The polyamino acid derivative and those applications null in the constituent for the treatment of the keratin

摘要

The following general formula (57) [summary] The present invention, (I): The _{R 1,} represents a _{C 1} -C ₄₀ alkyl group or a hydrogen atom in particular;; _{R 2} is optionally substituted hydrogen atoms or -, - be -NR ₃ or S- -O is X: [In the above formula _{R 4} represents a group _NH 2, OH, SH, -CHOHCH _3, the -CONH ₂ or a hydrogen atom; polyamino acid derivatives n represents a hydrogen atom or an alkyl group _{R 3;} represents an alkyl group which may the use in cosmetic compositions of polyamino acid at least one] is a number more than one molecular weight such that the 200-200000.The present invention relates to the use of said derivatives for the care strengthen keratin fibers.