 28.84 (CH2), 28.88 (CH2), 29.01 (CH2), 31.21 (CH2), 31.45 (CH2), 35.94 (CH), 46.11 (CH2), 92.35 (CH), 168.32 (br., C), 170.22 (C),1H NMR (DMSO-d6, 500 MHz, 48°C, minor isomer): δ 0.86 (t, J=6.9 Hz, 3H), 0.91 (br. d, J=6.4 Hz, 3H), 1.10–1.50 (m, 16H), 1.92–2.07 (br. m, 1H), 2.00 (s, 3H), 4.20–4.44 (m, 2H), 5.76 (br. s, 1H). Firmenich SA13C NMR (DMSO-d6, 125.8 MHz, 48°C, minor isomer): δ 13.80 (CH3), 14.34 (br., CH3), 21.99 (CH2), 22.40 (br., CH3), 26.25 (CH2), 28.15 (CH2), 28.58 (CH2), 28.84 (CH2), 28.88 (CH2), 29.05 (CH2), 31.24 (CH2), 36.53 (CH), 46.27 (CH2), 93.09 (CH), 168.68 (br., C), 170.22 (C). Synthesis of (±)-(7aS)-3-(undecan-2-yl)dihydro-1H,3H-pyrrolo[1,2-c]oxazole-1,5(6H)-dione (Compound 32) A suspension of L-pyroglutamic acid (3.30 g, 25.0 mmol), (±)-2-methylundecanal (5.07 g, 27.5 mmol) and 3–4 drops of trifluoroacetic acid (TFA) in toluene (50 mL) was heated under reflux with constant removal of water (Dean-Stark apparatus) for 18 h. After cooling to room temperature, more toluene was added and the mixture heated under reflux for another 7 h. Then molecular sieves (4 Å, 3.00 g) and another 3–4 drops of TFA were added and the mixture heated under reflux for 4 days. After cooling to room temperature, the reaction mixture was poured into a saturated aqueous solution of NaHCO3(100 mL) and stirred for 15 min. After filtration, EtOAc (100 mL) was added, and the aqueous phase saturated with NaCl. After extraction of the aqueous phase with EtOAc, the combined organic phases were washed with a saturated aqueous solution of NaCl (2x, 50 mL), dried (Na2SO4), filtered and concentrated. Bulb-to-bulb distillation (140–160°C, 0.3 mbar) to remove remaining (±)-2-methylundecanal and column chromatography (SiO2, n-heptane / EtOAc 8:2, then 7:3) afforded 1.46 g (20%) of the target compound as a mixture of two diastereoisomers (ca.55:45).1H NMR (CDCl3, 500 MHz, major isomer): δ 0.88 (t, J= 6.9 Hz, 3H), 1.01 (d, J=6.7 Hz, 3H), 1.10–1.36 (m, 14H), 1.36–1.60 (m, 2H), 1.74–1.88 (m, 1H), 2.21–2.32 (m, 1H), 2.48 (dd, J=9.9, 2.6 Hz, 1H), 2.56–2.66 (m, 1H), 2.74 (t, J=10.3 Hz, 1H), 4.29–4.35 (m, 1H), 5.63 (d, J=6.4 Hz, 1H).13C NMR (CDCl3, 125.8 MHz, major isomer): δ 14.00 (CH3), 14.12 (CH3), 22.68 (CH2), 23.47 (CH2), 26.67 (CH2), 29.30 (CH2), 29.53 (CH2), 29.55 (CH2), 29.70 (CH2), 30.84 (CH2), 31.89 (CH2), 31.94 (CH2), 38.68 (CH), 56.64 (CH), 93.45 (CH), 173.60 (C), 179.73 (C).1H NMR (CDCl3, 500 MHz, minor isomer): δ 0.88 (t, J=6.9 Hz, 3H), 0.95 (d, J=6.7 Hz, 3H), 1.10–1.36 (m, 14H), 1.36–1.60 (m, 2H), 1.74–1.88 (m, 1H), 2.21–2.32 (m, 1H), 2.45 (dd, J=9.9, 2.6 Hz, 1H), 2.56–2.66 (m, 1H), 2.77 (t, J=10.3 Hz, 1H), 4.29–4.35 (m, 1H), 5.65 (d, J=6.4 Hz, 1H). Firmenich SA13C NMR (CDCl3, 125.8 MHz, minor isomer): δ 13.73 (CH3), 14.12 (CH3), 22.68 (CH2), 23.54 (CH2), 26.53 (CH2), 29.30 (CH2), 29.53 (CH2), 29.56 (CH2), 29.71 (CH2), 31.16 (CH2), 31.89 (CH2), 31.94 (CH2), 38.46 (CH), 56.78 (CH), 93.30 (CH), 173.59 (C), 179.80 (C). Synthesis of (±)-benzyl 5-oxo-2-(undecan-2-yl)oxazolidine-3-carboxylate (Compound 33) A suspension of N-benzyloxycarbonylglycine (3.0 g, 14.3 mmol), (±)-2-methylundecanal (2.4 g, 13.0 mmol) and acetic anhydride (1.46 g, 14.3 mmol) in EtOAc (130 mL) was stirred at room temperature while sulfuric acid (96%, 0.64 g, 6.5 mmol) was added dropwise. The reaction mixture stirred at room temperature for 3 h. Solid Na2CO3(2.0 equiv.) was added to neutralize the reaction causing it to become cloudy. The mixture was diluted with Et2O and extracted with 10% Na2CO3(aq). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over MgSO4, filtered, and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography (5 – 30% EtOAc in Hexanes) to afford 3.44 g (64%) of the title compound as a colorless oil as a mixture of two diastereoisomers (ca.55:45).1H NMR (CDCl3, 500 MHz): δ 0.88 (d, J=6.8 Hz, 2H), 0.91 (t, J=6.8 Hz, 3H), 0.96-1.05 (br., 1H), 1.07-1.57 (m, 16H), 2.04 and 2.17 (br. s, 1H), 3.87-4.01 (m, 1H), 4.16-4.44 (br.1H), 5.20 (AB quartet, J=12.2 Hz, 2H), 5.67-5.87 (br., 1H), 7.33-7.43 (m, 5H).13C NMR (CDCl3, 125.8 MHz): δ 11.5 (CH3), 13.7 (CH3), 14.1 (CH3), 14.5 (CH3), 17.8 (CH2), 17.9 (CH2), 22.7 (CH2), 26.8 (CH2), 27.0 (CH2), 28.5 (CH2), 29.3 (CH2), 29.5 (CH2), 29.6 (CH2), 29.7 (CH2), 29.74 (CH2), 31.9 (CH2), 36.6 (CH), 36.9 (CH2), 37.2 (CH), 46.1 (CH2), 46.2 (CH2), 93.6 (CH), 94.4 (CH), 169.3 (C), 169.35 (C), 170.7 (C), 171.0 (C). Synthesis of benzyl (±)-2-(4-methoxyphenyl)-5-oxooxazolidine-3-carboxylate (Compound 34) A suspension of N-benzyloxycarbonylglycine (3.0 g, 14.3 mmol), 4-methoxybenzaldehyde (Anisaldehyde, 1.95 g, 14.3 mmol) and acetic anhydride (8.78 g, 86.0 mmol) in EtOAc (130 mL) was stirred at room temperature while sulfuric acid (96%, 0.5 g, 7.1 mmol) was added dropwise. The reaction mixture stirred at room temperature for 3 h. Solid Na2CO3(6 g) was added to neutralize the reaction causing it to become cloudy. The mixture was diluted with Et2O and extracted with 10% Na2CO3(aq). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over MgSO4, filtered, Firmenich SA and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 – 35% EtOAc in Hexanes) to afford 3.75 g (80%) of the title compound as a white solid.1H NMR (CDCl3, 500 MHz): δ 3.81 (s, 3H), 4.13 (d, J=17.4 Hz, 1H), 4.35 (d, J=17.2 Hz, 1H), 5.09 (d, J=12.1Hz, 1H), 5.15 (br., 1H), 6.63 (br. s, 1H), 6.89 (d, J=8.3 Hz, 2H), 7.31 (br., 7H).13C NMR (CDCl3, 125.8 MHz): δ 45.01 (CH2), 55.37 (CH3), 68.01 (CH2), 89.94 (CH), 114.19 (CH), 127.65 (CH), 128.17 (CH), 128.54 (CH), 128.59 (CH), 135.34 (C), 152.79 (C), 160.81 (C), 169.25 (C). Synthesis of benzyl (±)-2-((E / Z)-5-cyclohexyl-4-methylpent-4-en-2-yl)-5-oxooxazolidine-3- carboxylate (Compound 35) A suspension of N-benzyloxycarbonylglycine (3.00 g, 14.3 mmol), (E / Z)-5-cyclohexyl-2,4- dimethyl-pent-4-enal (Muguissimo®, 2.86 g, 14.7 mmol) and acetic anhydride (4.00 mL, 42.6 mmol) in EtOAc (100 mL) was stirred at room temperature while sulfuric acid (0.38 mL, 7.13 mmol) was added dropwise. The reaction mixture stirred at room temperature for 2 days. Solid Na2CO3(2.0 equiv.) was added to neutralize the reaction causing it to become cloudy. The mixture was extracted with sat. Na2CO3(aq). The organic phase was collected, and the aqueous phase was washed twice with EtOAc. The organic phases were combined, dried over Na2SO4, filtered, and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 – 10% EtOAc in Hexanes) to afford 3.37 g (61%) of the title compound as a colorless oil as a mixture of two diastereoisomers.1H NMR (CDCl3, 500 MHz): δ 0.81 (d, J=6.9 Hz, 2.5H), 0.84 (d, J=6.9 Hz, 0.5H), 0.90 – 1.05 (m, 2H), 1.10 – 1.20 (m, 1H), 1.20 – 1.30 (m, 2H), 1.40 – 1.75 (m, 7H), 1.85 – 2.45 (m, 5H), 3.92 (dd, J=20.7 and 17.7 Hz, 1H), 4.23 (br., 1H), 4.97 (d, J=8.8 Hz, 0.2H), 5.05 (br., 0.8H), 5.10 – 5.25 (m, 2H), 5.74 (br. s, 1H), 7.30 – 7.40 (m, 5H).13C NMR (CDCl3, 125 MHz): δ 11.44 (CH3), 15.59 (CH3), 25.86 (CH2), 25.89 (CH2), 25.93 (CH2), 26.02 (CH2), 26.04 (CH2), 26.07 (CH2), 33.17 (CH2), 33.24 (CH2), 33.26 (CH2), 33.39 (CH2), 33.44 (CH2), 33.51 (CH2), 36.69 (CH), 36.83 (CH), 37.03 (CH), 39.24 (CH2), 42.22 (CH2), 45.57 (CH2), 45.59 (CH2), 45.70 (CH2), 67.97 (CH2), 68.20 (CH2), 91.94 (CH), 92.81 (CH), 94.03 (CH), 128.30 (CH), 128.33 (CH), 128.61 (CH), 128.69 (CH), 129.45 (C), 134.36 (CH), 134.87 (CH), 152.88 (C), 153.15 (C), 169.62 (C), 169.67 (C). Firmenich SA Synthesis of (±)-3-(2-phenoxyacetyl)-2-(undecane-2-yl)oxazolidine-5-one (Compound 36) Step 1. In a round bottom flask, glycine (5.01 g, 66.7 mmol) was dissolved in an aqueous solution of NaOH (2N, 73 mL). The colorless solution was placed in an ice bath and 2- phenoxyacetyl chloride (9.00 mL, 65.2 mmol) was added dropwise. Reaction mixture was allowed to stir for an additional 30 min on ice before warming to room temperature and stirring for an additional 3 h. The pH of the reaction mixture was adjusted to 2 using HCl (1 M, aq.) causing a white solid to precipitate out of solution. The mixture was filtered using a fritted funnel and the white solid was then washed three times with water followed by three pentane washes. The solid was dried overnight on the frit prior to recrystallization using ethyl ether. The white crystals were collected through filtration and dried overnight to yield pure 2-[(2- phenoxyacetyl)amino]acetic acid (5.16 g, 38%).1H NMR (DMSO-d6, 500 MHz): δ 3.84 (d, J=6.0 Hz, 2H), 4.54 (s, 2H), 6.95 – 7.00 (m, 3H), 7.25 – 7.35 (m, 2H), 8.39 (t, J=6.0 Hz, 1H), 12.64 (br. s, 1H).13C NMR (DMSO-d6, 125 MHz): δ 40.88 (CH2), 67.26 (CH2), 115.25 (CH), 121.74 (CH), 129.97 (CH), 158.11 (C), 168.64 (C), 171.49 (C). Step 2. In a round bottom flask, 2-[(2-phenoxyacetyl)amino]acetic acid (2.54 g, 12.1 mmol), (±)-2-methylundecanal (2.31 g, 12.5 mmol), and acetic anhydride (3.5 mL, 37.0 mmol) were suspended EtOAc (87 mL). The mixture was stirred vigorously as concentrated sulfuric acid (0.30 mL, 5.63 mmol) was added. The reaction mixture was stirred at room temperature for 2 days. Solid Na2CO3(2.0 eq.) was added to neutralize the reaction causing it to become cloudy. The mixture was diluted with Et2O and extracted with sat. Na2CO3(aq.). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over Na2SO4, filtered, and the solvent of the filtrate was removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 – 18% EtOAc in Hexanes). The pure fractions were pulled together and the solvent was removed under reduce pressure. The title compound was collected as a white solid as a mixture of two diastereomers (0.72 g, 16%).1H NMR (CDCl3, 500 MHz): δ 0.61 (d, J=6.9 Hz, 1.5H), 0.85 – 1.15 (m, 5.5H), 1.20 – 1.50 (m, 15H), 2.00 – 2.10 (m, 0.5H), 2.10 – 2.20 (m, 0.5H), 4.16 (dd, J=17.0 and 4.6 Hz, 1H), 4.37 (d, J=17.3 Hz, 1H), 4.68 (s, 2H), 6.00 (dd, J=15.1 and 2.0 Hz, 1H), 6.93 (d, J=8.1 Hz, 2H), 7.03 (t, J=7.3 Hz, 1H), 7.25 – 7.35 (m, 2H). Firmenich SA13C NMR (CDCl3, 125 MHz): δ 11.15 (CH3), 14.12 (CH3), 14.19 (CH3), 22.68 (CH2), 26.84 (CH2), 26.93 (CH2), 28.39 (CH2), 29.31 (CH2), 29.42 (CH2), 29.51 (CH2), 29.55 (CH2), 29.64 (CH2), 29.70 (CH2), 31.68 (CH2), 31.89 (CH2), 36.54 (CH), 37.15 (CH), 45.82 (CH2), 46.07 (CH2), 68.05 (CH2), 68.09 (CH2), 93.55 (CH), 94.25 (CH), 114.15 (CH), 114.20 (CH), 122.39 (CH), 129.91 (CH), 129.94 (CH), 156.74 (C), 156.78 (C), 166.73 (C), 167.17 (C), 169.55 (C). Synthesis of (±)-(4S)-3-acetyl-4-methyl-2-(undecan-2-yl)oxazolidin-5-one (Compound 37) A suspension of N-acetyl-L-alanine (2.6 g, 19.8 mmol), (±)-2-methylundecanal (3.0 g, 16.3 mmol) and acetic anhydride (6.36 g, 62.3 mmol) in EtOAc (150 mL) was stirred at room temperature while sulfuric acid (98%, 1.02 g, 10.4 mmol) was added dropwise. The reaction mixture stirred at room temperature for one day during which time it became homogeneous. Solid Na2CO3(7.8 g) was added to neutralize the reaction causing the mixture to become cloudy. The mixture was diluted with Et2O and extracted with 10% Na2CO3(aq). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over MgSO4, filtered, and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography (5 – 30% EtOAc in Hexanes) to afford 3.56 g (73%, colorless oil) of the title compound as a mixture of four diastereoisomers (ca.31:28:23:18).1H NMR (CDCl3, 500 MHz): δ 0.73 (d, J=6.8 Hz), 0.83 (d, J=6.6 Hz), 0.89 (t, J=6.8 Hz), and 1.05 (d, J=7.0Hz) (6H), 0.99-1.60 (m, 16H), 1.64 (d, J=6.8 Hz, 3H), 1.69-1.81, 1.86-1.97, 1.97- 2.05 and 2.47-2.64 (all m, 1H), 2.08, 2.13 and 2.16 (all s, 3H), 4.22-4.41 (m, 0.9H), 4.54 (br., 0.1H), 5.55, 5.65, 5.70, 5.78, 5.81, 5.84 and 5.87 (all s, 1H).13C NMR (CDCl3, 125.8 MHz): δ 10.8 (CH3), 14.1 (CH3), 15.1 (CH3), 19.5 (CH3), 22.7 (CH2), 23.2 (CH3), 26.7 (CH2), 27.1 (CH2), 29.29 (CH2), 29.3 (CH2), 29.5 (CH2), 29.55 (CH2), 29.6 (CH2), 31.87 (CH2), 31.88 (CH2), 32.2 (CH2), 34.3 (CH), 37.0 (CH), 39.1 (CH), 52.6 (CH), 52.7 (CH), 52.9 (CH), 91.7 (CH), 93.1 (CH), 94.3 (CH), 168.0 (C), 168.1 (C), 172.5 (C), 172.6 (C). Synthesis of (±)-(4S)-3-butyryl-4-methyl-2-(undecan-2-yl)oxazolidin-5-one (Compound 38) Step 1. In a round bottom flask, L-alanine (10.0 g, 112 mmol) was dissolved in an aqueous solution of NaOH (2N, 56 mL). The colorless solution was placed in an ice bath and butyrl chloride (13.0 mL, 124 mmol) was added dropwise. The reaction mixture was allowed to stir Firmenich SA for an additional 30 min on ice before warming to room temperature and stirring for an additional 3 h. The pH was adjusted to 2 using HCl (1 M, aq.) and the reaction mixture extracted with diethyl ether (3 x 250 mL). The organic layers were combined, dried over Na2SO4, filtered, and the solvent of the filtrate was removed under reduce pressure. The white solid was washed with hexanes to yield butyrylalanine (8.22 g, 46%).1H NMR (DMSO-d6, 500 MHz): δ 0.86 (t, J=7.4 Hz, 3H), 1.25 (d, J=7.3 Hz, 3H), 1.50 (sext., J=7.4 Hz, 2H), 2.07 (t, J=7.4 Hz, 2H), 4.19 (pent., J=7.3 Hz, 1H), 8.06 (d, J=7.3 Hz, 1H), 12.40 (br. s, 1H).13C NMR (DMSO-d6, 125 MHz): δ 13.47 (CH3), 17.12 (CH3), 18.55 (CH2), 36.84 (CH2), 47.26 (CH), 171.82 (C), 174.27 (C). Step 2. A solution of butyrylalanine (2.61 g, 16.4 mmol), (±)-2-methylundecanal (3.01 g, 16.3 mmol) and acetic anhydride (4.70 mL, 49.7 mmol) in EtOAc (118 mL) was stirred at room temperature while sulfuric acid (0.44 mL, 7.92 mmol) was added dropwise. The reaction mixture stirred at room temperature for two days. Solid Na2CO3(5.0 g) was added to neutralize the reaction causing the mixture to become cloudy. The mixture was diluted with Et2O and extracted with sat. Na2CO3(aq.). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over Na2SO4, filtered, and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 – 18% EtOAc in hexanes) to afford 2.54 g (48%, colorless oil) of the title compound as a mixture of diastereoisomers.1H NMR (CDCl3, 500 MHz): δ 0.71 (d, J=6.7 Hz, 0.5H), 0.82 (br., 0.3H), 0.88 (t, J=6.7 Hz, 3.9H), 0.95 – 1.00 (m, 3.4H), 1.04 (d, J=6.4 Hz, 0.9H), 1.20 – 1.55 (m, 16H), 1.62 (d, J=6.8 Hz, 3H), 1.72 (sext., J=7.3 Hz, 2H), 1.85 – 2.10 (m, 0.8H), 2.15 – 2.40 (m, 2H), 2.50 – 2.65 (m, 0.2H), 4.31 (br., 1H), 5.55 – 6.00 (m, 1H).13C NMR (CDCl3, 125 MHz): δ 10.84 (CH3), 12.62 (CH3), 13.73 (CH3), 13.81 (CH3), 14.12 (CH3), 15.07 (CH3), 18.02 (CH2), 18.08 (CH2), 18.51 (CH2), 18.58 (CH2), 19.00 (CH3), 19.84 (CH3), 22.68 (CH2), 26.70 (CH2), 26.85 (CH2), 27.07 (CH2), 27.14 (CH2), 29.32 (CH2), 29.53 (CH2), 29.56 (CH2), 29.66 (CH2), 29.74 (CH2), 29.98 (CH2), 31.89 (CH2), 32.08 (CH2), 32.28 (CH2), 34.23 (CH), 35.95 (CH2), 36.05 (CH2), 36.41 (CH2), 37.08 (CH2), 37.28 (CH2), 38.74 (CH), 39.34 (CH), 51.99 (CH), 52.36 (CH), 52.55 (CH), 93.04 (CH), 93.39 (CH), 93.68 (CH), 94.35 (CH), 171.09 (C), 172.40 (C), 172.77 (C). Firmenich SA Synthesis of (±)-(4S)-4-methyl-3-octanoyl-2-(undecan-2-yl)oxazolidin-5-one (Compound 39) Step 1. In a round bottom flask, L-alanine (30.0 g, 333 mmol) was dissolved in an aqueous solution of NaOH (2N, 450 mL). The colorless solution was placed in an ice bath and octanoyl chloride (54.2 g, 333 mmol) was added dropwise. The reaction mixture was allowed to stir for an additional 30 min on ice before warming to room temperature and stirring for an additional 3 h. The pH was adjusted to 2 using HCl (1 M, aq.) and the reaction mixture extracted with diethyl ether (3 X 250 mL). The organic layers were combined, dried over MgSO4, filtered, and the solvent of the filtrate was removed under reduce pressure. The white solid was washed with hexanes to yield N-octanoyl-L-alanine (44.0 g, 72%). Step 2. A suspension of N-octanoyl-L-alanine (2.0 g, 9.29 mmol), (±)-2-methylundecanal (2.4 g, 13.0 mmol) and acetic anhydride (4.74 g, 46.4 mmol) in EtOAc (75 mL) was stirred at room temperature while sulfuric acid (98%, 0.36 g, 3.72 mmol) was added dropwise. The reaction mixture stirred at room temperature for one day during which time it became homogeneous. Solid Na2CO3(2.74 g) was added to neutralize the reaction causing the mixture to become cloudy. The mixture was diluted with Et2O and extracted with 10% Na2CO3(aq). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over MgSO4, filtered, and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 – 20% EtOAc in hexanes) to afford 1.14 g (32%, colorless oil) of the title compound as a mixture of diastereoisomers.1H NMR (CDCl3, 500 MHz): δ [0.71 (d, J=6.8 Hz), 0.82 (d, J=6.1 Hz), 0.88 (t, J=6.5 Hz), 1.00 (br.) and 1.04 (d, J=6.8) (9H)], 1.18-1.54 (m, 24H), 1.62 (d, J=6.7 Hz, 3H), 1.64-1.73 (m, 2H), 1.79-2.15 (br. m, 0.8H), 2.15-2.40 (m, 1.8H), 2.43-2.64 (m, 0.4H), 4.21-4.42 (m, 0.85H), 4.42- 4.67 (br. m, 0.15H), 5.58, 5.67, 5.72, 5.80, 5.82, 5.85 and 5.88 (all br. s, 1H).13C NMR (CDCl3, 125.8 MHz,): δ 10.9 (CH3), 14.07 (CH3), 14.12 (CH3), 15.1 (CH3), 16.3 (CH3), 19.9 (CH3), 22.6 (CH2), 22.7 (CH2), 24.6 (CH2), 24.65 (CH2), 25.1 (CH2), 26.7 (CH2), 27.07 (CH2), 27.14 (CH2), 29.04 (CH2), 29.07 (CH2), 29.29 (CH2), 29.33 (CH2), 29.55 (CH2), 29.56 (CH2), 29.57 (CH2), 29.66 (CH2), 31.7 (CH2), 31.9 (CH2), 34.2 (CH), 40.4 (CH), 40.6 (CH), 52.0 (CH), 52.4 (CH), 52.6 (CH), 93.0 (CH), 93.4 (CH), 93.7 (CH), 94.3 (CH), 171.3 (C), 172.5 (C), 172.8 (C). Firmenich SA Synthesis of (±)-(4S)-4-methyl-3-octanoyl-2-((Z)-undec-3-en-1-yl)oxazolidin-5-one (Compound 40) Following a modified procedure for Compound 39 and starting with N-octanoyl-L-alanine (3.04 g, 14.1 mmol), (Z)-4-dodecenal (2.72 g, 14.9 mmol), acetic anhydride (4.00 mL, 42.6 mmol), and sulfuric acid (0.37 mL, 6.94 mmol), 2.69 g (50%, colorless oil) of the title compound was obtained as a mixture of two diastereomers.1H NMR (CDCl3, 500 MHz): δ 0.88 (t, J=7.0 Hz, 6H), 1.20 – 1.40 (m, 20H), 1.62 (d, J=6.7 Hz, 3H), 1.68 (t, J=6.7 Hz, 2H), 1.85 – 2.40 (m, 6H), 4.29 (br., 1H), 5.25 – 5.55 (m, 2H), 5.65 – 6.00 (m, 1H).13C NMR (CDCl3, 125 MHz): δ 14.06 (CH3), 14.12 (CH3), 16.74 (CH3) 19.57 (CH3), 20.78 (CH2), 22.60 (CH2), 22.67 (CH2), 22.69 (CH2), 25.01 (CH2), 27.23 (CH2), 29.06 (CH2), 29.16 (CH2), 29.18 (CH2), 29.23 (CH2), 29.27 (CH2), 29.34 (CH2), 29.42 (CH2), 29.49 (CH2), 29.60 (CH2), 31.67 (CH2), 31.87 (CH2), 31.91 (CH2), 31.58 (CH2), 35.31 (CH2), 51.66 (CH), 51.90 (CH), 88.34 (CH), 90.08 (CH), 126.06 (CH), 127.29 (CH), 131.47 (CH), 132.81 (CH), 170.36 (C), 171.31 (C), 172.45 (C), 172.90 (C). Synthesis of (±)-3-acetyl-4-isobutyl-2-phenethyloxazolidin-5-one (Compound 41) General procedure to prepare 3-acetyl-4-isobutyloxazolidin-5-ones: In a round bottom flask, N-acetyl-DL-leucine (5.0 g, 28.9 mmol), aldehyde (0.8-1.5 equiv), and acetic anhydride (3-6 equiv) were suspended either in dichloromethane or EtOAc (150 mL). The mixture was stirred vigorously as concentrated sulfuric acid (0.3-0.5 equiv) was added. The reaction mixture was stirred at room temperature for one day. Solid Na2CO3(2.0 equiv.) was added to neutralize the reaction causing it to become cloudy. The mixture was diluted with Et2O and extracted with 10% Na2CO3(aq). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over MgSO4, filtered, and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 – 20% EtOAc in Hexanes). Following the general procedure and starting from N-acetyl-DL-leucine (5.0 g, 28.9 mmol), 3- phenylpropanal (5.81 g, 43.3 mmol), acetic anhydride (8.84 g, 86.6 mmol), H2SO4(1.41 g, 14.4 Firmenich SA mmol) and dichloromethane (150 mL), 6.4 g (76%, colorless oil) of the title compound was collected as a mixture of two diastereomers (ca.55:45).1H NMR (CDCl3, 500 MHz): δ 0.88-1.07 (overlapping d, J=6.6 Hz, 6H), 1.55-1.66 and 1.66- 1.78 (both m, 1H), 1.79-2.29 (m, 3H), 1.96 and 2.10 (both s, 3H), 2.30-2.45 and 2.45-2.60 (both m, 1H), 2.62-3.00 (m, 2H), 4.16 (br. d, J=7.3 Hz, 0.4H), 4.21 (br. d, J=9.1 Hz, 0.3H), 4.36 (br. s, 0.1H), 4.58 (br. s, 0.2H), 5.57 (br. s, 0.2H), 5.71 (br. s, 0.1H), 5.85 (br. s, 0.4 H), 5.91 (br. d, J=7.5 Hz, 0.3H), 7.16-7.25 (m, 3H), 7.25-7.35 (m, 2H).13C NMR (CDCl3, 125.8 MHz): δ 21.4 (CH3), 21.6 (CH3), 21.9 (CH3), 22.8 (CH3), 23.4 (CH3), 23.5 (CH3), 23.9 (CH), 24.3 (CH), 28.9 (CH2), 30.6 (CH2), 33.4 (CH2), 37.9 (CH2), 41.2 (CH2), 43.5 (CH2), 54.3 (CH), 55.2 (CH), 89.3 (CH), 89.8 (CH), 126.2 (CH), 126.3 (CH), 128.3 (CH), 128.4 (CH), 140.1 (C), 168.2 (C), 168.5 (C), 171.7 (C). Synthesis of (±)-(Z)-3-acetyl-4-isobutyl-2-(non-3-en-1-yl)oxazolidin-5-one (Compound 42) Following the general procedure described for Compound 41 and starting from N-acetyl-DL- leucine (4.0 g, 23.1 mmol), (Z)-4-decenal (3.2 g, 20.8 mmol), acetic anhydride (12.7 g, 124.7 mmol), H2SO4(0.71 g, 7.3 mmol) and ethyl acetate (150 mL), 1.89 g (29%, colorless oil) of the title compound was isolated as a mixture of two diastereomers (ca. 65:35).1H NMR (CDCl3, 500 MHz): δ 0.89 (t, J=6.9 Hz, 3H), 0.91-1.08 (br. overlapping d, 6H), 1.21- 1.41 (m, 6H), 1.57 and 2.24 (m, 12H), 4.11-4.49 (m, 0.85H), 4.52-4.66 (m, 0.15H), 5.24-5.58 (m, 2H), 5.65 (br. s, 0.1H), 5.70-6.00 (m, 0.9H).13C NMR (CDCl3, 125.8 MHz): δ 14.1 (CH3), 20.8 (CH2), 21.7 (CH3), 22.6 (CH2), 23.0 (CH3), 24.0 (CH), 24.3 (CH), 27.17 (CH2), 27.21 (CH2), 29.24 (CH2), 29.27 (CH2), 31.5 (CH2), 41.3 (CH2), 55.3 (CH), 90.3 (CH), 127.3 (CH), 131.4 (CH), 168.1 (C), 171.7 (C). Synthesis of (±)-3-acetyl-4-isobutyl-2-(undecan-2-yl)oxazolidin-5-one (Compound 43) Following the general procedure described for Compound 41 and starting from N-acetyl-DL- leucine (5.63 g, 32.5 mmol), (±)-2-methylundecanal (5.0 g, 27.1 mmol), acetic anhydride (8.31 g, 81.3 mmol), H2SO4(1.33 g, 13.6 mmol) and dichloromethane (150 mL), 6.45 g (70%, colorless oil) of the title compound was isolated as a mixture of diastereomers.1H NMR (CDCl3, 600 MHz): δ 0.69-1.10 (overlapping methyl group signals, 12H), 1.21-1.35 (m, 13H), 1.12-1.20, 1.35-1.52, 1.52-1.68, 1.68-1.84, 1.84-1.93 and 1.93-2.02 (all m, 6H), 2.03, Firmenich SA 2.07, 2.12 and 2.13 (all s, 3H), 2.05-2.15 and 2.56-2.70 (both m, 1H), 4.20 (br. s, 0.4H), 4.26 (d, J=7.9 Hz, 0.3H), 4.36 (br. d, J=5.4 Hz, 0.1H), 4.46-4.68 (br. m, 0.2H), 5.48, 5.54, 5.69, 5.75, 5.79 and 5.81 (all br. s, 1H).13C NMR (CDCl3, 150.8 MHz): δ 10.8 (CH3), 13.2 (CH3), 14.1 (CH3), 15.2 (CH3), 21.7 (CH3), 22.7 (CH2), 23.1 (CH3), 23.6 (CH3), 23.9 (CH), 24.9 (CH), 26.6 (CH2), 26.9 (CH2), 27.2 (CH2), 29.3 (CH2), 29.53 (CH2), 29.56 (CH2), 29.61 (CH2), 29.74 (CH2), 29.78 (CH2), 30.75 (CH2), 31.9 (CH2), 32.3 (CH2), 33.86 (CH), 33.95 (CH), 37.9 (CH), 39.6 (CH), 41.37 (CH2), 41.42 (CH2), 43.5 (CH2), 50.6 (CH), 55.4 (CH), 55.7 (CH), 55.9 (CH), 91.6 (CH), 93.2 (CH), 93.3 (CH), 94.5 (CH), 168.07 (C), 168.14 (C), 171.90 (C), 171.98 (C), 172.05 (C). Synthesis of (±)-(4S)-3-acetyl-4-benzyl-2-(undecan-2-yl)oxazolidin-5-one (Compound 44) A suspension of N-acetyl-L-phenylalanine (2.0 g, 9.65 mmol), and acetic anhydride (6.36 g, 62.3 mmol) in EtOAc (150 mL) was stirred at room temperature while sulfuric acid (98%, 1.02 g, 10.4 mmol) was added dropwise. The mixture was stirred for 1 h and became homogeneous. (±)-2-Methylundecanal (3.0 g, 16.3 mmol) was added and the solution was stirred for 1 week. Solid Na2CO3(4.0 g) was added to neutralize the reaction causing the mixture to become cloudy. The mixture was diluted with Et2O and extracted with 10% Na2CO3(aq). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over MgSO4, filtered, and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography (5 – 30% EtOAc in hexanes) to afford 1.65 g (46%, colorless oil) of the title compound as a mixture of four diastereoisomers (ca.35:24:21:15).1H NMR (CDCl3, 500 MHz): δ 0.67 (d, J=6.8 Hz, 0.5H), 0.80 (d, J=6.7 Hz, 0.8H), 0.86-0.93 (m, 3.7H), 0.96 (d, J=6.8 Hz, 1H), 1.00-1.48 (m, 16H), 1.48-1.58 (br. m, 0.3H), 1.58-1.73 (br. m, 0.8H), 1.83-1.97 (m, 0.5H), 1.99, 2.10 and 2.30 (all s, 2.2H), 2.49-2.64 (m, 0.2H), 2.96-3.20 (m, 0.7H), 3.20-3.47 (m, 1H), 3.68 (dd, J=13.8,5.6 Hz, 0.3H), 4.44 (br. s, 0.3H), 4.56-4.62 (m, 0.3H), 4.63-4.70 (m, 0.4H), 4.94, 4.98 and 5.01 (all s, 0.7H), 5.68-5.90 (br. s, 0.3H), 7.06-7.16 (m, 1H), 7.19-7.40 (m, 4H).13C NMR (CDCl3, 125.8 MHz): δ 10.7 (CH3), 10.8 (CH3), 14.1 (CH3), 14.13 (CH3), 15.0 (CH3), 15.1 (CH3), 22.5 (CH3), 22.53 (CH3), 22.67 (CH2), 22.7 (CH2), 23.37 (CH3), 23.4 (CH3), 26.4 (CH2), 26.9 (CH2), 27.1 (CH2), 29.26 (CH2), 29.33 (CH2), 29.5 (CH2), 29.6 (CH2), 29.9 (CH2), 31.88 (CH2), 31.9 (CH2), 32.1 (CH2), 32.16 (CH2), 33.4 (CH), 33.5 (CH), 33.9 (CH2), 38.1 Firmenich SA (CH2), 38.5 (CH), 38.7 (CH), 58.4 (CH), 58.6 (CH), 58.9 (CH), 59.0 (CH), 91.2 (CH), 93.5 (CH), 94.2 (CH), 95.3 (CH), 127.3 (CH), 128.0 (CH), 128.6 (CH), 129.1 (CH), 129.6 (CH), 133.26 (C), 133.3 (C), 134.93 (C), 134.95 (C), 167.4 (C), 167.5 (C), 167.9 (C), 168.0 (C), 171.1 (C), 171.2 (C), 171.7 (C), 171.8 (C). Synthesis of (±)-(4S)-3-acetyl-4-(2-(methylthio)ethyl)-2-(undecan-2-yl)oxazolidin-5-one (Compound 45) A suspension of N-acetyl-L-methionine (3.0 g, 15.7 mmol), (±)-2-methylundecanal (3.0 g, 16.3 mmol), and acetic anhydride (10.0 g, 98 mmol) in EtOAc (150 mL) was stirred at room temperature while sulfuric acid (98%, 0.74 g, 7.6 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 3 h. Solid Na2CO3(6.54 g) was added to neutralize the reaction causing it to become cloudy. The mixture was diluted with Et2O and extracted with 10% Na2CO3(aq). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over MgSO4, filtered, and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 – 20% EtOAc in Hexanes) to afford 3.05 g (54%, colorless oil) of the title compound as a mixture of diastereoisomers.1H NMR (CDCl3, 600 MHz): δ 0.72, 0.83, 1.04 and 1.10 (all d, J=6.9 Hz, 3H), 0.88 (t, J=7.0 Hz, 3H), 0.96-1.59 (m, 16H), 2.00-2.13 (m, 0.8H), 2.07, 2.09, 2.11 and 2.16 (all s, 6h), 2.23- 2.35 (m, 1.4H), 2.36-2.45 (m, 0.4H), 2.48-2.72 (m, 2H), 2.78-2.90 (m, 0.4H), 4.35-4.54 (m, 0.9H), 4.66 (br. s, 0.1H), 5.44-5.66 (br. m, 0.1H), 5.70, 5.77 and 5.84 (all s, 0.9H).13C NMR (CDCl3, 150.9 MHz): δ 10.8 (CH3), 11.0 (CH3), 14.1 (CH3), 15.0 (CH3), 15.1 (CH3), 15.7 (CH3), 22.4 (CH3), 22.5 (CH3), 22.67 (CH2), 22.68 (CH2), 23.1 (CH3), 26.6 (CH2), 26.8 (CH2), 26.88 (CH2), 26.9 (CH2), 27.0 (CH2), 27.1 (CH2), 27.2 (CH2), 28.2 (CH2), 28.7 (CH2), 29.3 (CH2), 29.47 (CH2), 29.52 (CH2), 29.55 (CH2), 29.6 (CH2), 29.69 (CH2), 29.71 (CH2), 29.8 (CH2), 31.8 (CH2), 31.9 (CH2), 32.2 (CH2), 33.88 (CH), 33.94 (CH), 38.7 (CH), 38.9 (CH), 55.6 (CH), 55.76 (CH), 55.8 (CH), 55.9 (CH), 91.9 (CH), 93.5 (CH), 93.7 (CH), 94.9 (CH), 167.1 (C), 167.2 (C), 167.9 (C), 167.95 (C), 171.5 (C), 171.6 (C), 172.1 (C), 172.2 (C). Synthesis of (±)-(4S)-3-acetyl-4-isopropyl-2-(undecan-2-yl)oxazolidin-5-one (Compound 46) A suspension of N-acetyl-L-valine (3.0 g, 18.8 mmol), (±)-2-methylundecanal (3.15 g, 17.1 mmol), and acetic anhydride (5.25 g, 51 mmol) in EtOAc (150 mL) was stirred at room Firmenich SA temperature while sulfuric acid (98%, 1.07 g, 10.9 mmol) was added dropwise. After stirring at room temperature for 17 h additional acetic anhydride (5.25 g, 51 mmol) was added and the mixture stirred for another 7 h. Solid Na2CO3(8.2 g) was added to neutralize the reaction causing it to become cloudy. The mixture was diluted with Et2O and extracted with 10% Na2CO3(aq). The organic phase was collected, and the aqueous phase was washed twice with Et2O. The organic phases were combined, dried over MgSO4, filtered, and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 – 10% EtOAc in Hexanes) to afford 1.25 g (22%, pale-yellow oil) of the title compound as a mixture of four diastereoisomers (ca.28:25:23:22).1H NMR (CDCl3, 500 MHz): δ [0.71 (d, J=6.9 Hz), 0.82 (d, J=6.8 Hz), 0.84 (d, J=6.9 Hz), 0.95 (dd, J=6.9, 2.6 Hz), 1.04 (dd, J=6.4, 2.3 Hz), 1.10 (d, J=7.0 Hz), 1.17 (d, J=7.0 Hz), 1.22 (dd, J=6.8, 2.3 Hz) 9H], 0.89 (t, J=6.6 Hz, 3H), 0.99-1.58 (m, 15H), 1.61-1.80 (m, 1H), 1.93-2.11 (m, 1H), 2.10 and 2.14 (both s, 3H), 2.21-2.38, 2.55-2.73 and 2.85-2.97 (all m, 1H), 3.93 (br. s, 0.3H), 4.15 (d, J=2.8 H, 0.4H), 4.32 (d, J=2.7 H, 0.3H), 5.43 (br. s, 0.2H), 5.65 (s, 0.1H), 5.73 (s, 0.3H), 5.79 (s, 0.3H), 5.88 (s, 0.1H).13C NMR (CDCl3, 125.8 MHz): δ 10.75 (CH3), 10.88 (CH3), 14.10 (CH3), 15.17 (CH3), 15.22 (CH3), 15.72 (CH3), 15.77 (CH3), 17.76 (CH3), 18.20 (CH3), 19.98 (CH3), 20.05 (CH3), 22.66 (CH2), 22.67 (CH2), 22.92 (CH3), 22.94 (CH3), 26.42 (CH2), 26.77 (CH2), 26.81 (CH2), 27.10 (CH2), 27.12 (CH2), 27.16 (CH2), 29.28 (CH2), 29.30 (CH2), 29.31 (CH2), 29.52 (CH2), 29.54 (CH2), 29.56 (CH2), 29.73 (CH2), 29.76 (CH2), 31.87 (CH2), 32.30 (CH2), 32.76 (CH), 32.78 (CH), 33.68 (CH), 33.80 (CH), 38.81 (CH), 39.03 (CH), 61.55 (CH), 61.76 (CH), 62.22 (CH), 62.39 (CH), 91.70 (CH), 93.26 (CH), 93.72 (CH), 94.96 (CH), 166.97 (C), 167.04 (C), 167.98 (C), 168.07 (C), 169.76 (C), 169.85 (C), 170.34 (C), 170.46 (C). Synthesis of benzyl 2,2-dimethyl-5-oxooxazolidine-3-carboxylate (Compound 47) A suspension of ((benzyloxy)carbonyl)glycine (3.0 g, 14.1 mmol) and acetic anhydride (4.30 g, 42.2 mmol) in acetone (50 mL) was stirred at room temperature while sulfuric acid (98%, 0.63 g, 6.40 mmol) was added dropwise. The mixture was stirred at room temperature for 3 days. Solid Na2CO3(10.0 g) was added to neutralize the reaction causing it to become cloudy. The mixture was filtered, and the filtrate was concentrated. The crude oil was purified by vacuum distillation to afford 1.7 g (49%) of the title compound. Firmenich SA1H NMR (CDCl3, 600 MHz): δ 1.70 (br. s, 2H), 1.78 (br. s, 4H), 4.14 (s, 2H), 5.10 – 5.25 (m, 2H), 7.30 – 7.40 (m, 5H).13C NMR (CDCl3, 150 MHz): δ 25.71 (CH3), 45.62 (CH2), 67.36 (CH2), 97.71 (C), 128.08 (CH), 128.46 (CH), 128.68 (CH), 135.72 (C), 151.56 (C), 168.16 (C). Example 2 Performance of the invention’s compounds of formula (I) in a model fabric softener application The performance of the present invention’s compounds of formula (I) was tested in a fabric softening surfactant emulsion with the following final composition: Stepantex®VL90 A (origin: Stepan) 12.21 % by weight Calcium chloride (10% aq. solution) 0.40 % by weight Proxel®GXL (origin: Avecia) 0.04 % by weight Water 87.35 % by weight The invention’s precursor compound of formula (I) (0.1 mmol) was dissolved in ethanol (0.2 mL) and completed to 7.0 g of the above-described fabric softener formulation. After homogenization, an aliquot of the sample (0.07 g) was placed in a flask and diluted with demineralized cold tap water (23.0 g). Then, one cotton sheet (EMPA cotton test cloth Nr.221, origin: Eidgenössische Materialprüfanstalt), pre-washed with an unperfumed detergent powder and cut to ca. 15 x 15 cm sheets, ca. 5.2 g) was added and shaken manually for 3 min, left standing for 2 min, then wrung out by hand, and weighed (ca. 10.0 g) to obtain a constant quantity of residual water. A reference sample consisting of an equimolar amount of the corresponding unmodified compound of formula (II) to be released form the precursor compound of formula (I) was prepared and analyzed the same way. The cotton sheets were line- dried for 1 or 3 days before being analyzed. For the measurements, the sheets were put into a headspace sampling cell (ca. 160 mL inner volume), which were thermostatted at 25°C and exposed to a constant air flow of ca.200 mL / min. The air was filtered through active charcoal Firmenich SA and aspirated through a saturated solution of NaCl (to ensure a constant humidity of the air of ca.75%). The system was equilibrated during 15 min while adsorbing the volatiles on a waste Tenax®cartridge. Then, seven times consecutively, the volatiles were adsorbed for 15 min on a clean Tenax®cartridge and for 45 min on a waste Tenax®cartridge. A final data point was collected by adsorbing the volatiles for 15 min on a clean Tenax®cartridge. Altogether eight data points were collected. Each cartridge contained 100 mg of poly(2,6-diphenyl-p-phenylene oxide) (Tenax®TA). The waste cartridges were discarded; the other cartridges were desorbed on a Markes TD100-xr thermodesorber coupled to an Agilent Technologies 7890A gas chromatograph equipped with a Supelco MDN-1 capillary column (30 m, i.d.0.32 mm, film 1 µm) and a flame ionization detector. The volatiles were analyzed using a temperature gradient moving from 60°C (for 1 min) to 250°C at 10°C / min. Headspace concentrations (in ng / L air) were obtained by external standard calibrations using different concentrations of the fragrance to be released in ethanol. Each calibration solution (0.2 µL) was injected onto a clean Tenax®cartridge, which was desorbed and analyzed under the same conditions. Table 1 lists the sum of the headspace concentrations collected from the eight data points for the release of the respective compounds of formula (II) as compared to an equimolar amount of the corresponding unmodified compounds of formula (II) above dry cotton after line-drying for 1 day; the corresponding data recorded after 3 days are listed in Table 2. All values are average values of at least two measurements. Table 1: Average headspace concentrations (sum of eight data points) of compounds of formula (II) measured on dry cotton after line-drying for 1 day after a fabric softener application. irmenich SA Table 2: Average headspace concentrations (sum of eight data points) of compounds of formula (II) measured on dry cotton after line-drying for 3 days after a fabric softener application. Firmenich SA Precursors according to formula (I) released higher quantities of aldehydes or ketones according to formula (II) into the headspace than the corresponding unmodified reference compound of formula (II). Compounds of formula (I) according to the present invention are capable to increase the long-lastingness of active aldehydes or ketones. Example 3 Performance of the invention’s compounds of formula (I) in a model fabric softener application The performance of the present invention’s compounds of formula (I) was tested in a fabric softening surfactant emulsion with the composition described in Example 2. The invention’s precursor compound of formula (I) (0.15 mmol) was dissolved in acetone (0.35 mL). Liquid fabric softener (9.0 g) was added to the vial and the mixture shaken by hand to mix. Reference samples were prepared in the same manner using 0.15 mmol of the released volatile. The fabric softener samples were rinsed with deionized water into a 4 L beaker and the beaker was filled to a total volume of 3.0 L. Six, 5 g cotton swatches (ca.12.5 x 12.5 cm, weight 270 g / m2, item 403 from Testfabrics, West Pittston, PA) were added to the beaker and agitated by hand for 3 min. After an additional 2 min of standing, the swatches were retrieved, and excess water squeezed out by hand. The three clothes were hung to dry overnight (15 – 16 h) at room temperature while the remaining three were dried for 3 days (72 h) at room temperature. The swatches were then subjected to dynamic headspace analysis. Firmenich SA Each swatch was placed inside a thermostatted (25 °C) headspace sampling cell (about 160 mL volume). Using an air-sampling pump, a constant flow of air (200 mL / min) was filtered through active charcoal and aspirated through a saturation solution of NaCl (to ensure a constant relative humidity of 75% of the air). Volatiles were adsorbed on a clean cartridge containing Tenax®(100 mg) for 15 min followed by 45 min on a waste Tenax®cartridge. A total of four points were collected. The waste cartridges were discarded while the other cartridges were thermally desorbed with a Gerstel TDU 3.5 with cyrofocusing at -30 °C and desorbed into an Agilent 8890 gas chromatograph equipped with a HP1 capillary column (30 m, i.d.0.25 mm, film 0.25 µm) and coupled with Agilent 5977B mass spectrometer. The GC oven temperature profile was 52 °C to 110 °C at 20 °C / min (hold 2 min) then ramped to 210 °C (20 °C / min). The amount of each fragrance volatile collected (reported as ng / L of air) was determined using external standard calibrations of the different concentrations of the fragrance to be released. At least five acetone solutions were prepared with concentrations of the analytes ranging from 0.05 g / L to 5 g / L. The solutions were injected (0.2 µL) onto Tenax®cartridges and desorbed as described above. Each solution was analyzed in triplicate. Calibration curves were forced through the origin. Table 3 lists the sum of the headspace concentrations collected from the four data points for the release of the respective compounds of formula (II) as compared to an equimolar amount of the corresponding unmodified compounds of formula (II) above dry cotton after line-drying for 1 day; the corresponding data recorded after 3 days are listed in Table 4. All values are average values of at least three measurements. Table 3: Headspace concentrations (sum of four averaged data points) of compounds of formula (II) measured on dry cotton after line-drying for 1 day after a fabric softener application. irmenich SA Table 4: Average headspace concentrations (sum of four data points) of compounds of formula (II) measured on dry cotton after line-drying for 3 days after a fabric softener application. Firmenich SA Precursors according to formula (I) released higher quantities of aldehydes or ketones according to formula (II) into the headspace than the corresponding unmodified reference compound of formula (II). Compounds of formula (I) according to the present invention are capable to increase the long-lastingness of active aldehydes or ketones. Example 4 Dynamic headspace analysis of the release of a perfuming ingredient from the invention’s compounds of formula (I) in a laundry application Ten, cotton terry, hand towels (weight 1.2 kg) were washed in a top-loading washing machine (Maytag Model LSG7806AAE, large load setting) using 115 grams of an unfragranced liquid laundry detergent (Tide®Free and Gentle). A warm-water wash with cold-water rinse was used. A model, liquid fabric softener was prepared by mixing a triethanolamine-esterquat (Stepantex®VL 90A, origin: Stepan) (12.3%), 10% aqueous calcium chloride (0.4%) and deionized water (87.3%). Thirty grams of the fabric softener containing either 1 or 0.5 wt.% of Compound 5 was added during the rinse stage. At the end of the wash, the towels were hung on racks to air dry overnight in a laboratory. The dry towels were wrapped in aluminum foil and stored at room temperature. For comparison, control towels were prepared using fabric softener containing an equivalent molar level of 2-methylundecanal. Dynamic headspace analyses were performed comparing towels treated with fabric softener containing Compound 5 against towels treated with fabric softener containing 2- Firmenich SA methylundecanal. A towel was placed in a 3-liter glass vessel. Air (filtered through active charcoal) was pulled through the vessel and then through a Tenax®cartridge (100 mg) at a rate of 130 mL / min for one hour. The Tenax®cartridges were thermally desorbed (Perkin Elmer ATD 400) and analyzed by GC-MS and GC-FID (Perkin Elmer AutoSystem XL coupled to a Perkin Elmer TurboMass mass detector). Using the GC-FID peak areas, the amount of 2- methylundecanal in the headspace samples of the towels treated with Compound 5 is reported relative to the towels treated with 2-methylundecanal. These data are presented in Table 5 (duplicate analyses were performed for each data point). Table 5: Relative GC-FID peak area for 2-methylundecanal obtained from line-dried cotton towels treated with fabric softener containing Compound 5 relative to control towels treated with fabric softener containing 2-methylundecanal. These data show that, when applied to cotton fabric from a liquid fabric softener application, Compound 5 released significantly higher amounts of the perfumery ingredient relative to the control at all the time points measured. This demonstrates the ability of the invention’s compounds to continuously release perfumery ingredients over an extended period of time. Example 5 Preparation of a perfume oil A non-limiting example of a typical perfume oil is prepared by admixing the following perfuming co-ingredients: Ingredients weight-% Ethyl 2-methylbutanoate 0.16 Hexyl acetate 0.37 Limonene 1.67 2,6-Dimethyl-7-octen-2-ol 0.94 menich SA 2-Phenylethanol 2.15 Linalool 0.73 (2RS,4SR / 4RS)-4-Methyl-2-(2-methyl-1-propen-1-yl)tetrahydro-2H-pyran 0.30 Ethyl 2-methyl-1,3-dioxolane-2-acetate 0.32 Benzyl acetate 2.46 Allyl heptanoate 0.38 alpha-Terpineol 0.88 3,7-Dimethyl-6-octen-1-ol 0.55 4-Methoxybenzaldehyde 1.00 (E)-4-Methyl-3-decen-5-ol 0.37 [cis / trans-4-(2-Propanyl)cyclohexyl]methanol 0.47 1-Methoxy-4-[(1E)-1-propen-1-yl]benzene 0.15 (1RS,2RS / 2SR)-2-(2-Methyl-2-propanyl)cyclohexyl acetate 1.95 1,1-Dimethyl-2-phenylethyl acetate 0.95 Tricyclo[5.2.1.02,~]dec-3 / 4-en-8-yl acetate 3.34Allyl 3-cyclohexylpropanoate0.263-(4-Isopropylphenyl)-2-methylpropanal 8.18 (3E)-3-Methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one and (1E)- 1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-1-penten-3-one 1.13 2-Phenoxyethyl 2-methylpropanoate 5.38 Tricyclo[5.2.1.0(2,6)]dec-3 / 4-en-8-yl propanoate 2.32 5-Heptyldihydro-2(3H)-furanone 2.30 2 / 3-Methylbutyl salicylate 1.42 (3Z)-3-Hexen-1-yl salicylate 0.31 1-(2,3,8,8-Tetramethyl-1,3,4,5,6,7-hexahydronaphthalen-2-yl)ethanone 16.03 Hexyl 2-hydroxybenzoate 5.04 (2E)-2-Benzylideneoctanal 21.22 (-)-(3aR,5aS,9aS,9bR)-3a,6,6,9a-Tetramethyldodecahydronaphtho[2,1-b]furan 0.27 1-Oxa-12 / 13-cyclohexadecen-2-one 4.78 Oxacyclohexadecan-2-one 3.82Benzyl 2-hydroxybenzoate3.01Dipropylene glycol 5.39 Total: 100 Firmenich SA Example 6 Preparation of transparent isotropic shampoo formulations comprising an invention’s compound of formula (I) A typical unperfumed transparent isotropic shampoo formulation is listed in Table 6. The unperfumed shampoo formulation is prepared by dispersing Polyquaternium-10 in water. The remaining ingredients of Phase A are mixed separately by addition of one after the other while mixing well after each adjunction. This pre-mix is added to the Polyquaternium-10 dispersion and mixed for another 5 min. Then, the premixed Phase B and the premixed Phase C are added (Monomuls®90L-12 is heated to melt in Texapon®NSO IS) while agitating. Phase D and Phase E are added while agitating. The pH is adjusted with a citric acid solution to 5.5–6.0. Table 6: Composition of a typical unperfumed transparent isotropic shampoo formulation. (1)Ucare®Polymer JR-400; origin: Noveon(2)Origin: Brenntag Schweizerhall AG(3)Glydant®; origin: Lonza Firmenich SA(4)Texapon®NSO IS; origin: Cognis(5)Tego®Betain F 50; origin: Evonik(6)Amphotensid GB 2009; origin: Zschimmer & Schwarz(7)Brij®S20; origin: Croda(8)Monomuls®90 L-12; origin: Gruenau GmbH(9)Nipagin Monosodium; origin: NIPA The perfumed shampoo formulation is then obtained by adding, under gentle shaking, a perfume oil of Example 5 (0.1 to 0.8% by weight relative to the total weight of the unperfumed shampoo formulation) and at least one of the compounds of formula (I) (0.05 to 0.50% by weight relative to the total weight of the unperfumed shampoo formulation) into the unperfumed shampoo formulation listed in Table 6. Example 7 Preparation of pearly shampoo formulations comprising an invention’s compound of formula (I) A typical unperfumed pearly shampoo formulation is listed in Table 7. The unperfumed shampoo formulation is prepared by dispersing Tetrasodium EDTA, Guar hydroxypropyltrimonium chloride and Polyquaternium-10 in water. NaOH (10% aqueous solution, Phase B) is added once Phase A is homogeneous. Then, the premixed Phase C is added, and the mixture heated to 75°C. Phase D ingredients are added and mixed until the mixture is homogeneous. The mixture is cooled. At 45°C, Phase E ingredients are added while mixing. The final viscosity is adjusted with NaCl (25% aqueous solution) and a pH of 5.5-6.0 is adjusted with NaOH (10% aqueous solution). Table 7: Composition of a typical pearly shampoo formulation. Firmenich SA (1)EDETA®B Powder; origin: BASF(2)Jaguar®C14 S; origin: Rhodia(3)Ucare®Polymer JR-400; origin: Noveon(4)Sulfetal®LA B-E; origin: Zschimmer & Schwarz(5)Zetesol®LA; origin: Zschimmer & Schwarz(6)Tego®Betain F 50; origin: Evonik(7)Xiameter®MEM-1691; origin: Dow Corning(8)Lanette®16; origin: BASF(9)Comperlan®100; origin: Cognis(10)Cutina®AGS; origin: Cognis(11)Kathon®CG; origin: Rohm & Haas(12)D-Panthenol; origin: Roche A perfumed pearly shampoo formulation is then obtained by adding, under gentle shaking, a perfume oil (as e.g. described in Example 5, 0.1 to 0.8% by weight relative to the total weight of the unperfumed shampoo formulation) and at least one of the compounds of formula (I) (0.05 to 0.50% by weight relative to the total weight of the unperfumed shampoo formulation) into the unperfumed pearly shampoo formulation listed in Table 7. Firmenich SA Example 8 Preparation of rinse-off hair conditioner formulations comprising an invention’s compound of formula (I) A typical unperfumed rinse-off hair conditioner formulation is listed in Table 8. The unperfumed rinse-off hair conditioner formulation is prepared by mixing the ingredients of Phase A until a uniform mixture was obtained. Tylose®is allowed to completely dissolve. Then the mixture is heated to 70-75°C. The ingredients of Phase B are combined and melted at 70- 75°C. Then the ingredients of Phase B are added to Phase A with good agitation, and the mixing is continued until that the mixture has a temperature of 60°C. Then, the ingredients of Phase C are added while agitating and keeping mixing until the mixture cooled to 40°C. The pH is adjusted with a citric acid solution to 3.5–4.0. Table 8: Composition of a typical rinse-off hair conditioner formulation. (1)Genamin®KDMP; origin: Clariant(2)Tylose®H10 Y G4; origin: Shin Etsu(3)Lanette®O; origin: BASF(4)Arlacel®165; origin: Croda(5)Incroquat®Behenyl TMS-50-PA- (MH); origin: Croda Firmenich SA(6)Brij®S20; origin: Croda(7)Xiameter®MEM-949; origin: Dow Corning(8)Origin: Alfa Aesar A perfumed rinse-off hair conditioner formulation is then obtained by adding, under gentle shaking, a perfume oil (as e.g. described in Example 5, 0.2 to 1.0% by weight relative to the total weight of the unperfumed conditioner formulation) and at least one of the compounds of formula (I) (0.05 to 0.5% by weight relative to the total weight of the unperfumed conditioner formulation) into the unperfumed rinse-off hair conditioner formulation listed in Table 8. Example 9 Preparation of structured shower gel formulations comprising an invention’s compound of formula (I) A typical unperfumed structured shower gel formulation is listed in Table 9. A perfumed structured shower gel is prepared by adding, under gentle shaking, a perfume oil (as e.g. described in Example 5, 0.1 to 1.5% by weight relative to the total weight of the structured shower gel) and at least one of the invention’s compounds of formula (I) (0.05 to 0.50% by weight relative to the total weight of the structured shower gel) into the unperfumed structured shower gel formulation of Table 9. Table 9: Composition of a typical unperfumed structured shower gel formulation. (1)EDETA B powder; origin: BASF Firmenich SA(2)Carbopol Aqua SF-1 polymer; origin: Noveon(3)Zetesol AO 328 U; origin: Zschimmer & Schwarz(4)Tego Betain F 50; origin: Goldschmidt(5)Kathon®CG; origin: Rohm & Haas Example 10 Preparation of transparent shower gel formulations comprising an invention’s compound of formula (I) A typical unperfumed transparent shower gel formulation is listed in Table 10. A perfumed transparent shower gel is prepared by adding, under gentle shaking, a perfume oil (as e.g. described in Example 5, 0.5 to 1.5% by weight relative to the total weight of the transparent shower gel) and at least one of the invention’s compounds of formula (I) (0.05 to 0.50% by weight relative to the total weight of the transparent shower gel) into the unperfumed transparent shower gel formulation of Table 10. Table 10: Composition of a typical unperfumed transparent shower gel formulation (1)EDETA B powder; origin: BASF(2)Zetesol AO 328 U; origin: Zschimmer & Schwarz(3)Tego Betain F 50; origin: Goldschmidt(4)Merquat®550; origin: Lubrizol Firmenich SA Example 11 Preparation of milky shower gel formulations comprising an invention’s compound of formula (I) A typical unperfumed milky shower gel formulation is listed in Table 11. A perfumed milky shower gel is prepared by adding, under gentle shaking, a perfume oil (as e.g. described in Example 5, 0.1 to 1.5% by weight relative to the total weight of the milky shower gel) and at least one of the invention’s compounds of formula (I) (0.05 to 0.50% by weight relative to the total weight of the milky shower gel) into the unperfumed milky shower gel formulation of Table 11. Table 11: Composition of a typical unperfumed milky shower gel formulation. (1)EDETA®B powder; origin: BASF(2)Texapon®NSO IS; origin: Cognis(3)Merquat®550; origin: Lubrizol(4)Dehyton®AB-30; origin: Cognis(5)Glucamate®LT; origin: Lubrizol(6)Euperlan®PK 3000 AM; origin: Cognis(7)Cremophor®RH 40; origin: BASF Firmenich SA Example 12 Preparation of anhydrous antiperspirant spray formulations comprising an invention’s compound of formula (I) A typical unperfumed anhydrous antiperspirant spray formulation is listed in Table 12. The anhydrous antiperspirant spray formulation is prepared by using a high-speed stirrer. Silica and Quaternium-18-hectorite are added to the mixture of isopropyl myristate and cyclomethicone. Once completely swollen, aluminium chlorohydrate is added portion-wise under stirring until the mixture becomes homogeneous and without lumps. Table 12: Composition of a typical unperfumed anhydrous antiperspirant spray. (1)Dow Corning®345 Fluid; origin: Dow Corning(2)Aerosil®200 ; origin: Evonik(3)Bentone®38; origin: Elementis Specialities(4)Micro Dry Ultrafine; origin: Reheis The perfumed formulation is then obtained by adding a perfume oil (as e.g. described in Example 5, 0.85% by weight relative to the total weight of the antiperspirant spray formulation) and at least one of the invention’s compounds of formula (I) (0.15% by weight relative to the total weight of the antiperspirant spray formulation) into the unperfumed antiperspirant spray formulation of Table 12. Firmenich SA Example 13 Preparation of deodorant spray emulsion formulations comprising an invention’s compound of formula (I) A typical deodorant spray emulsion formulation is prepared by mixing and dissolving all the ingredients according to the sequence of Table 13. Then a perfume oil (as e.g. described in Example 5, 1.35% by weight relative to the total weight of the deodorant spray formulation) and at least one of the invention’s compounds of formula (I) (0.10 to 0.20% by weight relative to the total weight of the deodorant spray formulation) are added under gentle shaking. Then aerosol cans are filled, and the propellant is crimped and added. Aerosol filling: 40% active solution 60% propane / butane (2.5 bar). Table 13: Composition of a typical unperfumed deodorant spray formulation. (1)Irgasan®DP 300; origin: BASF Example 14 Preparation of deodorant stick formulations comprising an invention’s compound of formula (I) A typical unperfumed deodorant stick formulation is listed in Table 14. The deodorant stick formulation is obtained by weighing all the components of Part A and heating to 70-75°C. Ceteareth-25 is added once the other Part A ingredients are mixed and heated. Once the Ceteareth-25 is dissolved, stearic acid is added. Part B is prepared by dissolving Triclosan in 1,2-propylene glycol. Evaporated water is compensated. Then, slowly, under mixing, Part B is poured into Part A. Firmenich SA Table 14: Composition of a typical unperfumed deodorant stick formulation. (1)Edeta®B Power; origin: BASF(2)Cremophor®A25; origin: BASF(3)Tegosoft®APM; origin: Evonik(4)Irgasan®DP 300; origin: BASF The perfumed deodorant stick formulation is then obtained by adding perfume oil (as e.g. described in Example 5, 0.85% by weight relative to the total weight of the deodorant stick formulation) and at least one of the invention’s compounds of formula (I) (0.10 to 0.20% by weight relative to the total weight of the deodorant stick formulation) under gentle shaking. To stock, a plastic bag is put into the bucket to be sealed after cooling. Moulds were filled at about 70°C. Example 15 Preparation of deodorant roll-on formulations comprising an invention’s compound of formula (I) A typical unperfumed deodorant roll-on formulation is listed in Table 15. Part A is prepared by sprinkling little-by-little the hydroxyethylcellulose into the water, whilst rapidly stirring with a turbine until the hydroxyethylcellulose is entirely swollen giving a limpid gel. Part B is slowly poured into Part A, whilst continuing stirring until the entire mixture is homogeneous. Then Part C is added. Firmenich SA Table 15: Composition of a typical unperfumed deodorant roll-on formulation. (1)Natrosol®250 H; origin: Ashland(2)Irgasan®DP 300; origin: BASF(3)Cremophor®RH 40; origin: BASF The perfumed deodorant roll-on formulation is then obtained by adding perfume oil of Example 5 (0.85% by weight relative to the total weight of the deodorant stick formulation) and at least one of the invention’s compounds of formula (I) (0.10-0.20% by weight relative to the total weight of the deodorant stick formulation) under gentle shaking. Example 16 Preparation of day cream base O / W emulsions comprising an invention’s compound of formula (I) A typical day cream base O / W emulsion formulation comprising an invention’s compound of formula (I) is listed in Table 16. Phases A and B are heated separately to 70-75 °C, then Phase A is added to Phase B and vacuum is applied. The mixture is stirred and cooled to 55°C for 15 min. After cooling to room temperature, phenoxyethanol (and) piroctone olamine (Part C) are added when a temperature of 45°C is reached. The mixture is stirred for 5 min before sodium carbomer (Part D), a perfume oil (as e.g. described in Example 5) and at least one of the invention’s compounds of formula (I) (Part E) are added. The mixture is stirred for 3 min, then the stirring was stopped for 15 min. When the temperature of the mixture reaches 30°C, the stirring is resumed for another 15 min until the cream becomes homogeneous, glossy and Firmenich SA without lumps. If necessary, the pH is adjusted to 6.70-7.20 with Glydant®, Phenoni®p or Nipaguard®PO5 or to 6.30-7.00 with Nikkoguard®. Table 16: Composition of a typical day cream base O / W emulsion. (1)Arlacel®985; origin: Croda(2)Tefose®2561; origin: Gattefossé(3)Biolip P 90; origin: Gattefossé(4)Mineral oil 30-40 CPS(5)Petroleum jelly(6)Nipaguard®PO 5; origin: Clariant(7)PNC 400 Example 17 Preparation of hand dishwash formulations comprising an invention’s compound of formula (I) A typical unperfumed hand dishwash formulation is listed in Table 17. The unperfumed hand dishwash is prepared by mixing water with sodium hydroxide and diethanolamide. Then the Firmenich SA linear alkylbenzene sulfonic acid is added. After neutralizing, the remaining ingredients are added and the pH is adjusted to 7-8 if necessary. Table 17: Composition of a typical unperfumed hand dishwash formulation. (1)Biosoft®S-118; origin: Stepan(2)Ninol®40-CO; origin: Stepan(3)Stepanate®SXS; origin: Stepan(4)Tergitol®15-S-9; origin: Dow Chemicals The perfumed hand dishwash formulation is then obtained by adding perfume oil (as e.g. described in Example 5, 0.85% by weight relative to the total weight of the hand dishwash formulation) and at least one of the invention’s compounds of formula (I) (0.10 to 0.20% by weight relative to the total weight of the dishwash formulation) under gentle shaking into the unperfumed hand dishwash formulation of Table 17. Example 18 Preparation of liquid detergent formulations comprising an invention’s compound of formula (I) A typical liquid detergent formulation is prepared by mixing the ingredients listed in Table 18. Then a perfume oil (as e.g. described in Example 5, 0.3 to 0.8% by weight relative to the total weight of the liquid detergent) and at least one of the invention’s compounds of formula (I) (0.05 to 1.0% by weight relative to the total weight of the liquid detergent) are added under gentle shaking into the unperfumed liquid detergent formulation of Table 18. Firmenich SA Table 18: Composition of a typical unperfumed liquid detergent formulation. (1)Hostapur®SAS 60; origin: Clariant(2)Edenor®K 12-18; origin: Cognis(3)Genapol®LA 070; origin: Clariant(4)Origin: Genencor International(5)Aculyn®88; origin: Dow Chemicals Example 19 Performance of the invention’s compounds of formula (I) in a model liquid detergent application The invention’s precursor compound of formula (I) (dosed to release a total of 0.07 mmol of the compound of formula (II)) was dissolved in ethanol (0.1 mL) and completed to 4.5 g with an unperfumed standard liquid detergent formulation (Le Chat Sensitive 0%, origin: Henkel). The sample was strongly shaken (10x) to homogenize. After homogenization, an aliquot of the sample (0.45 g) was placed in a stainless-steel container of a Linitest®washing machine (Original Hanau Linitest®, origin: Heraeus AG) and diluted with demineralized cold tap water (120 g). After shaking (10x), four cotton sheets (EMPA cotton test cloth Nr. 221, origin: Eidgenössische Materialprüfanstalt), pre-washed with an unperfumed detergent powder and cut Firmenich SA to ca. 15 x 15 cm sheets, ca. 5.2 g) were added. The container was closed, shaken manually (5x), placed inside the Linitest®machine and agitated mechanically in a water bath (ca.40°C) for 1 h. Then the container was removed and the washing water decanted. The four cotton sheets were twice rinsed with demineralized cold tap water (200 g) and left for 5 min with occasional shaking. Then each cotton sheet was wrung out by hand and weighed (ca. 10.0 g) to obtain a constant quantity of residual water. A reference sample consisting of an equimolar amount of the corresponding unmodified compound of formula (II) to be released form the precursor compound of formula (I) was prepared and analyzed the same way. The cotton sheets were line- dried for 1 or 3 days before being analyzed. Headspace sampling of the volatiles evaporating from the cotton surface onto Tenax®cartridges was performed as described in Example 2. The Tenax®TA cartridges were desorbed on a Markes TD100-xr thermodesorber coupled to an Agilent Technologies 7890A gas chromatograph equipped with a HP-1 capillary column (30 m, i.d. 0.25 mm, film 0.25 µm) and an Agilent 5975C mass spectrometer. The volatiles were analyzed using a temperature gradient moving from 60°C (for 5 min) to 260°C at 20°C / min. Headspace concentrations (in ng / L air) were obtained by external standard calibrations using different concentrations of the fragrance to be released in ethanol. Each calibration solution (0.2 µL) was injected onto a clean Tenax®cartridge, which was desorbed and analyzed under the same conditions. Table 19 lists the sum of the headspace concentrations collected from the eight data points for the release of the respective compounds of formula (II) as compared to the corresponding unmodified compounds of formula (II) above dry cotton after line-drying for 1 day; the corresponding data recorded after 3 days are listed in Table 20. All values are average values of at least two measurements. Table 19: Average headspace concentrations (sum of eight data points) of compounds of formula (II) measured on dry cotton after line-drying for 1 day after a liquid detergent application. Firmenich SA Table 20: Average headspace concentrations (sum of eight data points) of compounds of formula (II) measured on dry cotton after line-drying for 3 days after a liquid detergent application. Precursors according to formula (I) released higher quantities of aldehydes or ketones according to formula (II) into the headspace than the corresponding unmodified reference compound of formula (II). Compounds of formula (I) according to the present invention are capable to increase the long-lastingness of active aldehydes or ketones. Example 20 Performance of the invention’s compounds of formula (I) in a scent booster application The performance of the invention's compounds of formula (I) was evaluated olfactively on fabric in a model scent booster application after a machine washing cycle. For the tests, a solid scent booster was prepared by melting poly(ethylene glycol)-8000 (PEG-8000, 22.5 g, origin: Thermo Fisher Scientific) in a beaker. Then the invention's compounds of formula (I) or an equivalent of the unmodified fragrance used as the reference and, optionally, a dye were added and mixed with a spatula to obtain a homogenous sample. The molten product was poured onto a baking paper and evenly spread across the surface using a flat wide metal spatula. After completely cooling to room temperature, the solidified product was manually crushed into little pieces. Firmenich SA A washing machine (Miele WMB 100-20 CH) was loaded with about 2.2 kg of fabric composed of 18 cotton towels, 18 cotton T-shirts and 12 polyester T-shirts. The solid scent booster pieces (22.5 g) containing the compounds of formula (I) or the reference, and an unperfumed detergent pod (Tide®Free & Gentle, origin: Procter & Gamble) were added. The fabric was washed at 20°C without a pre-washing cycle, followed by a rinse cycle and spun at 1200 rotations per minute. The fabric was then line dried at room temperature, before being olfactively evaluated by an expert panel after 3 days. The panelists (9-10 persons) rated the olfactive intensity of the released fragrance at a scale from 0 (imperceptible) to 10 (very intense) against that of the reference sample. The dosages of the compounds of formula (I) and of the reference fragrance in the scent booster, as well as the average intensities perceived by the panelists on the different substrates are indicated in Table 21. Table 21: Perceived average olfactive intensities of compounds of formula (I) in a scent booster application as compared to the corresponding reference fragrance. The data in Table 21 show that the invention's compound of formula (I) performed better than the corresponding reference sample in a scent booster application by providing a long-lasting fragrance effect to various types of substrates. Firmenich SA Example 21 Performance of the invention’s compounds of formula (I) in a fabric softening application The invention's compounds of formula (I) were added to an unperfumed standard fabric softening formulation with the following final composition: Stepantex®VL90 A (origin: Stepan) 8.88 % by weight Calcium chloride (10% aq. solution) 0.36 % by weight Proxel®GXL (origin: Avecia) 0.04 % by weight Water 90.72 % by weight The performance of the compounds of formula (I) was then evaluated olfactively on fabric after a machine washing and softening cycle. For the tests, a washing machine (Miele WMB 100-20 CH) was loaded with about 2.2 kg of fabric composed of 18 cotton towels, 18 cotton T-shirts and 12 polyester T-shirts. An unperfumed liquid detergent (50 g) was loaded into the detergent drawer of the washing machine and an unperfumed fabric softener formulation (30 g) containing the compounds of formula (I) or, alternatively, an equivalent of the corresponding fragrance as a reference, into the fabric enhancer compartment. The fabric was washed at 40°C with a short washing cycle without pre-wash and two rinse cycles and spun at 900 rotations per minute (ca.20 min) and followed by the fabric softening cycle. The fabric was then line dried for 1 day at room temperature, before being stored in plastic boxes and being olfactively evaluated after 3 days by an expert panel. The panelists (7 persons) rated the olfactive intensity of the released fragrance at a scale from 0 (imperceptible) to 10 (very intense) against that of the reference sample. The dosages of the compounds of formula (I) and of the reference fragrance in the fabric softener, as well as the average intensities perceived by the panelists on the different substrates are indicated in Table 22. Table 22: Perceived average olfactive intensities of compounds of formula (I) in a fabric softener application after 3 days as compared to the corresponding reference fragrance. Firmenich SA The data in Table 22 show that the invention's compound of formula (I) performed better than the corresponding reference sample in a fabric softener application by providing a long-lasting fragrance effect to various types of substrates. Example 22 Comparison of the stability of a compound of formula (I) with comparative compounds in a model fabric softener application The stability of the present invention’s compounds of formula (I) was compared to that of comparative Compounds A, C and D in a fabric softening surfactant emulsion with the composition described in Example 2. The invention’s precursor compound of formula (I) and the comparative Compounds (0.08 g) were added to the liquid fabric softener (80 g) and mixed in a FlackTec SpeedMizerTMmodel DAC 150.1 FVZ-K (FlackTec, Inc., Landrum, SC USA) for 3 minutes at 2000 rpm (rotations per minute). Aliquots (1.0 mL each) were removed from the stock solution at various timepoints (0, 3, 7, 1430, 60, and 90 days) in triplicate. The remaining stock solution was kept at room temperature to age further. A calcium chloride solution (aq., 3mL, 0.23M) was added to each aliquot and then extracted with a solution of pentane containing an internal standard of 1,4- dibromobenzene (0.42 mM, 15 mL). The organic layer was analyzed by an Agilent 7890B gas chromatograph equipped with a HP-5 capillary column (2 x 20 m x 250 µm x 0.25µm) with mid-pint flow controller and coupled with Agilent 5975B mass spectrometer. The amount of precursor compound of formula (I) was determined using an external standard calibration of the Firmenich SA compound diluted in a pentane solution containing 250 ppm of 1,4-dibromobenzene. At least 6 pentane calibration solutions were prepared with concentrations of the analyte of formula (I) ranging from 25 ppm to 500 ppm. Each solution was analyzed in triplicate. Table 23 lists the percent compound remaining relative to time = 0 days (100%). All values are average values of at least three measurements. Table 23: Stability measurements of compounds of formula (I) and comparative compounds as percentage of amount remaining relative to t = 0 in a fabric softener application at room temperature. Firmenich SA When based on the same compound of formula (II) to be released, 3-acyl-oxazolidin-5-one derivatives according to formula (I) are more stable when stored in a fabric softener application than the comparative oxazolidine-4-carboxylates (e.g. Compounds C and D) and of comparable stability as the comparative imidazolidin-4-ones (e.g. Compound A). Example 23 Comparison of the performance of a compound of formula (I) with comparative compounds in a fabric softener application The efficiency of Compound 5 according to the present invention to release (±)-2- methylundecanal in a fabric softener application was compared to that of comparative Compounds A and B. Samples were prepared and tested similar to the procedure described in Example 2. The collected Tenax®TA cartridges were desorbed on a Perkin Elmer TurboMatrix ATD thermodesorber coupled to an Agilent Technologies 7890A gas chromatograph equipped with a HP-1 capillary column (30 m, i.d.0.32 µm, film 0.25 µm) and a flame ionization detector. The volatiles were analyzed using a temperature gradient moving from 80°C to 260°C at 15°C / min. Headspace concentrations (in ng / L air) were obtained by external standard calibrations using different concentrations of the fragrance to be released in ethanol. Each calibration solution (0.2 µL) was injected onto a clean Tenax®cartridge, which was desorbed and analyzed under the same conditions. The data summarized in Table 24 are average values of at least two measurements. Table 24: Average headspace concentrations (sum of eight data points) of (±)-2- methylundecanal released from Compound 5 and from comparative Compounds A and B measured on dry cotton after line-drying for 1 and 3 days after a fabric softener application. Firmenich SA The data in Table 24 show that Compound 5 according to formula (I) is considerably more efficient in releasing an aldehyde or ketone compound of formula (II) (e.g. (±)-2- methylundecanal) than comparative Compounds A and B. Compound 5 is about 48 times more efficient than Compound A after 1 day and about 23 times more efficient after 3 days. Similarly, Compound 5 is about 10 times more efficient than Compound B after 1 day and about 12 times more efficient after 3 days. The low performance of Compound A might be the due to an inherent high hydrolytic stability (see Table 23 in Example 22), resulting in a fragrance release rate that is too slow for the targeted application. 3-Acyl-oxazolidin-5-one properfumes according to the present invention are thus significantly more suitable to provide a long-lasting perfuming effect in application than 1-acyl- imidazolidin-4-ones or 3-acyl-oxazolidine-4-carboxylates. Example 24 Comparison of the performance of a compound of formula (I) with comparative compounds in a fabric softener application after storage at room temperature for 26 d The efficiency of Compound 22 according to the present invention to release (±)-2- methylundecanal in a fabric softener application was compared to that of comparative Compound C. Samples were prepared and tested as described in Example 2, except that the fabric softener formulation containing Compound 22 or Compound C was stored at room temperature for 26 days before being diluted with cold tap water and being brought into contact with the cotton sheets. The collected Tenax®TA cartridges were desorbed on a Markes TD100- xr thermodesorber coupled to an Agilent Technologies 7890A gas chromatograph equipped Firmenich SA with a HP-1 capillary column (30 m, i.d.0.25 mm, film 0.25 µm) and an Agilent 5975C mass spectrometer. The volatiles were analyzed using a temperature gradient moving from 60°C (for 5 min) to 260°C at 20°C / min. The data summarized in Table 25 are average values of at least two measurements. Table 25: Average headspace concentrations (sum of eight data points) of (±)-2- methylundecanal measured on dry cotton after line-drying for 1 and 3 days for the release from Compound 22 and from comparative Compound C after being stored in a fabric softener formulation for 26 days. The data in Table 25 show that Compound 22 according to formula (I) is considerably more efficient in releasing an aldehyde or ketone compound of formula (II) (e.g. (±)-2- methylundecanal) than comparative Compound C after being stored at room temperature in a fabric softener formulation for 26 days. Compound 22 was about 13 times more efficient than Compound C after 1 day and about 5 times more efficient after 3 days. This difference might be explained by a better shelf-life stability of Compound 22 in the fabric softener formulation with respect to that of Compound C (see Table 23 in Example 22). 3-Acyl-oxazolidin-5-one properfumes according to the present invention are thus more suitable to provide a long-lasting perfuming effect in application than the comparative 3-isopropyl- oxazolidine-4-carboxylates after storage in a water-based consumer article. Firmenich SA Example 25 Comparison of the performance of a compound of formula (I) with comparative compounds in a liquid detergent application after storage at room temperature for 26 d The efficiency of Compounds 5 and 22 according to the present invention to release (±)-2- methylundecanal in a liquid detergent application was compared to that of comparative Compound C. Samples were prepared and tested as described in Example 19, except that the liquid detergent formulation containing Compounds 5 or 22 or comparative Compound C was stored at room temperature for 26 days before being diluted with demineralized cold tap water and being brought into contact with the cotton sheets. The collected Tenax®TA cartridges were desorbed on a Markes TD100-xr thermodesorber coupled to an Agilent Technologies 7890A gas chromatograph equipped with a HP-1 capillary column (30 m, i.d.0.25 mm, film 0.25 µm) and an Agilent 5975C mass spectrometer. The volatiles were analyzed using a temperature gradient moving from 60°C (for 5 min) to 260°C at 20°C / min. The data summarized in Table 26 are average values of at least two measurements. Table 26: Average headspace concentrations (sum of eight data points) of (±)-2- methylundecanal measured on dry cotton after line-drying for 1 and 3 days for the release from Compounds 5 and 22 and from comparative Compound C after being stored in a liquid detergent formulation for 26 days. The data in Table 26 show that Compounds 5 and 22 according to formula (I) are more efficient in releasing an aldehyde or ketone compound of formula (II) (e.g. (±)-2-methylundecanal) than Firmenich SA comparative Compound C after being stored at room temperature in a liquid detergent formulation for 26 days. Compounds 5 and 22 were about 1.5 times more efficient than Compound C after 1 day and after 3 days. This difference might be explained by a better shelf- life stability of Compounds 5 and 22 in the liquid detergent formulation with respect to that of Compound C. 3-Acyl-oxazolidin-5-one properfumes according to the present invention are thus more suitable to provide a long-lasting perfuming effect in application than the comparative 3-isopropyl- oxazolidine-4-carboxylates after storage in a water-based consumer article.

Claims

P61779 / WO Firmenich SA CLAIMS 1. A method to release from a precursor compound of formula (I), an aldehyde or a ketone of formula (II)wherein R1is a hydrogen atom or a C1 to C18 hydrocarbon group, optionally comprising one or more O or S atoms, and R is a C4to C22hydrocarbon group, optionally comprising one or more O or S atoms, R and R1, when taken together, form a C5-16hydrocarbon group, optionally comprising one or more O or S atoms, wherein the precursor compound comprises a compound of formulain the form of any one of its stereoisomers or a mixture thereof, and wherein R and R1are as defined herein-above, R2is a hydrogen atom or a C1to C18hydrocarbon group, optionally comprising one or more N, O or S atoms, R3is a hydrogen atom or a C1to C4alkyl or alkenyl group, R4is a C1to C18hydrocarbon group, optionally comprising one or more N, O or S atoms, R2and R3, when taken together, form a double bond, substituted with one or two hydrogen atoms or one or two C1to C12hydrocarbon groups, andP61779 / WO Firmenich SA R3and R4, when taken together, form a five-, six-or seven-membered lactam or a five- or six-membered cyclic carbamate.

2. The method according to claim 1, wherein R contains at least 5 carbon atoms, preferably at least 6 carbon atoms, more preferably at least 7 carbon atoms, even more preferably at least 8 carbon atoms.

3. The method according to any of the preceding claims, wherein R is either one of formula (i) or (ii)wherein R5is a C3 to C18 hydrocarbon group, optionally comprising one or more O or S atoms, R6and R7, each independently, is a hydrogen atom or a C1to C18hydrocarbon group, R8is a methyl or ethyl group, R1and R5, when taken together, form a cyclic C5to C14hydrocarbon group, optionally comprising one or two O atoms, and R5and R6, when taken together, form a cyclic alkyl or alkenyl group.

4. The method according to any of the preceding claims, wherein the compound of formula (I) is a C11-C70compound, preferably a C15-36compound.

5. The method according to any of the preceding claims, wherein the aldehyde or ketone of formula (II) is a fragrance aldehyde or ketone.

6. Use of a compound of formula (I) as defined in any one of claims 1 to 5 as a perfuming ingredient to provide a long-lasting odor.

7. A method to confer, enhance, improve or modify the odor properties of a perfuming composition, the air surrounding the perfuming composition, a surface or a perfumedP61779 / WO Firmenich SA article, comprising adding to the composition, the air, or article, or contacting or treating the surface with an effective amount of at least one compound of formula (I) as defined in any one of claims 1 to 5.

8. A method for intensifying or prolonging the diffusion effect of the characteristic fragrance of at least one aldehyde or ketone compound of formula (II), as defined in any one of claims 1 to 5, on a surface or the air surrounding a perfuming composition, wherein the surface, or the air is treated with at least one compound of formula (I) as defined in any one of claims 1 to 5, or with a composition or article containing at least one compound of formula (I), under conditions susceptible of allowing the release of at least one ketone or aldehyde compound formula (II), over time.

9. A perfuming composition comprising i) at least one compound of formula (I), as defined in any one of claims 1 to 5; ii) at least one ingredient selected from the group consisting of a perfumery carrier and a perfumery base; and iii) optionally at least one perfumery adjuvant.

10. A perfumed consumer product comprising at least one compound of formula (I), as defined in any one of claims 1 to 5 or a perfuming composition as defined in claim 9.

11. The perfumed consumer product according to claim 10, wherein the perfumery consumer product is a perfume, a fabric care product, a body-care product, a cosmetic preparation, a skin-care product, an air care product or a home care product.

12. The perfumed consumer product according to claim 11, wherein the perfumery consumer product is a fine perfume, a splash or eau de parfum, a cologne, a shave or after-shave lotion, a liquid or solid detergent optionally in the form of a pod or tablet, a fabric softener, a fabric rinse, a liquid or solid scent booster, a dryer sheet, a fabric refresher, an ironing water, a paper, a bleach, a carpet cleaner, a curtain–care product, a shampoo, a leave-on or rinse-off hair conditioner, a coloring preparation, a color-care product, a hair shaping product, a dental care product, a disinfectant, an intimate careP61779 / WO Firmenich SA product, a hair spray, skin cream or lotion, a vanishing cream, a deodorant or antiperspirant, a hair remover, a tanning or sun or after sun product, a nail product, a skin cleansing, a makeup, a perfumed soap, a shower or bath mousse, oil or gel, a foot / hand care product, a hygiene product, an air freshener, a “ready to use” powdered air freshener, a mold remover, a furnisher care, a wipe, a dish detergent or hard-surface detergent, a leather care product, a car care product.

13. A compound of formula (Ia) or (Ib)in the form of any one of its stereoisomers or a mixture thereof, and wherein R1, R6and R7, each independently, is a hydrogen atom or a C1to C18hydrocarbon group, optionally comprising one or more O or S atoms, R2is a hydrogen atom or a C1to C18hydrocarbon group, optionally comprising one or more N, O or S atoms, R3is a hydrogen atom or a C1to C4alkyl or alkenyl group, R4is a C1to C18hydrocarbon group, optionally comprising one or more N, O or S atoms, R5is a C3to C18hydrocarbon group, optionally comprising one or more O or S atoms, R8is methyl or ethyl, R1and R5, when taken together, form a cyclic C5to C14hydrocarbon group, optionally comprising one or two O atoms, R2and R3, when taken together, form a double bond, substituted with one or two hydrogen atoms or one or two C1to C12hydrocarbon groups, R3and R4, when taken together, form a five-, six-or seven-membered lactam or a five- or six-membered cyclic carbamate, R5and R6, when taken together, form a cyclic alkyl or alkenyl group, with the proviso that benzyl (1-(2,4-dibenzyl-5-oxooxazolidin-3-yl)-3-methyl-1- oxobutan-2-yl)carbamate, 2-(2-oxo-2-(2-oxo-1-oxa-4-azaspiro[4.5]decan-4-P61779 / WO Firmenich SA yl)ethyl)isoindoline-1,3-dione, benzyl 2-nonyl-5-oxooxazolidine-3-carboxylate, 2,4- dibenzyl-3-(3-methylbutanoyl)oxazolidin-5-one and benzyl 4-allyl-5-oxo-2- pentyloxazolidine-3-carboxylate are excluded.

14. Compound according to claim 13, wherein R2is a hydrogen atom, a phenyl group, a benzyl group, a cyclohexyl group or a C1to C10alkyl group optionally substituted by an amide, a guanidine, a thiol, a primary amine (i.e. NH2), a C1to C3thioether, preferably a SCH3, a phenyl, a hydroxyphenyl, a carboxylic acid, a hydroxy or a C4to C8heterocycloalkenyl group, wherein the heteroatom is one or two nitrogen atoms, such as an imidazolyl or an indolyl group and R3is a hydrogen atom.

15. Compound according to any of claims 13 and 14, wherein R2is a hydrogen atom, a phenyl group, a cyclohexyl group or a residue derived from an amino acid of formula R2CH(NH2)COOH, and in particular of a natural α-amino acid, such as S-alanine (R2= CH3), S-arginine [R2= (CH2)3NHC(NH)(NH2)], S-asparagine (R2= CH2CONH2), R- cysteine (R2= CH2SH), S-glutamine [R2= (CH2)2CONH2], glycine (R2= H), S-histidine [R2= CH2(C3N2H3)], S-isoleucine [R5= C(CH3)CH2CH3], S-leucine [R5= CH2CH(CH3)2], S-lysine [R5= (CH2)4NH2], S-methionine [R2= (CH2)2SCH3], S- phenylalanine (R2= CH2C6H5), S-serine (R2= CH2OH), S-threonine [R2= CH(OH)CH3], S-tryptophane [R2= CH2(C8H6N)], S-tyrosine (R2= CH2C6H4OH), S- valine [R2= CH(CH3)2], S-aspartic acid (R2= CH2COOH), and S-glutamic acid [R2= (CH2)2COOH], or of an artificial α-amino acid selected from the group of norleucine [R2= (CH2)3CH3], norvaline [R2= (CH2)2CH3], 2-phenylglycine (R2= C6H5), ornithine [R2= (CH2)3NH2], homoalanine (R2= CH2CH3), homocysteine [R2= (CH2)2SH], and homoserine [R2= (CH2)2OH] and R3is a hydrogen group.

16. Compound according to any one of the claims 13 to 15, wherein the compound of formula (Ia) is 3-(undecan-2-yl)dihydro-1H,3H-pyrrolo[1,2-c]oxazole-1,5(6H)-dione, 3-acetyl-4-isobutyl-2-(undecan-2-yl)oxazolidin-5-one, 3-benzoyl-2-(undecan-2- yl)oxazolidin-5-one, 3-benzoyl-4-isobutyl-2-(undecan-2-yl)oxazolidin-5-one, 3-acetyl- 2-(undecan-2-yl)oxazolidin-5-one, 3-acetyl-4-phenyl-2-(undecan-2-yl)oxazolidin-5- one, 3-acetyl-4-benzylidene-2-(undecan-2-yl)oxazolidin-5-one, 3-(2-phenylacetyl)-2- (undecan-2-yl)oxazolidin-5-one, 3-octanoyl-2-(undecan-2-yl)oxazolidin-5-one, 4-P61779 / WO Firmenich SA methyl-3-octanoyl-2-(undecan-2-yl)oxazolidin-5-one, 4-isopropyl-3-octanoyl-2- (undecan-2-yl)oxazolidin-5-one, 4-benzyl-3-octanoyl-2-(undecan-2-yl)oxazolidin-5- one, 2-nonyl-3-octanoyloxazolidin-5-one, 3-octanoyl-2-pentyloxazolidin-5-one, 3- octanoyl-2-phenethyloxazolidin-5-one, 2-(4-(tert-butyl)phenethyl)-3- octanoyloxazolidin-5-one, 2-(non-3-en-1-yl)-3-octanoyloxazolidin-5-one, 3-octanoyl- 2-(undec-3-en-1-yl)oxazolidin-5-one, 3-octanoyl-2-(2-phenylpropyl)oxazolidin-5-one, 3-octanoyl-2-(1-(p-tolyl)propan-2-yl)oxazolidine-5-one, 2-(2-(4,4-dimethylcyclohex- 1-en-1-yl)ethyl)-3-octanoyloxazolidin-5-one, 2-(4,8-dimethylnon-3-en-1-yl)-3- octanoyloxazolidin-5-one, 2-(6-methylhept-5-en-2-yl)-3-octanoyloxazolidin-5-one, 3- butyryl-2-(undecane-2-yl)oxazolidine-5-one, 3-butyryl-2-(2-(4,4-dimethylcyclohex-1- en-1-yl)ethyl)oxazolidin-5-one, 3-butyryl-2-(2,4-dimethylcyclohex-3-en-1- yl)oxazolidin-5-one, 3-butyryl-2-(dec-9-en-1-yl)oxazolidin-5-one, 3-butyryl-2-(4,8- dimethylnon-3-en-1-yl)oxazolidin-5-one, 3-butyryl-2-(6-methylhept-5-en-2- yl)oxazolidin-5-one, 3-isobutyryl-2-(undecane-2-yl)oxazolidine-5-one, 3-pivaloyl-2- (undecane-2-yl)oxazolidine-5-one, 2-(2-(4,4-dimethylcyclohex-1-en-1-yl)ethyl)-3-(2- phenylacetyl)oxazolidin-5-one, 3-(2-phenylacetyl)-2-(undec-3-en-1-yl)oxazolidin-5- one, 2-(3-methyl-4-(4-methylphenyl)but-3-en-1-yl)-3-(2-phenylacetyl)oxazolidin-5- one, 2-(2-(1,1- and 3,3-dimethyl-2,3-dihydro-1H-inden-5- and 4-yl)ethyl)-3-(2- phenylacetyl)oxazolidin-5-one, 2-(2-(3-isopropylphenyl)propyl)-3-(2- phenylacetyl)oxazolidin-5-one, 2-nonyl-3-(2-phenylacetyl)oxazolidin-5-one, 2-(6- methylhept-5-en-2-yl)-3-(2-phenylacetyl)oxazolidin-5-one, 2-(4,8-dimethylnon-3-en- 1-yl)-3-(2-phenylacetyl)oxazolidin-5-one, benzyl 5-oxo-2-(undecan-2-yl)oxazolidine- 3-carboxylate, 2-(4-methoxyphenyl)-5-oxooxazolidine-3-carboxylate, 2-(5-cyclohexyl- 4-methylpent-4-en-2-yl)-5-oxooxazolidine-3-carboxylate, 3-(2-phenoxyacetyl)-2- (undecane-2-yl)oxazolidine-5-one, 3-acetyl-4-methyl-2-(undecan-2-yl)oxazolidin-5- one, 3-butyryl-4-methyl-2-(undecan-2-yl)oxazolidin-5-one, 4-methyl-3-octanoyl-2- (undec-3-en-1-yl)oxazolidin-5-one, 3-acetyl-4-isobutyl-2-phenethyloxazolidin-5-one, 3-acetyl-4-isobutyl-2-(non-3-en-1-yl)oxazolidin-5-one, 3-acetyl-4-benzyl-2-(undecan- 2-yl)oxazolidin-5-one, 3-acetyl-4-(2-(methylthio)ethyl)-2-(undecan-2-yl)oxazolidin-5- one or 3-acetyl-4-isopropyl-2-(undecan-2-yl)oxazolidin-5-one or a mixture thereof.