4,4-Dihydroxypyrazolin-5-one compounds, procedures for their preparation and their use as cosmetics

0001The invention relates to novel 4,4-dihydroxypyrazolin-5-ones, their methods of preparation and their uses in the cosmetic field for coloring the skin and / or the hair but also for coloring certain parts of the skin in particular the face in order to to produce a "healthy glow" effect, by enhancing the radiance of the complexion while retaining transparency. The invention also relates to their uses in the cosmetic field for coloring the skin and more particularly with a view to giving the latter a tanning appearance.

0002It is known that dihydroxyacetone, or DHA, is a particularly interesting product which is commonly used in cosmetics as an artificial tanning agent for the skin; applied on the latter, in particular on the face, it makes it possible to obtain a tanning or browning effect of appearance very close to that which can result from a prolonged exposure to the sun (natural tanning) or under a UV lamp. Such use also has the advantage of completely avoiding the risks of skin reaction generally associated with the above-mentioned prolonged exposures (erythema, burns, loss of elasticity, appearance of wrinkles, premature aging of the skin, and the like).

0003However, the use of DHA has certain drawbacks.

0004Indeed, although the color produced on the skin by the application of a composition containing DHA is very close to that obtained by a natural tan, some users may still consider it too yellow.

0005Other drawbacks also appear during the storage of compositions containing DHA. Thus, the latter has an unfortunate tendency, more or less pronounced depending on the nature of the medium in which it is formulated, to degrade over time, this degradation generally resulting in the long term by an undesirable yellowing of the compositions which contain it. It also happens that over time such compositions have a foul odor. Finally, the pH of the compositions containing DHA decreases over time, making them ultimately incompatible with use in topical application. These various phenomena mean that the activity of DHA, and in particular its ability to color the skin, is greatly reduced when these compositions are applied to the skin.

0006In addition, the intensity of the coloration obtained on the skin and especially the speed with which this coloration develops are often judged to be very insufficient by users of self-tanning products based on DHA. Indeed, the duration necessary for the appearance on the skin of the desired intensity is generally several hours.

0007In order to increase the rapidity of the appearance of the color due to DHA, attempts have been made to combine the latter with other substances. Thus, application EP-A-547 864 proposes to provide DHA in the presence of an amino acid and a silicone, the DHA and the amino acid being stored before application to the skin in different compartments. We can also cite application WO-A-9404130 which describes a device for supplying DHA at the same time as a primary amine, these two compounds also being stored in different compartments.

0008However, these devices have the disadvantage of being complicated and of not bringing any real improvement as regards the waiting time necessary to obtain satisfactory coloring on the skin. Finally, they also do not completely solve the problems due to the conservation of compositions containing DHA.

0009In conclusion, it appears that DHA as an agent for artificial coloring of the skin is not completely satisfactory, and that there is therefore a need for having other agents which, preferably, have no disadvantages mentioned above.

0010To this end, new compositions are now proposed containing, in a cosmetically acceptable carrier, at least one 4,4-dihydroxypyrazolin-5-one. The time required to reveal the color after applying these compositions to the skin is remarkably short. These compositions also have excellent stability and give the skin a color very close to that imparted by a natural tan. Finally, the resistance over time of the coloring on the skin is also remarkable.

0011The compounds according to the invention can also be used to specifically color certain parts of the skin, in particular the face, in order to produce a “healthy glow” effect. Traditionally, use is made of makeup compositions and in particular foundations based on pigments and fillers which have the disadvantage of making a screen and consequently of masking the skin too much.

0012The use of the compositions of the invention based on 4,4-dihydroxypyrazolin-5-ones which will be defined subsequently makes it possible, on the contrary, to enhance the radiance of the complexion while retaining transparency.

0013Furthermore, these compositions can find an interesting application in hair coloring.

0014The first object of the invention therefore is therefore new 4,4-dihydroxypyrazolin-5-ones compounds corresponding to formula (I) below:<chemistry id="chem0001" num="0001"><img file="EP0903342B1_D0001.tif" /></chemistry> in which R₁ is chosen from:<ul id="ul0001" list-style="dash"><li>a hydrogen atom; a linear or branched C alkyl radical₁-VS₈,</li><li>a radical - (CH₂)₂-OR 'in which R' represents a phenyl or naphthyl radical;</li><li>a radical - (CH₂) qR "in which q is equal to 1 or 2 and R" represents a phenyl radical optionally substituted by a trifluoromethyl radical;</li><li>a phenyl radical optionally substituted by a nitro radical, a Cl radical, a C 1 alkyl radical₁-VS₄ or a C alkoxy radical₁-VS₄,</li></ul> and R₂ is chosen from:<ul id="ul0002" list-style="dash"><li>a hydrogen atom; a C 1 alkyl radical₁-VS₄, linear or branched; a C 4 hydroxyalkyl radical₁-VS₄ ; a methoxymethyl radical;</li><li>a phenyl radical optionally substituted by a halogen atom, a nitro radical, a C 1 alkyl radical₁-VS₄ or a C alkoxy radical₁-VS₄ ;</li><li>a C alkoxy radical₁-VS₄ ; a trifluoromethyl radical; acetamido; C dialkylamino₁-VS₄ ; carboxy; methoxycarbonyl; ethoxycarbonyl;</li><li>a thienyl radical, a furyl radical, a pyridyl radical or a pyrazolyl radical,</li><li>a radical -NHCOR₅ in which R₅ denotes a linear or branched C alkyl radical₁-VS₈.</li></ul>

0015The above conditions for the choice of R₁ and R₂ preferably being cumulative.

0016Thus, among the 4,4-dihydroxypyrazolin-5-ones which can be used in the compositions according to the invention, there may be mentioned in particular:<ul id="ul0003" list-style="dash"><li>1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-tert-butyl 1-phenyl 4,4-dihydroxypyrazolin-5-one; 1,3-diphenyl 4,4-dihydroxypyrazolin-5-one; 1-phenyl 3- (4'-methylphenyl) 4,4-dihydroxypyrazolin-5-one; 1-phenyl 3- (3'-methoxymethyl) 4,4-dihydroxypyrazolin-5-one; 1-phenyl 3- (4'-methoxymethyl) 4,4-dihydroxypyrazolin-5-one; 1-phenyl 3- (4'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one; 3-methoxy 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-ethoxy 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-acetamido 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-dimethylamino 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-diethylamino 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-carboxy 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-methoxycarbonyl 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-ethoxycarbonyl 1-phenyl 4,4-dihydroxypyrazolin-5-one;</li><li>1 - [(3'-trifluoromethyl) benzyl)] 3-methyl 4,4-dihydroxypyrazolin-5-one; 1 - [(1'-phenyl) ethyl)] 3-methyl 4,4-dihydroxypyrazolin-5-one; 3-methyl 4,4-dihydroxypyrazolin-5-one; 1,3-dimethyl 4,4-dihydroxypyrazolin-5-one; 1- (2'-phenoxy) ethyl 3-methyl 4,4-dihydroxypyrazolin-5-one; 1- (2'-naphthyloxy) ethyl 3-propyl 4,4-dihydroxypyrazolin-5-one; 1- (2'-naphthyloxy) ethyl 3-hydroxymethyl 4,4-dihydroxypyrazolin-5-one; 3-tert-butyl 1- (2'-phenoxy) ethyl 4,4-dihydroxypyrazolin-5-one; 3-methoxymethyl 1- (2'-naphthyloxy) ethyl 4,4-dihydroxypyrazolin-5-one; 3-methyl 1- (4'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one; 3-methoxy 4,4-dihydroxypyrazolin-5-one; 3-ethoxy 4,4-dihydroxypyrazolin-5-one;</li><li>1-methyl 4,4-dihydroxypyrazolin-5-one; 1-methyl 3-phenyl 4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (4'-chlorophenyl) 4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (3'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (3'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (4'-methylphenyl) 4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (2'-furyl) -4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (2'-thienyl) -4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (5'-pyrazolyl) 4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (4'-pyridyl) 4,4-dihydroxypyrazolin-5-one; 1-methyl 3-methoxy 4,4-dihydroxypyrazolin-5-one; 3-ethoxy 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-dimethylamino 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-diethylamino 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-acetamido 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-carboxy 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-methoxycarbonyl 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-ethoxycarbonyl 1-methyl 4,4-dihydroxypyrazolin-5-one;</li><li>1-ethyl 4,4-dihydroxypyrazolin-5-one; 1-methyl 3-methyl 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-phenyl 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3- (4'-chlorophenyl) 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3- (3'methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3- (3'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3- (4'-methylphenyl) 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3- (2'-furyl) 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3- (2'-thienyl) 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3- (5'-pyrazolyl) 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-methoxy 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-ethoxy 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-dimethylamino 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-diethylamino 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-acetamido 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-carboxy 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-methoxycarbonyl 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-ethoxycarbonyl 4,4-dihydroxypyrazolin-5-one;</li><li>1-isopropyl 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-methyl 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-phenyl 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3- (4'-chlorophenyl) 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3- (3'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3- (3'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3- (4'-methylphenyl) 4,4-dihydroxypyrazolin-5-one; 1-sopropyl 3- (2'-furyl) 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3- (2'-thienyl) 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3- (5'-pyrazolyl) 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-methoxy 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-ethoxy 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-dimethylamino 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-diethylamino 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-acetamido 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-carboxy 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-methoxycarbonyl 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-ethoxycarbonyl 4,4-dihydroxypyrazolin-5-one;</li><li>1-tert-butyl 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3-methyl 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3-phenyl 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3- (4'-chlorophenyl) 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3- (3'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3- (3'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3- (4'-methylphenyl) 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3- (2'-furyl) 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3- (2'-thienyl) 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3- (5'-pyrazolyl) 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3-methoxy 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3-ethoxy 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3-dimethylamino 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3-diethylamino 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3-acetamido 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3-carboxy 4,4-dihydroxypyrazolin-5-one 1-tert-butyl 3-methoxycarbonyl 4,4-dihydroxypyrazolin-5-one; 1-tert-butyl 3-ethoxycarbonyl 4,4-dihydroxypyrazolin-5-one;</li><li>1-octyl 4,4-dihydroxypyrazolin-5-one; 1-octyl 3-methyl 4,4-dihydroxypyrazolin-5-one; 1-octyl 3-phenyl 4,4-dihydroxypyrazolin-5-one; 1-octyl 3- (4'-chlorophenyl) 4,4-dihydroxypyrazolin-5-one; 1-octyl 3- (3'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-octyl 3- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-octyl 3- (3'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one;</li><li>1- (4'-methylphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3-methyl 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3 phenyl 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3- (4'-chlorophenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3- (3'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3- (3'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3- (4'-methylphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3- (2'-furyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3- (2'-thienyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3- (5'-pyrazolyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3-methoxy 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3-ethoxy 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3-dimethylamino 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3-diethylamino 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3-acetamido 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3-carboxy 4,4-dihydroxypyrazolin-5-one; 1- (4'-methylphenyl) 3-methoxycarbonyl 4,4-dihydroxypyrazolin-5 one; 1- (4'-methylphenyl) 3-ethoxycarbonyl 4,4-dihydroxypyrazolin-5-one;</li><li>1-benzyl 4,4-dihydroxypyrazolin-5-one; 1-benzyl 3-methyl 4,4-dihydroxypyrazolin-5-one; 1-benzyl 3-phenyl 4,4-dihydroxypyrazolin-5-one; 1-benzyl 3- (4'methylphenyl) 4,4-dihydroxypyrazolin-5-one; 1-benzyl 3- (3'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-benzyl 3- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1-benzyl 3- (3'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one;</li><li>1- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3-methyl 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3- (3'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3-phenyl 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3- (4'-chlorophenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3- (3'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3-methoxy 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3-ethoxy 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3-dimethylamino 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3-diethylamino 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3-acetamido 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3-carboxy 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3-methoxycarbonyl 4,4-dihydroxypyrazolin-5-one; 1- (4'-methoxyphenyl) 3-ethoxycarbonyl 4,4-dihydroxypyrazolin-5-one;</li><li>1- (4'chlorophenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3-methyl 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3-phenyl 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3- (4'-methylphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3- (3'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3- (3'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3-methoxy 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3-ethoxy 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3-dimethylamino 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3-diethylamino 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3-acetamido 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3-carboxy 4,4-dihydroxy-pyrazolin-5-one; 1- (4'-chloro-phenyl) 3-methoxycarbonyl 4,4-dihydroxypyrazolin-5-one; 1- (4'-chlorophenyl) 3-ethoxycarbonyl 4,4-dihydroxypyrazolin-5-one;</li><li>1- (4'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-nitrophenyl) 3-methyl 4,4-dihydroxypyrazolin-5-one; 1- (4'-nitrophenyl) 3-phenyl 4,4-dihydroxypyrazolin-5-one; 1- (4'-nitrophenyl) 3- (4'-methylphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-nitrophenyl) 3- (3'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-nitrophenyl) 3- (4'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 1- (4'-nitrophenyl) 3- (3'-nitrophenyl) 4,4-dihydroxypyrazolin-5-one;</li><li>1-phenyl 3-trifluoromethyl 4,4-dihydroxypyrazolin-5-one; 1-methyl 3-trifluoromethyl 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-trifluoromethyl 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-trifluoromethyl 4,4-dihydroxypyrazolin-5-one; 3-trifluoromethyl 4,4-dihydroxypyrazolin-5-one.</li></ul>

0017Among the 4,4-dihydroxypyrazolin-5-ones which can be used in the context of the present invention, very particularly preferred are those for which, cumulatively, R₁ is chosen from:<ul id="ul0004" list-style="dash" compact="compact"><li>hydrogen and methyl, ethyl, isopropyl, tert-butyl or substituted or unsubstituted phenyl radicals;</li></ul> and R₂ is chosen from:<ul id="ul0005" list-style="dash" compact="compact"><li>hydrogen or methyl, phenyl, methoxyphenyl, methoxy, ethoxy, carboxy, methoxycarbonyl, ethoxycarbonyl, acetamido, dimethylamino, diethylamino, trifluoromethyl, furyl, pyridyl radicals.</li></ul>

0018It is more particularly preferred to use 3-methyl 4,4-dihydroxypyrazolin-5-one; 1,3-dimethyl 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-methyl 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-methyl 4,4-dihydroxypyrazolin-5-one; 1-tertbutyl 3-methyl 4,4-dihydroxypyrazolin-5-one; 1-methyl 3-phenyl 4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (3'-methoxyphenyl) 4,4-dihydroxypyrazolin-5-one; 3 (2'-furyl) 1-methyl 4,4-dihydroxypyrazolin-5-one; 1-methyl 3- (4'-pyridyl) 4,4-dihydroxypyrazolin-5-one; 1-methyl 3-methoxy 4,4-dihydroxypyrazolin-5-one; 3-ethoxy 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-dimethylamino 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-diethylamino 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-acetamido 1-methyl 4,4-dihydroxypyrazolin-5-one; 1-phenyl 4,4-dihydroxypyrazolin-5-one; 1-methyl 4,4-dihydroxypyrazolin-5-one; 1-ethyl 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 4,4-dihydroxypyrazolin-5-one; 1-tertbutyl 4,4-dihydroxypyrazolin-5-one; 3-methoxy 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-ethoxy 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-acetamido 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-dimethylamino 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-diethylamino 1-phenyl 4,4-dihydroxypyrazolin-5-one; 1-phenyl 3-trifluoromethyl 4,4-dihydroxypyrazolin-5-one; 1-methyl 3-trifluoromethyl 4,4-dihydroxypyrazolin-5-one; 1-isopropyl 3-trifluoromethyl 4,4-dihydroxypyrazolin-5-one; 1-ethyl 3-trifluoromethyl 4,4-dihydroxypyrazolin-5-one; 3-trifluoromethyl 4,4-dihydroxypyrazolin-5-one; 3-carboxy 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-methoxycarbonyl 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-ethoxycarbonyl 1-phenyl 4,4-dihydroxypyrazolin-5-one; 3-methoxy 4,4-dihydroxypyrazolin-5-one; 3-methoxy 4,4-dihydroxypyrazolin-5-one; 3-carboxy 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-methoxycarbonyl 1-methyl 4,4-dihydroxypyrazolin-5-one; 3-ethoxycarbonyl 1-methyl 4,4-dihydroxypyrazolin-5-one.

0019The subject of the invention is also cosmetic or dermatological compositions comprising, in a cosmetically acceptable carrier, at least one 4,4-dihydroxypyrazolin-5-one corresponding to formula (I) above.

0020In a preferred embodiment of the invention, these compositions are intended for artificial tanning of the skin.

0021These new compositions have the advantage of giving the skin a tan very close to the natural tan, in an extremely short time. Indeed, a few minutes are enough to obtain a tanned complexion.

0022Another subject of the present invention is a method of cosmetic treatment of the skin intended for tanning and / or artificially browning it, consisting in applying to it an effective amount of a cosmetic composition in accordance with the invention or of a 4,4-dihydroxypyrazolin-5-one as mentioned above.

0023The present invention also relates to the use of a 4,4-dihydroxypyrazolin-5-one as mentioned above in, or for the manufacture of, compositions intended for artificial tanning and / or browning of the skin.

0024In another embodiment of the invention, these cosmetic compositions are intended for make-up and more particularly for coloring the skin, in particular the face to give it a "healthy glow" appearance by enhancing the radiance of the complexion.

0025Another subject of the present invention is a method for making up the skin, in particular the face, intended to give it a "healthy glow" appearance by enhancing the radiance of the complexion, consisting in applying to the skin an effective amount of a composition cosmetic according to the invention or a 4,4-dihydroxypyrazolin-5-one as mentioned above.

0026The present invention also relates to the use of a 4,4-dihydroxypyrazolin-5-one as mentioned above in, or for the manufacture of, compositions for making up the skin, in particular of the face intended for it give a “good-looking” appearance by enhancing the radiance of the complexion.

0027In another embodiment of the invention, these cosmetic compositions are intended for coloring the hair.

0028The present invention thus also relates to a method of cosmetic treatment of hair intended for coloring them, consisting in applying to the hair an effective amount of a composition in accordance with the invention or of a 4,4-dihydroxypyrazolin-5- one as mentioned above.

0029The present invention also relates to the use of a 4,4-dihydroxypyrazolin-5-one as mentioned above in, or for the manufacture of, compositions intended for coloring the hair.

0030Other characteristics, aspects and advantages of the present invention will appear on reading the detailed description which follows.

0031The 4,4-dihydroxypyrazolin-5-ones are used in an amount effective to impart coloring either to the skin or to the hair, as the case may be. Thus, they are generally present in the compositions according to the invention at a concentration of between 0.05 and 10% by weight, preferably between 0.05 and 5% by weight, relative to the total weight of the composition.

0032When the compositions according to the invention are applied to the skin, the pH can vary between 3 and 10. It is preferably between 3 and 7.

0033When the compositions according to the invention are intended for coloring the hair, the pH can vary between 2 and 8. It is preferably between 2 and 6.

0034The vehicle (or cosmetically acceptable support) for the compositions according to the invention is preferably water, alone or with one or more organic solvents or fatty substances.

0035The solvents which can be used are preferably chosen from alcohols such as ethyl alcohol or cetyl alcohol, or also from propylene glycol, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether

0036As fatty substances, there may be mentioned oils and waxes of mineral, animal or vegetable origin.

0037By oil is meant a compound which is liquid at room temperature. The term “wax” is intended to mean a compound which is solid or substantially solid at room temperature, and the melting point of which is generally greater than 35 ° C.

0038As oils, mention may be made of mineral oils (petrolatum); vegetable (sweet almond, macadamia, blackcurrant seed oil); synthetics such as perhydrosqualene, alcohols, fatty acids or esters (octyl palmitate, isopropyl lanolate, triglycerides including those of capric / caprylic acids), fatty esters and ethers oxyethylenated or oxypropylenated; silicone (cyclomethicone, polydimethysiloxanes or PDMS) or fluorinated, polyalkylenes.

0039As waxy compounds, mention may be made of jojoba oil, paraffin, carnauba wax, beeswax, hydrogenated castor oil.

0040The other constituents which can be used in the formulation of the compositions targeted by the invention, in particular thickeners, emulsifiers, gelling agents are those which are conventionally used in the cosmetic and / or dermatological field.

0041As emulsifiers, it is possible to use fatty acid and polyethylene glycol (PEG) esters, fatty acid and glycerol esters (glyceryl stearate) or fatty acid and sugar esters (sorbitan stearate), as well as their polyoxyethylenated or polyoxypropylenated derivatives, cyclomethicones and dimethicones copolyols, anionic surfactants (K or Na alkylphosphate), polyalkoxylated fatty alcohols.

0042Preferably, polyalkoxylated fatty alcohols are used, such as oxypropylenated butyl alcohols, oxyethylenated caprylic alcohols, oxyethylenated cetyl alcohols.

0043As thickeners, use may be made of crosslinked polyacrylic acids, guar gums and modified or unmodified celluloses such as hydroxypropylated guar gum, methylhydroxyethylcellulose, hydroxypropylmethyl cellulose or even hydroxyethylcellulose.

0044As gelling agents, mention may be made of modified clays (bentones), metal salts of fatty acids (aluminum stearate), ethylene / acrylate copolymers, silicas, polyethylenes, calcium silicates or ethylcellulose.

0045The compositions according to the invention may also contain any other cosmetically or dermatologically acceptable constituent usually used in this type of composition, such as softeners, antioxidants, opacifiers, stabilizers, emollients, repellents against insects, organic sunscreens active in UV-A and / or UV-B, photoprotective pigments and nanopigments, hydrating agents, vitamins, perfumes, preservatives, fillers, sequestrants, dyes, and in particular the compounds known for their self-tanning action, such as, for example, dihydroxyacetone, methylglycoxal, glyceric aldehyde, erythrulose, alloxane, dialdehyde 2, 3-dihydroxysuccinic, 2-amino-3-hydroxysuccinic dialdehyde, 2-benzylamino-3-hydroxysuccinic dialdehyde.

0046Of course, those skilled in the art will take care to choose this or these optional additional compounds and / or their amounts in such a way that the advantageous properties intrinsically attached to the composition according to the invention are not, or not substantially, altered. by the addition (s) envisaged.

0047This composition can be in particular in the form of an emulsion, simple or complex (O / W, W / O, O / W / O or W / O / W) such as a cream, a milk, a gel or a cream gel, powder, solid stick and optionally be packaged as an aerosol and be in the form of a foam or spray.

0048Preferably, this composition is in the form of an oil-in-water emulsion.

0049The compositions concerned by the invention can be prepared according to techniques well known to those skilled in the art, in particular those intended for the preparation of emulsions of oil-in-water or water-in-oil type.

0050A subject of the invention is also a process for the preparation of the compounds of formula (I), this process being characterized in that it comprises the following stages (the meanings of R₁ and R₂ are as given above):<ul id="ul0006" list-style="none"><li>(i) reacting a monosubstituted hydrazine R₁NH-NH₂ with a structural β-ketoester:<chemistry id="chem0002" num="0002"><img file="EP0903342B1_D0002.tif" /></chemistry> in which R₆ denotes a linear or branched C alkyl radical₁-VS₄, preferably in an alcoholic medium such as in methanol, ethanol or isopropanol, at a temperature between 65 and 85 ° C, preferably at reflux of the solvent used so as to obtain a pyrazolin-5-one ① which is then made react with a nitroso-aromatic compound ② so as to obtain the corresponding 4-arylimino pyrazolin-5-one ③:<chemistry id="chem0003" num="0003"><img file="EP0903342B1_D0003.tif" /></chemistry> this reaction being preferably carried out in a lower alcohol such as methanol, ethanol or isopropanol at a temperature between 65 ° C and 85 ° C, at reflux of the solvent used, and preferably in the presence of a base low carbonate or bicarbonate type in catalytic amount,</li><li>(ii) then the 4-arylimino pyrazolin-5-one ③ is hydrolyzed, preferably in a strong dilute acid medium, to obtain the corresponding 4,4-dihydroxypyrazolin-4,5one derivative of formula (I):<chemistry id="chem0004" num="0004"><img file="EP0903342B1_D0004.tif" /></chemistry></li></ul>

0051In such a process, the aromatic nitroso derivative of the first step is preferably a p-nitrosodialkylaniline of formula ②:<chemistry id="chem0005" num="0005"><img file="EP0903342B1_D0005.tif" /></chemistry> in which R₇ and R₈ represent a C 1 alkyl radical₁-VS₄, linear or branched.

0052The acid hydrolysis of the second step of the preparation process according to the invention is preferably carried out with dilute sulfuric acid or aqueous hydrochloric acid at room temperature in the presence of a co-solvent of 4.4 -dihydroxypyrazolin-5-one, immiscible with water, which advantageously extracts the compound as it is formed, facilitating its isolation with very high purity. The water-immiscible co-solvent can be a halogenated solvent such as, for example, dichloromethane or 1,2-dichloroethane. In a preferred embodiment of the invention, the water-immiscible co-solvent is an ether such as diethyl or diisopropyl ether.

0053Concrete, but in no way limiting, examples intended to illustrate the invention will now be given.

<u>PREPARATION EXAMPLE</u> : Synthesis of 3-acetamido-4,4-dihydroxy 1-phenyl pyrazolin-5-one

<u>Step 1</u> : Preparation of 3-acetamido-5-hydroxy-1-phenyl-pyrazole:

0054<chemistry id="chem0006" num="0006"><img file="EP0903342B1_D0006.tif" /></chemistry>

0055To a solution of 100 g (0.571 mole) of 3-amino-1-phenyl-pyrazolin-5-one in 2 liters of acetic acid were added dropwise 55 cm3 of acetic anhydride. The solution was brought to reflux for 4 hours 30 minutes then cooled to about 17 ° C. The precipitate was drained on No. 4 sintered glass and washed with diisopropyl ether. The filtrate was concentrated and then ice-cold. A second crystallized jet formed, was drained, washed with diisopropyl ether and dried under vacuum at 40 ° C with the first jet. After recrystallization from ethanol, 76.24 g of beige powder were isolated. NMR spectra¹H and NMR¹³C of the product obtained conform to the expected structure.

<u>2nd step</u> : Preparation of 3-acetamido-4- (N- (4'-dimethylaminophenyl) imino-1-phenyl-pyrazolin-5-one:

0056<chemistry id="chem0007" num="0007"><img file="EP0903342B1_D0007.tif" /></chemistry>

0057To a solution of 75.84 g (0.349 mole) of 3-acetamido-5-hydroxy-1-phenyl-pyrazole in 5 liters of propan-1-ol warmed to 45 ° C. was added a solution of 52.43 g (0.349 mole) of N, N-dimethyl-4-nitrosoaniline in 1 liter of propan-1-ol, then 5 g of potassium carbonate (0.035 mole). The reaction mixture was brought to reflux for 4 hours. The propan-1-ol was then distilled at 3/4 then the ice-cold solution. The product crystallized, was drained and washed with cyclohexane on No. 4 sintered glass. After drying under vacuum at 40 ° C., 80.48 g of a black powder were obtained. NMR spectra¹H and NMR ¹³C of the product obtained conform to the expected structure.

<u>Stage 3</u> : Preparation of 3-acetamido-1-phenyl-4,4-dihydroxypyrazolin-5-one of formula (I):

0058<chemistry id="chem0008" num="0008"><img file="EP0903342B1_D0008.tif" /></chemistry>

0059To a solution of 65 g (0.186 mole) of 3-acetamido-4- (N- (4'-dimethylaminophenyl) imino-1-phenyl-pyrazolin-5-one in 3.4 liters of THF were added dropwise 600 ml of 2N sulfuric acid The reaction mixture was stirred at room temperature for 3 hours 30 minutes. The precipitate corresponding to N, N-dimethyl-p-phenylenediamine sulfate was drained. After adding diethyl ether and water saturated with sodium chloride to the filtrate, the aqueous phase is extracted with diethyl ether. The organic phases were combined and washed until neutral with water saturated with sodium chloride, they were dried over Na₂SO₄ and we concentrated them to dryness. After recrystallization from a mixture of ethyl acetate and heptane then air drying, 15.25 g of khaki powder were obtained, corresponding to the expected structure. NMR spectra¹H and NMR¹³C of the product obtained conform to the expected structure.

<u>COMPOSITION EXAMPLE</u> :

0060A concrete example of a self-tanning oil-in-water emulsion according to the invention is given below: <tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row rowsep="1"><entry namest="col1" nameend="col2" align="left">Phase A:</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">- mixture of cetylstearyl alcohol and cetylstearyl alcohol oxyethylenated (33 OE) 80/20 sold under the name "DEHSCONET 390" by the company TENSIA</entry><entry namest="col2" nameend="col2" align="left">7 %</entry></row><row><entry namest="col1" nameend="col1" /></row><row><entry namest="col1" nameend="col1" align="left">- mixture of glycerol mono and distearate sold under the name "CERASYNTH SD" by ISP</entry><entry namest="col2" nameend="col2" align="left">2 %</entry></row><row><entry namest="col1" nameend="col1" align="left">- cetyl alcohol</entry><entry namest="col2" nameend="col2" align="left">1,5 %</entry></row><row><entry namest="col1" nameend="col1" align="left">- polydimethylsiloxane sold under the name "DC200 Fluid" by the company DOW CORNING</entry><entry namest="col2" nameend="col2" align="left">1,5 %</entry></row><row><entry namest="col1" nameend="col1" align="left">- alcohol benzoate C₁₂/VS₁₅ sold under the name</entry><entry namest="col2" nameend="col2" /></row><row><entry namest="col1" nameend="col1" align="left">"FINSOLV TN" by the company FINETEX</entry><entry namest="col2" nameend="col2" align="left">15 %</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">- 3-acetamido-1-phenyl-4,4-dihydroxypyrazolin-5-one</entry><entry namest="col2" nameend="col2" align="left">1 %</entry></row></tbody></tgroup></table></tables><tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row rowsep="1"><entry namest="col1" nameend="col2" align="left">Phase B:</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">- glycerin</entry><entry namest="col2" nameend="col2" align="left">20 %</entry></row><row><entry namest="col1" nameend="col1" align="left">- preservatives</entry><entry namest="col2" nameend="col2" align="left">qs</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">- demineralized water qs</entry><entry namest="col2" nameend="col2" align="left">100 %</entry></row></tbody></tgroup></table></tables>

0061This emulsion was produced according to the following procedure: phases A and B were brought to 80 ° C. separately. Then phase A was poured into phase B with Moritz stirring. The mixture was then homogenized and then allowed to cool to room temperature.