Diaminopyrazole derivatives and their use for oxidation dyeing of keratinous fibres

Abstract

The invention concerns novel diaminopyrazole derivatives of formula (I), wherein: R1 represents C1-C6 alkyl or C2, preferably up to C4, alkenyl, linear or branched, bearing at least a substituent selected among OR, NHR, NRR′, SR, SO2R, COOH, CONH2, CONRR′, PO(OH)2, SH, SO3X, a non-cationic heterocycle, Cl, Br or I; X represents H, Na, K or NH4; R and R′, identical or different, represent C1-C6 alkyl or C2-C6, preferably up to C4, alkenyl, linear or branched, unsubstituted or substituted by one or several functional groups selected among OH, NH2, OR, NHR, NRR′, SR, SOR, SO2R, COOH, CONH2, CONRR′, PO(OH)2, SH, SO3X, a non-cationic heterocycle, Cl, Br or I, X, R and R′ having the definitions mentioned above; R2 represents H, or C1-C6 alkyl or C2-C6, preferably up to C4, alkenyl, linear or branched, unsubstituted or substituted by one or several functional groups selected among OH, NH2, OR, NHR, NRR′, SR, SOR, SO2R, COOH, CONH2, CONRR′, PO(OH)2, SH, SO3X, a non-cationic heterocycle, Cl, Br or I, X, R and R′ having the definitions mentioned above; and their physiologically acceptable salts, and their use for oxidation dyeing of keratinous fibres, in particular human hair.

Description

[0001] The present invention relates to novel diaminopyrazole derivatives, to a composition for the oxidation dyeing of keratin fibers, and in particular of human keratin fibers such as the hair, comprising at least one diaminopyrazole derivative as oxidation base, and to the oxidation dyeing processes using it.

[0002] It is known practice to dye keratin fibers, and in particular human hair, with dye compositions containing oxidation dye precursors, in particular ortho- or paraphenylenediamines, ortho-aminophenols or paraminophenols and heterocyclic compounds such as diaminopyrazole derivatives, which are generally referred to as oxidation bases. The oxidation dye precursors, or oxidation bases, are colorless or weakly colored compounds which, when combined with oxidizing products, can give rise to colored compounds and dyes by a process of oxidative condensation.

[0003] It is also known that the shades obtained with these oxidation bases can be varied by combining them with couplers or coloration modifiers, the latter being chosen in particular from aromatic meta-diamines, metaminophenols, meta-diphenols and certain heterocyclic compounds.

[0004] The variety of molecules used as oxidation bases and couplers makes it possible to obtain a wide range of colors.

[0005] The so-called “permanent” coloration obtained by means of these oxidation dyes must moreover satisfy a certain number of requirements. Thus, it must have no toxicological drawbacks and it must allow shades of the desired strength to be obtained and have good resistance to external agents (light, bad weather, washing, permanent-waving, perspiration and friction).

[0006] The dyes must also allow white hairs to be covered, and, lastly, they must be as unselective as possible, i.e. they must allow the smallest possible differences in coloration to be produced over the entire length of the same keratin fiber, which may indeed be differently sensitized (i.e. damaged) between its tip and its root. They must also show good chemical stability in the formulations, and must have a good toxicological profile.

[0007] Furthermore, for a certain number of applications, dyes that produce chromatic shades on the hair are desired.

[0008] Patent applications DE 42 34 885, 196 43 059 and 196 46 609 disclose 4,5-diaminopyrazole derivatives, which, when used together with various couplers, especially benzoxazines, give chestnut-brown shades with blue, red, violet, aubergine or coppery glints.

[0009] However, these dyes do not satisfy all the above requirements.

[0010] The Applicant has now discovered, entirely surprisingly and unexpectedly, that it is possible to obtain dyes, which are capable of producing powerful, particularly chromatic, bright and relatively unselective colorations, which have excellent properties of resistance to the various attacking factors to which keratin fibers may be subjected, by using as oxidation base the diaminopyrazoles of the formula (I) below or physiologically acceptable salts thereof.

[0011] One subject of the present invention is thus the novel diaminopyrazoles having the following structure: 1

[0012] in which

[0013] R1 denotes a linear or branched C1-C6 alkyl radical or C2-C6 and preferably up to C4 alkenyl radical, bearing at least one substituent chosen from OR, NHR, NRR′, SR, SOR, SO2R, COOH, CONH2, CONRR′, PO(OH)2, SH, SO3X, a non-cationic heterocycle, Cl, Br and I,

[0014] X denotes H, Na, K or NH4,

[0015] R and R′, which may be identical or different, denote a linear or branched C1-C6 alkyl radical or C2-C6 and preferably up to C4 alkenyl radical, which is unsubstituted or substituted with one or more functional groups chosen from OH, NH2, OR, NHR, NRR′, SR, SOR, SO2R, COOH, CONH2, CONRR′, PO(OH)2, SH, SO3X, a non-cationic heterocycle, Cl, Br and I, X, R and R′ having the meanings given above,

[0016] R2 denotes H or a linear or branched C1-C6 alkyl radical or C2-C6 and preferably up to C4 alkenyl radical, which is unsubstituted or substituted with one or more functional groups chosen from OH, NH2, OR, NHR, NRR′, SR, SOR, SO2R, COOH, CONH2, CONRR′, PO(OH)2, SH, SO3X, a non-cationic heterocycle, Cl, Br and I, X, R and R′ having the definitions given above.

[0017] A subject of the invention is also the salts with physiologically acceptable acids or bases of the compounds of formula (I), such as the hydrochlorides, hydrobromides, sulfates, tartrates, lactates or acetates, or the salts obtained with sodium hydroxide, potassium hydroxide, ammonia, amines or alkanolamines.

[0018] A subject of the invention is also a composition for the oxidation dyeing of keratin fibers, and in particular of human keratin fibers such as the hair, characterized in that it contains, in a medium that is suitable for dyeing, as oxidation base, at least one diaminopyrazole of formula (I) above, or salts thereof with physiologically acceptable acids or bases.

[0019] As mentioned above, the colorations obtained with the oxidation dye composition in accordance with the invention are powerful, particularly bright and chromatic. They in particular produce shades that are free of or contain very little blue or yellow. Furthermore, they show excellent properties of resistance with respect to the action of various external agents (light, bad weather, washing, permanent-waving, perspiration and friction).

[0020] A subject of the invention is also a process for the oxidation dyeing of keratin fibers using such a dye composition.

[0021] As examples of diaminopyrazoles of formula (I) according to the invention, mention may be made of the compounds belonging to the following classes:

Structure	Name	Structure	Name	Structure	Name
2	2-(4,5- diamino- pyrazol-1- yl)ethane- sulfonic acid	3	2-(4,5- diamino- pyrazol-1- yl)- propane-1- sulfonic acid	4	1-(4,5- diamino- pyrazol-1- yl)- propane-2- sulfonic acid
5	3-(4,5- diamino- pyrazol-1- yl)butane- 2-sulfonic acid	6	3-(4,5- diamino- pyrazol-1- yl)- propane-1- sulfonic acid	7	3-(4,5- diamino- pyrazol-1- yl)butane- 1-sulfonic acid
8	3-(4,5- diamino- pyrazol-1- yl)-2- methyl- propane-1- sulfonic acid	9	4-(4,5- diamino- pyrazol-1- yl)butane-2- sulfonic acid	10	4-(4,5- diamino- pyrazol-1- yl)butane- 1-sulfonic acid
11	4-(4,5- diamino- pyrazol-1- yl)- pentane-1- sulfonic acid	12	4-(4,5- diamino- pyrazol-1- yl)-3- methyl- butane-1- sulfonic acid	13	4-(4,5- diamino- pyrazol-1- yl)-2- methyl- butane-1- sulfonic acid
14	5-(4,5- diamino- pyrazol-1- yl)- pentane-2 sulfonic acid	15	5-(4,5- diamino- pyrazol-1- yl)- pentane-1- sulfonic acid	16	5-(4,5- diamino- pyrazol-1- yl)hexane- 1-sulfonic acid
17	5-(4,5- diamino- pyrazol-1- yl)-4- methyl- pentane-1 sulfonic acid	18	5-(4,5- diamino- pyrazol-1- yl)-3- methyl- pentane-1- sulfonic acid	19	5-(4,5- diamino- pyrazol-1- yl)-2- methyl- pentane-1- sulfonic acid
20	6-(4,5- diamino- pyrazol-1- yl)hexane- 2-sulfonic acid	21	6-(4,5- diamino- pyrazol-1- yl)hexane-1- sulfonic acid	22	2-(4-amino- 5-methyl- amino- pyrazol-1- yl)ethane- sulfonic acid
23	2-(4- amino-5- ethyl- amino- pyrazol-1- yl)ethane- sulfonic acid	24	2-[4-amino- 5-(2- hydroxy- ethylamino)- pyrazol-1- yl]ethane- sulfonic acid	25	2-[4-amino- 5-(2-meth- oxyethyl- amino)- pyrazol-1- yl]ethane- sulfonic acid
26	[4-amino- 2-[2- ethyl)-2H- pyrazol-3- ylamino]- acetic acid	27	2-[4-amino- 5-(2-amino- ethylamino]- pyrazol-1- yl]ethane- sulfonic acid	28	3-(4-amino- 5-methyl- aminopyrazol- 1-yl)- propane-1- sulfonic acid
29	3-(4- amino-5- ethyl- amino- pyrazol-1- yl)- propane-1- sulfonic acid	30	3-[4-amino- 5-(2- hydroxy- ethyl- amino)- pyrazol-1- yl})- propane-1- sulfonic acid	31	3-[4-amino- 5-(2- methoxyethyl- amino)- pyrazol-1- yl]propane- 1-sulfonic acid
32	[4-amino- 2-(3- sulfo- propyl)- 2H- pyrazol-3- ylamino]- acetic acid	33	3-[4-amino- 5-(2-amino- ethylamino)- pyrazol-1- yl]-propane- 1-sulfonic acid
34	2-(4,5- diamino- pyrazol-1- yl)- acetamide	35	2-(4,5- diamino- pyrazol-1- yl)propion- amide	36	3-(4,5- diamino- pyrazol-1- yl)propion- amide
37	3-(4,5- diamino- pyrazol-1- yl)butyr- amide	38	3-(4,5- diamino- pyrazol-1- yl)-2- methyl- propionamide	39	4-(4,5- diamino- pyrazol-1- yl)butyr- amide
40	4-(4,5- diamino- pyrazol-1- yl)pentan- oic acid amide	41	4-(4,5- diamino- pyrazol-1- yl)-3- methyl- butyramide	42	4-(4,5- diamino- pyrazol-1- yl)-2- methyl- butyramide
43	5-(4,5- diamino- pyrazol-1- yl)penta- noic acid amide	44	5-(4,5- diamino- pyrazol-1- yl)hexanoic acid amide	45	5-(4,5- diamino- pyrazol-1- yl)-4- methyl- pentanoic acid amide
46	5-(4,5- diamino- pyrazol-1- yl)-3- methyl- pentanoic acid amide	47	5-(4,5- diamino- pyrazol-1- yl)-2- methyl- pentanoic acid amide	48	6-(4,5- diamino- pyrazol-1- yl)hexanoic acid amide
49	2-(4- amino-5- methyl- amino- pyrazol-1- yl)acet- amide	50	2-(4-amino- 5- ethylamino- pyrazol-1- yl)acetamide	51	2-[4-amino 5-(2- hydroxy- ethyl- amino)pyra- zol-1- yl]acet- amide
52	2-[4- amino-5- (2- methoxy- ethyl- amino)- pyrazol-1- yl]- acetamide	53	2-[4-amino- 5-(2-amino- ethylamino)- pyrazol-1- yl]acetamide	54	(3-amino-2- carbamoyl- methyl-2H- pyrazol-3- ylamino)- acetic acid
55	3-(4- amino-5- methyl- aminopyraz- ol-1- yl)propion amide	56	3-(4-amino- 5-ethyl- amino- pyrazol-1- yl)propion- amide	57	3-[4-amino- 5-(2- hydroxy- ethyl- amino)- pyrazol-1- yl]propion- amide
58	3-[4- amino-5- (2- methoxy- ethylamino)- pyrazol-1- yl]propion amide	59	3-[4-amino 5-(2-amino- ethylamino)- pyrazol-1- yl]propion- amide	60	[4-amino-2- (2- carbamoyl- ethyl)-2H- pyrazol-3- ylamino]- acetic acid
61	(4,5- diamino- pyrazol-1- yl)acetic acid	62	2-(4,5- diamino-nl pyrazol-1- yl)propionic acid	63	3-(4,5- diamino- pyrazol-1- yl)- propionic acid
64	3-(4,5- diamino- pyrazol-1- yl)butyric acid	65	3-(4,5- diamino- pyrazol-1- yl)-2- methyl- propionic acid	66	4-(4,5- diamino- pyrazol-1- yl)butyric acid
67	4-(4,5- diamino- pyrazol-1- yl)penta- noic acid	68	4-(4,5- diamino- pyrazol-1- yl)-3- methyl- butyric acid	69	4-(4,5- diamino- pyrazol-1- yl)-2- methyl- butyric acid
70	5-(4,5- diamino- pyrazol-1- yl)penta- noic acid	71	5-(4,5- diamino- pyrazol-1- yl)hexanoic acid	72	5-(4,5- diamino- pyrazol-1- yl)-4- methyl- pentanoic acid
73	5-(4,5- diamino- pyrazol-1- yl)-3- methyl- pentanoic acid	74	5-(4,5- diamino- pyrazol-1- yl)-2- methyl- pentanoic acid	75	6-(4,5- diamino- pyrazol-1- yl)hexanoic acid
76	(4-amino- 5-methyl- amino- pyrazol-1- yl)acetic acid	77	(4-amino-5- ethylamino- pyrazol-1- yl)acetic acid	78	[4-amino-5- (2-hydroxy- ethyl- amino)- pyrazol-1- yl]acetic acid
79	[4-amino 5- (carboxy- methyl- amino)- pyrazol-1- yl]acetic acid	80	[4-amino-5- (2- aminoethyl- amino)- pyrazol-1- yl]acetic acid
81	2-(2- dimethyl- amino- ethyl)-2H- pyrazole- 3,4-diamine	82	2-(2- dimethyl- amino-1- methyl- ethyl)-2H- pyrazol- 3,4-diamine	83	2-(2- dimethyl- amino- propyl)-2H- pyrazole- 3,4-diamine
84	2-(2- dimethyl- amino-1- methyl- propyl)- 2H- pyrazol- 3,4- diamine	85	2-(3- dimethyl- amino- propyl)-2H- pyrazole- 3,4-diamine	86	2-(3- dimethyl- amino-1- methyl- propyl)-2H- pyrazole- 3,4-diamine
87	2-(3- dimethyl- amino-2- methyl- propyl)- 2H- pyrazol- 3,4- diamine	88	2-(3- dimethyl- aminobutyl)- 2H-pyrazole- 3,4-diamine	89	2-(4- dimethyl- amino- butyl)-2H- pyrazol- 3,4-diamine
90	2-(4- dimethyl- amino-1- methyl- butyl)-2H- pyrazol- 3,4- diamine	91	2-(4- dimethyl- amino-2- methyl- butyl)-2H- pyrazol- 3,4-diamine	92	2-(4- dimethyl- amino-3- methyl)- butyl)-2H- pyrazol- 3,4-diamine
93	2-(4- dimethyl- amino- pentyl)- 2H- pyrazole- 3,4- diamine	94	2-(5- dimethyl- amino- pentyl)-2H- pyrazole- 3,4-diamine	95	2-(5- dimethyl- amino-1- methyl- pentyl)-2H- pyrazole- 3,4-diamine
96	2-(5- dimethyl- amino-2- methyl- pentyl)- 2H- pyrazole- 3,4- diamine	97	2-(5- dimethyl- amino-3- methyl- pentyl)-2H- pyrazole- 3,4-diamine	98	2-(5- dimethyl- amino-4- methyl- pentyl)-2H- pyrazole- 3,4-diamine
99	2-(5- dimethyl- amino- hexyl)-2H- pyrazole- 3,4- diamine	100	2-(6- dimethyl- aminohexyl)- 2H-pyrazole- 3,4-diamine	101	2-(2- dimethyl- amino- ethyl)-N3- methyl-2H- pyrazole- 3,4-diamine
102	2-(2- dimethyl- amino- ethyl)-N3- ethyl-2H- pyrazole- 3,4- diamine	103	2-[4-amino- 2-(2- dimethyl- aminoethyl)- 2H-pyrazol- 3-ylamino]- ethanol	104	2-(2- dimethyl- amino- ethyl)-N3- (2-methoxy- ethyl)-2H- pyrazole- 3,4-dimaine
105	[4-amino- 2-(2- dimethyl- amino- ethyl)-2H- pyrazol-3- ylamino]- acetic acid	106	N3-(2-amino- ethyl)-2-(2- dimethyl- aminoethyl)- 2H-pyrazole- 3,4-diamine	107	2-(3- dimethyl- amino- propyl)-N3- methyl-2H- pyrazole- 3,4-diamine
108	2-(3- dimethyl- amino- propyl)- N3-ethyl- 2H- pyrazol- 3,4- diamine	109	2-[4-amino- 2-(3-di- methylamino- propyl)-2H- pyrazol-3- ylamino]- ethanol	110	2-(3- dimethyyl- amino- propyl)-N3- (2-methoxy- ethyl)-2H- pyrazole- 3,4-diamine
111	[4-amino- 2-(3- dimethyl- amino- propyl)- 2H- pyrazol-3- ylamino]- acetic acid	112	N3-(2- aminoethyl)- 2-(3- dimethyl- propyl)-2H- pyrazole- 3,4-diamine	113	2-(2- methyl- amino- ethyl)-2H- pyrazole- 3,4-diamine
114	2-(2- ethyl- amino- ethyl)-2H- pyrazole- 3,4- diamine	115	2-[2-(4,5- diamino- pyrazol-1- yl)ethyl- amino]- ethanol	116	2-(2- pyrrolidin- 1-ylethyl)- 2H- pyrazole- 3,4-diamine
117	1-[2-(4,5- diamino- pyrazol-1- yl)ethyl]- pyrrol- idin-3-ol	118	2-(2- imidazo- lidin-1-yl- ethyl)-2H- pyrazzole- 3,4-diamine	119	2-(2- piperazin- 1-ylethyl)- 2H- pyrazole- 3,4-diamine
120	2-{4-[2- (4,5- diamino- pyrazol-1- yl)ethyl]- piperazin- 1- yl}ethanol	121	N3-methyl-2- (2-methyl- aminoethyl)- 2H-pyrazole- 3,4-diamine	122	2-(2-ethyl- amino- ethyl)-N3- methyl-2H- pyrazole- 3,4-diamine
123	2-[2-(4- amino-5- methyl- amino- pyrazol-1- yl)ethyl- amino]- ethanol	124	N3-methyl-2- (2- pyrrolidin- 1-ylethyl)- 2H-pyrazole- 3,4-diamine	125	1-[2-(4- amino-5- methyl- amino- pyrazol-1- yl)ethyl]- pyrrolidin- 3-ol
126	2-(2- imidazo- lidin-1- ylethyl)- N3-methyl- 2H- pyrazole- 3,4- diamine	127	N3-methyl-2- (2- piperazin-1- ylethyl)-2H- pyrazole- 3,4-diamine	128	2-{4-[2-(4- amino-5- methyl- amino- pyrazol-1- yl)ethyl]- piperazin- 1- yl}ethanol
129	2-(2- methoxy- ethyl)-2H- pyrazole- 3,4- diamine	130	2-(2- methoxy-1- methyl- ethyl)-2H- pyrazole- 3,4-diamine	131	2-(2- methoxy- propyl)-2H- pyrazole- 3,4-diamine
132	2-(2- methoxy-1- methyl- propyl)- 2H- pyrazole- 3,4- diamine	133	2-(3- methoxy- propyl)-2H- pyrazole- 3,4-diamine	134	2-(3- methoxy-1- methyl- propyl)-2H- pyrazole- 3,4-diamine
135	2-(3- methoxy-2- methyl- propyl)- 2H- pyrazole- 3,4- diamine	136	2-(3- methoxy- butyl-2H- pyrazole- 3,4-diamine	137	2-(4- methoxy- butyl)-2H- pyrazole- 3,4-diamine
138	2-(4- Methoxy-1- methyl- butyl)-2H- pyrazole- 3,4- diamine	139	2-(4-Methoxy- 2-methyl- butyl)-2H- pyrazole-3,4- dianmine	140	2-(4- Methoxy-3- methyl- butyl)-2H- pyrazole- 3,4-diamine
141	2-(4- Methoxy- pentyl)- 2H- pyrazole- 3,4- diamine	142	2-(5-Methoxy- pentyl)-2H- pyrazole-3,4- diamine	143	2-(5- Methoxy-1- methyl- pentyl)-2H- pyrazole- 3,4-diamine
144	2-(5- Methoxy-2- methyl- pentyl)- 2H- pyrazole- 3,4- diamine	145	2-(5-Methoxy- 3-methyl- pentyl)-2H- pyrazole-3,4- diamine	146	2-(5- Methoxy-4- methyl- pentyl)-2H- pyrazole- 3,4-diamine
147	2-(5- Methoxy- hexyl)-2H- pyrazole- 3,4- diamine	148	2-(6-Methoxy- hexyl)-2H- pyrazole-3,4- diamine	149	2-(2- Methoxy- ethyl)-N3- methyl-2H- pyrazole- 3,4-diamine
150	N3-Ethyl- 2-(2- methoxy- ethyl)-2H- pyrazole- 3,4- diamine	151	2-[4-Amino-2- (2-methoxy- ethyl)-2H- pyrazol-3- ylamino]- ethanol	152	2,N3-Bis- 2-(methoxy- ethyl)-2H- pyrazole- 3,4-diamine
153	[4-Amino- 2-(2- methoxy- ethyl)-2H- pyrazol-3- ylamino]- acetique acide	154	N3-(2-Amino- ethyl)-2-(2- methoxy- ethyl)-2H- pyrazole-3,4- diamine	155	2-(3- Methoxy- propyl)-N3- methyl-2H- pyrazole- 3,4-diamine
156	N3-ethyl- 2-(3- methoxypro- pyl)-2H- pyrazole- 3,4- diamine	157	2-[4-amino- 2-(3- methoxy- propyl)-2H- pyrazol-3- ylamino]- ethanol	158	N3-(2- methoxy- ethyl)-2- (3-methoxy- propyl)-2H- pyrazole- 3,4-diamine
159	[4-amino- 2-(3- methoxy- propyl)- 2H- pyrazol-3- ylamino]- acetic acid	160	N3-(2-amino- ethyl)-2-(3- methoxy- propyl)-2H- pyrazole- 3,4-diamine	161	2-(2- ethoxy- ethyl)-2H- pyrazole- 3,4-diamine
162	2-[2-(4,5- diamino- pyrazol-1- yl)ethoxy]ethanol	163	2-[2-(2- methoxy- ethoxy)- ethyl]-2H- pyrazole- 3,4-diamine	164	2-[2-(2- amino- ethoxy)- ethyl]-2H- pyrazole- 3,4-diamine
165	2-[2-(4,5- diamino- pyrazole- 3,4- diamine	166	2-(tetra- hydrofuran- 2-ylmethyl)- 2H-pyrazole- 3,4-diamine	167	2-(tetra- hydropyran- 2- ylmethyl)- 2H- pyrazole- 3,4-diamine
168	2-(2- ethoxy- ethyl)-N3- methyl-2H- pyrazole- 3,4- diamine	169	2-[2-(4- amino-5- methylamino- pyrazol-1- yl)ethoxy]ethanol	170	2-[2-(2- methoxy- ethoxy)- ethyl]-N3- methyl-2H- pyrazole- 3,4-diamine
171	2-[2-(2- amino- ethoxy)- ethyl]-N3- methyl-2H- pyrazole- 3,4- diamine	172	2-[2-(2- dimethyl- amino- ethoxy)- ethyl]-N3- methyl-2H- pyrazole- 3,4-diamine	173	N-3methyl- 2-(tetra- hydrofuran- 2- ylmethyl)- 2H- pyrazole- 3,4-diamine
174	N3-methyl- 2-(tetra- hydro pyran-2- ylmethyl)- 2H- pyrazole- 3,4- diamine

[0022] According to one preferred embodiment of the invention in formula (I), R1 is a linear C1-C3 alkyl radical substituted with an SO3H, COOH, CONH2, methoxy, 25 hydroxyethyloxy, 2-hydroxyethylamino, mono- or dimethylamino, 1-pyrrolidinyl-3-ol, 1-imidazolidinyl, 1-piperazinyl, 1-piperazinylethanol, 2-tetrahydrofuryl or 2-tetrahydropyranyl group and R2 denotes H, methyl, ethyl, 2-hydroxyethyl, 2-methoxyethyl, 2-aminoethyl or carboxymethyl.

[0023] The diaminopyrazoles of formula (I) that are preferred according to the invention have the following structures:

Structure	Name	Structure	Name	Structure	Name
175	2-(4,5- diamino- pyrazol- 1-yl)- ethane- sulfonic acid	176	3-(4,5- diamino- pyrazol- 1-yl)- propion- amide	177	(4,5- diamino- pyrazol- 1-yl)- acetic acid
178	2-(2- dimethyl- amino- ethyl)- N3- methyl- 2H- pyrazole- 3,4- diamine	179	2-(2- methoxy- ethyl)- N3- methyl- 2H- pyrazole- 3,4- diamine	180	2-(2- methoxy- ethyl)- 2H- pyrazole- 3,4- diamine
181	2-(2- dimethyl- amino- ethyl)- 2H- pyrazole- 3,4- diamine			182	3-(4,5- diamino- pyrazol- 1-yl)pro- pane-1- sulfonic acid
183	2-(4- amino-5- methyl- amino- pyrazol- 1-yl)- ethane- sulfonic acid	184	2-[4- amino-5- (2- hydroxy- ethyl- amino)- pyrazol- 1-yl)- ethane- sulfonic acid	185	2-[4- amino-5- (2- methoxy- ethyl- amino)- pyrazol- 1-yl]- ethane- sulfonic acid
186	[4-amino- 2-(3- sulfo- propyl)- 2H- pyrazol- 3-yl- amino]- acetic acid	187	2-(4,5- diamino- pyrazol- 1-yl)- acetamide	188	4-(4,5- diamino- pyrazol- 1-yl)- butyr- amide
189	2-(4- amino-5- methyl- amino- pyrazol- 1- yl)acet- amide	190	2-[4- amino-5- (2- hydroxy- ethyl- amino)- pyrazol- 1-yl]- acetamide	191	(4-amino- 2-carba- moyl- methyl- 2H- pyrazol- 2- ylamino)- acetic acid
192	3-[4- amino-5- (2-amino- ethyl- amino)- pyrazol- 1-yl]- propion- amide	193	(4,5- diamino- pyrazol- 1-yl)- acetic acid	194	3-(4,5-diamino- pyrazol- 1-yl)- propionic acid
195	(4-amino- 5-methyl- amino- pyrazol- 1-yl)- acetic acid	196	[4-amino- 5-(2- hydroxy- ethyl- amino)- pyrazol- 1-yl]- acetic acid	197	[4-amino- 5- (carboxy- methyl- amino)- pyrazol- 1-yl]- acetic acid
198	[4-amino- 5-(2- amino- ethyl- amino)- pyrazol- 1-yl]- acetic acid	199	2-(2- dimethyl- amino- ethyl)- 2H- pyrazole- 3,4- diamine	200	2-(3- dimethyl- amino- propyl)- 2H- pyrazole- 3,4- diamine
201	2-(3- dimethyl- amino- propyl)- N3- methyl- 2H- pyrazole- 3,4- diamine	202	2-[4- amino-2- (2- dimethyl- amino- ethyl)- 2H- pyrazol- 3- ylamino]- ethanol	203	[4-amino- 2-(2- dimethyl- amino- ethyl)- 2H- pyrazol- 3- ylamino]- acetic acid
204	2-(3- dimethyl- amino- propyl)- N3-ethyl- 2H- pyrazole- 3,4- diamine	205	N3-(2- amino- ethyl)-2- (3- dimethyl- amino- propyl)- 2H- pyrazole- 3,4- diamine	206	2-(2- methyl- amino- ethyl)- 2H- pyrazole- 3,4- diamine
207	2-[2- (4,5- diamino- pyrazol- 1-yl)- ethyl- amino]- ethanol	208	1-[2- (4,5- diamino- pyrazol- 1-yl)- ethyl]- pyrroli- din-3-ol	209	2-(2- imidazol- idin-1- ylethyl)- N3- methyl- 2H- pyrazole- 3,4- diamine
210	N3- methyl-2- (2- pipera- zin-1-yl- ethyl)- 2H- pyrazole- 3,4- diamine	211	2-{4-[2- (4-amino- 5-methyl- amino- pyrazol- 1-yl)- ethyl]- piper- azin-1- yl}- ethanol
212	2-(3- methoxy- propyl)- 2H- pyrazole- 3,4- diamine	213	2-(2- methoxy- ethyl)- N3- methyl- 2H- pyrazole- 3,4- diamine	214	2-[4- amino-2- (2- methoxy- ethyl)- 2H- pyrazol- 3- ylamino]- ethanol
215	[4-amino- 2-(2- methoxy- ethyl)- 2H- pyrazol- 3- ylamino]- acetic acid	216	N3-(2- methoxy- ethyl)-2- (3- methoxy- propyl)- 2H- pyrazole- 3,4- diamine	217	N3-(2- amino- ethyl)-2- (3- methoxy- propyl)- 2H- pyrazole- 3,4- diamine
218	2-[2- (4,5- diamino- pyrazol- 1-yl)- ethoxy]- ethanol	219	2-[2-(2- methoxy- ethoxy)- ethyl]- 2H- pyrazole- 3,4- diamine	220	2-[2-(2- amino- ethoxy)- ethyl]- 2H- pyrazole- 3,4- diamine
221	2-[2-(2- dimethyl- amino- ethoxy)- ethyl]- 2H- pyrazole- 3,4- diamine	222	N3- methyl-2- (tetra- hydro- furan-2- yl- methyl)- 2H- pyrazole- 3,4- diamine	223	N3- methyl-2- (tetra- hydro- pyran-2- yl- methyl)- 2H- pyrazole- 3,4- diamine

[0024] The diaminopyrazoles of formula (I) that are more particularly preferred according to the invention are 4,5-diamino-1-(2′-methoxyethyl)pyrazole and 4-amino-1-(2′-methoxyethyl)-5-methylaminopyrazole, or the addition salts thereof with physiologically acceptable acids.

[0025] The diaminopyrazoles of formula (I) according to the invention are prepared, for example, according to the following general preparation method:

[0026] The synthetic approach shown below is described in the literature up to intermediate (2) (J. H. P. Juffermanns, C. L.; Habraken; J. Org. Chem., 1986, 51, 4656; Klebe et al., Synthesis, 1973, 294; R. Hüttel, F. Büchele; Chem. Ber., 1955, 88, 1586).

[0027] The alkylation and the amination to obtain the compounds of the type (5) of formula (I) according to the invention are mentioned in document DE 42 34 885. 224

[0028] Examples of Synthesis:

[0029] Synthesis of 3,4,5-tribromopyrazole (1):

[0030] NaOH (24 g, 0.6 mol) was added to an aqueous solution of pyrazole (10 g, 0.147 mol) with stirring (the temperature of the reaction medium is raised to 35° C.). After cooling the reaction medium to 20° C., Br2 (72 g, 0.45 mol) was added dropwise over 1 hour, while maintaining the temperature between 20° C. and 25° C. The reaction was monitored by TLC (thin layer chromatography) (50% hexane/50% EtOAc or ethyl acetate). The precipitate was filtered off and washed with demineralized water (100 ml). The filtrate was acidified to pH 6-7 using HCl (10%, 33 g, 0.27 mol) and maintaining the temperature between 20 and 25° C. The precipitate thus formed was filtered off and washed with demineralized water (100 ml). The combined solids were maintained at reflux in Dean-Stark apparatus in the presence of toluene (200 ml). At the end of collection of the water, the organic phase was filtered while hot. The solvent was evaporated down to a residual volume of 110 ml. The solution was cooled to 0-5° C. for 1 hour. The precipitate formed was collected by filtration, washed with cold toluene (20 ml) and dried under vacuum at 80° C. to give the tribromide (1) in the form of an off-white solid (30 g, 67%).

NMR: 13C (100 MHz, d6-DMSO): 97.7, 116.1, 126.4
IR (KBr; cm−1):              3100, 2861, 1531, 1356, 1019, 969
m.p.:                        182-184° C.

[0031] Synthesis of 3,5-dibromo-4-nitropyrazole (2):

[0032] HNO3 (d=1.50 g/ml; 18 ml, 0.429 mol) was added dropwise over 10 minutes to a solution of 3,4,5-tribromopyrazole (50 g, 0.164 mol) 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 hours. Once the reaction was complete, the reaction mixture was poured onto crushed ice (1 kg). After stirring for 1 hour, the crude product was filtered off and then washed with demineralized water (2×60 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 Dean-Stark apparatus. The toluene solution was maintained at reflux for a further 30 minutes until a TLC (eluent: toluene) showed that the rearrangement of the 1-nitro-3,4,5-tribromopyrazole (Rf=0.77), the intermediate formed, into 3,4,5-dibromo-4-nitropyrazole 2 (Rf=0.05) was complete. The solution was concentrated to a residual volume of 150 ml and then allowed to cool to 60° C., followed by addition of hexane (275 ml). The solution was cooled to 0-5° C. for 1 hour and the 3,5-dibromo-4-nitropyrazole 2 (29.1 g, 65%) was recovered by filtration and drying under vacuum in the form of a pale yellow solid.

IR (KBr, cm−1): 3211, 1541, 1441, 1370, 1334, 976,
                960, 824
m.p.:           127.6-130.1° C.

[0033] General Method for Synthesizing the 1-alkyl-3,5-dibromo-4-nitropyrazole (3):

[0034] A solution of 3,5-dibromo-4-nitropyrazole (2) (1 mmol) in DMF (dimethylformamide) (4.8 ml) was added dropwise to a solution of NaH (1.1 mmol; 60% dispersion in oil, prewashed with hexane under an inert atmosphere) in DMF (8 ml) with stirring. An evolution of hydrogen gas took place. After 30 minutes, a solution of alkyl halide (1.2 mmol) in DMF (1.6 ml) was added dropwise over 10 minutes, followed by heating the reaction medium to 50-60° C. for 3 hours (monitored by TLC). The DMF was evaporated off under reduced pressure and the residue was taken up in a mixture of DCM (dichloromethane) (4 ml) and water (10 ml). The aqueous phase was extracted with DCM (3×10 ml) and the combined organic phases were washed with water (50 ml). The organic phase was dried over MgSO4 and the solvent was evaporated off under reduced pressure to give the alkylated products of the type (3) in the form of oils or solids. The products were used without further purification in the amination step.

[0035] General Method for Synthesizing the 1-alkyl-5-alkylamino-3-bromo-4-nitropyrazole (4):

[0036] A mixture of 1-alkyl-3,5-dibromo-4-nitropyrazole (1 mmol) and alkylamine (14 mmol) in ethanol (25 ml) was refluxed for 4 hours (monitored by TLC). The ethanol and the excess alkylamine were evaporated off under reduced pressure. After trituration of the crude reaction mixtures with isopropyl ether, the compounds of the type (4) were obtained as solids.

[0037] Synthesis of 3-bromo-1-(2′-methoxyethyl)-5-methylamino4-nitropyrazole (compound of the type 4):

[0038] Aqueous 40% methylamine solution (300 ml, 8.71 mol) was added to a solution of 3,5-dibromo-1-(2′-methoxyethyl)4-nitropyrazole (15 g, 0.483 mol) in ethanol (300 ml). The reaction mixture was stirred at 20-25° C. for 2 hours and then cooled to 0-5° C. for 30 minutes. The precipitate formed was filtered off and washed with a cold mixture of water/ethanol (1/1, 30 ml). The final amine product was obtained in the form of a yellow solid (4.6 g, 36%) after drying under reduced pressure.

TLC (1/1: hexane/ethyl acetate): Rf = 0.31
m.p.:                            154.4-156.8° C.
IR (KBr, cm−1):                  3336, 1625, 1541, 1473,
                                 1446, 1338, 1239, 1049,
                                 839
NMR: 1H (400MHz, d6-DMSO):       4.27(2H, t,
                                 J=5.0Hz, CH2N),
                                 3.74(2H, t, J=5.0Hz,
                                 CH2O),
                                 3.34(3H, s, OCH3),
                                 3.24(3H, d, J=5.5Hz,
                                 CH3N).

[0039] Synthesis of 3-bromo-1-(2′-methoxyethyl)-5-benzylamino-4-nitropyrazole (compound of the type 4):

[0040] The general method was applied using benzylamine. The final amine product was recrystallized in an MeOH/H2O mixture (1/1) and was isolated in the form of a yellow solid (48%).

TLC (1/1: hexane/ethyl acetate): Rf = 0.46
m.p.:                            91.1-93.8° C.
IR (KBr, cm−1):                  3333, 1602, 1583, 1536,
                                 1469, 1410, 1332, 1296,
                                 1229, 1106, 1060, 732
NMR: 1H (400MHz, CDCl3):         7.34(5H, m, Harom),
                                 4.77(2H, d, J=6.5Hz,
                                 NHCH2),4.11(2H, t,
                                 J=5.0Hz, CH2N),
                                 3.71(2H, t, J=5.0Hz,
                                 CH2O), 3.34(3H, s,
                                 OCH3).

[0041] 4-Amino-1-(2′-methoxyethyl)-5-methylaminopyrazole dichlorohydrate (compound of the type 5) or (I):

[0042] A mixture of 3-bromo-1-(2′-methoxyethyl)-5-methylamino-4-pyrazole (5 g, 18 mmol) in ethanol (500 ml) containing 10% Pd/C catalyst (Johnson-Mattey Type 487, 0.5 g dry weight) and 36% hydrochloric acid (4.1 g, 40.4 mmol) was hydrogenated in a Parr autoclave (1 l) at 1.1 MPa for 3 hours (monitored by TLC). The catalyst was removed by filtration and washed with ethanol, and the filtrate was evaporated under reduced pressure. Under an inert atmosphere, the crude oil was taken up in ethanol (80 ml) and heated to 50° C. EtOAc (80 ml) was added and the mixture was maintained at room temperature for 3 hours and then cooled to 0-5° C. for 2 hours. The precipitate was recovered by filtration, washed with a cold mixture of EtOH/EtOAc (1/1, 2×30 ml) and dried under vacuum to give the final diamine dihydrochloride in the form of an off-white solid (4.1 g, 93%).

Structure                   Name
225                         2-(2-Methoxyethyl)- N3-methyl-2H- pyrazole-3,4- diamine
HPLC (purity):              99.5%
TLC (MeOH):                 Rf = 0.57 (colorless spot
                            turning red on contact with
                            oxygen)
m.p.:                       157.6-159.8° C.
IR (KBr, cm−1):             3237, 3128, 2760, 2546,
                            1621, 1112
NMR: 1H (400 MHz, d6-DMSO): 7.46 (1H, s, NHarom), 4.10,
                            (2H,m t, J = 5.5 Hz, CH2N),
                            3.62 (2H, t, J = 5.5 Hz,
                            CH2O), 3.22 (3H, s, OCH3),
                            2.84 (3H, s, NCH3).

[0043] 4,5-Diamino-1-(2′-methoxyethyl)pyrazole dihydrochloride (compound of the type 5) or (I):

[0044] A mixture of 5-benzylamino-3-bromo-1-(2′-methoxyethyl)-4-nitropyrazole (4 g, 2.8 mmol) in ethanol (500 ml) containing 10% Pd/C catalyst (Johnson-Mattey type 487, 0.5 g dry weight) and 36% hydrochloric acid (0.57 g, 5.6 mmol) was hydrogenated in a Parr autoclave (1 l) at 1 MPa for 1 hour (monitored by TLC). The catalyst was removed by filtration and washed with ethanol, and the filtrate was evaporated under reduced pressure. A crude orange solid was obtained (2.8 g, 108%), which was triturated in EtOAc (20 ml) for 1 hour. The solid was filtered off and washed with cold EtOAc (20 ml) and then dried under vacuum to give the diamine (type 5) in the form of a beige-colored solid (0.7 g, 27%).

Structure                   Name
226                         2-(2-Methoxyethyl)- 2H-pyrazole-3,4- diamine
HPLC (purity):              99.5%
TLC (MeOH):                 Rf = 0.48 (colorless spot
                            turning red on contact with
                            oxygen)
m.p.:                       168.1-173.0° C.
IR (KBr, cm−):              3309, 3158, 3050, 2892,
                            1647, 1619, 1587, 1504,
                            1422, 1344, 1281, 1111
NMR: 1H (400 MHz, d6-DMSO): 7.34 (1H, s, NHarom), 5.18
                            (1H, slarge, NH), 4.09 (2H,
                            t, J = 5.5 Hz, CH2N), 3.61
                            (2H, t, J = 5.5 Hz, CH2O),
                            3.23 (3H, s, OCH3).

[0045] The dye composition according to the invention especially contains 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 salts thereof.

[0046] The dye composition in accordance with the invention may also contain, in addition to the diaminopyrazole(s) defined above, at least one additional oxidation base that may be chosen from the oxidation bases conventionally used in oxidation dyeing and among which mention may be made especially of paraphenylenediamines, bis(phenyl)alkylenediamines, paraminophenols, ortho-aminophenols and heterocyclic bases other than the 4,5-diaminopyrazole used in accordance with the invention.

[0047] Among the para-phenylenediamines that may be mentioned more particularly, for example, are paraphenylenediamine, para-tolylenediamine, 2,6-dimethylpara-phenylenediamine, 2-β-hydroxyethyl-para-phenylenediamine, 2-n-propyl-para-phenylenediamine, 2-isopropylpara-phenylenediamine, N-(β-hydroxypropyl)-paraphenylenediamine, N,N-bis (β-hydroxyethyl)-paraphenylenediamine, 4-amino-N-(β-methoxyethyl)aniline and the para-phenylenediamines described in French patent application FR 2 630 438, and the addition salts thereof.

[0048] Among the bis-phenylalkylenediamines that may be mentioned more particularly, for example, are N,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diaminopropanol, N,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)ethylenediamine, N,N′-bis(4-aminophenyl)tetramethylenediamine, N,N′-bis(P-hydroxyethyl)-N,N′-bis(4-aminophenyl)tetramethylenediamine, N,N′-bis(4-methylaminophenyl)tetramethylenediamine and N,N′-bis(ethyl)-N,N′-bis(4′-amino-3′-methylphenyl)ethylenediamine, and the addition salts thereof.

[0049] Among the para-aminophenols that may be mentioned more particularly, for example, are para-aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol, 4-amino-3-hydroxymethylphenol, 4-amino-2-methylphenol, 4-amino-2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol, 4-amino-2-aminomethylphenol and 4-amino-2-(β-hydroxyethylaminomethyl)phenol, and the addition salts thereof.

[0050] Among the ortho-aminophenols that may be mentioned more particularly, for example, are 2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol and 5-acetamido-2-aminophenol, and the addition salts thereof.

[0051] Among the heterocyclic bases that may be mentioned more particularly, for example, are pyridine derivatives, pyrimidine derivatives, pyrazole derivatives other than the diaminopyrazoles of formula (I) used in accordance with the invention, and the addition salts thereof.

[0052] When they are used, these additional oxidation bases preferably represent from 0.0005% to 12% by weight relative to the total weight of the dye composition and even more preferably from 0.005% to 6% by weight relative this weight.

[0053] The oxidation dye compositions in accordance with the invention may also contain at least one coupler and/or at least one direct dye, especially to modify the shades or to enrich them with glints.

[0054] The couplers that may be used in the oxidation dye compositions in accordance with the invention may be chosen from the couplers conventionally used in oxidation dyeing, and among which mention may be made especially of meta-phenylenediamines, metaminophenols, meta-diphenols, mono- or polyhydroxylated naphthalene derivatives and heterocyclic couplers such as, for example, indole or pyridine derivatives, and the addition salts thereof.

[0055] These couplers are chosen more particularly from 2-methyl-5-aminophenol, 5-N-(β-hydroxyethyl)amino-2-methylphenol, 6-chloro-2-methyl-5-aminophenol, 3-aminophenol, 1,3-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene, 4-chloro-1,3-dihydroxybenzene, 2,4-diamino-1-(β-hydroxyethyloxy)benzene, 2-amino-4-(β-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene, 1,3-bis(2,4-diaminophenoxy)propane, 3-ureidoaniline, 3-ureido-1-dimethylaminobenzene, sesamol, 1-β-hydroxyethylamino-3,4-methylenedioxybenzene, α-naphthol, 2-methyl-1-naphthol, 6-hydroxyindole, 4-hydroxyindole, 4-hydroxy-N-methylindole, 2-amino-3-hydroxypyridine, 6-hydroxybenzomorpholine, 3,5-diamino-2,6-dimethoxypyridine, 1-N-(β-hydroxyethyl)amino-3,4-methylenedioxybenzene and 2,6-bis(β-hydroxyethylamino)toluene, and the addition salts thereof.

[0056] When they are present, these couplers especially represent from 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.

[0057] In general, the addition salts with an acid that may be used in the context of the dye compositions of the invention (oxidation bases and couplers) are chosen especially from the hydrochlorides, hydrobromides, sulfates, tartrates, lactates and acetates. The addition salts with a base are especially those obtained with sodium hydroxide, potassium hydroxide, ammonia, amines or alkanolamines.

[0058] The medium that is 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 C1-C4 lower alkanols, polyols and polyol ethers, aromatic alcohols, similar products and mixtures thereof.

[0059] 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 or zwitterionic surfactants or mixtures thereof, anionic, cationic, nonionic, amphoteric or zwitterionic polymers or mixtures thereof, mineral or organic thickeners, antioxidants, reducing agents, sunscreens, penetrating agents, sequestering agents, fragrances, buffers, dispersants, conditioners, for instance silicones, film-forming agents, preserving agents and opacifiers.

[0060] The pH of the dye composition according to the invention is between 3 and 12.

[0061] Needless to say, a person skilled in the art will take care to select this or these optional additional compound(s) such that the advantageous properties intrinsically associated with the oxidation dye composition in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition(s).

[0062] The dye composition according to the invention may be in various forms, such as in the form of liquids, creams or gels, or in any other form that is suitable for dyeing keratin fibers, and especially human hair.

[0063] Another subject of the invention is a process for dyeing keratin fibers, and in particular human keratin fibers such as the hair, using the dye composition as defined above.

[0064] According to this process, at least one dye composition as defined above is applied to the fibers, for a time that is sufficient to develop the desired coloration, either in air or using an oxidizing agent. The dye composition may optionally contain oxidation catalysts, so as to accelerate the oxidation process.

[0065] According to a first embodiment of the process of the invention, the coloration of the fibers may be performed without adding an oxidizing agent, solely by contact with atmospheric oxygen.

[0066] 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 that is added to the composition just at the time of use, or which is present in an oxidizing composition applied simultaneously or sequentially in a separate manner.

[0067] According to this second embodiment of the dyeing process of the invention, the dye composition described above is preferably mixed, at the time of use, with an oxidizing composition containing, in a medium that is suitable for dyeing, at least one oxidizing agent present in an amount that is sufficient to develop a coloration. The mixture obtained is than applied to the keratin fibers and is left for an action time of 3 to 50 minutes and preferably 5 to 30 minutes, after which the fibers are rinsed, washed with shampoo, rinsed again and dried.

[0068] The oxidizing agent present in the oxidizing composition as defined above may 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, urea peroxide, alkali metal bromates and persalts such as perborates and persulfates. Hydrogen peroxide is particularly preferred.

[0069] 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 ranges 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 the dyeing of keratin fibers, and as defined above.

[0070] The oxidizing composition as defined above may also contain various adjuvants conventionally used in compositions for dyeing the hair and as defined above.

[0071] The composition that is finally applied to the keratin fibers may be in various forms, such as in the form of liquids, creams or gels, or in any other form that is suitable for dyeing keratin fibers, and especially human hair.

[0072] Another subject of the invention is a multi-compartment device or dyeing “kit” or any other multi-compartment packaging system, 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 may be equipped with a means for applying the desired mixture to the hair, such as the devices described in patent FR-2 586 913 in the name of the Applicant.

[0073] The examples that follow are intended to illustrate the invention.

EXAMPLES 1 TO 4

Dyeing in Alkaline Medium

[0074] The dye formulations below are prepared:

4,5-diaminopyrazole	5 × 10−3	mol
coupler	5 × 10−3	mol
oleyl alcohol polyglycerolated with	4.0	g
2 mol of glycerol
oleyl alcohol polyglycerolated with	5.7	g A.M.
4 mol of glycerol, containing 78%
active material (A.M.)
oleic acid	3.0	g
oleylamine containing 2 mol of ethylene	7.0	g
oxide, sold under the trade name
Ethomeen O12 by the company Akzo
diethylaminopropyl laurylamino succinamate,	3.0	g A.M.
sodium salt, at 55% A.M.
oleyl alcohol	5.0	g
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 as an aqueous	0.455	g A.M.
solution containing 35% A.M.
ammonium acetate	0.8	g
antioxidant, sequestering agent	qs
fragrance, preserving agent	qs
aqueous ammonia containing 20% NH3	100	g
pH = 9.5
A.M. means “active material”

[0075]

DYEING AT ALKALINE pH
Example	Base	Coupler
1	4,5-diamino-1-(2-	6-chloro-2-methyl-5-
	methoxyethyl) pyrazole	aminophenol
	dihydrochloride
2	4,5-diamino-1-(2′-	2,4-diamino-1-(β-
	methoxyethyl) pyrazole	hydroxyethyloxy)-
	dihydrochloride	benzene dihydrochloride
3	4-amino-1-(2′-methoxyethyl)-	6-chloro-2-methyl-5-
	5-methylaminopyrazole	aminophenol
	dihydrochloride
4	4-amino-1-(2′-methoxyethyl)-	2,4-diamino-1-(β-
	5-methylaminopyrazole	hydroxyethyloxy)-
	dihydrochloride	benzene dihydrochloride

[0076] At the time of use, each dye composition is mixed, weight for weight, with a 20-volumes aqueous hydrogen peroxide solution (6% by weight), the pH of which has been adjusted to about 2.5 with orthophosphoric acid.

[0077] The mixture is applied to natural or permanent-waved grey hair containing 90% white hairs, at a rate of 5 g per 0.5 g of hair, for 30 minutes.

[0078] The hair is then rinsed, washed with a standard shampoo and dried.

[0079] The color of the locks was evaluated in the L*a*b* system, on white and permanent-waved hair, using a Minolta CM 2002 spectrophotometer.

[0080] In the L*a*b* space, the lightness is indicated by the value L* on a scale from 0 to 100, while the shade and the saturation are expressed by a* and b*: a* and b* indicate two color axes, a* the red-green axis and b* the yellow-blue axis.

[0081] According to this system, the higher the value of L, the paler and less intense the color. Conversely, the lower the value of L, the darker or more intense the color.

	Natural white hair	Permanent-waved white hair
Example	L*	a*	b*	L*	a*	b*
Example 1	39.47	30.8	16.2	33.62	32.8	17.29
Example 2	25.86	23.5	0.93	19.29	19.0	1.35
Example 3	36.43	28.3	1.48	29.32	30.3	1.98
Example 4	25.75	14.8	−8.36	19.53	13.2	−8.02

[0082] The 4,5-diaminopyrazoles according to the invention thus make it possible to obtain strong and chromatic shades at alkaline pH.

EXAMPLES 5 AND 6

Dyeing in Neutral Medium

[0083] The same formulations as above are prepared, replacing the aqueous ammonia with citric acid in an amount such that the pH is equal to 7.

DYEING AT NEUTRAL pH
Example	Base	Coupler
5	4,5-diamino-1-(2′-methoxyethyl)	2-methyl-5-
	pyrazole dihydrochloride	aminophenol
6	4,5-diamino-1-(2′-methoxyethyl)	2-methyl-5-
	pyrazole dihydrochloride	aminophenol

[0084] Locks of natural and permanent-waved grey hair containing 90% white hairs are dyed with the dye compositions 5 and 6 above in the same manner as for the dyeing at alkaline pH.

[0085] The following shades are obtained:

	Natural white hair	Permanent-waved white hair
Example	L	a*	b*	L*	a*	b*
Example 5	43.29	17.4	18.0	35.02	26.8	23.56
Example 6	42.43	18.6	8.61	32.91	27.2	9.82

[0086] At neutral pH, the 4,5-diaminopyrazoles according to the invention make it possible to obtain strong shades.

Claims

1. A diaminopyrazole derivative of formula:

2. The compound of formula (I) as claimed in claim 1, characterized in that the physiologically acceptable salts are acid salts chosen from the hydrochlorides, hydrobromides, sulfates, tartrates, lactates and acetates, or salts of bases chosen from sodium hydroxide, potassium hydroxide, ammonia, amines and alkanolamines.

3. The compound of formula (I) as claimed in claim 1 or 2, characterized in that R, is a linear C1-C3 alkyl radical substituted with a SO3H, COOH, CONH2, methoxy, 2-hydroxyethyloxy, 2-hydroxyethylamino, mono- or dimethylamino, 1-pyrrolidinyl-3-ol, 1-imidazolidinyl, 1-piperazinyl, 1-piperazinylethanol, 2-tetrahydrofuryl or 2-tetrahydropyranyl group and R2 denotes H, methyl, ethyl, 2-hydroxyethyl, 2-methoxyethyl, 2-aminoethyl or carboxymethyl.

4. The compound of formula (I) as claimed in any one of claims 1 to 3, characterized in that it is 4,5-diamino-1-(2′-methoxyethyl)pyrazole or 4-amino-1-(2′-methoxyethyl)-5-methylaminopyrazole, or a salt thereof with physiologically acceptable acids.

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

6. The composition as claimed in claim 5, characterized in that it contains from 0.001% to 10% by weight of at least one diaminopyrazole of formula (I) or salt thereof.

7. The composition as claimed in 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 salts thereof.

8. The composition as claimed in any one of claims 5 to 7, characterized in that the medium that is suitable for dyeing (or support) consists of water or of a mixture of water and at least one organic solvent chosen from C1-C4 lower alkanols, polyols and polyol ethers, aromatic alcohols, similar products and mixtures thereof.

9. The composition as claimed in any one of claims 5 to 8, characterized in that it has a pH of between 3 and 12.

10. The composition as claimed in any one of claims 5 to 9, characterized in that it contains at least one additional oxidation base chosen from paraphenylenediamines, bis(phenyl)alkylenediamines, paraminophenols, ortho-aminophenols and heterocyclic bases other than the diaminopyrazole of formula (I), and addition salts thereof with an acid.

11. The composition as claimed in claim 10, characterized in that the additional oxidation base(s) represent(s) from 0.0005% to 12% by weight relative to the total weight of the dye composition.

12. The composition as claimed in any one of claims 5 to 11, characterized in that it contains at least one coupler and/or at least one direct dye.

13. The composition as claimed in claim 12, characterized in that the coupler(s) is (are) chosen from meta-phenylenediamines, meta-aminophenols, metadiphenols, mono- or polyhydroxylated naphthalene derivatives and heterocyclic couplers, and the addition salts thereof with an acid.

14. The composition as claimed in either of claims 12 and 13, characterized in that the coupler(s) represent(s) from 0.0001% to 10% by weight relative to the total weight of the dye composition.

15. The composition as claimed in any one of claims 5 to 14, characterized in that the addition salts with an acid are chosen from the hydrochlorides, hydrobromides, sulfates, tartrates, lactates and acetates, and the addition salts with a base are chosen from those obtained with sodium hydroxide, potassium hydroxide, ammonia or amines.

16. A 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 16 is applied to these fibers, for a time that is sufficient to develop the desired coloration, either in air or using an oxidizing agent, optionally in the presence of oxidation catalysts.

17. The process as claimed in claim 16, characterized in that the coloration is revealed solely on contact with atmospheric oxygen.

18. The process as claimed in claim 16, characterized in that the color is revealed at acidic, neutral or alkaline pH with the aid of an oxidizing agent, which is added to the dye composition just at the time of use, or which is present in an oxidizing composition applied simultaneously or sequentially in a separate manner.

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

20. A multi-compartment device or multi-compartment dyeing “kit”, 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.