Administration of 2-oxyacetamide compounds for promoting and/or inducing and/or stimulating the pigmentation of keratin materials and/or for limiting the depigmentation and/or bleaching thereof

A regime or regimen for promoting and/or inducing and/or stimulating the pigmentation of human keratin materials and/or for preventing and/or limiting the depigmentation and/or bleaching thereof, comprising administering to an individual in need of such treatment, a this effective amount of at least one 2-oxyacetamide compound of formula (I) below, or a salt and/or solvate thereof:

• in which:
• a) R1 and R2 are independently selected from among:
• 1) a hydrogen, with R1 different from R2,
• 2) a C1-C20 alkyl radical optionally substituted with at least one substituent A1
• 3) a hydrocarbon-based ring C1 of 3 to 7 atoms optionally fused to at least one ring C2 of 4 to 7 atoms, the ring C2 optionally containing at least one heteroatom to form a heterocycle Hy2, these rings C1 and C2 optionally comprising a carbonyl or thiocarbonyl function and/or being substituted with at least one substituent A2,
• 4) a heterocycle Hy1 optionally fused to a ring C2 of 4 to 7 atoms, the ring C2 optionally containing at least one heteroatom to form a heterocycle Hy2, these rings Hy1 and C2 optionally comprising a carbonyl or thiocarbonyl function and/or being substituted with at least one substituent A1,
• 5) one of the groups C(═NR)R′, C(═NR)NR′R″, COR, CSR, COOR, CONRR′, SO2R or SO2NRR′;
• b) R3 is selected from among:
• 1) a C1-C20 alkyl radical optionally substituted with at least one substituent A1,
• 2) a hydrocarbon-based ring C3 of 3 to 7 atoms optionally fused to at least one ring C4 of 4 to 7 atoms optionally containing at least one heteroatom to form a heterocycle Hy4, these rings C3 and C4 optionally comprising a carbonyl or thiocarbonyl function and/or being substituted with at least one substituent A2,
• 3) a heterocycle Hy3 selected from among pyrrole, furan, thiophene and pyrazole rings and/or optionally fused to a ring C5 representing a phenyl, a pyridine or a pyrimidine, the heterocycle Hy3 and the ring C5 being optionally substituted with at least one substituent A1,
• 4) a heterocycle Hy5 different from Hy3 and optionally fused to a ring C6 of 4 to 7 atoms, these rings Hy5 and C6 optionally comprising a carbonyl or thiocarbonyl function and/or being substituted with at least one substituent A1, this ring C6 optionally containing at least one heteroatom to form a heterocycle Hy6;
• c) R, R′ and R″ are independently selected from:
• 1) a hydrogen,
• 2) a C1-C20 alkyl radical optionally substituted with at least one substituent A1,
• 3) a ring C7 of 4 to 7 atoms optionally containing at least one heteroatom to form a heterocycle Hy7 and/or being optionally fused to a ring C8 of 4 to 7 atoms optionally containing at least one heteroatom to form a heterocycle Hy8, the rings C7 and C8 being optionally substituted with at least one substituent A1 and optionally comprising a carbonyl or thiocarbonyl function;
• d) A1 is selected from among:
• 1) a halogen,
• 2) a C1-C20 alkyl radical optionally substituted with a group OR5,
• 3) a ring C9 of 4 to 15 atoms optionally containing at least one heteroatom to form a heterocycle Hy9 and/or being optionally fused to a ring C10 of 4 to 7 atoms, these rings C9 and C10 optionally comprising a carbonyl or thiocarbonyl function and/or at least one substituent A3 selected from among OR5, CF3, a halogen and a C1-C20 alkyl radical,
• 4) one of the groups CF3, CN, OR4, SR4, NR4R′4, NR4C(═NR′4)NR″4R′4, COR4, CSR4, COOR4, CONR4R′4, NR4COR′4, NR4CONR′4R″4, SO2NR4R′4, NR4SO2R′4, SO2R4, SiR4R′4R″4, Si(OR4)(OR′4)OR″4 and SO3H, in which R4, R′4, R″4 and R′4 independently are each a hydrogen or a C1-C20 alkyl radical optionally substituted with a heterocycle Hy10 or a group CONR5R′5;
• e) A2 is selected from among:
• 1) a halogen,
• 2) one of the groups CF3, CN, OR4, SR4, NR4R′4, OCOR4, COR4, CSR4, COOR4, SO2R4, SiR4R′R″4, NO2 and OCF3, in which R4, R′4 and R″4 independently are each a hydrogen or a C1-C20 alkyl radical optionally substituted with a phenyl radical,
• 3) a C1-C20 alkyl radical optionally substituted with a group OR5,
• 4) a ring C11 of 4 to 7 atoms optionally containing at least one heteroatom to form a heterocycle Hy11 and/or being optionally fused to a ring C12 of 4 to 7 atoms, these rings C11 and C12 optionally comprising a carbonyl or thiocarbonyl function and/or at least one substituent A3 selected from among OR5, CF3, a halogen and a C1-C20 alkyl radical;
• f) R5 and R′5 are independently selected from among:
• 1) a hydrogen,
• 2) a C1-C20 alkyl radical;
• g) Hy1, Hy2, Hy4 to Hy8, Hy10 and Hy11 independently are each a heterocycle of 4 to 7 atoms optionally having from 1 to 4 heteroatoms selected from N, O and S and combinations thereof and/or comprising a carbonyl or thiocarbonyl function,
• h) Hy9 is a heterocycle of 4 to 15 atoms optionally having from 1 to 5 heteroatoms selected from N, O and S and combinations thereof and/or comprising a carbonyl or thiocarbonyl function, formulated into a cosmetically/pharmaceutically acceptable medium therefor.