Drug – bio-affecting and body treating compositions – Topical body preparation containing solid synthetic organic... – Skin cosmetic coating
Patent
1998-04-15
1999-08-10
Richter, Johann
Drug, bio-affecting and body treating compositions
Topical body preparation containing solid synthetic organic...
Skin cosmetic coating
558402, 558416, 514772, 5147721, A61K 3174, C07C25507
Patent
active
059355638
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to substituted benzylidenecyanoacetic esters of the formula I ##STR3## to the use thereof as sunscreen agents, to the use thereof in cosmetic products, and to cosmetic compositions comprising these compounds.
Sunscreen agents based on substituted benzylidenecyanoacetic esters are known.
BE 757 036 describes, inter alia, the compound ##STR4## as light-sensitive photomaterial.
DE 10 87 902 describes condensates of benzaldehydes with compounds containing active methylene groups. Among many other compounds, mention is also made of condensates of 4-hydroxy-3,5-di-t-butylbenzaldehyde with diethyl malonate, cyanoacetic ester, malononitrile or malonic acid (page 1, second column, group VI). These compounds are described as suitable light stabilizers for films, sheets, fibers and filaments.
DE 28 16 819 describes substituted benzylidenecyanoacetic esters of the following structure as UV-A filters: ##STR5## it being found that, with regard to possible substitution on the aromatic ring, para monosubstitution represents the optimum and, in turn, the methoxy radical confers optimal properties here. Concerning the radical R, it is found that compounds with R=n-hexyl, n-octyl, n-decyl, isononyl, and isodecyl are most suitable.
Since cosmetic sunscreen agents must, besides the photoproperties such as suitable absorption maximum, high specific extinction and photostability, have a number of other use properties such as good oil solubility, pH stability, oxidation stability, thermal stability, minimum intrinsic color and no intrinsic odor and, moreover, must also be toxicologically acceptable, it is an object of the present invention to optimize the previously disclosed products in respect of the abovementioned properties.
We have found that this object is achieved in that compounds of the formula I ##STR6## where R.sup.1 is i-propyl, i-butyl or t-butyl, ##STR7## with R.sup.3 =H or C.sub.1 -C.sub.4 -alkyl and m, n=0 or 1, have better properties in respect of many of the abovementioned requirements, especially in respect of the photostability, than prior art compounds.
Particularly suitable sunscreen agents have been found to be compounds of the formula I where both R.sup.1 radicals are tert-butyl and R.sup.2 is a branched alkyl radical with 8-12 carbon atoms or --C.sub.2 H.sub.4 --C.sub.6 H.sub.5 or ##STR8## Moreover R.sup.2 can be, for example, the radical ##STR9## A particularly advantageous compound of the formula I is the one in which both R.sup.1 radicals are tert-butyl and R.sup.2 is ##STR10##
The compounds according to the invention can be prepared in a conventional way from the corresponding benzaldehydes and cyanoacetic esters in a Knoevenagel condensation (see, for example, Organikum, 1988 edition, page 459). The corresponding cyanoacetic esters were prepared by transesterification of a commercially obtainable cyanoacetic ester with the appropriate alcohol in a conventional way.
The compounds according to the invention are particularly suitable as light stabilizers for materials which are attacked by UV rays, for example filaments, fibers, sheets, films and other plastic moldings.
The compounds according to the invention are particularly suitable for protecting the human skin from UV rays. They can be used in a wide variety of cosmetic and medicinal products such as sun oils, sun creams, sun lotions, sun gels, lipsticks, skin creams, hair gels and non-greasy gels.
EXAMPLES
Example 1
2-Phenylethyl
3,5-di-tertiary-butyl-4-hydroxybenzylidenecyanoacetate 50 ml of toluene.
4.7 g of 2-phenylethyl cyanoacetate, 0.1 g of piperidine and 0.25 g of acetic acid were heated to reflux. 0.4 g of H.sub.2 O was removed azeotropically in 2 h. The mixture was cooled, washed with water and with sodium bicarbonate solution, dried and concentrated. The crude product was recrystallized.
Example 2
2-Ethylhexyl 3,5-di-tertiary-butyl-4-hydroxybenzylidenecyanoacetate
28.1 g of 3,5-di-tertiary-butyl-4-hydroxybenzaldehyde were dissolved in 60 ml of toluene. 21.7 g of 2-ethylhexyl cyanoacetate, 0.27 g of
REFERENCES:
patent: 3462475 (1969-08-01), Strobe
patent: 3707375 (1972-12-01), Reiichi et al.
patent: 4284621 (1981-08-01), Preuss et al.
Chem. Abst. Vol. 71, No. 23, Dec. 1969.
BASF - Aktiengesellschaft
Richter Johann
Sackey Ebenezer
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