Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
1999-09-30
2001-11-06
Padmanabhan, Sreeni (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S425000
Reexamination Certificate
active
06313354
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a process for the production of aromatic aldehydes from phenone ketals having a special structure. In this process, the phenone ketal is first condensed with a vinyl ether in the presence of Lewis acids, the acetal formed is subjected to acidic hydrolysis to form the corresponding &agr;,&bgr;-unsaturated aldehyde and, if desired, the C═C double bond of this aldehyde is selectively hydrogenated in the usual way.
BACKGROUND OF THE INVENTION
Judging by demand, many natural perfumes are available in totally inadequate quantities. For example, 5,000 kg of rose blossoms are required to obtain 1 kg of rose oil. The consequences are extremely limited annual world production and a high price. Accordingly, it is clear that there is a constant need in the perfume industry for new perfumes with interesting fragrance notes in order to extend the range of naturally available perfumes, to make the necessary adaptations to changing fashion trends and to be able to meet the steadily increasing demand for odor enhancers for products of everyday use, such as cosmetics and cleaners.
Accordingly, it is clear that there is a constant need in the perfume industry for new perfumes with interesting fragrance notes in order to extend the range of naturally available perfumes, to make the necessary adaptations to changing fashion trends and to be able to meet the steadily increasing demand for odor enhancers for products of everyday use, such as cosmetics and cleaners.
In addition, there is generally a constant need for synthetic perfumes which can be favorably produced in a consistent quality and which have desirable olfactory properties, i.e. pleasant, near-natural and qualitatively new odor profiles of adequate intensity, and which are capable of advantageously influencing the fragrance of cosmetic and consumer products.
In this connection, the purity and hence the odor profile of synthetic perfumes are having to meet increasingly more stringent requirements. This means that the development of processes by which synthetic perfumes with improved purity and an improved odor characteristic can be obtained are acquiring increasing significance. These improved production processes generally have the additional advantage that the perfumes thus produced also show more favorable ecotoxicological properties by virtue of their greater purity.
At present, there is a particular demand among perfume experts for perfumes which have a pronounced musk odor characteristic.
4-tert.butylvinyl propionaldehyde and its &agr;-methyl analog are known are possible perfume components from U.S. Pat. No. 626,548. According to U.S. Pat. No. 626,548, they can be obtained by hydroformylating &agr;-methyl styrene with hydrogen and carbon monoxide in the presence of rhodium or cobalt catalysts.
DESCRIPTION OF THE INVENTION
The problem addressed by the present invention was to provide an improved process for the production of aromatic aldehydes having perfume properties.
The present invention relates to a process for the production of aromatic aldehydes having perfume properties which correspond to general formula (I):
where R
1
is a methyl, ethyl or propyl group, R
2
is a methyl, ethyl, isopropyl, tert.butyl or methoxy group, R
3
is hydrogen or a methoxy group and R
4
is hydrogen or a methyl group and where the chain line represents a C—C single bond or C═C double bond which may have an E or Z configuration, characterized in that
a) a phenone ketal corresponding to general formula (II):
where X and Y independently of one another represent methoxy, ethoxy, propoxy or butoxy groups and R
1
is a methyl, ethyl or propyl group, R
2
is a methyl, ethyl, isopropyl, tert.butyl or methoxy group, R
3
is hydrogen or a methoxy group and R
4
is hydrogen or a methyl group, is added onto a vinyl ether corresponding to general formula (III):
where R
5
is an alkyl group containing 1 to 4 carbon atoms, in the presence of Lewis acids,
b) the acetal formed is subjected to acidic hydrolysis to form the corresponding &agr;,&bgr;-unsaturated aldehyde and
c) if desired, the C═C double bond of this aldehyde is selectively hydrogenated in the usual way.
Zinc chloride is preferably used as the Lewis acid catalyst in step a).
The compounds corresponding to formula (I) may be produced either in pure form or in the form of mixtures with one another by the process according to the invention.
The aromatic aldehydes (I) produced by the process according to the invention are distinguished from corresponding compounds produced by hydroformylation of corresponding styrenes in accordance with the prior art by improved purity and an improved odor characteristic.
In another embodiment, therefore, the invention relates to the use of the aromatic aldehydes (I) produced by the process according to the invention as perfumes.
In one preferred embodiment of the invention, the hydrogenation step c) is compulsory.
The individual steps of the reaction sequence a) to c) of the process according to the invention are known per se from the literature.
For example, the addition of ketals onto vinyl ether in the presence of boron trifluoride etherate is known from Houben-Weyl, Methoden der organischen Chemie, 4th Edition, Vol. VII, Part 1, pages 112 and 115-117 (Stuttgart 1954).
J. Org. Chem., Vol. 43, No. 10, 1978 pages 2068-2069 describes a synthesis route for the production of pheromonene in which 1,1-dioxyethyl-3,3-dimethyl cyclohexane is converted into the corresponding acetal by reaction with ethyl vinyl ether in the presence of zinc chloride and the acetal obtained is hydrolyzed with acetic acid/sodium acetate/water to form the corresponding isomeric unsaturated aldehydes.
The present invention also relates to the new substance 3-(2,4-dimethylphenyl)-butanal.
REFERENCES:
patent: 4113781 (1978-09-01), Aquila et al.
patent: 4556743 (1985-12-01), McKenna et al.
patent: 4614611 (1986-09-01), Sprecker
patent: 23 40 812 (1975-02-01), None
patent: 0 052 775 (1982-06-01), None
Tetrahedron Letters, 35(31), pp. 5595-5598, 1994.*
Chem. Abstracts, vol. 99, No. 21, abstract No. 17309d, p. 580 (1983).
Maslo. Zhir. Prom. St., vol. 7, pp. 32-34 (1983).
Journal of Amer. Chem. Soc., vol. 78, pp. 3209-3210 (1956).
Houben-Weyl, Methoden der organischen Chemie, 4thEd., vol. VII, Part 1, pp. 112 and 115-117, 1954.
J.Org. Chem., vol. 43, No. 10, pp. 2068-2069 (1983).
Synthetic Communications, vol. 27, No. 1, XP002073790, pp. 11-15 (1997).
Markert Thomas
Nemitz Ralph
Drach John E.
Henkel Kommanditgesellschaft auf Aktien
Millson, Jr. Henry E.
Padmanabhan Sreeni
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