Compositions for dyeing keratinous fibres, containing 3-aminopyrazolo [1,5-a]pyrimidines, method of dyeing and novel 3-aminopyrazolo [1,5-a]pyrimidines

The invention relates to novel compositions for the oxidation dyeing of keratinous fibers, comprising at least one 3-aminopyrazolo[1,5-a]-pyrimidine, to the method of dyeing which employs this composition, to novel 3-aminopyrazolo[1,5-a]pyrimidines and to the process for their preparation.

The invention relates to novel compositions for the oxidation dyeing of
 keratinous fibers, comprising at least one
 3-aminopyrazolo[1,5-a]-pyrimidine as an oxidation base, the method of
 dyeing which employs this composition, novel
 3-amino-pyrazolo[1,5-a]pyrimidines, and the process for their preparation.
 It is well known to dye keratinous fibers, and in particular human hair,
 using dyeing compositions comprising oxidation dye precursors, such as
 ortho- or para-phenylenediamines and ortho- or para-aminophenols, 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 lightly colored compounds which, when
 combined with oxidizing products, are able to give rise to colored
 compounds and dyes by a process of oxidative condensation. These compounds
 have the common feature of possessing one amino group and one hydroxyl
 group or two amino groups, which give them their oxidation-base character.
 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, meta-aminophenols,
 meta-diphenols and certain heterocyclic compounds.
 The diversity of molecules employed as oxidation bases and couplers makes
 it possible to obtain a wide range of colors.
 The "permanent" coloration obtained by these oxidation dyes should
 optimally meet, certain conditions. Hence it should have no toxicological
 effects, should allow shades of the desired intensity to be obtained, and
 should have good resistance to external agents (light, inclement weather,
 washing, permanent-waving, perspiration and friction).
 The dyes should also allow white hairs to be covered and, finally, they
 should be as unselective as possible - in other words, they should allow
 the smallest possible differences in coloration to be produced over the
 entire length of a single keratinous fiber, which may vary in condition of
 sensitization or damage from its tip to its root.
 Patent application DE 4 029 324 proposes the use of certain
 2-hydroxypyrazolo[1,5-a]pyrimidines, which may be substituted by C.sub.1
 -C.sub.4 alkyl radicals in positions 4, 5 and/or 6, as couplers for the
 oxidation dyeing of keratinous fibers.
 Patent application DE 4 133 957 also proposes the use of certain
 pyrazolo-[1,5-a]pyrimidine derivatives, belonging to the class of the
 tetrahydropyrazolo[1,5-a]pyrimidines, as oxidation dye precursors for the
 oxidation dyeing of keratinous fibers.
 The inventors have now made the unexpected and surprising discovery that a
 new class of 3-aminopyrazolo[1,5-a]pyrimidines of formula (I) defined
 below, some of which are themselves novel, are suitable for use as an
 oxidation base. These compounds contain only a single amino group that
 makes it possible to obtain dyeing compositions which lead to colorations
 which are strong and have good resistance to external agents (light,
 inclement weather, washing, permanent-waving, perspiration and friction).
 Finally, these compounds can be easy to synthesize.
 These discoveries form the basis of the present invention.
 The invention therefore provides a composition for the oxidation dyeing of
 keratinous fibers, and in particular human keratinous fibers such as hair,
 that comprises, in a medium suitable for dyeing, at least one
 3-aminopyrazolo[1,5-a]pyrimidine chosen from compounds of formula (I)
 below and acid and base addition salts thereof, as oxidation base:
 ##STR1##
 in which
 R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are identical or different and
 represent a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.4 alkyl
 radical, a C.sub.1 -C.sub.4 trifluoroalkyl radical, a C.sub.1 -C.sub.4
 alkoxy radical, an aryl radical, a C.sub.1 -C.sub.4 monohydroxyalkyl
 radical, a C.sub.2 -C.sub.4 polyhydroxyalkyl radical, a C.sub.1 -C.sub.4
 (C.sub.1 -C.sub.4 alkoxy)alkyl radical, a C.sub.1 -C.sub.4 aminoalkyl
 radical, a C.sub.1 -C.sub.4 (C.sub.1 -C.sub.4 alkyl)aminoalkyl radical, a
 C.sub.1 -C.sub.4 di(C.sub.1 -C.sub.4 alkyl)aminoalkyl radical, a C.sub.1
 -C.sub.4 monohydroxy (C.sub.1 -C.sub.4 alkyl)aminoalkyl radical or a
 C.sub.1 -C.sub.4 di[hydroxy(C.sub.1 -C.sub.4 alkyl)]aminoalkyl radical.
 Among the 3-aminopyrazolo[1,5-a]pyrimidines of formula (I) which can be
 used as an oxidation base in the compositions in accordance with the
 invention generally preferred 3-aminopyrazolo[1,5-a]pyrimidines are:
 pyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,6,7-trimethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 7-methylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,6,7-trimethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 7-methylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5-methylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 7-methoxy-5-methylpyrazolo[1,5-a]pyrimidin-3 -ylamine;
 2,5,6,7-tetramethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 2-methoxy-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,7-di-tert-butylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,7-di-trifluoromethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 2,6-dimethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 2-chloro-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 7-methyl-2-tert-butyl-5-trifluoromethylpyrazolo-[1,5-a]pyrimidin-3-ylamine;
 and the acid or base addition salts thereof.
 Among the 3-aminopyrazolo[1,5-a]pyrimidines of formula (I) which can be
 used as an oxidation base in the compositions in accordance with the
 invention particularly preferred 3-aminopyrazolo [1,5-a]pyrimidines are:
 pyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,6,7-trimethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 2,5,6,7-tetramethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 2-methoxy 5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,7-di-trifluoromethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 7-methylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5-methylpyrazolo[1,5-a]pyrimidin-3-ylamine; and the acid or base addition
 salts thereof.
 The great majority of the 3-aminopyrazolo[1,5-a]pyrimidines of formula (I)
 are compounds which are known in the pharmaceutical field and are
 described, in particular, in patent applications EP-A-0 433 854 and EP-A-0
 433 855.
 The 3-aminopyrazolo[1,5-a]pyrimidine or -pyrimidines of formula (I) above
 makes or make up preferably from 0.0005 to 12% by weight approximately
 relative to the total weight of the dyeing composition and, more
 preferably, from 0.005 to 6% by weight, approximately, of the total
 weight.
 A medium (or vehicle) suitable for dyeing is, for example, water,
 water/alcohol mixtures, and a mixture of water and at least one organic
 solvent to dissolve any compounds which are not sufficiently water
 soluble. Preferred organic solvents are, for example, C.sub.1 -C.sub.4
 lower alkanols, such as ethanol and isopropanol; glycerol; glycols and
 glycol ethers such as 2-butoxyethanol, propylene glycol, propylene glycol
 monomethyl ether and diethylene glycol monoethyl and monomethyl ether, and
 aromatic alcohols such as benzyl alcohol or phenoxyethanol, similar
 products and mixtures thereof.
 The solvents can be present in proportions preferably ranging from 1 to 40%
 by weight approximately relative to the total weight of the dyeing
 composition, and even more preferably from 5 to 30% by weight
 approximately.
 The pH of the dyeing composition in accordance with the invention generally
 ranges from 3 to 12, approximately, and preferably approximately from 5 to
 11. It can be adjusted to the desired value by means of acidifying or
 basifying agents commonly used in the dyeing of keratinous fibers, or by
 using conventional buffer systems.
 Preferred acidifying agents include, for example, mineral acids or organic
 acids, such as hydrochloric acid, orthophosphoric acid, sulphuric acid,
 carboxylic acids such as acetic acid, tartaric acid, citric acid and
 lactic acid, and sulphonic acids.
 Preferred basifying agents include, for example, of aqueous ammonia, alkali
 metal carbonates, alkanolamines such as mono-, di- and triethanolamines
 and derivatives thereof, sodium hydroxide, potassium hydroxide, and the
 compounds of the following formula (II):
 ##STR2##
 in which W is a propylene residue optionally substituted by a hydroxyl
 radical or a C.sub.1 -C.sub.4 alkyl radical; R.sub.5, R.sub.6, R.sub.7 and
 R.sub.8, which may be identical or different, represent a hydrogen atom, a
 C.sub.1 -C.sub.4 alkyl radical or a C.sub.1 -C.sub.4 hydroxyalkyl radical.
 In a preferred embodiment, the oxidation dyeing composition in accordance
 with the invention additionally includes at least one coupler in order to
 modify or enrich with glints the shades obtained by employing the
 compounds of formula (I).
 The couplers which can be used in the oxidation dyeing compositions in
 accordance with the invention may be chosen from the couplers used
 conventionally in oxidation dyeing, among which generally preferred
 couplers are: meta-phenylenediamines, meta-aminophenols, meta-diphenols
 and heterocyclic couplers.
 More particularly preferred couplers are chosen from
 2-methyl-5-aminophenol, 5-N-(.beta.-hydroxyethyl)amino-2-methylphenol,
 3-aminophenol, 1,3-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene,
 4-chloro-1,3-dihydroxy-benzene,
 2,4-diamino-1-(.beta.-hydroxyethoxy)benzene,
 2-amino-4-(.beta.-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene,
 1,3-bis(2,4-diaminophenoxy)propane, sesamol, .alpha.-naphthol,
 6-hydroxyindole, 4-hydroxyindole, 4-hydroxy-N-methylindole,
 6-hydroxyindoline, 2,6-dihydroxy-4-methylpyridine,
 1H-3-methylpyrazol-5-one, 1-phenyl-3-methylpyrazol-5-one, and the addition
 salts thereof.
 When present, the coupler(s) preferably represent(s) from 0.0001 to 10% by
 weight approximately relative to the total weight of the dyeing
 composition, and even more preferably from 0.005 to 5% by weight
 approximately relative to this weight.
 The dyeing composition in accordance with the invention may additionally
 comprise, as well as the above-defined dyes, at least one additional
 oxidation base chosen from the oxidation bases which are conventionally
 employed in oxidation dyeing, among which preferred oxidation bases are:
 para-phenylenediamines, bisphenylalkylenediamines, para-aminophenols,
 ortho-aminophenols and heterocyclic bases which are different from the
 3-aminopyrazolo[1,5-a]-pyrimidines of formula (I) that are employed in
 accordance with the invention.
 Among the para-phenylenediamines, preferred para-phenylenediamines are:
 para-phenylenediamine, para-tolylenediamine,
 2-chloro-para-phenylenediamine, 2,3-dimethyl-para-phenylene-diamine,
 2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,
 2,5-dimethyl-para-phenylenediamine, N,N-dimethyl-para-phenylenediamine,
 N,N-diethyl-para-phenylenediamine, N,N-dipropyl-para-phenylenediamine,
 4-amino-N,N-diethyl-3-methylaniline,
 N,N-bis(.beta.-hydroxyethyl)-para-phenylenediamine,
 4-N,N-bis(.beta.-hydroxyethyl)amino-2-methylaniline,
 4-N,N-bis(.beta.-hydroxyethyl)amino-2-chloroaniline,
 2-.beta.-hydroxyethyl-para-phenylenediamine,
 2-fluoro-para-phenylenediamine, 2-isopropyl-para-phenylenediamine,
 N-(.beta.-hydroxypropyl)-para-phenylenediamine,
 2-hydroxymethyl-para-phenylenediamine,
 N,N-dimethyl-3-methyl-para-phenylenediamine,
 N,N-(ethyl,.beta.-hydroxyethyl)-para-phenylenediamine,
 N-(.beta.,.gamma.-dihydroxypropyl)-para-phenylenediamine,
 N-(4'-aminophenyl)-para-phenylenediamine, N-phenyl-para-phenylenediamine,
 2-.beta.-hydroxyethyloxy-para-phenylenediamine,
 2-.beta.-acetylaminoethyloxy-para-phenylenediamine,
 N-(.beta.-methoxyethyl) -para-phenylenediamine and the acid addition salts
 thereof.
 Among the abovementioned para-phenylenediamines more preferred
 para-phenylenediamines are: para-phenylenediamine, para-tolylenediamine,
 2-isopropyl-para-phenylenediamine,
 2-.beta.-hydroxyethyl-para-phenylenediamine,
 2-.beta.-hydroxyethyloxy-para-phenylenediamine,
 2,6-dimethyl-para-phenylenediamine, 2,6-diethyl- para-phenylenediamine,
 2,3-dimethyl-para-phenylenediamine,
 N,N'-bis(.beta.-hydroxyethyl)-para-phenylenediamine,
 2-chloro-para-phenylenediamine,
 2-.beta.-acetylaminoethyloxy-para-phenylenediamine, and the acid addition
 salts thereof.
 Among the bisphenylalkylenediamines preferred bisphenylalkylenediamines
 are:
 N,N'-bis(.beta.-hydroxyethyl)-N,N'-bis(4'-aminophenyl)-1,3-diaminopropanol
 , N,N'-bis(.beta.-hydroxyethyl)-N,N'-bis(4'-aminophenyl)ethylenediamine,
 N,N'-bis(4-aminophenyl)-tetramethylenediamine, N,N
 '-bis(.beta.-hydroxyethyl)-N,N '-bis(4-aminophenyl)tetramethylenediamine,
 N,N'-bis(4methylaminophenyl)tetramethylenediamine,
 N,N'-bis(ethyl)-N,N'-bis(4'-amino-3'-methylphenyl)-ethylenediamine,
 1,8-bis(2,5-diaminophenoxy)-3,5-dioxaoctane, and the acid addition salts
 thereof.
 Among the para-aminophenols, preferred para-aminophenols 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,
 4-amino-2-(.beta.-hydroxyethylaminomethyl)phenol, 4-amino-2-fluorophenol,
 and the acid addition salts thereof.
 Among the ortho-aminophenols, preferred ortho-aminophenols are:
 2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol,
 5-acetamido-2-aminophenol, and the acid addition salts thereof.
 Among the heterocyclic bases, preferred heterocyclic bases are: pyridine
 derivatives, pyrimidine derivatives and pyrazole derivatives.
 When used, the additional oxidation base(s) preferably represent(s) from
 0.0005 to 12% by weight approximately relative to the total weight of the
 dyeing composition and, more preferably from 0.005 to 6% by weight
 approximately relative to this weight.
 In general terms, the acid addition salts used within the scope of the
 dyeing compositions of the invention (compounds of formula (I), additional
 oxidation bases and couplers) are chosen in particular from
 hydrochlorides, hydrobromides, sulphates, citrates, succinates, tartrates,
 lactates and acetates.
 The base addition salts used within the scope of the dyeing compositions of
 the invention (compounds of formula (I), additional oxidation bases and
 couplers) are chosen from sodium hydroxide solution, potassium hydroxide
 solution, aqueous ammonia, or amines.
 The dyeing composition in accordance with the invention can additionally
 comprise one or more direct dyes which can be chosen in particular from
 the nitrated dyes of the benzene series.
 The dyeing composition in accordance with the invention can also contain
 various adjuvants used conventionally in hair dyeing compositions, such as
 anionic, cationic, nonionic, amphoteric or zwitterionic surfactants or
 mixtures thereof, anionic, cationic, nonionic, amphoteric or zwitterionic
 polymers or mixtures thereof, organic or inorganic thickeners,
 antioxidants, penetration agents, sequestrants, fragrances, buffers,
 dispersants, conditioners such as, for example, modified or unmodified,
 volatile or nonvolatile silicones, film formers, ceramides, preservatives
 and opacifiers.
 The person skilled in the art can select the optional complementary
 compound(s) such that the advantageous properties intrinsically associated
 with the dyeing composition in accordance with the invention are not, or
 not substantially, adversely affected by the additions envisaged.
 The dyeing composition according to the invention may be in various forms,
 such as in the form of liquids, creams, gels or any other form which is
 suitable for dyeing keratinous fibers, and in particular human hair.
 The invention also provides a process for dyeing keratinous fibers, and in
 particular human keratinous fibers such as hair using the dyeing
 composition as defined above.
 According to this process, at least one dyeing composition as defined above
 is applied to the fibers for a period which is sufficient to develop the
 desired coloration either in air or with the aid of an oxidizing agent.
 The dyeing composition can optionally include oxidation catalysts in order
 to accelerate the process of oxidation.
 According to one embodiment of the process of the invention, the dyeing of
 the fibers can be carried out without the addition of an oxidizing agent,
 solely by contact with the oxygen in the air.
 According to another embodiment of the process of the invention at least
 one dyeing composition as defined above is applied to the fibers, the
 color being developed at an acidic, neutral or alkaline pH with the aid of
 an oxidizing agent which is added right at the time when the dyeing
 composition is employed or which is present in an oxidizing composition
 which is applied simultaneously or sequentially and separately.
 According to this embodiment of the dyeing process of the invention, the
 above-described dyeing composition is preferably mixed at the time of use
 with an oxidizing composition comprising, in a medium suitable for dyeing,
 at least one oxidizing agent which is present in an amount sufficient for
 color development. The resulting mixture is subsequently applied to the
 keratinous fibers and left to act for approximately 3 to 50 minutes,
 preferably for approximately 5 to 30 minutes, after which the fibers are
 rinsed, optionally 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 keratinous fibers, among which preferred oxidizing
 agents are: hydrogen peroxide, urea peroxide, alkali metal bromates, and
 persalts, such as perborates and persulphates, and enzymes, such as
 peroxidases and oxidoreductases with 2 unpaired electrons. It is
 particularly preferred to use hydrogen peroxide.
 The pH of the oxidizing composition comprising the oxidizing agent as
 defined above is such that, after it has been mixed with the dyeing
 composition, the pH of the resulting composition applied to the keratinous
 fibers preferably ranges from approximately 3 to 12, and more preferably,
 from 5 to 11. The pH can be adjusted to the desired value by means of
 acidifying or basifying agents which are commonly employed in the dyeing
 of keratinous fibers and are as defined above.
 The oxidizing composition as defined above can also contain various
 adjuvants which are conventionally employed in hair-dyeing compositions
 and are as defined above.
 The composition which is ultimately applied to the keratinous fibers can be
 in various forms, such as in the form of liquids, creams or gels or in any
 other form suitable for dyeing keratinous fibers, and in particular human
 hair.
 Another aspect of the invention is a multi-compartment dyeing device or
 "kit" or any other multi-compartment packaging system a first compartment
 of which contains the dyeing 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 delivering the desired
 mixture onto the hair, such as the devices described in patent FR-2 586
 913 the disclosure of which is specifically incorporated by reference
 herein.
 Certain compounds of formula (I) which are used as an oxidation base within
 the scope of the present invention are novel and, to that extent, are
 further provided by the invention.
 These novel 3-aminopyrazolo[1,5-a]pyrimidines are:
 pyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,6,7-trimethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 7-methylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5-methylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 7-methylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5-methoxypyrazolo[1,5-a]pyrimidin-3-ylamine;
 7-methoxy-5-methylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 2,5,6,7-tetramethylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,7-di-tert-butylpyrazolo[1,5-a]pyrimidin-3-ylamine;
 5,7-ditrifluoromethylpyrazolo[1,5-a]pyrimidin-3-ylamine; and the acid or
 base addition salts thereof.
 These novel 3-aminopyrazolo[1,5-a]pyrimidines can be prepared by methods
 which are known and are described in the literature.
 For example, a cyclocondensation reaction is carried out between a
 3(5)-amino-4-nitropyrazole derivative and a .beta.-keto ester, a
 .beta.-diketone or a .beta.-keto aldehyde in order to form the
 pyrazolo[1,5-a]pyrimidine structure. This reaction is carried out in a
 manner according to the methods described in the following references:
 EP-A-628559 BEIERSDORF-LILLY
 G. Muhmel, R. Hanke, E. Breitmaier, Synthesis, 673, 1982.
 The resulting nitro derivative is subsequently reduced to give the expected
 3-amino-pyrazolo[1,5-a]pyrimidine in accordance with known processes (R.
 Hemmer, W. Lurken in Houben-Weyl, "Methoden der Organischen Chemie"
 [Methods of Organic Chemistry], Vol. E 16d, p. 815 ff.). Preference is
 given to the use of metals such as palladium (Pd), platinum (Pt) or nickel
 (Ni) in the presence of a hydrogen donor such as ammonium formate, formic
 acid or else cyclohexene in place of hydrogen (S. Ram, R. E. Ehrenkaufer,
 Synthesis, 91, 1988). It is also possible to use metals such as zinc (Zn),
 tin (Sn) or iron (Fe) in an acidic medium such as aqueous hydrochloric
 acid or aqueous acetic acid, optionally with addition of an organic
 solvent such as methanol, ethanol or tetrahydrofuran.
 Alternatively, it is possible to carry out a cyclocondensation reaction
 between a 3(5)-aminopyrazole derivative and a .beta.-keto ester, a
 .beta.-diketone or a .beta.-keto aldehyde in order to form the
 pyrazolo[1,5-a]pyrimidine structure. This reaction is carried out in a
 manner according to the methods described in the following references:
 R. H. Springer, M. B. Scholten, D. E. O'Brien, T. Novinson, J. P. Miller,
 R. K. Robins, J. Med. Chem., 25,235,1982.
 T. Novinson, R. K. Robins, T. R. Matthews, J. Med. Chem., 20, 386,1977.
 K. Nagahara, H. Kawano, S. Sasaoka, C. Ukawa, T. Hirama, A. Takada, J.
 Heterocyclic Chemistry, 239,1994.
 It is also possible to carry out a nitration reaction of this
 pyrazolo[1,5-a]pyrimidine structure by well-known methods. By way of
 example, reference is made to the following document:
 K. Senga, T. Novinson, R. H. Springer, R. P. Rao, D. E. O'Brien, R. K.
 Robins, H. R. Wilson, J. Med. Chem., 18(3), 312, 1975.
 The nitro derivative is subsequently reduced as above to give the expected
 3-aminopyrazolo-[1,5-a]pyrimidine.
 The 3-aminopyrazolo[1,5-a]pyrimidines of formula (I) and the addition salts
 thereof, as defined above, can likewise be used as an oxidation base in
 and for the preparation of compositions intended for photography or
 chemical imaging.
 The following examples serve to illustrate the invention without, however,
 limiting its scope.

SYNTHESIS EXAMPLES
 EXAMPLE 1
 Synthesis of pyrazolo[1,5-a]pyrimidin-3-ylamine hydrochloride
 ##STR3##
 a) Preparation of 3-nitropyrazolo[1,5-a]pyrimidine
 44 g of malonaldehyde bisdiethyl acetal, 300 cc of acetic acid and 30 g of
 4-nitro-2H-pyrazol-3-ylamine hydrochloride (prepared according to H. Dorn
 and H. Dilcher, Liebigs Ann. Chem., 707, 141, 1967) were introduced into a
 500 ml three-necked round-bottomed flask fitted with a magnetic stirrer, a
 condenser and a thermometer. The medium was refluxed for 5 hours and then
 approximately 100 cc of acetic acid were evaporated off. The solid was
 filtered off and washed with diisopropyl ether. Drying under vacuum and
 over phosphoric anhydride at 40.degree. C. yielded 27.7 g of
 3-nitropyrazolo[1,5-a]pyrimidine (yield=92.5%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200 MHz): 3.34 (s; 1H); 7.51 (dxd; J1=4.3 Hz
 and J2=6.9 Hz; 1 H); 9.04 (dxd; J1=4.3 Hz and J3=1.2 Hz; 1 H); 9.09 (s;
 1H); 9.44 (dxd; J2=6.9 Hz and J3=1.2 Hz; 1H)
 b) Preparation of pyrazolo[1,5-a]pyrimidin-3-ylamine hydrochloride
 100 cc of ethanol, 12 cc of water, 3.3 g of ammonium chloride and 10 g of
 3-nitropyrazolo[1,5-a]-pyrimidine obtained above in the preceding step
 were introduced into a 250 ml three-necked round-bottomed flask fitted
 with a magnetic stirrer, a condenser and a thermometer. The medium was
 then refluxed. The heating was withdrawn, and 16 g of zinc powder were
 added in small portions in order to maintain the reflux. When this
 addition was complete, the mixture was heated at reflux for 3 hours. The
 zinc salts were filtered off hot. The filtrate was cooled until
 crystallization took place. The crystalline product was filtered off and
 dissolved in 100 cc of absolute ethanol. After bubbling gaseous
 hydrochloric acid through the ethanolic solution, the hydrochloride was
 precipitated by addition of 1 litre of diisopropyl ether. Drying under
 vacuum and over phosphoric anhydride yielded 6 g of
 pyrazolo[1,5-a]-pyrimidin-3-ylamine hydrochloride (red solid)
 (yield=57.5%).
 .sup.1 H NMR (D.sub.2 O; 200 MHz): 7.18 (dxd; J.sub.1 =4.2 Hz and J.sub.2
 =7.1 Hz; 1H); 8.33 (s; 1H); 8.65 (dxd; J.sub.1 =4.2 Hz and J.sub.3 =1.6
 Hz; 1H); 8.90 (dxd; J.sub.2 =7.1 Hz and J.sub.3 =1.6 Hz; 1H)
 EXAMPLE 2
 Synthesis of 5,6,7-trimethylpyrazolo[1,5-a]pyrimidin-3-ylamine
 hydrochloride
 ##STR4##
 a) Preparation of 5,6,7-trimethyl-3-nitropyrazolo-[1,5-a]pyrimidine
 80 cc of acetic acid, 8.2 g of 4-nitro-2H-pyrazol-3-ylamine hydrochloride
 (prepared according to H. Dorn and H. Dilcher, Liebigs Ann. Chem., 707,
 141, 1967) and 7.2 g of 3-methylpentane-2,4-dione were introduced into a
 100 ml three-necked round-bottomed flask fitted with a magnetic stirrer, a
 condenser and a thermometer. The medium was refluxed for 3 hours. The
 medium was filtered at room temperature and the solid was washed with
 diisopropyl ether. This yielded 9.4 g of crude product. 3.5 g of this
 product was recrystallized in 23 cc of absolute ethanol. Drying under
 vacuum and over phosphoric anhydride yielded 3.1 g of
 5,6,7-trimethyl-3-nitropyrazolo[1,5-a]pyrimidine (yield=80%).
 hu 1H NMR (DMSO-d.sub.6 ; 200 MHz): 2.31 (s; 3H); 2.62 (s; 3H); 2.75 (s;
 3H); 8.89 (s; 1H)
 b) Preparation of 5,6,7-trimethylpyrazolo[1,5-a]-pyrimidin-3-ylamine
 hydrochloride
 90 cc of ethanol, 10 cc of water, 1.5 g of ammonium chloride and 6.18 g of
 5,6,7-trimethyl-3-nitropyrazolo[1,5-a]pyrimidine obtained above in the
 preceding step were introduced into a 250 ml three-necked round-bottomed
 flask fitted with a magnetic stirrer, a condenser and a thermometer. The
 medium was then refluxed. The heating was withdrawn, and 7.8 g of zinc
 powder were added in small portions in order to maintain the reflux. When
 this addition was complete, the mixture was heated at reflux for 1 hour.
 The zinciferous sludges were filtered off hot. The filtrate was
 concentrated to a tenth of its volume, and the product which crystallized
 was filtered off. This product was washed with petroleum ether. Drying
 under vacuum and over phosphoric anhydride yielded 4.9 g of
 5,6,7-trimethylpyrazolo[1,5-a]pyrimidine hydrochloride (yield=82%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200 MHz): 2.27 (s; 3H); 2.55 (s; 3H); 2.70 (s;
 3H); 8.22 (s; 1H); 10.61 (broad s; 3H)
 EXAMPLE 3
 Synthesis of 7-methylpyrazolo[1,5-a]-pyrimidin-3-ylamine hydrochloride
 ##STR5##
 a) Preparation of 7-methyl-3-nitropyrazolo[1,5-a]-pyrimidine
 This compound was obtained by following the protocol described in the first
 step of Example 2. All quantities were multiplied by four and the
 3-methylpentane-2,4-dione was replaced by 1.1 molar equivalent of
 acetylacetaldehyde dimethyl acetal. At the end of the reaction, the green
 solution was concentrated and poured onto ice. The greenish solid which
 precipitated was filtered off and washed with diisopropyl ether and
 petroleum ether. Drying under vacuum and over phosphoric anhydride at
 40.degree. C. yielded 26 g of crude
 7-methyl-3-nitropyrazolo[1,5-a]pyrimidine (Yield=73%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200 MHz): 2.82 (s; 3H); 7.46 (d; J=4.5 Hz,
 1H); 8.90 (d; J=4.5 Hz; 1H); 9.09 (s; 1H)
 b) Preparation of 7-methylpyrazolo[1,5-a]pyrimidin-3-ylamine hydrochloride
 19.3 g of 7-methyl-3-nitropyrazolo[1,5-a]-pyrimidine, 500 cc of methanol
 and 2.2 g of 5% palladium on charcoal with a water content of 50% were
 introduced into a 1 litre hydrogenation reactor. The medium was heated to
 about 60.degree. C. and 7.7 bars of hydrogen were introduced. Following
 complete reduction, the reactor was cooled and the catalyst was filtered
 off. A stream of gaseous hydrochloric acid was passed through the
 filtrate, and the hydrochloride which precipitated was filtered off.
 Drying under vacuum and over phosphoric anhydride yielded 14.6 g of
 7-methyl-pyrazolo[1,5
 -a]pyrimidin-3-ylamine hydrochloride (yield=72%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200 MHz): 2.75 (s; 3H); 7.17 (d; J=3.4 Hz,
 1H); 8.40 (s; 1H); 8.75 (d; J=4.2 Hz; 1H); 10.77 (broad s; 3H)
 EXAMPLE 4
 Synthesis of 2,5,6,7-tetramethyl-pyrazolo[1,5-a]pyrimidin-3-ylamine
 hydrochloride
 ##STR6##
 a) Preparation of 2,5,6,7-tetramethylpyrazolo-[1,5-a]pyrimidine
 12.6 g of 3-methyl-2,4-pentanedione, 30 cc of acetic acid and 9.6 g of
 3-amino-5-methylpyrazole were introduced into a 100 ml three-necked
 round-bottomed flask fitted with a magnetic stirrer, a condenser and a
 thermometer. The medium was refluxed for 1 hour. The acetic acid was
 evaporated off and the product was taken up in 50 cc of petroleum ether.
 The solid was filtered off and washed with petroleum ether. Drying under
 vacuum and over phosphoric anhydride yielded 15 g of
 2,5,6,7-tetramethylpyrazolo[1,5-a]pyrimidine (yield=85.7%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200 MHz): 2.06 (s; 3H); 2.25 (s; 3H); 2.31 (s;
 3H); 2.50 (s; 3H) 6.13 (s; 1H)
 b) Preparation of 2,5,6,7-tetramethyl-3-nitropyrazolo[1,5-a]pyrimidine
 50 cc of 98% sulphuric acid, in which 12.25 g of
 2,5,6,7-tetramethylpyrazolo[1,5-a]pyrimidine obtained above in the
 preceding step had been dissolved, were introduced into a 100 ml
 three-necked round-bottomed flask fitted with a magnetic stirrer, a
 condenser, a dropping funnel and a thermometer. At about 0.degree. C. 4.4
 g of 100% nitric acid diluted in 2.5 cc of 98% sulphuric acid were added
 dropwise. At the end of the addition, stirring was continued at 0.degree.
 C. for 1 hour and then the medium was poured onto 200 g of ice. The pH was
 brought to using 20% aqueous ammonia. The precipitate was filtered off. It
 was washed with water and with ethanol and with diisopropyl ether. Drying
 under vacuum and over phosphoric anhydride yielded 11 g of
 2,5,6,7-tetramethyl-3-nitropyrazolo[1,5-a]pyrimidine (yield=71.4%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200 MHz): 2.33 (s; 3H); 2.63 (s; 3H); 2.67 (s;
 3H); 2.75 (s; 3 H)
 c) Preparation of 2,5,6,7-tetramethylpyrazolo-[1,5-a]pyrimidin-3-ylamine
 hydrochloride
 2.2 g of 2,5,6,7-tetramethyl-3-nitropyrazolo[1,5-a]pyrimidine, 40 cc of
 ethanol and 1 g of ammonium chloride were introduced into a 100 ml
 three-necked round-bottomed flask fitted with a magnetic stirrer, a
 condenser and a thermometer. The medium was brought to reflux, and 2.5 g
 of zinc powder were added in small portions in order to maintain the
 reflux. After 0.5 hour of refluxing, the zinciferous sludges were
 filtered. The filtrate was concentrated until it crystallized. The
 crystals were filtered off. Drying under vacuum and over phosphoric
 anhydride yielded 2 g of
 2,5,6,7-tetramethylpyrazolo[1,5-a]pyrimidin-3-ylamine hydrochloride
 (yield=88.2%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200 MHz): 2.24 (s; 3H); 2.35 (s; 3H); 2.49 (s;
 3H); 2.62 (s; 3H); 6.34 (broad s; 3H)
 EXAMPLE 5
 Synthesis of 5,7-di-tert-butylpyrazolo[1,5-a]pyrimidin-3-ylamine
 hydrochloride
 ##STR7##
 a) Preparation of 5,7-di-tert-butyl-3-nitropyrazolo[1,5-a]pyrimidine
 36.85 g of 2,2,6,6-tetramethyl-3,5-heptanedione, 200 cc of acetic acid and
 32.91 g of 4-nitro-2H-pyrazol-3-ylamine hydrochloride (prepared in
 accordance with H. Dorn and H. Dilcher, Liebigs Ann. Chem., 707,141, 1967)
 were introduced into a 500 ml three-necked flask fitted with a condenser,
 a thermometer and a magnetic bar. The mixture was refluxed for 8.5 hours.
 The solution was poured, hot, onto ice. The yellow solid which
 precipitated was filtered off. It was recrystallized from an acetic
 acid/water mixture. Drying under vacuum and over phosphoric anhydride
 yielded 25.4 g of 5,7-di-tert-butyl-3-nitropyrazolo[1,5-a]pyrimidine
 (yield=46%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200 MHz): 1.40 (s; 9H); 1.57 (s; 9H); 7.26 (s;
 1H); 8.98 (s; 1H);
 b) Preparation of 5,7-di-tert-butylpyrazolo[1,5-a]-pyrimidin-3-ylamine
 hydrochloride
 8 g of 5,7-di-tert-butyl-3-nitropyrazolo-[1,5-a]pyrimidine, 350 cc of
 ethanol and 2 g of 5% palladium on charcoal with a water content of 50%
 were introduced into a 1 litre hydrogenation reactor. The medium was
 brought to 65.degree. C., and 10.6 bars of hydrogen pressure were
 introduced. After 1.5 hours, the catalyst was filtered off, with the
 filtrate running into 5 M hydrochloric ethanol. This filtrate was treated
 with vegetable black. Filtration to remove the carbon black, evaporation
 of the ethanol, drying under vacuum and over phosphoric anhydride yielded
 4.5 g of 5,7-di-tert-butylpyrazolo[1,5-a]pyrimidin-3-ylamine hydrochloride
 (yield=54.9%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200 MHz): 1.40 (s; 9H); 1.58 (s; 9H); 7.02 (s;
 1H); 8.35 (s; 1H); 10.55 (broad s; 3H)
 EXAMPLE 6
 Synthesis of 5,7-di-trifluoromethyl-pyrazolo[1,5-a]pyrimidin-3-ylamine
 hydrochloride
 ##STR8##
 a) Preparation of 5,7-di-trifluoromethyl-3-nitropyrazolo[1 5-a]pyrimidine
 31.2 g of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, 125 cc of acetic acid
 and 24.7 g of 4-nitro-2H-pyrazol-3-ylamine hydrochloride (prepared in
 accordance with H. Dorn and H. Dilcher, Liebigs Ann. Chem., 707, 141,
 1967) were introduced into a 500 ml three-necked flask fitted with a
 condenser, a thermometer and a magnetic bar. The mixture was refluxed for
 8.5 hours. The solution was poured, hot, onto ice. The yellow solid which
 precipitated was filtered off. It was washed with petroleum ether. Drying
 under vacuum and over phosphoric anhydride yielded 31.9 g of
 5,7-di-trifluoromethyl-3-nitropyrazolo[1,5-a]pyrimidine (yield=71%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200MHz): 8.67 (s; 1H); 9.54 (s; 1H);
 b) Preparation of 5,7-di-trifluoromethylpyrazolo-[1,5-a]pyrimidin-3-ylamine
 hydrochloride
 3 g of 5,7-di-trifluoromethyl-3-nitro-pyrazolo[1,5-a]pyrimidine, 100 cc of
 ethanol and 0.4 g of 5% palladium on charcoal with a water content of 50%
 were introduced into a 250 cc hydrogenation reactor. 4.2 bars of hydrogen
 pressure were introduced. After 1 hour and 40 minutes, the catalyst was
 filtered off, with the filtrate running into 5 M hydrochloric ethanol. The
 ethanol was evaporated to yield 2 g of crude
 5,7-di-trifluoromethylpyrazolo[1,5-a]pyrimidin-3-ylamine hydrochloride.
 1.6 g of this crude product was recrystallized from 7 cc of hydrochloric
 ethanol. Drying under vacuum and over phosphoric anhydride yielded 1 g of
 5,7-di-trifluoromethylpyrazolo[1,5-a]pyrimidin-3-ylamine hydrochloride
 (yield=32.6%).
 .sup.1 H NMR (DMSO-d.sub.6 ; 200 MHz): 8.23 (s; 1H); 8.72 (s; 1H); 9.54
 (broad s; 3H)
 Application Examples
 EXAMPLES 1 to 4
 Dyeing in an Alkaline Medium
 The following dyeing compositions in accordance with the invention were
 prepared (contents in grams):

EXAMPLE Resulting shade
 1 Coppery orange
 2 Coppery orange
 3 Very light orange-yellow
 4 Light orange-yellow
 EXAMPLES 5 to 7
 Dyeing in an Alkaline Medium
 The following dyeing compositions in accordance with the invention were
 prepared (contents in grams):

COMPOSITION 5 6 7
 7-Methylpyrazolo[1,5-a]-pyrimidin-3-ylamine 0.55 -- --
 hydrochloride (oxidation base
 of formula (I))
 5,7-Di-tert-butylpyrazolo[1,5-a]-pyrimidin-3- -- 0.85 --
 ylamine hydrochloride (oxidation base of formula
 (I))
 2-Methoxy 5,7-dimethylpyrazolo[1,5-a]-pyrimidin- -- -- 0.69
 3-ylamine hydrochloride (oxidation base of
 formula (I))
 2-Methyl-5-aminophenol (coupler) 0.37 0.37 0.37
 Common dye vehicle No. 2 (**) (**) (**)
 Demineralized water q.s. 100 g 100 g 100 g
 Each of the above dyeing compositions was mixed at the time of use with an
 equal weight of a 20-volume (6% by weight) solution of hydrogen peroxide
 with a pH of 3.
 The mixture obtained was applied to locks of natural grey hair containing
 90% white hairs for 30 minutes. The locks were subsequently rinsed, washed
 with a standard shampoo rinse again and then dried.
 The shades obtained are given in the following table:

EXAMPLE Resulting shade
 5 Coppery
 6 Yellow
 7 Coppery gold
 EXAMPLES 8
 Dyeing in an Alkaline Medium
 The following dyeing composition was prepared:

5,7-Di-trifluoromethylpyrazolo[1,5-a]- 0.92 g
 pyrimidin-3-ylamine hydrochloride (oxidation
 base of formula (I))
 2-Methyl-5-aminophenol (coupler) 0.37 g
 Benzyl alcohol 2 g
 Polyethylene glycol containing 6 mol of 3 g
 ethylene oxide
 96.degree. Ethanol 18 g
 C.sub.8 -C.sub.10 -Alkyl polyglucoside in aqueous 6 g
 solution containing 60% of active
 substance, buffered with ammonium citrate,
 sold under the name ORAMIX CG110 .RTM. by the
 company SEPPIC
 Aqueous ammonia containing 20% NH.sub.3 10 g
 Sodium metabisulphite 0.23 g
 Sequestrant q.s.
 Demineralized water q.s. 100 g
 The above composition was mixed at the time of use with an equal weight of
 a 20-volume (6% by weight) solution of hydrogen peroxide with a pH of 3.
 The mixture obtained was applied to locks of natural grey hair containing
 90% white hairs for 30 minutes. The locks were subsequently rinsed, washed
 with a standard shampoo, rinsed again and then dried.
 The locks of hair had been dyed in a reddish copper shade.