Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Reexamination Certificate
2000-03-16
2001-02-20
McKane, Joseph K. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
C560S224000, C564S159000
Reexamination Certificate
active
06191301
ABSTRACT:
The invention relates to the use of 4,4-diarylbutadienes as water-soluble photostable UV filters in cosmetic and pharmaceutical preparations for protecting the human epidermis or human hair from UV radiation, specifically in the range from 320 to 400 nm
The sunscreens employed in cosmetic and pharmaceutical preparations have the task of preventing, or at least diminishing the consequences of, harmful effects of sunlight on the human skin. However, these sunscreens also serve to protect other ingredients from decomposition or breakdown by UV radiation. In hair cosmetic formulations the aim is to reduce damage to the keratin fibers by UV rays.
The sunlight reaching the surface of the earth contains UV-B radiation (280 to 320 nm) and UV-A radiation (>320 nm), which are directly adjacent to the visible light region. The effect on the human skin is manifested, particularly in the case of UV-B radiation, by sunburn. Accordingly, the industry offers a relatively large number of substances which absorb UV-B radiation and thus prevent sunburn.
Dermatoglogical investigations have now shown that UV-A radiation is also perfectly capable of causing skin damage and allergies by, for example, damaging the keratin or elastin. This reduces the elasticity and water storage capacity of the skin, i.e. the skin becomes less supple and tends to form wrinkles. The noticeably high incidence of skin cancer in regions where the sun's radiation is strong shows that damage to the genetic information in the cells is evidently also caused by sunlight, specifically by UV-A radiation. All these findings therefore make it appear necessary to develop efficient filter substances for the UV-A region.
There is a growing demand for sunscreens for cosmetic and pharmaceutical preparations which can be used in particular as UV-A filters and whose absorption maxima ought therefore to be in the range from about 320 to 380 nm. In order to achieve the required effect by using the minimum amount, sunscreens of this type ought additionally to have a high specific extinction. Sunscreens for certain cosmetic products must also meet a large number of other requirements, for example good solubility in water or in water-miscible solvents, such as alcohols, high stability of the solutions or emulsions produced with them, toxicological acceptability, and slight intrinsic odor and slight intrinsic color.
Another requirement which sunscreens must meet is adequate photostability. However, this is only inadequately ensured, if at all, with the UV-A-absorbing sunscreens hitherto available.
French Patent No. 2 440 933 describes 4-(1,1-dimethylethyl)-4′-methoxydibenzoylmethane as a UV-A filter. It is proposed to combine this specific UV-A filter, which is sold by GIVAUDAN under the name “PARSOL 1789”, with various UV-B filters in order to absorb all UV rays having a wavelength from 280 to 380 nm.
However, this UV-A filter does not have sufficient photochemical stability, when used alone or in combination with UV-B filters, to ensure sustained protection of the skin during sunbathing for prolonged periods, which means that repeated applications at regular and short intervals are required if effective protection of the skin from all UV rays is desired.
For this reason, EP-A-0 514 491 discloses the stabilization of the insufficiently photostable UV-A filters by adding 2-cyano-3,3-diphenylacrylic esters which themselves act as filters in the UV-B region.
It has furthermore already been proposed in EP-A-0 251 398 to combine chromophores absorbing UV-A radiation and UV-B radiation into one molecule by using a linker. This has the disadvantage that, firstly a free combination of UV-A and UV-B filters in the cosmetic preparation is no longer possible, and that difficulties in the chemical linkage of the chromophores allow only certain combinations.
U.S. Pat. No. 4,950,467 describes the use of 2,4-pentadienoic acid derivatives as UV absorbers in cosmetic products. The monoaryl-substituted compounds which are mentioned as preferred in this patent likewise have the disadvantage that their photostability is insufficient.
It is an object of the present invention to propose sunscreens for cosmetic and pharmaceutical purposes which absorb in the UV-A region with high extinction, are photostable, have a slight intrinsic color, i.e. a sharp band structure, and are readily soluble in water or in water-miscible solvents.
This object is achieved according to the invention by use of 4,4-diarylbutadienes of the formula I
where the diene system has the Z,Z; Z,E; E,Z or E,E configuration or a mixture thereof, and where the variables independently of one another have the following meanings:
R
1
and R
2
hydrogen, C
1
-C
20
-alkyl, C
2
-C
10
-alkenyl, C
3
-C
10
-cycloalkyl, C
3
-C
10
-cycloalkenyl, C
1
-C
12
-alkoxy, C
1
-C
20
-alkoxycarbonyl, C
1
-C
12
-alkylamino, C
1
-C
12
-dialkylamino, aryl, hetaryl, unsubstituted or substituted substituents which confer solubility in water and are selected from the group consisting of carboxylate, sulfonate or ammonium radicals;
R
3
hydrogen, COOR
5
, COR
5
, CONR
5
R
6
, CN;
R
4
COOR
6
, COR
6
, CONR
5
R
6
;
R
5
hydrogen, [X]
o
-R
7
, C
1
-C
6
-alkylene-SO
3
Y, C
1
-C
6
-alkylene-PO
3
Y, C
1
-C
6
-alkylene-N(R
8
)
3
+
A
31
;
R
6
[X]
o
-R
7
, C
1
-C
6
-alkylene-SO
3
Y, C
1
-C
6
-alkylene-PO
3
Y, C
1
-C
6
-alkylene-N(R
8
)
3
+
A
−
;
X —CH
2
—CH
2
-Z-, —CH
2
—CH
2
—CH
2
-Z-, —CH(CH
3
) —CH
2
-Z-, —CH
2
—CH
2
—CH
2
—CH
2
-Z-, —CH
2
—CH(CH
2
-CH
3
)-Z-;
A Cl, Br, I, SO
4
R
9
;
Y hydrogen, Na
+
, K
+
, Mg
2+
, Ca
2+
, Li
+
, Al
3+
, N(R
8
)
4
+
;
Z O, NH;
R
7
and R
8
hydrogen, C
1
-C
6
-alkyl, C
2
-C
6
-alkenyl, C
1
-C
6
-acyl;
R
9
hydrogen, C
1
-C
6
-alkyl, C
2
-C
6
-alkenyl;
n 1 to 3;
o 1 to 150
as water-soluble photostable UV filters in cosmetic and pharmaceutical preparations for protecting the human skin or human hair from the sun's rays, alone or together with compounds which absorb in the UV region and are known per se for cosmetic and pharmaceutical preparations.
Alkyl radicals R
1
and R
2
which may be mentioned are branched or unbranched C
1
-C
20
-alkyl chains, preferably methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl or n-eicosyl.
Alkenyl radicals R
1
and R
2
which may be mentioned are branched or unbranched C
2
-C
10
-alkenyl chains, preferably vinyl, propenyl, isopropenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 2-methyl-2-butenyl, 3-methyl-1-butenyl, 1-hexenyl, 2-hexenyl, 1-heptenyl, 2-heptenyl, 1-octenyl or 2-octenyl.
Cycloalkyl radicals which may be mentioned for R
1
and R
2
are preferably branched or unbranched C
3
-C
10
-cycloalkyl radicals such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, 1-methylcyclopropyl, 1-ethylcyclopropyl, 1-propylcyclopropyl, 1-butylcyclopropyl, 1-pentylcyclopropyl, 1-methyl-1-butylcyclopropyl, 1,2-dimethylcyclopropyl, 1-methyl-2-ethylcyclopropyl, cyclooctyl, cyclononyl or cyclodecyl.
Cycloalkenyl radicals which may be mentioned for R
1
and R
2
are preferably branched or unbranched C
3
-C
10
-cycloalkenyl radicals with one or more double bonds such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, 1,3-cyclohexadienyl, 1,4-cyclohexadienyl, cycloheptenyl, cycloheptatrienyl, cyclooctenyl, 1,5-cyclooctadienyl, cyclooctatetraenyl, cyclononenyl or cyclodecenyl.
The cycloalkenyl a
Habeck Thorsten
Westenfelder Horst
Wunsch Thomas
BASF - Aktiengesellschaft
Keil & Weinkauf
McKane Joseph K.
Murray Joseph
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