UV-B filters

Abstract

Disclosed is a 2-phenyl-benzimidazolesulfonic acid according to the formula in which n is 0, 1 or 2 and m is 2 or 3, R1, R2, R3, R4 and R5, are each a radical such as H, C 1-8 -alkyl, C 1-8 -alkoxy, hydroxyl, sulfate, nitro, F, Cl, Br or I radicals, and R6 is a C 1-8 -alkyl or C 1-8 -alkoxy radical. This compound can be effectively used as a UV filter, and as part of a cosmetic formulation which comprise these compounds. A process for preparation of the compound is disclosed as well.

1 . A 2-Phenylbenzimidazolesulfonic acid according to the formula I  
       
         
           
           
               
               
           
         
       
       wherein 
 n is 0-2 and  
 m is 2-3,  
 R1, R2, R3, R4 and R5 each are a radical selected from H, C 1-8 -alkyl, C 1-8 -alkoxy, hydroxyl, sulfate, nitro, F, Cl, Br or an I radical, and  
 R6 is a C 1-8 -alkyl or C 1-8 -alkoxy radical.  
 
     
     
         2 . A 2-Phenylbenzimidazolesulfonic acid according to  claim 1 , wherein m=2 and n=0-1, and wherein at least 4 radicals from the group R1, R2, R3, R4 and R5 are H radicals.  
     
     
         3 . A process for the preparation of a compound according to  claim 1 , wherein an o-phenylenediamine according to formula II  
       
         
           
           
               
               
           
         
       
       is reacted with a compound according to the formula III  
       
         
           
           
               
               
           
         
       
       wherein R1, R2, R3, R4 and R5, are each, independently of one another, a radical selected from H, C 1-8 -alkyl, C 1-8 -alkoxy, hydroxyl, nitro, F, Cl, Br or an I radical, 
 and wherein X is a radical selected from —COOH, —COCl, —COBr, —CN or —COOR,  
 and wherein R is a C 1-20 -alkyl radical.  
 
     
     
         4 . A method according to  claim 3 , wherein the reaction is carried out in sulfuric acid.  
     
     
         5 . A UV filter substance comprised of a 2-phenylbenzimidazolesulfonic acid according to  claim 1 .  
     
     
         6 . A cosmetic formulation having UV protection properties comprising at least one filter substance comprised of at least one 2-phenylbenzimidazolesulfonic acid according to  claim 1 .  
     
     
         7 . A cosmetic formulation according to  claim 6 , wherein the formulation comprises at least one oil phase and at least one water phase, and wherein the 2-phenylbenzimidazolesulfonic acid is present in the at least one water phase.  
     
     
         8 . A cosmetic formulation according to  claim 6 , further comprising at least one additional UV filter substance, wherein each filter substance is present in the formulation in an amount of from 0.5 to 20% by weight of the entire formulation.  
     
     
         9 . A cosmetic formulation according to  claim 6 , further comprising at least one of the following compounds 3-(4′-methylbenzylidene)-dl-camphor, 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione, 4-isopropyldibenzoylmethane, 2-hydroxy-4-methoxybenzophenone, octyl methoxycinnamate, 3,3,5-trimethylcyclohexyl salicylate, 2-ethylhexyl 4-(dimethylamino)benzoate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate coated titanium dioxide, 2-phenylbenzimidazole-5-sulfonic acid and 2,2′-(1,4-phenylene)bis(1H-benzimidazole-5-sulfonic acid).  
     
     
         10 . A stabilizing substance for a UV filter comprising a 2-phenylbenzimidazolesulfonic acid according to  claim 1 .  
     
     
         11 . A method according to  claim 2 , wherein the radicals R1-R5 are each an H radical.  
     
     
         12 . A method according to  claim 3 , wherein R is a C 1-8  alkyl radical.  
     
     
         13 . A method according to  claim 4 , wherein the sulphuric acid is activated sulphuric acid.  
     
     
         14 . A method according to  claim 4 , wherein the reaction is carried out at a temperature of 160° C. to 190° C.  
     
     
         15 . A method according to  claim 13 , further comprising activating the sulphuric acid using chlorosulfonic acid or oleum.  
     
     
         16 . A method according to  claim 13 , further comprising activating the sulphuric acid using oleum.  
     
     
         17 . A UV filter substance according to  claim 5 , wherein the UV filter substance further comprises a UV-B filter substance.  
     
     
         18 . A formulation according to  claim 8 , wherein the filter substance is a UV-A filter substance.  
     
     
         19 . A formulation according to  claim 8 , wherein each filter substance is present in the formulation in an amount from 1 to 15% by weight of the entire formulation.  
     
     
         20 . A formulation according to  claim 8 , wherein each filter substance is presence in the formulation in an amount from 2 to 8% by weight of the entire formulation.  
     
     
         21 . A formulation according to  claim 8 , wherein the filter substances together comprise from 5 to 25% by weight of the entire formulation.  
     
     
         22 . A formulation according to  claim 6 , further comprising 2-phenylbenzimidazole-5-sulfonic acid and/or 2,2′-(1,4-phenylene)bis(1H-benzimidazole-5-sulfonic acid).  
     
     
         23 . A substance according to  claim 10 , wherein the UV filter is dibenzoylmethane or a derivative of dibenzoylmethane.  
     
     
         24 . A formulation according to  claim 6 , further comprising at least one antioxidant.  
     
     
         25 . A formulation according to  claim 6 , further comprising at least one vitamin.