EP1362035A1

EP1362035A1 - Diaminopyrazole compounds and the use thereof in the oxidation dyeing of keratinous fibres

Info

Publication number: EP1362035A1
Application number: EP02704830A
Authority: EP
Inventors: Thilo Fessmann; Eric Terranova
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2001-02-21
Filing date: 2002-02-14
Publication date: 2003-11-19
Also published as: FR2821077B1; FR2821077A1; US7285136B2; WO2002066441A1; US20040103487A1

Abstract

The invention relates to novel diaminopyrazole compounds having formula (I): wherein R1 represents a linear or branched C4-C5 alkyl or n-propyl group, or a linear or branched C3-C5 mono or polyhydroxy alkyl group, and the addition salts thereof with a physiologically acceptable acid. The invention also relates to the compositions containing such a compound for the dyeing of keratinous fibres and the method for using said compositions.

Description

DIAMINOPYRAZOLE COMPOUNDS AND THEIR USE IN OXIDATION DYES OF KERATINIC FIBERS

The present invention relates to new diaminopyrazole compounds, to a composition for the oxidation dyeing of keratin fibers, and in particular human keratin fibers such as the hair, comprising at least, as oxidation base, a diaminopyrazole compound. , and to the oxidation dyeing processes using it.

It is known to dye keratin fibers and in particular human hair with dye compositions containing oxidation dye precursors, in particular ortho- or paraphenylenediamines, ortho- or para-aminophenols, heterocyclic compounds such as derivatives diaminopyrazole, generally called oxidation bases. The precursors of oxidation dyes, or oxidation bases, are colorless or weakly colored compounds which, associated with oxidizing products, can give rise, through an oxidative condensation process, to colored and coloring compounds.

We also know that we can vary the nuances obtained with these oxidation bases by associating them with couplers or color modifiers, the latter being chosen in particular from aromatic metadiamines, meta-aminophenols, metadiphenols and certain compounds. heterocyclic.

The variety of molecules involved in the oxidation bases and couplers, allows obtaining a rich palette of colors.

The so-called "permanent" coloration obtained by means of these oxidation dyes must moreover satisfy a certain number of requirements. Thus, it must be without drawbacks from the toxicological point of view, it must allow nuances to be obtained in the desired intensity, present good resistance to external agents (light, bad weather, washing, permanent waving, perspiration, friction). The dyes must also make it possible to cover gray hair, and finally be the least selective possible, that is to say allow to obtain the smallest possible color differences throughout the same keratin fiber, which can be in fact differently sensitized (that is to say damaged) between its tip and its root. They must also have good chemical stability in the formulations. They must have a good toxicological profile.

In addition, for a certain number of applications, dyes are sought which give chromatic nuances to the hair. We know from patent applications DE 42 34 885 and DE

196 46 609 derivatives of 4,5-diaminopyrazole which, when used in conjunction with different couplers, in particular benzoxazines, give chestnut-like nuances with blue reflections,

• red, purple, eggplant or coppery. However, these dyes do not meet all of the above requirements.

Now, the Applicant has now discovered, in a totally unexpected and surprising manner, that it was possible to obtain dyes, capable of leading to powerful colorings, particularly chromatic and brilliant, not very selective, and having excellent properties of resistance to the various aggressions that keratin fibers can undergo by using diaminopyrazoles of formula (I) below or their physiologically acceptable salts as oxidation base. The subject of the present invention is therefore the new diaminopyrazoles having the following structure (I):

(I) in which R 1 denotes a linear or branched n-propyl or C ₄ -C ₅ alkyl group, or a linear or branched mono or polyhydroxy C ₃ -C ₅ alkyl group.

A subject of the invention is also the physiologically acceptable acid salts of the compounds of formula (I) such as hydrochlorides, hydrobromides, sulfates, tartrates, lactates or acetates.

Ri preferably denotes an n-propyl group; linear or branched butyl or pentyl; a propyl, butyl or pentyl group, linear or branched substituted by 1 to 4 OH radicals, according to the possibilities of substitution of the abovementioned groups.

A subject of the invention is also a composition for the oxidation dyeing of keratin fibers, and in particular human keratin fibers such as the hair, characterized in that it contains, in a medium suitable for dyeing, as a base oxidizing at least one diaminopyrazole of formula (I) above, or its acid salts.

As indicated above, the colors obtained with the oxidation dye composition according to the invention are powerful, particularly bright and chromatic. They make it possible in particular to achieve more red shades free or containing very little blue or yellow. They also have excellent resistance properties vis-à-vis the action of various external agents (light, bad weather, washing, permanent waving, perspiration, friction).

The subject of the invention is also a process for the oxidation dyeing of keratin fibers using such a dye composition.

As examples of diaminopyrazoles of formula (I) according to the invention, mention may be made of the compounds belonging to the following classes:

The diaminopyrazoles of formula (I) preferred according to the invention have the following structures:

The diaminopyrazoles of formula (I) more particularly preferred according to the invention are 2-Propyl-2H-pyrazole-3,4-diamine, 2-Isobutyl-2H-pyrazole-3, 4-diamine 2- (2,2- Dimethyl-propyl) -2H-pyrazole-3,4-diamine le 3- (4,5-Diamino-pyrazol- l -yl) -propan- l -ol l - (4,5-Diamino-pyrazol- l -yl) -propan-2-ol

3- (4,5-Diamino-pyrazol- l-yl) -propane- 1,2,2-diol

4- (4,5-Diamino-pyrazol- l -yl) -butan- l -ol

4- (4,5-Diamino-pyrazol-l -yl) -butane-1,2,2-diol

5- (4,5-Diamino-pyrazol-1-yl) -pentan -ol or their addition salts with physiologically acceptable acids.

The diaminopyrazoles of formula (I) according to the invention are prepared for example according to the following general method of preparation:

The synthetic approach shown below is described in the literature up to intermediary (2) (J. H. P. Juffermanns, C. L.

Habraken, J. Org. Chem., 1986, 51, 4656; Klebe et al., Synthesis, 1973, 294; R. Hϋttel, F. Bϋchele, Chem. Ber., 1955, 88, 1586.). The alkylation and amination to arrive at the compounds of type (5) of formula (I) according to the invention are mentioned for example in document DE 42 34 885.

The dye composition according to the invention contains in particular from 0.001 to 10% by weight, preferably from 0.05 to 6% by weight, and even more preferably from 0.1 to 3% by weight, of at least one diaminopyrazole of formula (I) or its salts. The dye composition in accordance with the invention can also contain, in addition to (or) diaminopyrazole (s) defined above, at least one additional oxidation base which can be chosen from the oxidation bases conventionally used in oxidation dyeing and among which mention may be made of paraphenylenediamines, bis-phenylalkylenediamines, para-aminophenols, ortho- aminophenols and heretocyclic bases other than the 4,5-diaminopyrazoles used in accordance with the invention.

Among the paraphenylenediamines, there may be more particularly mentioned by way of example, paraphenylenediamine, paratoluylenediamine, 2,6-dimethyl paraphenylenediamine, 2-β-hydroxyethyl paraphenylenediamine, 2-n-propyl paraphenylenediamine, 2-isopropyline paraphenyl , N- (β- hydroxypropyl) paraphenylenediamine, N, N-bis- (β-hydroxyethyl) paraphenylenediamine, 4-amino N- (β-methoxyethyl) aniline, the paraphenylenediamines described in the French patent application FR

2630438, and their addition salts.

Mention may more particularly be made, among bis-phenylalkylenediamines, by way of example, of N, N'-bis- (β-hydroxyethyl) N, N'-bis- (4'-aminophenyl) 1, 3-diaminopropanol, N, N'-bis- (β- hydroxyethyl) N, N'-bis- (4'-aminophenyl) ethylene diamine, N, N'-bis-

(4-amino phenyl) tetra-methylenediamine, la- N, N'-bis- (β-hydroxyethyl), N, N'-bis- (4-aminophenyl) tetramethylenediamine, N, N'-bis- (4- methylaminophenyl) tetramethylene diamine, N, N'-bis- (ethyl) N, N'- bis- (4'-amino, 3'-methylphenyl) ethylenediamine, and their addition salts. Among the para-aminophenols, mention may more particularly be made, for example, of para-aminophenol, 4-amino 3-methyl phenol, 4-amino 3-fluoro phenol, 4-amino 3-hydroxy-methyl phenol , 4-amino 2-methyl phenol, 4-amino 2-hydroxymethyl phenol, 4-amino 2- methoxymethyl phenol, 4-amino 2-aminomethyl phenol, 4-amino 2- (β-hydroxyethyl aminomethyl) phenol , and their addition salts.

Among the ortho-aminophenols that may be mentioned more particularly by way of example, 2-amino phenol, 2-amino 5-methyl phenol, 2-amino 6-methylphenol, 5-acetamido 2-amino phenol, and their addition salts. Among the heterocyclic bases that may be mentioned more particularly by way of example, pyridine derivatives, pyrimidine derivatives, pyrazole derivatives other than the diamino pyrazoles of formula (I) used in accordance with the invention, and their addition salts. When used, these additional oxidation bases preferably represent from 0.0005 to 12% by weight of the total weight of the dye composition, and even more preferably from 0.005 to 6% by weight of this weight. The oxidation dye compositions in accordance with the invention may also contain at least one coupler and / or at least one direct dye, in particular for modifying the nuances or enriching them with reflections.

Couplers usable in dye compositions. oxidation according to the invention can be chosen from the couplers conventionally used in oxidation dyeing and among which mention may be made of metaphenylenediamines, meta-aminophenols, metadiphenols, mono or polyhydroxylated derivatives of naphthalene and heterocyclic couplers such as, for example, indole or pyridine derivatives and their addition salts.

These couplers are more particularly chosen from 2-methyl 5-aminophenol, 5-N- (β-hydroxyethyl) amino 2-methyl phenol, 6-chloro-2-methyl-5-aminophenol, 3-amino phenol, 1,3-dihydroxy benzene, 1,3-dihydroxy 2-methyl benzene, 4-chloro 1,3-dihydroxy benzene, 2,4-diamino l- (β-hydroxyethyloxy) benzene, 2-amino 4 - (β- hydroxyethylamino) 1-methoxybenzene, 1,3-diamino benzene, 1,3- bis- (2,4-diaminophenoxy) propane, 3-ureido aniline, 3-ureido 1-dimethylamino benzene, sesamol, l-β-hydroxyethylamino-3,4-methylenedioxybenzene, α-naphthol, 2 methyl-1-naphthol, 6-hydroxy indole, 4-hydroxy indole, 4-hydroxy N-methyl indole, 2-amino-3-hydroxy pyridine, 6-hydroxy benzomorpholine 3,5-diamino-2,6-dimethoxypyridine, lN- (β-hydroxyethyl) amino-3,4-methylene dioxybenzene, 2,6- bis- (β-hydroxyethylamino) toluene and their addition salts. When present, these couplers represent in particular

0.0001 to 10% of the total weight of the dye composition, preferably from 0.005 to 5% by weight, and even more preferably from 0.1 to 3% of this weight. In general, the addition salts with an acid which can be used in the context of the dye compositions of the invention (oxidation bases and couplers) are in particular chosen from hydrochlorides, hydrobromides, sulfates, tartrates, lactates and acetates. The addition salts with a base are especially those obtained with soda, potash, ammonia, amines or alkanolamines.

The medium suitable for dyeing (or support) used according to the invention consists of water or of a mixture of water and at least one organic solvent chosen from lower C ₁ -C ₄ alkanols, polyols and polyol ethers, aromatic alcohols, analogues and their mixtures.

The dye composition according to the invention may also contain various adjuvants conventionally used in compositions for dyeing the hair, such as anionic, cationic, nonionic, amphoteric, zwitterionic surfactants. or their mixtures, anionic, cationic, non-ionic, amphoteric, zwitterionic polymers or their mixtures, thickening agents

^• inorganic or organic, antioxidants, reducing agents, ^'sunscreens, penetration agents, sequestering agents, fragrances, buffers, dispersants, conditioning agents such as for example silicones, agents film-forming agents, preserving agents, opacifying agents.

The pH of the dye composition according to the invention is between 3 and 12.

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

The dye composition according to the invention can be in various forms, such as in the form of liquids, creams, gels, or in any other form suitable for dyeing keratin fibers, and in particular human hair. The subject of the invention is also a process for dyeing keratin fibers and in particular human keratin fibers such as the hair using the dye composition as defined above. According to this process, at least one dye composition as defined above is applied to the fibers, for a time sufficient to develop the desired coloration, either in air or using an oxidizing agent. The dye composition may optionally contain oxidation catalysts, in order to accelerate the oxidation process.

According to a first embodiment of the process of the invention, the coloring of the fibers can be carried out without the addition of an oxidizing agent, only in contact with the oxygen in the air.

According to a second embodiment of the process of the invention, at least one dye composition as defined above is applied to the fibers, the color being revealed at acidic, neutral or alkaline pH using an oxidizing agent which is added just at the time of use to the dye composition or which is present in an oxidizing composition applied simultaneously or sequentially separately.

According to this second form of implementation of the dyeing process of the invention, the dye composition described above is preferably mixed with an oxidizing composition containing, in a medium suitable for dyeing, at the time of use, at least one oxidizing agent present in an amount sufficient to develop coloring. The mixture obtained is then applied to the keratin fibers and left to stand for 3 to 50 minutes, preferably 5 to 30 minutes, after which it is rinsed, washed with shampoo, rinsed again and dried. The oxidizing agent present in the oxidizing composition as defined above can be chosen from the oxidizing agents conventionally used for the oxidation dyeing of keratin fibers, and among which mention may be made of hydrogen peroxide, peroxide of urea, alkali metal bromates, persalts such as perborates and persulfates. Hydrogen peroxide is particularly preferred.

The pH of the oxidizing composition containing the oxidizing agent as defined above is such that after mixing with the dye composition, the pH of the resulting composition applied to the keratin fibers preferably varies between 3 and 12, and even more preferably between 5 and 11. It is adjusted to the desired value by means of acidifying or basifying agents usually used in dyeing keratin fibers and as defined above. The oxidizing composition as defined above may also contain various adjuvants conventionally used in compositions for dyeing the hair and as defined above.

The composition which is finally applied to the keratin fibers can be in various forms, such as in the form of liquids, creams, gels, or in any other form suitable for dyeing keratin fibers, and in particular human hair. .

Another object of the invention is a device with several compartments or "kit" for dyeing or any other packaging system with several compartments, a first compartment of which contains the dye composition as defined above and a second compartment of which contains the oxidizing composition. as defined above. These devices can be equipped with a means enabling the desired mixture to be delivered to the hair, such as the devices described in patent FR-2 586 913 in the name of. Applicant.

The examples which follow are intended to illustrate the invention without however limiting its scope. EXAMPLES

EXAMPLES OF SYNTHESIS OF COMPOUNDS OF FORMULA

01

Synthesis of 3.4.5-tribromopyrazole (1):

An aqueous solution (350 ml) containing sodium hydroxide (24 g, 0.6 moles) and pyrazole (10 g, 0.147 moles) was prepared with stirring. After cooling the reaction medium to 20 ° C, Br ₂ (72 g, 0.45 mole) was added dropwise for 1 h while maintaining the temperature between 20 ° C and 25 ° C. The reaction was followed by thin layer chromatography (TLC) (50% Hexane / 50% AcOEt or ethyl acetate). The precipitate was filtered and washed with demineralized water (100 ml). The filtrate was acidified to pH 6-7 using HCl (10%, 33 g, 0.27 mole) and keeping the temperature between 20 and 25 ° C.

The precipitate thus formed is filtered and washed with demineralized water (100 ml). The combined solids are brought to reflux in a Dean-Stark apparatus in the presence of toluene (200 ml). At the end of the water collection, the organic phase is filtered hot. The solvent is evaporated to a residual volume of 110 ml. The solution is cooled to 0-5 ° C for 1 hour. The precipitate formed is collected by filtration, washed with cold toluene (20 ml) and dried under vacuum at 80 ° C to give 3,4,5-tribromopyrazole (1) as an off-white solid (30 g, 67% ).

¹³ C - NMR: (100 MHz, d6-DMSO): 97.7, 116.1, 126.4

Melting point: 182-184 ° C

Synthesis of 3.5-dibromo-4-nitropyrazole (2): HNO ₃ (d = 1.50 g / ml; 18 ml, 0.429 mole) was added dropwise for 10 min to a solution of 3,4,5- tribromopyrazole (1) (50 g, 0.164 mole) in glacial acetic acid (750 ml) while maintaining the temperature at 15 ° C. Acetic anhydride (250 ml) was added and the reaction mixture was stirred at room temperature for 2 h. After complete reaction, the reaction mixture was poured onto broken ice (1 kg). After 1 h stirring, the crude product was filtered, then washed with demineralized water (2 x 60 ml) to give crude 1 -nitro- 3,4,5-tribromopyrazole. The water (24.6 ml) contained in the wet product was removed by heating a solution of the product in toluene (750 ml) at reflux in a Dean-Stark apparatus. The toluene solution was kept at reflux for an additional 30 min until a TLC (eluent toluene) indicates that the rearrangement of the intermediate formed l -nitro-3,4,5-tribromopyrazole (Rf = 0.77) , in 3, 5-dibromo-4-nitropyrazole 2 (Rf = 0.05) is complete. The solution was concentrated to a residual volume of 150 ml, then allowed to cool to 60 ° C before adding hexane (275 ml). The solution was cooled to 0-5 ° C for 1 h and 3,5-dibromo-4-nitropyrazole (2) (29.1 g, 65%) was recovered by filtration and drying under vacuum in the form of a yellow solid -clear.

Melting point: 127.6-130.1 ° C.

Synthesis of 3-f3.5-Dibromo-4-nitro-pyrazol- l -ylVproρan- l -ol ( ^" 3- n:

A mixture of 3,5-dibromo-4-nitropyrazole (2) (2.0 g; 7.38 mmol) in DMF (9.5 ml) was added for 15 min to a suspension of NaH (0.32 g, 8.0 mmol; 60% dispersion in oil previously washed with hexane) in DMF (16 ml) with stirring and inert atmosphere. After 15 min of stirring, a solution of 3-bromol-propanol (1.0 g; 7.19 mmol) in DMF (3.2 ml) was added dropwise. The reaction mixture was heated at 80 ° C for 2 h (followed by TLC), then the DMF was evaporated under reduced pressure. A mixture of DCM / water (20 ml, 1/1) is added. The organic phase was dried over Na ₂ SO ₄ and the solvent was evaporated under reduced pressure. The crude reaction product was obtained as black oil (1.9 g, 79%) which was used without further purification in the amination step. Synthesis of -Propyl-3.5-dibromo-4-nitropyrazole (3-2):

A mixture of 3,5-dibromo-4-nitropyrazole (2) (25 g, 92 mmol) in DMF (120 ml) was added for 45 min to a suspension of NaH (4.0 g, 10 mmol; dispersion 60% "in oil previously washed with hexane) in DMF (200 ml) with stirring and inert atmosphere. After 30 min of stirring a solution of 1-bromopropane (13.6 g, 1 11 mmoles) in DMF (40 ml) was added for 10 min. The reaction mixture was heated at 50-60 ° C for 3 h (followed by TLC), then the DMF was evaporated under reduced pressure. A mixture of DCM / water (300 ml, 1/5) was added and the organic phase was then extracted with water (2 x 50 ml). The organic phase was dried over Na ₂ SO and the solvent was evaporated under reduced pressure. The crude reaction product was obtained as black oil (19.4 g, 70%) which was used without further purification in the amination stage.

Synthesis of l- (3.5-Dibromo-4-nitro-pyrazol- l -ylVpropan-2-ol (3 - 31--.

A mixture of 3,5-dibromo-4-nitropyrazole (2) (40.0 g; 147 mmol) in DMF (200 ml) was added for 15 min to a suspension of NaH (6.5 g, 162 mmol ; 60% dispersion in oil previously washed with hexane) in DMF (320 ml) with stirring and inert atmosphere. After stirring for 35 min, a solution of 1-bromo-2-propanol (26.8 ml; 221 mmol) in DMF (80 ml) was added dropwise. The reaction mixture was heated at 80 ° C for 2 h, then the DMF was evaporated under reduced pressure. A mixture of DCM / water (480 ml, 2/1) is added. The organic phase was extracted with DCM (2 x 160 ml). The combined organic phases were washed with water (3 x 400 ml). The organic phase was dried over Na ₂ SO and the solvent was evaporated under reduced pressure. The l - (3, 5-Dibromo-4-nitro- pyrazol-1-yl) -propan-2-ol was obtained as a white solid (23.3 g; 48%).

R _f (DCM / MeOH: 95/5) = 0.8

00 MHz, d ⁶ -DMSO): 5.10 (1H, d, OH), 4.22-4.02 (3 Η, m _EGR, CH ₂ CΗ and

CH ₂ CH), 1.15 (3 Η, d, CH ₃ ).

Synthesis of 3-f3.5-Dibromo-4-nitro-pyrazol-l -yl -propane-l, 2-diol G-4):

A mixture of 3,5-dibromo-4-nitropyrazole (2) (40.0 g; 147 mmol) in DMF (200 ml) was added for 15 min to a suspension of NaΗ (6.5 g, 162 mmol; dispersion 60% in oil previously washed with hexane) in DMF (320 ml) with stirring and inert atmosphere. After 30 min of stirring, a solution of 3-bromo-

1, 2-propanediol (19.4 ml; 221 mmol) in DMF (80 ml) was added dropwise. The reaction mixture was heated at 80 ° C for 3 h, then the DMF was evaporated under reduced pressure. A mixture of DCM / water (480 ml, 2/1) is added. A yellow solid precipitated. After washing with ether (50 ml), 3- (3, 5-Dibromo-4-nitro-pyrazol-1-yl) -propane- 1,2-diol (32.3 g, 63%) was obtained as a white solid (23.3 g; 48%).

R _f (DCM / MeOΗ: 90/10) = 0.35 1H - NMR (200 MHz, d ⁶ -DMSO): 5.09 (1 H, d, CHOH), 4.80-4.75 (1 Η, ti _ar ge, CΗ ₂ OH ), 4.27-4.15 (2 Η, m, CH ₂ OΗ), 3.35-3.29 (3 H, m, N-CH ₂ CH and CH ₂ CH).

Synthesis of 3-f5-Benzylamino-3 -bromo-4-nitro-pyrazol- l -yP- propan-1-ol (4- 1):

A mixture of 3- (3,5-Dibromo-4-nitro-pyrazol- l -yl) -propan- l -ol

(3-2) (17.1 g, 52 mmol), EtOΗ (100 ml) and benzylamine (27.9 g, 260 mmol) was heated at reflux for 15 h. The reaction medium was concentrated to the maximum under reduced pressure. The very viscous residue was suspended in AcOEt (100 ml) and EtOH (100 ml). The organic phase was washed with NaCl solution (10%, 100 ml), then dried over Na ₂ SO. After evaporation of the solvent under reduced pressure, an orange oil was obtained (13.6 g) which is subsequently purified by column chromatography (gradient 10% AcOEt / 90% hexane to 40% AcOEt / 60%) hexane) in order to obtain, after evaporation of the solvent, 3- (5-Benzylamino-3-bromo-4-nitro-pyrazol-1-yl) -propan-lol in the form of a yellow solid (8.8 g, 48%).

Melting point: 95.0-96.5 ° C.

1H - NMR (400 MHz, CDCfe): 7.40-7.30 (5H, m, H _Ar ); 4.68 (2 H, d, J = 7.0 Hz,

NHCH ₂ ), 4.16 (2 Η, t, J ≈ 7.0 Hz, CH ₂ N), 3.65 (2 Η, t, J = 7.0 Hz, CH ₂ O); 2.02 (2 Η, m, CΗ ₂ CH ₂ CΗ ₂ ).

Synthesis of Benzyl-f5-bromo-4-nitro-2-propyl-2H-pyrazol-3-yl) - amine (4-2):

A mixture of l -propyl-3,5-dibromo-4-nitropyrazole (19.4 g, 62 mmol), EtOH (500 ml) and benzylamine (40 g, 373 mmol) was heated at reflux for 15 h. The reaction medium was concentrated to the maximum under reduced pressure. The residue has been suspended in AcOEt

(100 ml) and the insoluble part was separated by filtration, and the filtrate was evaporated to dryness. The black oil obtained was purified by column chromatography (eluent: AcOEt / hexane) to give the benzyl- (5-bromo-4-nitro-2-propyl-2H-pyrazol-3-yl) -amine in the form of '' a yellow solid (9 g; 29%) from 3,5-dibromo-4-nitropyrazole.

Melting point: 91.8-92.3 ° C

1H - NMR (400 MHz, CDC1 ₃ ): 7.41 - 7.31 (5H, m, H _arom ); 4.61 (2 H, d, J = 6.5 Hz,

NHCH ₂ ), 3.94 (2 Η, t, J = 7.5 Hz, CH ₂ N), 1.83 (2 Η, m, CΗ ₃ CH ₂ ), 0.89 (3 Η, t, J = 7.5 Hz, CH ₃ ). Synthesis of l - (5-Benzylamino-3-bromo-4-nitro-pyrazol- l -yl) - propan-2-ol (4-3):

A mixture of l - (3,5-Dibromo-4-nitro-pyrazol- l -yl) -propan-2-ol

(3-3) (22 g, 666 mmol), EtOH (300 ml) and benzylamine (102 g, 936 mmol) was heated at reflux for 1.5 h. The reaction medium was concentrated to the maximum under reduced pressure. DCM (100 ml) was added to the residue. The organic phase was washed with dilute acid (5 x 50 ml). The organic phase was dried over Na ₂ SO ₄ and the solvent was evaporated under reduced pressure. The brown oil obtained was treated with diisopropyl ether at 0 ° C to give l - (5-Benzylamino-3-bromo-4-nitro-pyrazol-l -yl) -propan-2-ol (13.7 g , 58%) as a yellow solid.

Melting point: 81.3 ° C. m / z (ES ⁺ ): 355 [M + H] ⁺ ; 377 [M + Na; 733 [2M + Na] ⁺ .

Synthesis of 3- (5-Benzylamino-3-bromo-4-nitro-pyrazol-1-yl) - propane-1.2-diol (4-4):

A mixture of l - (3,5-Dibromo-4-nitro-pyrazol-l -yl) -propane- 1,2-diol (3-4) (31 g, 898 mmol), EtOH (420 ml) and benzylamine (138 g, 1.26 moles) was heated at reflux for 1.5 h. The reaction medium was concentrated to the maximum under reduced pressure. 100 ml of DCM were added to the residue. The organic phase was washed with dilute acid (5 x 50 ml). The organic phase was dried over Na ₂ SO ₄ and the solvent was evaporated under reduced pressure. The brown oil obtained was treated with diisopropyl ether at 0 ° C to give 3- (5-Benzylamino-3-bromo-

4-nitro-pyrazol-l -yl) -propane-1,2-diol (14.1 g, 42%) as a yellow solid.

Melting point: 90.1 ° C. m / z (ES ⁺ ): 372 [M + H] ⁺ ; 395 [M + Na] ⁺ ; 767 [2M + Na] ⁺ . Synthesis of hydrobromide and hydrochloride of 3- (4,5-Diamino-pyrazol-l -yl) -propan-l (5-1):

A mixture of 3- (5-Benzylamino-3-bromo-4-nitro-pyrazol-l -yl) - propan- 1 -ol (4- 1) (8.8 g; 24.8 mmol) in EtOH (500 ml) containing a 10% Pd / C catalyst (Johnson-Mattey Type 487, 0.9 g dry weight) and 36% hydrochloric acid (6.0 g, 59 mmol) was hydrogenated in an autoclave (l 1) at 11 bars for 5 h. The catalyst was filtered, washed with EtOH and the filtrate was evaporated under reduced pressure. Under an inert atmosphere, the crude oil was taken up in EtOH (50 ml) and was heated to 50 ° C. AcOEt (50 ml) was added and the mixture was first cooled to room temperature, then to 0-5 ° C for 2 h. The precipitate formed was collected by filtration, washed with a cold mixture of EtOH / AcOEt (1/1, 2 x 30 ml) and dried under vacuum to give 3- (4,5-Diamino-pyrazol-1-yl) -propan -ol in the form of hydrobromide and hydrochloride (1.06 eq. HBr and 0.94 eq. HC1) as an off-white solid (2.4 g, 42%).

Melting point: 275-280 ° C

Elementary analysis: C ₈ H ₁₄ N ₄ O (1.06 HBr, 0.94 HC1)

Found: C: 26.13%, H: 5.13%, N: 20.09%, O: 5.92%, Br: 29.05%, Cl: 12.60%

Theory: C: 26.34%, H: 5.16%, N: 20.48%, O: 5.85%, Br: 29.21%, Cl: 12.96% 1H - NMR (400 MHz, d ⁶ -DMSO): 8.26 (1 H , s, Hpy); 5.18 (1 H, sι _arg β, NH), 4.02 (2 Η, m, CH ₂ N), 3.45 (2 Η, m, CH ₂ O), 1.85 (2 Η, m , CH ₂ ) Synthesis of 4.5-Diamino-l - propylpyrazole hydrobromide and hydrochloride (5-2):

A mixture of Benzyl- (5-bromo-4-nitro-2-ρropyl-2H-pyrazol-

3-yl) -amine (7 g; 21 mmol) in EtOH (500 ml) containing a catalyst of 10% Pd / C (Johnson-Mattey Type 487, 0.5 g dry weight) and 36% hydrochloric acid (5, 0 g, 49 mmol) was hydrogenated in a Parr autoclave (1 1) at 11 bars for 3 h. The catalyst was filtered, washed with EtOH and the filtrate was evaporated under reduced pressure. Under an inert atmosphere, the crude orange oil was taken up in EtOH and was heated to 40 ° C. AcOEt (90 ml) was added and the mixture was kept at room temperature for 15 h. The precipitate formed was collected by filtration, washed with a cold mixture of EtOH / AcOEt (1/1, 2 x 20 ml) and dried under vacuum to give 4,5-Diamino-1-propylpyrazole in the form of hydrobromide and hydrochloride (0.55 eq HBr and 1.38 eq HCI) as an off-white solid (2.5 g, 57%).

Melting point: 168.1-173.0 ° C

Elementary analysis: C ₆ H ₁₂ N ₄ (0.55 HBr, 1.38 HCI) Found: C: 29.08%, H: 6.06%, N: 22.87% Theory: C: 27.98%, H: 5.48%, N: 21.75%

1H - NMR (400 MHz, d ⁶ -DMSO): 7.34 (1H, s, Hpy); 5.18 (1H, sι _ar ge, NH); 4.09 (2 Η, t,

J = 5.5 Hz, CH ₂ N); 3.61 (2 Η, t, J = 5.5 Hz, CH ₂ 0); 3.23 (3 Η, s, OCH ₃ ). Synthesis of 1- (4.5-Diamino-pyrazol-1-yl) hydrobromide - propan-2-ol hydrobromide (5-3):

A mixture of l - (5-Benzylamino-3-bromo-4-nitro-pyrazol- l -yl) - proρan-2-ol (4-3) (5.0 g; 14.0 mmol) in EtOH (140 ml) containing a 10% Pd / C catalyst (Engelhard, 50% wet, 0.5 g dry weight) and NaOH (solid, 560 mg, 14 mmol) was hydrogenated in an autoclave (11) at 11 bars for 2 h. The reaction mixture was filtered to remove the catalyst under an inert atmosphere in an ethanolic solution containing HBr (47%, 9.7 ml, 78 mmol). The solavant was evaporated under reduced pressure to give a solid. After washing with cold EtOH, l - (4,5-Diamino-pyrazol-l -yl) -propan-2-ol was obtained in the form of hydrobromide (3.47 eq. HBr) as a white solid (2 , 3 g, 42%).

Melting point: 222.3 ° C

Elementary analysis: C ₆ H ₁₂ N ₄ O (3.47 HBr) Found: C: 15.75%, H: 3.03%, N: 11.54%, O: 4.15%, Br: 59.26% Theory: C: 15.02%, H: 3.36 %, N: 11.68%, O: 3.33%, Br: 66.61%

1H - NMR (400 MHz, d ⁶ -DMSO): 7J2 (1 H, s, CH _arora ); 7.66-6.20 (7 h, sι _arg e, NH ₂ and

OH and HBr); 4.23-4.07 (3 Η, m, NCH ₂ CΗ and NCH ₂ CH); 1.29 (3 H, d, CH ₅ ). Synthesis of 3- (4,5-Diamino-pyrazol-1-yl) -propane-1,2-diol hydrobromide (5-4):

A mixture of 3- (5-Benzylamino-3-bromo-4-nitro-pyrazol-l -yl) - propane-1,2-diol (4-4) (7.0 g; 18.8 mmol) in EtOH (150 ml) containing a 10% Pd / C catalyst (Engelhard, 50% wet, 0.7 g dry weight) and NaOH (solid, 800 mg, 18.8 mmol) was hydrogenated in an autoclave (1 1 ) at 16 bars for 3.5 h. The reaction mixture was filtered to remove the catalyst under an inert atmosphere in an ethanolic solution containing HBr (47%, 7.1 ml, 57 mmol). The solvent was evaporated under reduced pressure to give a solid. After washing with cold EtOH, 3- (4,5-Diamino-pyrazol-l -yl) -propane-1,2-diol, HBr. was obtained as an off-white solid.

1H - NMR (400 MHz, d ⁶ -DMSO): 7.90 (1H, s, H _ar0m ); 4.30-4.14 (3 Η, m, NCH.CΗ and

NCH ₂ CH); 3.69-3.60 (2 Η, m, CH ₂ WHERE).

EXAMPLES OF FORMULATION IN AN ALKALINE MEDIUM

The following coloring formulations are produced:

- 4,5-diaminopyrazole of formula (I) 5 x 10 ^"3 mole

- Coupler 5x10 ^"3 mole

- Polyglycerolated oleic alcohol with 2 moles of glycerol 4.0g

- Polyglycerolated oleic alcohol with 4 moles of glycerol at 5.7g M.A. 78% of active ingredients (M.A.)

- Oleic acid 3.0g - Oleic amine containing 2 moles of ethylene oxide sold 7.0 g under the trade name ETHOMEEN 012 by the company AKZO

- Laurylamino diethylaminopropyl succinamate, sodium salt 3.0g M.A at 55% M.A

- Oleic alcohol 5.0g

- Oleic acid diethanolamide 12.0 g

- Propylene glycol 3.5 g

- Ethyl alcohol 7.0 g

- Dipropylene glycol 0.5 g

- Propylene glycol monomethyl ether 9.0 g

- Sodium metabisulfite in a 35% aqueous solution of 0.455 g M.A M.A

- Ammonium acetate 0.8 g

- Antioxidant, sequestrant. q.s.

- Perfume, preservative. q.s.

- Ammonia at 20% NH3 10 g

The pH of the composition is 9.5 M.A. means "active material"

At the time of use, each weight-for-weight dye composition is mixed with a solution of hydrogen peroxide at 20 volumes (6% by weight), the pH of which has been adjusted to approximately 2.5 with orthophosphoric acid.

The mixture is applied to gray hair with 90% white, natural or permanent, at a rate of 5 g for 0.5 g of hair, for 30 min.

The hair is then rinsed, washed with a standard shampoo and dried.

The color of the locks was evaluated in the L * a * b * system, on white and permanent hair, using a CM 2002 MINOLTA spectrophotometer.

In space L * a * b *, clarity is indicated by the value L * on a scale from 0 to 100 while the chromatic coordinates are expressed by a * and b * which indicate two axes of color, a * l red-green axis and b * the yellow-blue axis.

According to this system, the higher the value of L, the lighter and less intense the color. Conversely, the lower the value of L, the darker or very intense the color.

The 4,5-diaminopyrazoles according to the invention therefore make it possible to obtain intense and chromatic shades at alkaline pH.

EXAMPLES OF NEUTRAL FORMULATIONS

The same formulations are produced as above, replacing the ammonia with citric acid in an amount such that the pH of the composition is equal to 7 and from the bases and couplers below.

Gray hair strands containing 90% natural and permanent whites are dyed with the dye compositions 5 and 6 above in the same way as for dyeing at alkaline pH.

The following nuances are obtained:

At neutral pH, the 4,5-diaminopyrazoles according to the invention make it possible to obtain intense and chromatic nuances.

Claims

1. Diaminopyrazole compounds of formula (I):

(I)

in which R 1 denotes an n-propyl or alkyl group

Linear or branched C -C ₅ , or a linear or branched mono or polyhydroxy C ₃ -C ₅ alkyl group, and their physiologically acceptable acid addition salts.

2. Compounds of formula (I) according to claim 1 characterized in that the physiologically acceptable salts are salts of acids chosen from hydrochlorides, hydrobromides, sulfates, tartrates, lactates or acetates.

3. Compounds of formula (I) according to claim 1 or 2, characterized in that R _t an n-propyl group; linear or branched butyl or pentyl; propyl, butyl or pentyl, linear or branched, substituted by 1 to 4 OH radicals.

4. Compounds of formula (I) according to any one of claims 1 to 3, characterized in that it is 2-Propyl-2H-pyrazole-3, 4-diamine and 3- (4,5- Diamino-pyrazol-l -yl) -propan-lol or one of their physiologically acceptable acid salts.

5. Composition for the oxidation dyeing of keratin fibers and in particular human keratin fibers such as the hair, characterized in that it contains, in a medium suitable for dyeing, as oxidation base at least one 4 , 5-diaminopyrazole of formula (I):

Formula I

in which RI denotes a linear or branched n-propyl or C -C ₅ alkyl group, or a linear or branched mono or polyhydroxy C ₃ -C ₅ alkyl group, or one of its addition salts with an acid physiologically acceptable.

6. Composition according to claim 5, characterized in that it contains from 0.001 to 10% by weight of at least one diaminopyrazole of formula (I) or of its salts.

7. Composition according to claim 6, characterized in that it contains from 0.05 to 6% by weight, and preferably 0.1 to 3% by weight, of at least one diaminopyrazole of formula (I) or of its salts.

8. Composition according to any one of claims 5 to 7, characterized in that the medium suitable for dyeing consists of water or of a mixture of water and at least one organic solvent chosen from C 1 -C ₄ lower alkanols, polyols and polyol ethers, aromatic alcohols, analogues and their mixtures.

9. Composition according to any one of claims 5 to 8, characterized in that it has a pH of between 3 and 12.

10. Composition according to any one of claims 5 to 9, characterized in that it contains at least one additional oxidation base chosen from paraphenylenediamines, bis-phenylalkylenediamines, para-aminophenols, ortho-aminophenols, heterocyclic bases other than the N-substituted diaminopyrazole of formula (I) and their addition salts with an acid.

11. Composition according to Claim 10, characterized in that the additional oxidation base (s) represent from 0.0005 to 12% by weight of the total weight of the dye composition.

12. Composition according to any one of claims 5 to 1 1, characterized in that it contains at least one coupler and / or at least one direct dye.

13. Composition according to Claim 12, characterized in that the coupler or couplers are chosen from metaphenylenediamines, meta-aminophenols, metadiphenols, mono- or polyhydroxylated derivatives of naphthalene and heterocyclic couplers and their addition salts with an acid.

14. Composition according to any one of claims 12 or 13, characterized in that the coupler (s) represent from 0.0001 to 10% by weight of the total weight of the dye composition.

15. Composition according to any one of claims 5 to 14, characterized in that the addition salts with an acid are chosen from hydrochlorides, hydrobromides, sulfates, tartrates, lactates and acetates.

16. Process for dyeing keratin fibers and in particular human keratin fibers such as the hair, characterized in that at least one dye composition as defined in any one of claims 5 to 15 is applied to these fibers. , for a time sufficient to develop the desired coloration, either in air or using an oxidizing agent, optionally in the presence of oxidation catalysts.

17. The method of claim 16, characterized in that the coloring is revealed on contact with air oxygen.

18. The method of claim 16 characterized in that the color is revealed at acidic, neutral or alkaline pH using an oxidizing agent which is added just at the time of use to the dye composition or which is present in an oxidizing composition applied simultaneously or sequentially separately.

19. The method of claim 16 or 18, characterized in that the oxidizing agent is chosen from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such as perborates and persulfates.

20. Multi-compartment device, or “kit” for dyeing with several compartments, a first compartment of which contains a dye composition as defined in any one of claims 5 to 15 and a second compartment of which contains an oxidizing composition.