Organosiloxanes containing ester derivatives of ascorbic acid

Abstract

Organosiloxanes containing ester derivatives of ascorbic acid are disclosed having the formula (R 3 SiO) n R (3-n) Si—X-A wherein R is an alkyl group containing 1 to 6 carbon atoms, n is 1 to 3 inclusive, X is a divalent organic linking group, A is an ester derivative of ascorbic acid. A method of making an organosiloxane containing ester derivatives of ascorbic acid and the products prepared according to the method are also taught. The compounds and compositions of the present disclosure are useful to affect tissue lightening when applied topically to keratinaceous tissue.

1 . A method of making an organosiloxane containing ester derivative of ascorbic acid comprising:
 I) providing a protected ascorbic acid by forming a protecting group from at least one hydroxy-functional group thereon;   II) mixing the protected ascorbic acid with a carboxy-functional organosiloxane having the formula (R 3 SiO) n R (3-n) Si—X—C(O)OR 1  
 where R is an alkyl group containing 1 to 6 carbon atoms,
 n is 1 to 3 inclusive, X is a divalent organic linking group, 
 R 1  is a hydrocarbyl containing 1 to 20 carbon atoms or hydrogen, to form a solution; 
 
   III) contacting the solution with a biocatalyst which is capable of catalyzing ester bond formation;   IV) optionally, removing the protecting group, and wherein the protecting group may comprise a functional group.   
     
     
         2 . The method of  claim 1  wherein the protecting group comprises a trimethylsilyl ether. 
     
     
         3 . The method of  claim 1  wherein the carboxy-functional organosiloxane formula R is methyl and n=2. 
     
     
         4 . The method of  claim 1  wherein the carboxy-functional organosiloxane formula X is a linear or branched C 1 -C 30  alkylene chain. 
     
     
         5 . The method of  claim 1  wherein the carboxy-functional organosiloxane formula X is —(CH 2 ) 10 —. 
     
     
         6 . The method of  claim 1  wherein the carboxy-functional organosiloxane formula R 1  is methyl or ethyl. 
     
     
         7 . The method of  claim 1  wherein the biocatalyst comprises an enzyme. 
     
     
         8 . The method of  claim 7  wherein the enzyme comprises a hydrolase enzyme. 
     
     
         9 . The method of  claim 8  wherein the hydrolase enzyme exits in either free or immobilized form and is selected from the group consisting of a lipase, a protease, a phosphoesterase, an esterase, a cutinase, and combinations thereof. 
     
     
         10 . The method of  claim 8  wherein the hydrolase enzyme comprises a lipase. 
     
     
         11 . The product produced by the method of  claim 1 . 
     
     
         12 . A keratinaceous tissue lightening agent composition comprising the product as claimed in  claim 11 . 
     
     
         13 . The keratinaceous tissue lightening agent composition of  claim 12  wherein the keratinaceous tissue comprises human skin. 
     
     
         14 . The keratinaceous tissue lightening agent composition of  claim 13  further comprising a suitable vehicle or base. 
     
     
         15 . The keratinaceous tissue lightening agent composition of  claim 14  further comprising free ascorbic acid. 
     
     
         16 . The keratinaceous tissue lightening agent composition of  claim 14  wherein the composition is in the form of an emulsion. 
     
     
         17 . A personal care composition comprising the product of  claim 11 .