Beta-ketoester compounds

Details Beta-ketoester compounds Beta-ketoester compounds

2000-08-18

2002-02-19

Killos, Paul J. (Department: 1623)

Organic compounds -- part of the class 532-570 series

Organic compounds

Carboxylic acid esters

Reexamination Certificate

active

06348618

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to new beta-keto esters which are useful as precursors for compounds, especially organoleptic compounds, such as flavours, fragrances and masking agents and antimicrobial compounds and insect repellents.
BACKGROUND OF THE INVENTION
A principal strategy currently employed in imparting odours to consumer products is the admixing of the fragrance directly into the product. There are, however, several drawbacks to this strategy. The fragrance material can be too volatile and or too soluble, resulting in fragrance loss during manufacturing, storage, and use. Many fragrance materials are also unstable over time. This again results in loss during storage.
In many consumer products it is desirable for the fragrance to be released slowly over time. Micro-encapsulation and inclusion complexes with cyclodextrins have been used to help decrease volatility, improve stability and provide slow-release properties. However, these methods are for a number of reasons often not successful. In addition, cyclodextrins can be too expensive.
Fragrance precursors for scenting fabrics being washed in the presence of a lipase-containing detergents are described in WO 95/04809. The fragrance precursors contained in the detergent and/or in the softener are cleaved by the lipase and a single odoriferous compound, either an odoriferous alcohol or aldehyde or ketone is yielded. Thereby a prolonged scenting effect on the fabric is obtained.
Beta-amino ester compounds of perfume alcohols and their use as precursors for active alcohols which are released under alkaline conditions are described in the EP-A 0 771 786.
Certain beta-ketoester pro-accords for personal care and personal hygiene articles are disclosed in WO 98/07407.
SUMMARY OF THE INVENTION
The present invention provides beta-keto ester compounds which are useful as precursors for organoleptic compounds, especially for flavours, fragrances and masking agents and antimicrobial compounds.
One object of the present invention is to provide new precursors for compounds with different activities. A further object of the invention is to provide new compounds which are stable under transport and storage conditions. A further object of the present invention is to provide precursor molecules supplying different active compounds simultaneously or successively.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to new beta-keto esters of the formula I
wherein
Y is the residue of an organoleptic ketone or lactone of the formula YH, and if Y is the residue of a cyclic ketone, the carbonyl group may be part of the cyclic structure.
R is H or the residue of a phenol or of a mono- or polyalcohol of the formula R—(OH)
s
with s≧1,
p=1, 2
n≧1 and
q=1,2
whereby if n>1 the rests Y may be different or the same with the exception of
3-oxo-5-(2,6,6-trimethyl-cyclohex-1-enyl)-pentanoic acid methyl ester,
3-oxo-5-(2,6,6-trimethyl-cyclohex-2-enyl)-pentanoic acid methyl ester,
3-oxo-5-(2,6,6-trimethyl-cyclohex-1-enyl)-pent-4-enoic acid methyl ester,
3-oxo-2-(2,6,6-trimethyl-cyclohex-1-enylmethyl)-butyric acid ethyl ester,
3-isopropyl-6-methyl-2-oxo-cyclohexane carboxylic acid methyl ester, and
3-isopropyl-6-methyl-2-oxo-cyclohexane carboxylic acid ethyl ester.
The compounds of formula I are not limited to any particular stereoisomers. All possible stereoisomers (E/Z isomers, enantiomers, diastereomers) and all mixtures are thus included within the scope of the invention.
The compounds of formula I are mostly or nearly odourless at room temperature, atmospheric conditions and about 20 to 100% relative humidity. However, under activating conditions, they are cleaved and one or more active compounds with organoleptic and/or antimicrobial properties are generated.
The activating conditions which lead to cleavage and the desired active compounds comprise the presence of skin bacteria, especially axilla bacteria, of an enzyme such as protease or lipase, elevated temperature, acidic or alkaline pH-values or light. Under activating conditions the beta-keto esters of formula I are cleaved into an unstable beta-keto acid and an alcohol or phenol or water (if R═H), then the beta-keto acid decomposes to a ketone or lactone which may be organoleptic according to the following:
(thereby ROH is an alcohol or phenol which may be organoleptic)
The compounds of formula I, upon cleavage, provide ketones or lactones and/or alcohols or phenols optionally having organoleptic and/or antimicrobial activity and therefore permit the development of useful consumer products with enhanced organoleptic and/or antimicrobial properties. The organoleptic compounds obtained are useful as fragrances, flavours and masking agents and antimicrobial agents. Therefore, the invention also relates to the use of all compounds of formula I as precursors for organoleptic compounds, e.g. flavours, fragrances, masking agents and as precursors for antimicrobial agents.
The beta-keto esters of formula I can act as fragrance precursors in personal care products, in laundry products, cleaning compositions, pet care products and environment scents such as air fresheners. They can also act as precursors for odour masking agents in the same products as the fragrance precursors. They also can act as precursors for antimicrobial agents. Further, they can act as flavour precursors in food and beverage products. The fragrance precursors and the precursors for odour masking agents as well as the flavour precursors of the invention may be used individually in an amount effective to enhance or to mask the characteristic odour or flavour of a material. More commonly, however, the compounds are mixed with other fragrance or flavour components in an amount sufficient to provide the desired odour or flavour characteristics.
Due to the in situ generation of the active compounds the desired effect is prolonged and the substantivity on different substrates is enhanced. If two or more active compounds are provided, they can be generated, depending on the precursor and/or the activating conditions, simultaneously or successively. Further, the precursors of the invention provide slow release of the active compounds.
Compounds of formula I wherein Y is the residue of an organoleptic ketone or lactone are preferred.
Compounds of formula I wherein R═H or the residue of a nonfragrant phenol or of a nonfragrant mono- or polyalcohol, especially having more than 3-C atoms are also preferred.
One preferred group of beta-keto esters of formula I are those in which Y is the residue of a cyclic ketone where the carbonyl group is part of the cyclic structure.
Another preferred group of beta-keto esters of formula I are those in which
Y is a residue of the formula
wherein R
1
is an aliphatic rest optionally substituted by one or more cycloaliphatic or aromatic rests or R
1
is an cycloaliphatic rest optionally substituted by one or more aliphatic rests,
R
2
is H or an aliphatic rest.
R
3
is H or an aliphatic rest and
R
1
, R
2
and R
3
may be the same or different,
x=0 or 1 and
when x=1, R
1
and R
2
together may form an aliphatic ring.
Compounds of formula I may generate the following organoleptic ketones of formula YH:
2-heptyl-cyclopentanone
2,2,6,10-tetramethyltricyclo[5.4.0.0(6, 10)]-undecan-4-one benzylacetone*
1,2,3,5,6,7-hexahydro-1,1,2,3,3-pentamethyl-4H-inden-4-one*
2,5-dimethyl-oct-2-en-6-one**
2-(butan-2-yl)-cyclohexanone*
2-hexyl-cyclopent-2-en-1-one*
2-(1-methylethyl)-5-methyl-cyclohexanone*
2-(2-methylethyl)-5-methyl-cyclohexanone**
3-methyl-cyclopentadecanone
4-(1,1-dimethylpropyl)pentyl-cyclohexanone*
3-oxo-2-pentyl-cyclopentane-acetic acid methyl ester**
1-(1,2,3,4,5,6,7,8,-octahydro-2,3,8,8-tetramethyl-2-naphthalenyl)-ethanone*
3-methyl-5-propyl-cyclohex-2-en-1-one*
4-(2,6,6-trimethylcyclohex-1-en-1yl)butan-2-one**
4-(2,6,6-trimethylcyclohex-2-en-1-yl)butan-2-one**
2-methyl-5-(1-methylethenyl)-cyclohex-2-en-1-one*
cyclopentadecanone**
1-(4-hydroxyphenyl)-butan-3-one**
4-benzo-1,3-dioxo-5-yl-but-2-one**
4-(1

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