Photostable cosmetic light screening compositions

Abstract: The invention relates to photostable, cosmetic light-screening compositions for the protection of the human epidermis and the hairs against the ultraviolet rays of wavelengths between 320 and 400 nm, and between 290 and 400 nm respectively. In particular, it relates to such compositions which comprise, in a cosmetically acceptable vehicle containing at least one fatty phase, about 0,75, to about 5 %, in particular about 1 to about 4 % by weight, of a dibenzoylmethane type UV-A screening agent and at least about 0,5 % to about 2 %, in particular about 0,5 to about 1 % by weight, of a benzylidene type stabiliser of the general formula represents a bridged cyclic compound having the camphor (1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one), norcamphor (bicyclo[2.2.1]heptan-2-one), nopinone (6,6-dimethyl-bicyclo[3.1.1]heptan-2-one), pinocamphone (4,6,6-trimethyl-bicyclo[3.1.1]heptan-3-one), verbanone (4,6,6-trimethyl-bicyclo[3.1.1]heptan-2-one, thujone (1-isopropyl-4-methyl-bicyclo[3.1.0] hexan-3-one) or the 4,7-methano-octahydro-inden-5-one structure, and wherein R 1 , R 2 , R 3 independently signify hydrogen, lower alkyl, lower alkoxy, or 2 adjacent radicals represent methylenedioxy, and where, in case of the camphor derivatives, the ratio of the UV-A filter to the stabiliser is greater than ca.1,5 : 1, preferably ca. 2 to ca. 6 : 1, and where 4-methylbenzylidene camphor is excluded from the scope of formula I, and, optionally, at least one conventional UV-B filter.

Description: The invention relates to photostable, cosmetic light-screening compositions for the protection of the human epidermis and the hairs against the ultraviolet rays of wavelengths between 320 and 400 nm, and between 280 and 400 nm respectively. In particular, it relates to such compositions which comprise, in a cosmetically acceptable vehicle containing at least one fatty phase, about 0,75 to about 5 %, in particular about 1 to about 4 % by weight, of a dibenzoylmethane type UV-A screening agent and at least about 0,5 % to about 2 %, in particular about 0,5 to about 1 % by weight, of a benzylidene type stabiliser of the general formula wherein represents a bridged cyclic compound having the camphor (1,7,7-trimethyl-bicycle[2.2.1]heptan-2-one), norcamphor (bicyclo[2.2.1]heptan-2-one), nopinone (6,6-dimethyl-bicyclo[3.1.1]heptan-2-one), pinocamphone (4,6,6-trimethyl-bicyclo[3.1.1]heptan-3-one), verbanone (4,6,6-trimethylbicyclo[3.1.1]heptan-2-one, thujone (1-isopropyl-4-methyl-bicyclo[3.1.0] hexan-3-one) or the 4,7-methano-octahydro-inden-5-one structure, and wherein R 1 , R 2 , R 3 independently signify hydrogen, lower alkyl, lower alkoxy, or 2 adjacent radicals represent methylenedioxy, and where, in case of the camphor derivatives, the ratio of the UV-A filter to the stabiliser is 2 to 6 : 1, and where 4-methylbenzylidene camphor is excluded from the scope of formula I, and, optionally, at least one conventional UV-B filter. The structures of these - as depicted ortho bound - formula II skeletons captioned above are as follows: R 1 , R 2 and R 3 signify hydrogen or an alkyl group having up to 10, preferably up to 8 carbon atoms. Particular examples include methyl, ethyl, propyl, isopropyl, n-butyl, secondary butyl, isobutyl, tert. butyl, n-pentyl, isopentyl, sec. pentyl, tert. pentyl, 2-methyl-butyl and neopentyl, hexyl, octyl, isooctyl, tert. octyl, etc. Suitable alkoxy radicals are methoxy, ethoxy, propoxy, isopropoxy, etc. From this listing, it can also be deduced that the alkyl and the alkoxy radicals may in the present context represent straight-chain and branched radicals. The preferred radicals are hydrogen, methyl, ethyl, propyl, isopropyl, t-butyl, methoxy, ethoxy, propoxy, isopropoxy. A further preferred aspect comprises compounds wherein R 1 and R 2 of (I) is hydrogen, or compounds wherein at least one R group of (I) is hydrogen, the other being hydrogen, methyl, isopropyl, t-butyl, methoxy or ethoxy. Formula I should cover all possible stereoisomers , e.g. the diastereomers, the optical isomers, and the geometric, in particular the Z and E isomers as occurring at the α,β- unsaturated ketone moiety of the molecule. Though the compounds I are themselves effective in absorbing the UV radiation, primarily in the erythemic region (290 - 320nm), their present function is to photostabilise the above captioned UV-A-filters. The documents WO-A-94 04131 and EP-A-0 365 370 disclose the stabilising effect of benzylidene camphor derivatives, e.g. 3-benzylidene camphor and 3-(4-methylbenzylidene camphor, on dibenzoylmethane UV-A filters, e.g. 4-tert.-butyl-4'-methoxy-dibenzoylmethane, when used in a camphor derivative: dibenzoylmethane ratio of at least 1 : 1.5 or at least 1:1. The documents EP-A-0 474 063 and EP-A-0 693 471 disclose benzylidene-camphor and -norcamphor derivatives which can be used as UV filters, optionally in combination with other UV-A and/or UV-B filters. The document, J.Chim.Phys. 1988, 85 (3) 374-8 (CA 110:74705) relates to circular dichroism of 3-arylmethylene nopinones and discloses the compound 3-(4'-methoxybenzylidene)-6,6-dimethyl-bicyclo[3.1.1]heptan-2-one. The document, C.R.,Acad.Sci., Ser.C (1974) 279(2), 71-4 (CA 82:85972) relates to nopinone and arylidene nopinones and discloses the compound 3-(4'-methoxybenzylidene)-6,6-dimethyl-bicycle[3.1.1]heptan-2-one. As far as the UV-A light screen agent of the novel combinations is concerned, the preferred compound is 4-tert. butyl-4'-methoxydibenzoylmethane, as disclosed e.g. in USP 4 387 089 or CH-Patent 642 536. Other suitable compounds of this particular type are: 2-methyldibenzoylmethane, 4-methyl-dibenzoyl-methane, 4-isopropyldibenzoylmethane, 4-tert-butyldibenzoyl-methane, 2,4-dimethyldibenzoylmethane, 2,5-dimethyldibenzoylmethane, 4,4'-diisopropyldibenzoylmethane, 2-methyl-5-isopropyl-4'-methoxydibenzoylmethane, 2-methyl-5-tert-butyl-4'-methoxydibenzoylmethane, 2,4-dimethyl-4'-methoxydibenzoylmethane and 2,6-dimethyl-4-tert-butyl-4'-methodydibenzoylmethane. The function of the formula I compound is, as pointed out above, to photostabilize the involved UV-A screening agents, i.e. to guarantee a constant protection during prolonged exposure to the UV light. This way, if a repeated application of the cosmetic formulation at various intervals is required, these intervals can be extended. The present invention relates thus also to a process for stabilising dibenzoylmethane UV-A screening agents with respect to the UV radiation of wavelengths between 320 and 400 nm, characterised in that about 0,5 to about 2 % by weight of the stabiliser is added to 0,75 to 5 % by weight of the dibenzoylmethane UV-A screening agent. The desired stabilisation of the material of UV-A filters is easily established by strictly parallel experiments with the respective UV-A filters and the novel compounds I using an appropriately equipped Xenon lamp as a solar simulator. Irradiated are standard preparations of the investigated products, e.g. solutions in, preferably, higher boiling cosmetic solvents, e.g. deltyl (isopropyl myristate), the resulting sunscreen being spread on glass plates. After the irradiation, the plates are immersed into a suitable solvent (e.g. ethanol) and the UV spectrum is recorded. The stabilising effect is directly correlated to the difference in absorbance at λ max . before and after the irradiation. Usually, a combination of 2 % UV-A filter and 1 % stabiliser is used for the assessment. Both components of the present combination of the light-screening agents are lipophilic. The cosmetic formulations contain thus at least one fatty phase, and the formulations can consequently present themselves in the form of emulsions, lotions or gels. Suitably the cosmetic screening composition takes the form of an oil, a lotion, a gel, a solid stick, an emulsion, e.g. cream, milk or of a vesicular dispersion of ionic or nonionic amphiphilic lipids, an aerosol, a spray, a foam, a powder, a shampoo, a hair conditioner or lacquer or a make-up, etc. The usual solvents known to the skilled practitioner can be used for the preparation of these forms, e.g. oils, waxes, alcohols, polyols, etc. The preferred agents are fatty acids, esters, fatty alcohols, but also ethanol, isopropanol, propylene glycol, glycerine, etc. The cosmetic formulations may contain further adjuvants, e.g. further solvents, thickeners, emollients, emulsifiers, humectants, tensides, preservatives, antifoams, fragrances, oils, waxes, lower polyols and monohydric alcohols, propellants, silicones, colourings and pigments, etc. UV-B filters may also be incorporated. Examples are given in USP 4 387 089 mentioned above. As still further suitable UV-B filters, microfine pigments, such as the usual micropigments of metal oxides may be used. Particularly in case of emulsions, such UV filters may, naturally, also be water-soluble derivatives. Suitable amounts of the UV-B filter are ca. 1 - ca. 12 %. An important advantage of the novel stabiliser stems from the low dosage of the novel stabiliser - which dosage can be even considerably smaller than the dosages of the UV-A filter used - the practical user is thus completely free in the choice regarding the material used for the filtration of the UV-B rays. In case of protection of the hairs, the suitable formulations are shampoos, conditioners, lotions, gels, emulsions, dispersions, lacquers, etc. The preparation of all these formulations is well known to the skilled artisan in this field. Examples of suitable stabilisers used for the present purpose are the ones of Table I below. Illustrative Compounds 1) 3-(4'-methoxy-benzylidene)-6,6-dimethyl-bicyclo[3.1.1]heptan-2-one; 2) 3-(benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 3) 6-benzylidene-octahydro-4,7-methano-inden-5-one; 4) 3-benzylidene-4,6,6-trimethyl-bicyclo[3.1.1]heptan-2-one; 5) 3-(4'-methoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 6) 3-(2'-methoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 7) 3-(2',3'-dimethoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 8) 3-(3',5'-dimethoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 9) 3-(3'-propoxy-benzylidene)-6,6-dimethyl-bicyclo[3.1.1]heptan-2-one; 10) 3-(2',4'-dimethyl-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 11) 2-(3'-methoxy-benzylidene)-1-isopropyl-4-methyl-bicyclo[3.1.0] hexan-3-one; 12) 3-(4'-tert.butyl-benzylidene)-6,6-dimethyl-bicyclo[3.1.1-heptan-2-one]; 13) * 3-(3',4',5'-trimethoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1] heptan-2-one; 14) * 3-(4'-tert.-butyl-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]-heptan-2-one; 15) 3-(4'-tert.-butyl-benzylidene)-bicyclo[2.2.1]heptan-2-one; 16) 6-(4'-tert.-butyl-benzylidene)-octahydro-4,7-methano-inden-5-one; 17) * 3-(4'-tert.-butyl-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-2-one; 18) * 3-(4'-methoxy-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-2-one; 19) * 2-(4'-tert.-butyl-benzylidene)-4,6,6-trimethyl-bicyclo-[3.1.1]heptan-3-one; 20) * 6-(4'-methoxy-benzylidene)-octahydro-4,7-methano-inden-5-one; 21) * 2-(4'-methoxy-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-3-one; 22) 3-(3',4'-methylenedioxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1] heptan-2-one; 23) * 3-(2'-methoxy-benzylidene)-bicyclo[2.2.1]heptan-2-one; 24) * 2-(2',4'-dimethyl-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-3-one; 25) 6-(3',4'-dimethoxy-benzylidene)-4,7-methano-octahydro-inden-5-one; 26) * 6-(2'-methoxy-benzylidene)-4,7-methano-octahydro-inden-5-one. The preferred compounds are Nos. 1, 5, 14, 16 , 25 and 26. Those compounds marked with a asterisk are novel compounds. The preparation of these novel compounds can be carried out using chemistry well-known to the skilled artisan. Thus a suitable process for the manufacture of the compounds I comprises subjecting the appropriate bi- or tricyclic compound II with the corresponding benzaldehyde to the conditions of an aldol condensation in basic medium, and encompassing a water separation, preferably at elevated temperatures, and separating the formed compound I from the reaction mixture. The conditions of the aldol condensation between an aldehyde and a formula II keto compound having two active ortho hydrogens atoms are well-known to the skilled chemist. The reaction partners are thus mixed, preferably in a ratio of ca. 1 : ca. 1, in a suitable solvent. Such solvent is conveniently aprotic, e.g. is any ether or any optionally halogenated hydrocarbon, such as diethyl ether, benzene, toluene, or also dimethylformamide, etc. Crown ethers may be added as catalysts. But also protic solvents, e.g. the usual aliphatic alcohols, such as methanol, ethanol or isopropanol are suitable. The reaction is preferably carried out at elevated temperatures, e.g. up to of the reflux temperature of the reaction mixture. But also ambient temperatures are suitable. One works in presence of any strong base, e.g. any inorganic or organic such base, usually employed for the aldol condensation. The palette of this bases encompasses thus in particular the (alkali) metal hydroxides, the alcoholates, the hydrides - and the (secondary) amines, such as pyrrolidine, morpholine, piperidine, etc. Examples 1. The following three procedures A, B and C served to prepare the compounds I; the physical data were in each case in accordance with the postulated structure. A. 10 g (65.7 mmoles) of camphor, 6,6 g of pulverized KOH and 2 g (7.5 mmoles) of 18-crown-6-ether are suspended under nitrogen in 180 ml of toluene. 12.9 g (65.7 mmoles) of 3,4,5-trimethoxy-benzaldehyde, dissolved in 50 ml of toluene are added. The mixture is heated to 70 °C for 18 hours. The reaction product is cooled and distributed between ether and water. The organic phases are dried with Na 2 SO 4 and concentrated. The crude material is recrystallised from ether and a small amount of ethanol. Yield: 13.2 g (61 %) of white crystals of compound No. 13; mp 123 °C, UV (EtOH): 313 nm (ε = 18319). B. 10 g (65.7 mmoles) of camphor, 6,6 g of pulverized KOH and 2 g (7.5 mmoles) of 18-crown-6-ether are suspended under nitrogen in 180 ml of THF. 10.2 g (65.7 mmoles) of piperonal, dissolved in 50 ml of toluene are added. The mixture is heated to 65 °C for 18 hours. The reaction product is cooled and distributed between ether and water. The organic phases are dried with Na 2 SO 4 and concentrated. The crude material is recrystallised from ether and a small amount of ethanol. Yield: 13.7 g (74 %) of white crystals of compound No. 22; mp 132 °C, UV (EtOH): 333 nm (ε = 17545). C. 21.8 g of potassium tert-butoxide are dissolved in 300 ml of tert-butanol. This mixture is added during 30 minutes to a well stirred solution of 22.8 g (+/-)-camphor and 40.8 g 2-methoxy benzaldehyde in 250 ml of tert-butanol. The reaction mixture is then stirred at room temperature for one day. The crude reaction product is transferred to a seperation funnel, diluted with about 500 ml of tert-butyl-methyl ether, and washed with several portions of 10 % sodium chloride in water. The organic layer is dried over magnesium sulfate, filtered and evaporated under reduced pressure. The crystalline faint yellow residue (51 g) is recrystallised from 25 ml of ethanol at 4 °C to give (after filtration and drying) 32.4 g (80 % yield) of pure compound 6. UV (EtOH): 324 nm (ε = 12180). 2. Sunscreen lotions are prepared with the following ingredients: Lotion a) % (w/w) A Glyceryl mono stearate 4.0 Octyl methoxycinnamate (PARSOL MCX®) 2.0 Octyl salicylate 2.0 Butylmethoxy dibenzoylmethane (1-[4-(1,1-dimethylethyl)phenyl]-3-(4-methoxyphenyl)-1,3-propandione) (sold under the trade name PARSOL 1789 by Givaudan-Roure S.A.) 2.0 3-(2'-Methoxy-benzylidene)-1,7,7-trimethyl-bicyclo [2.2.1]heptan-2-one 0.5 Cetyl alcohol 1.0 Coco-caprylate/caprate (Mixture of esters of coconut alcohol and n-octanoic acid and n-decanoic acid) (sold under the trade name CETIOL LC by Henkel) 6.0 Potassium cetyl phosphate (potassium salt of hexadecyl phosphate) (sold under the trade name AMPHISOL K by Givaudan-Roure S.A.) 2.0 EDTA Na 2 0.1 B Deionized water 34.75 Carbomer (1 % dispersion in water, homopolymer of acrylic acid crosslinked with an allyl ether of sucrose) (sold under the trade name Carbopol 980® by B.F. Goodrich) 10.0 Propylene glycol 5.0 Potassium hydroxide, 10 % solution 0.45 Mixture of parabens in phenoxy ethanol 0.6 C Phenylbenzimidazole sulfonic acid 2.0 Deionized water 20.0 Potassium hydroxide, 10 % solution 3.6 Lotion b): % (w/w) A Glyceryl mono stearate 4.0 Octyl methoxycinnamate (PARSOL MCX®) 2.0 Octyl salicylate 2.0 Butylmethoxy dibenzoylmethane (1-[4-(1,1-dimethylethyl)phenyl]-3-(4-methoxyphenyl)-1,3-propandione) (sold under the trade name PARSOL 1789 by Givaudan-Roure S A.) 2.0 3-(4'-Methoxy-benzylidene)-1,7,7-trimethyl-bicyclo [2.2.1]heptan-2-one 0.5 Cetyl alcohol 1.0 Coco-caprylate/caprate (Mixture of esters of coconut alcohol and n-octanoic acid and n-decanoic acid) (sold under the trade name CETIOL LC by Henkel) 6.0 Potassium cetyl phosphate (potassium salt of hexadecyl phosphate) (sold under the trade name AMPHISOL K by Givaudan-Roure S.A.) 2.0 EDTA Na 2 0.1 B Deionized water 34.75 Carbomer (1 % dispersion in water, homopolymer of acrylic acid crosslinked with an allyl ether of sucrose) (sold under the trade name Carbopol 980® by B.F. Goodrich) 10.0 Propylene glycol 5.0 Potassium hydroxide, 10 % solution 0.45 Mixture of parabens in phenoxy ethanol 0.6 C Phenylbenzimidazole sulfonic acid 2.0 Deionized water 20.0 Potassium hydroxide, 10 % solution 3.6 Lotion c): % (w/w) A Glyceryl mono stearate 4.0 Octyl dimethyl PABA (p-aminobenzoic acid) 3.0 Homosalate (Homomenthyl salicylate): 1.0 Benzophenone-3 2.0 Butylmethoxy dibenzoylmethane 2.0 3-(2'-Methoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one 0.5 Cetyl alcohol 1.0 Coco-caprylate/caprate 6.0 Potassium cetyl phosphate (potassium salt of hexadecyl phospate) (sold under the trade name AMPHISOL K by Givaudan-Roure S.A.) 2.0 EDTA Na 2 0.1 B Deionized water 62.16 Carbomer (1 % dispersion in water, homopolymer of acrylic acid crosslinked with an allyl ether of sucrose) (sold under the trade name Carbopol 980® by B.F. Goodrich) 10.0 Propylene glycol 5.0 Potassium hydroxide, 10 % solution 0.64 Mixture of parabens in phenoxyethanol 0.6 Lotion d): % (w/w) A Glyceryl mono stearate 4.0 Octyl dimethyl PABA (p-aminobenzoic acid) 3.0 Homosalate (Homomenthyl salicylate) 1.0 Benzophenone-3 2.0 Butylmethoxy dibenzoylmethane 2.0 3-(4'-Methoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one 0.5 Cetyl alcohol 1.0 Coco-caprylate/caprate 6.0 Potassium cetyl phosphate (potassium salt of hexadecyl phospate) (sold under the trade name AMPHISOL K by Givaudan-Roure S.A.) 2.0 EDTA Na 2 0.1 B Deionized water 62.16 Carbomer (1 % dispersion in water, homopolymer of acrylic acid crosslinked with an allyl ether of sucrose) (sold under the trade name Carbopol 980® by B.F. Goodrich) 10.0 Propylene glycol 5.0 Potassium hydroxide, 10 % solution 0.64 Mixture of parabens in phenoxyethanol 0.6

Claims: Photostable, cosmetic light-screening composition, comprising, in a cosmetically acceptable vehicle containing at least one fatty phase, about 0,75 to about 5 %, in particular about 1 to about 4 % by weight, of a dibenzoylmethane type UV-A screening agent and at least about 0,5 % to about 2 %, in particular about 0,5 to about 1 % by weight, of a stabiliser of the general formula wherein represents a bridged cyclic compound having the camphor (1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one), norcamphor (bicyclo[2.2.1]heptan-2-one), nopinone (6,6-dimethyl-bicyclo[3.1.1]heptan-2-one), pinocamphone (4,6,6-trimethyl-bicyclo [3.1.1]heptan-3-one), verbanone (4,6,6-trimethylbicyclo[3.1.1]heptan-2-one, thujone (1-isopropyl-4-methyl-bicyclo[3.1.0] hexan-3-one) or the 4,7-methano-octahydro-inden-5-one structure, and wherein R 1 , R 2 , R 3 independently signify hydrogen, lower alkyl, lower alkoxy, or 2 adjacent radicals represent methylenedioxy, and where, in case of the camphor derivatives, the ratio of the UV-A filter to the stabiliser is 2 to 6 : 1, and where 4-methylbenzylidene camphor is excluded from the scope of formula I, and, optionally, at least one conventional UV-B filter. A composition according to Claim 1, wherein the UV-A-filter is present in amounts of 1 - ca. 4 %, the stabiliser is present in amounts of 0.5 to 1 %, and the UV-B-filter is present in amounts of ca. 1 - 12 %. A composition according to Claim 1 or 2, wherein R 1 , R 2 and/or R 3 of (I) is selected from hydrogen, methyl, ethyl, propyl, isopropyl, tert. butyl, methoxy, ethoxy, propoxy, isopropoxy. A composition according to anyone of the preceding claims, wherein R 1 and R 2 of (I) is hydrogen. A composition according to anyone of the preceding claims, wherein at least one R group of (I) is hydrogen, the other being hydrogen, methyl, isopropyl or tert. butyl, methoxy or ethoxy. A composition according to anyone of Claims 1 to 5, wherein the compound of formula I is 3-(4'-methoxy-benzylidene)-6,6-dimethyl-bicyclo[3.1.1]heptan-2-one; 3-(benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptane-2-one; 6-benzylidene-octahydro-4,7-methano-inden-5-one; 3-benzylidene-4,6,6-trimethyl-bicyclo[3.1.1]heptan-2-one; 3-(4'-methoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 3-(2'-methoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 3-(2',3'-dimethoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 3-(3',5'-dimethoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 3-(3'-propoxy-benzylidene)-6,6-dimethyl-bicyclo[3.1.1]heptan-2-one; 3-(2',4'-dimethyl-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 2-(3'-methoxy-benzylidene)-1-isopropyl-4-methyl-bicyclo[3.1.0]hexan-3-one; 3-(4'-tert.butyl-benzylidene)-6,6-dimethyl-bicyclo[3..1.1-heptan-2-one]; 3-(4'-methoxy-benzylidene)-6,6-dimethyl-bicyclo[3.1.1]heptan-2-one; 3-(3',4',5'-trimethoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 3-(4'-tert.-butyl-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 3-(4'-tert.-butyl-benzylidene)-bicyclo[2.2.1]heptan-2-one; 6-(4'-tert.-butyl-benzylidene)-octahydro-4,7-methano-inden-5-one; 3-(4'-tert.-butyl-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-2-one; 3-(4'-methoxy-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-2-one; 2-(4'-tert.-butyl-benzylidene)-4,6,6-trimethyl-bicyclo-[3.1.1]heptan-3-one; 6-(4'-methoxy-benzylidene)-octahydro-4,7-methano-inden-5-one; 2-(4'-methoxy-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-3-one; 3-(3',4'-methylene-dioxy benzylidene)1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 3-(2'-methoxy-benzylidene)-bicyclo[2.2.1]heptane-2-one; 2-(2',4'-dimethyl-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-3-one; 6-(3',4'-dimethoxy-benzylidene)-4,7-methano-octahydro-indene-5-one or 6-(2'-methoxy-benzylidene)-4,7-methano-octahydro-inden-5-one. A composition according to anyone of Claims 1 to 5, wherein the compound of formula I is 3-(4'-methoxy-benzylidene)-6,6-dimethyl-bicyclo[3.1.1]heptan-2-one; 3-(4'-methoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one; 3-(4'-tert.-butyl-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]-heptan-2-one; 6-(4'-tert.-butyl-benzylidene)-octahydro-4,7-methano-inden-5-one; 6-(3',4'-dimethoxy-benzylidene)-4,7-methano-octahydro-indene-5-one or 6-(2'-methoxy-benzylidene)-4,7-methano-octahydro-inden-5-one. Composition according to anyone of the preceding claims, characterised in that the dibenzoylmethane derivative is selected from the following compounds: 2-methyldibenzoylmethane, 4-methyl-dibenzoylmethane, 4-isopropyldibenzoylmethane, 4-tert-butyldibenzoyl-methane, 2,4-dimethyldibenzoylmethane, 2,5-dimethyldibenzoylmethane, 4,4'-diisopropyldibenzoylmethane, 4-tert-butyl-4'-methoxydibenzoylmethane, 2-methyl-5-isopropyl-4'-methoxydibenzoylmethane, 2-methyl-5-tert-butyl-4'-methoxydibenzoylmethane, 2,4-dimethyl-4'-methoxydibenzoylmethane and 2,6-dimethyl-4-tert-butyl-4'-methoxydibenzoylmethane. Composition according to anyone of the preceding claims, characterised in that the dibenzoylmethane derivative is 4-tert-butyl-4'-methoxydibenzoylmethane. Composition according to anyone of the preceding claims, characterised in that it takes the form of an oil, a lotion, a gel, a solid stick, an emulsion e.g. cream, milk or of a vesicular dispersion of ionic or nonionic amphiphilic lipids, an aerosol, a spray, a foam, a powder, a shampoo, a hair conditioner or lacquer or a make-up. Composition according to anyone of the preceding claims, characterised in that it contains, in addition, cosmetic adjuvants selected from solvents, thickeners, emollients, emulsifiers, humectants, tensides, preservatives, antifoams, fragrances, oils, waxes, lower polyols and monohydric alcohols, propellants, silicones, colourings and pigments. A compound selected from the group consisting of 3-(4'-tert.-butyl-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]-heptan-2-one; 6-(4'-methoxy-benzylidene)-octahydro-4,7-methano-inden-5-one; 3-(4'-tert.-butyl-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-2-one; 2-(4'-tert.-butyl-benzylidene)-4,6,6-trimethyl-bicyclo-[3.1.1]heptan-3-one; 3-(4'-methoxy-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-2-one; 2-(4'-methoxy-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-3-one; 2-(2',4'-dimethyl-benzylidene)-4,6,6-trimethyl-bicyclo[3.1.1]heptan-3-one; 3-(3',4',5'-trimethoxy-benzylidene)-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-one or 6-(2'-methoxy-benzylidene)-4,7-methano-octahydro-inden-5-one. Process for stabilising dibenzoylmethane UV-A screening agents with respect to UV radiation of wavelengths between 320 and 400 nm, characterised in that 0,5 to 2 % by weight of the stabiliser I defined in Claim 1 is added to 0,75 to 5 % by weight of the dibenzoylmethane UV-A light-screening agent, and where, in case of the camphor devivatives, the ratio of the UV-A filter to the stabiliser is 2 to 6 : 1.

Inventors: GONZENBACH HANS ULRICH, GYGAX PETER, HOSTETTLER BERNHARD, HUBER ULRICH, GONZENBACH, HANS ULRICH, GYGAX, PETER, HOSTETTLER, BERNHARD, HUBER, ULRICH
Applicants: HOFFMANN LA ROCHE, F. HOFFMANN-LA ROCHE AG
Application year: 1996
Main classification: A61K7
IPC codes: C07C49, A61K8, A61Q17