Thioether substituted hydroxybenzophenones and stabilized...

Details Thioether substituted hydroxybenzophenones and stabilized... Thioether substituted hydroxybenzophenones and stabilized...

1994-03-31

2003-06-10

Barts, Samuel (Department: 1621)

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

Organic compounds

Sulfur containing

Reexamination Certificate

active

06576797

ABSTRACT:

This invention relates to 2-hydroxybenzophenone derivatives substituted in the 4′-position by a thioether moiety which exhibit enhanced UV absorption and to stabilized compositions containing said compounds.
BACKGROUND OF THE INVENTION
The use of various types of UV absorbers in the stabilization of polymers is well known. These stabilizers function by absorbing incident UV radiation and dissipating the absorbed energy in a non-destructive manner. The spectral region of greatest importance ranges from about 280 nm, the onset of solar radiation, through about 400 nm at which point absorbance imparts color to the system. Obviously, to be effective for general use, a compound should have a strong absorbance over a significant portion of this spectral region.
o-Hydroxybenzophenones have a long history of use as UV absorbers, but they suffer, however, from limited absorbance at the longer UV wavelengths.
Quite surprisingly, it is found that substitution of o-hydroxybenzophenones with a thioether at the 4′-position, i.e. on the non-hydroxy bearing ring, overcomes this shortcoming by significantly enhancing the longer wavelength absorption. This enhancement is particularly surprising since closely related 4′-sulfonyl substituted o-hydroxybenzophenones, some of which are previously disclosed, do not show this notable enhancement.
Examples of sulfur substitution on hydroxybenzophenones are known. Sulfonate groups have been added to either the hydroxy bearing or non-hydroxy bearing ring to improve water miscibility. There is no noted effect on UV absorption.
Thioether substitution on the hydroxy bearing ring of a benzophenone is known. U.S. Pat. No. 3,399,237 describes the preparation of 6,6′-thio-bis(4-benzoylresorcinol), in essence a sulfur-linked dimer of 2,4-dihydroxybenzophenone. This derivative has a broader range of UV absorption than the parent benzophenone. The sulfonyl and sulfonyl analogues have also been disclosed in U.S. Pat. No. 3,649,695, but no mention is made of any effect by this substituent on UV absorption.
Sulfonyl substitution on the non-hydroxy bearing ring is known. Various 4′-ethylsulfonyl-2-hydroxybenzophenones are found in U.S. Pat. No. 3,431,306. An example of a 4′-phenylsulfonyl derivative is found in U.S. Pat. No. 4,029,684. No change in absorbance due to this sulfonyl substitution is reported.
The generic description of the compounds provided by U.S. Pat. No. 4,029,684 describes an innumerable host of derivatives which would include some of the compounds of the instant invention. However, no thioether derivatives are actually prepared. The closest example is the previously mentioned, 4′-phenylsulfonyl derivative which fails to exhibit any of the enhanced UV absorbance of the corresponding instant 4′-phenylthio derivative.
Thus, the existing prior art anticipates neither the strong effect of thioether substitution on the non-hydroxy bearing ring of a benzophenone, nor the differences between a 4′-thioether substituent and a 4′-sulfonyl substituent on the nature of the UV absorption.
The present invention offers an improvement over the existing prior art compounds in that it provides a class of hydroxybenzophenone derivatives which absorb strongly over a broader range of UV wavelengths. It should be further noted that not only is the range of absorption increased, but that the intensity of absorption is also increased over much of this range. This increase in intensity is significant enough to result in stronger absorbance on a per weight basis despite the higher molecular weight of the instant compounds.
DETAILED DISCLOSURE
The instant invention pertains to compounds of formula I
wherein
n is 1 to 4,
T is alkyl of 1 to 20 carbon atoms, alkyl of 2 to 12 carbon atoms substituted by hydroxyl, by alkoxy of 1 to 12 carbon atoms, by siloxysilyl group of formula IV, by alkanoyloxy of 2 to 12 carbon atoms, by alkenoyloxy of 3 to 12 carbon atoms or by halogen, alkenyl of 3 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, aryl of 6 to 10 carbon atoms or said aryl substituted by one or two alkyl of 1 to 4 carbon atoms or 1,1,2,2-tetrahydroperfluoroalkyl where the perfluoroalkyl moiety is of 6 to 16 carbon atoms,
E
1
is hydrogen or —OE
2
,
E
2
is hydrogen or alkyl of 1 to 18 carbon atoms,
E
3
is hydrogen or alkyl of 1 to 8 carbon atoms,
E
4
is hydrogen or hydroxyl,
when n is 1, L is hydrogen, straight or branched chain alkyl of 1 to 20 carbon atoms, said alkyl substituted by alkoxycarbonyl of 2 to 20 carbon atoms, by carboxyl, by alkylcarbonyl of 2 to 20 carbon atoms, by alkenylcarbonyl of 3 to 18 carbon atoms, or by siloxysilyl group of formula IV, alkyl of 2 to 20 carbon atoms substituted by one or two hydroxyl, by alkoxy of 1 to 12 carbon atoms or by phenoxy, alkyl of 2 to 20 carbon atoms substituted by one hydroxyl and by alkoxy of 1 to 12 carbon atoms or by phenoxy, or alkyl of 2 to 20 carbon atoms substituted by alkanoyloxy of 2 to 20 carbon atoms or by alkenoyloxy of 3 to 20 carbon atoms, glycidyl, alkyl of 4 to 20 carbon atoms interrupted by one to six oxygen atoms, by one or two carbonyloxy or oxycarbonyl groups, or L is alkanoyl of 2 to 18 carbon atoms, alkenoyl of 3 to 18 carbon atoms, benzoyl, benzoyl substituted by one or two alkyl of 1 to 4 carbon atoms or a group of formula II or III
 where
x is 0, 1 or 2,
R
1
is alkyl of 1 to 12 carbon atoms or cycloalkyl of 5 to 8 carbon atoms,
R
2
is sec- or tert-alkyl of 3 to 12 carbon atoms or cycloalkyl of 5 to 8 carbon atoms,
L
1
has the same meaning as L when n is 2,
L
2
is hydrogen or alkyl of 1 to 18 carbon atoms,
when n is 2, L is straight or branched chain alkylene of 1 to 12 carbon atoms, alkylene of 3 to 12 carbon atoms substituted by hydroxyl, by alkoxy of 1 to 8 carbon atoms, by alkoxycarbonyl of 2 to 20 carbon atoms, by alkanoyloxy of 2 to 20 carbon atoms, by alkenoyloxy of 3 to 20 carbon atoms or by a siloxysilyl group of formula IV, or L is alkylene of 4 to 20 carbon atoms interrupted by one or two carbonyloxy or oxycarbonyl groups, alkylene of 4 to 20 carbon atoms interrupted by one to six oxygen atoms, o-xylylene, m-xylylene, p-xylylene, isophthaloyl, phthaloyl, terephthaloyl or &agr;,&ohgr;-alkanedioyl of 4 to 12 carbon atoms,
when n is 3, L is straight or branched chain alkanetriyl of 3 to 12 carbon atoms, alkanetrioyl of 3 to 12 carbon atoms, trimellitoyl or alkanetriyl of 6 to 20 carbon atoms interrupted by three carbonyloxy or oxycarbonyl groups,
when n is 4, L is straight or branched chain alkanetetrayl of 4 to 16 carbon atoms, alkanetetroyl of 4 to 16 carbon atoms, pyromellitoyl or alkanetetrayl of 8 to 24 carbon atoms interrupted by four carbonyloxy or oxycarbonyl groups, and
where, when T or L is a group of formula IV,
 where
a is 1-50,
b is 0-50,
c is 0-50,
G
1
is hydroxyl, alkyl of 1 to 12 carbon atoms, alkoxy of 1 to 4 carbon atoms, cyclohexyl or —O—Si(G
4
)
3
,
G
2
is G
4
or —O—Si(G
4
)
3
,
G
3
is a direct bond or a bivalent group of the formula —C
n
H
2n
—, —(CH
2
)
n
O—, —CH
2
CH(OH)CH
2
O— or —CH
2
CH(OH)CH
2
—O—(CH
2
)
3
— where n is 1 to 4,
G
4
is alkyl of 1 to 12 carbon atoms, alkoxy of 1 to 4 carbon atoms, cyclohexyl or phenyl,
G
5
is alkyl of 1 to 18 carbon atoms, alkoxy of 1 to 4 carbon atoms, cycloalkyl of 5 to 7 carbon atoms or phenyl, and
G
6
is hydrogen, alkyl of 1 to 12 carbon atoms, cyclohexyl, phenyl or —Si(G
4
)
3
, or G
1
and G
6
are linked together to form a direct bond.
Preferably, n is 1 or 2, most preferably 1.
Preferably, T is alkyl of 1 to 20 carbon atoms, alkenyl of 3 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, aryl of 6 to 10 carbon atoms or said aryl substituted by one or two alkyl of 1 to 4 carbon atoms.
Most preferably, T is alkyl of 1 to 18 carbon atoms, allyl, cyclohexyl, phenylalkyl of 7 to 9 carbon atoms, phenyl or said phenyl substituted by one or two methyl groups. Especially preferably, T is allyl of 4 to 12 carbon atoms or phenyl.
Preferably E
1
is hydrogen or is —OE
2

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