HYDROXAMIC ACID DERIVATIVES AND THE METHOD FOR PREPARING THEREOF

摘要

The present invention provides hydroxamic acid derivatives represented by the following formula (I), having anti-aging efficacy and a method for preparation thereof: wherein, R₁ is herein, R₅ and R₆ each independently represents a hydrogen atom, a C₁-C₁₀ alkyl group or a C₃-C₆ cyclic alkyl group; R₂ is CONH, NHCO, CONR₇ or NR₇CO, herein, R₇ represents a C₁-C₁₀ alkyl group; R₃ is -(CH)_n-, herein, n=0 or 1; and R₄ is a hydrogen atom or a C₁-C₁₀ alkyl group. Further, the present invention provides skin-care external compositions for preventing skin aging, containing said hydroxamic acid derivatives represented by the formula (I) as an active ingredient.