| abstract |
Disclosed are coumarin derived compounds of formula I as skin lightening agents alone or in combination with other skin benefit agents and together with a cosmetic vehicle: n n nWhere each or both R 1 and/or R 2 represents hydrogen (H); linear or branched, saturated or unsaturated C 1 -C 12 alkyl, alkenyl, acyl, or heteroalkyl (preferably, alkoxy) groups; and n nR 3 represents linear or branched, cyclic or acyclic, saturated or unsaturated C 1 -C 12 alkyl, alkenyl, cycloalkyl, cycloalkenyl, or heteroalkyl group; and n nR 4 represents a hydrogen atom (H); straight or branched, cyclic or acyclic, saturated or unsaturated, containing or not containing a heteroatom C 1 -C 22 alkyl, alkenyl, cycloalkyl, cycloalkenyl, heteroalkyl, aryl, or heteroaryl group. In a most preferred embodiment, each R 1 , R 2 and R 4 represent H, while R 3 represents a methyl group, referred to herein as a 4-methyl 7-hydroxy-coumarin derivative, or coumarin derived resorcinol derivative, which may be prepared by catalytic (nickel or paladium catalyst) hydrogenation of 4-methyl 7-hydroxy-coumarin followed by hydrolysis. The inventive compounds, compositions and methods have effective skin lightening properties, may be less irritating to the skin, and are cost-effective and relatively simple to manufacture. nAlso disclosed are processes for making the inventive compounds of general formula I from 4-substituted-7-hydroxy coumarin derivatives. |