Stable peptide-conjugated ascorbic acid derivative, method for preparing same, and cosmetic composition comprising same

A method for preparing a peptide-conjugated ascorbic acid derivative represented by formula I, the method comprising a step of subjecting a compound of the following formula II to a condensation reaction with a compound of the following formula IV, and then subjecting a product of the condensation reaction to a deprotection reaction if a protecting group is present in the product:

• wherein
• represents a peptide in which the same or different amino acid residues selected from among natural or non-natural amino acid residues are bonded by amide bonds;
• R1 represents side chains of the amino acid residues;
• R1′ is equal to R1 or is R1 in which amino group or carboxyl group is protected;
• X is hydrogen or carbonyl (C═O);
• R2 is null when X is hydrogen, or R2 is palmityl, lauryl or stearyl when X is carbonyl;
• n is an integer ranging from 2 to 5.

A cosmetic composition, comprising (i) a peptide-conjugated ascorbic acid derivative represented by the following formula I or a cosmetically acceptable salt thereof and (ii) cosmetically acceptable base:

• wherein
• represents a peptide in which the same or different amino acid residues selected from among natural or non-natural amino acid residues are bonded by amide bonds;
• R1 represents side chains of the amino acid residues;
• X is hydrogen or carbonyl (C═O);
• R2 is null when X is hydrogen, or R2 is palmityl, lauryl or stearyl when X is carbonyl;
• and
• n is an integer ranging from 2 to 5.