Bi-aromatic compounds linked via a heteroethynylene radical, and pharmaceutical and cosmetic compositions containing them

Bi-aromatic compounds linked via a heteroethynylene bond, corresponding to the general formula (I) below:

• in which:
• Ar represents a radical chosen from the formulae (b) or (c) below:
• Z being O or S, or N—R6,
• R1 represents a halogen atom, —CH3, —CH2—OR7, —OR7, —COR8 or a polyether radical,
• R2 and R3, taken together, form a 5- or 6-membered ring, optionally substituted with at least one methyl,
• R4 and R5 represent H, a halogen atom, linear or branched C1-C20 alkyl, —OR7 or a polyether radical,
• R6 represents H, linear or branched C1-C10 alkyl or —OCOR9,
• R7 represents H, linear or branched C1-C10 alkyl or —COR9,
• R8 represents H, linear of branched C1-C10 alkyl, —OR10 or
• R9 represents linear or branched C1-C10 alkyl,
• R10 represents H, linear or branched C1-C20 alkyl, mono- or polyhydroxyalkyl, allyl, optionally substituted aryl or aralkyl, or a sugar residue,
• r′ and r″, which may be identical or different, represent H, C1-C10 alkyl, mono- or polyhydroxyalkyl, optionally substituted aryl, an amino acid or peptide residue, or, taken together with the nitrogen atom, form a heterocycle,
• X represents a divalent radical which, from right to left or vice-versa, has the formula:
• in which:
• Y represents O, S(O)n or Se(O)n′,
• n and n′ being 0, 1 or 2,
• and the salts of the compounds of formula (I) when R1 represents a carboxylic acid function, as well as the optical isomers of the said compounds of formula (I).