Organic compounds -- part of the class 532-570 series – Organic compounds – Azo
Reexamination Certificate
2000-12-18
2002-12-10
Powers, Fiona T. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Azo
C534S770000, C534S885000
Reexamination Certificate
active
06492502
ABSTRACT:
The present invention relates to novel azo compounds of the 2-(4-amino)phenyidiazinecarboximidamide type, to a process for their synthesis, to their use for dyeing keratin fibers, to dye compositions containing them and to dyeing processes using them.
It is well known that hair dye compositions use either oxidation dyes or direct dyes. The former dyes lead to shades with better covering power and better staying power, but they have the disadvantage of not being entirely harmless and of requiring an oxidation which is generally accompanied by appreciable degradation of the keratin fibers. In addition, their staying power and their affinity for the hair usually entails the appearance of the phenomenon of demarcation between dyed ends and half-lengths and undyed roots.
These problems do not arise in the case of direct dyes. The use of direct dyes has the further advantage over oxidation dye precursors of reducing the potential risks of allergy.
Among the direct dyes most commonly used are nitrobenzene derivatives. However, these nitrobenzene dyes do not sufficiently withstand repeated washing. To overcome this flaw, attempts have been made to replace nitrobenzene dyes with aminoanthraquinone dyes or azo dyes. It has already been proposed, in particular in patent application FR-A-2,570,946, to use the azo dye of the following formula:
i.e. 4-amino-2′-methyl-4′-[N,N-bis(b-hydroxyethyl)amino]phenylazobenzene.
However, the use of this compound to dye the hair does not yield entirely satisfactory results, in particular, regarding the intensity of the colourings obtained.
The inventors have thus sought other azo dyes which have good solubility in a medium suitable for dyeing, such as water, water/alcohol mixtures and more generally common dye supports and which give, on keratin fibers, dyes with good resistance properties with respect to the various attacking factors to which keratin fibers may be subjected, and in particular with respect to washing, light, bad weather and perspiration.
Thus, following these investigations, the inventors have discovered azo compounds of the 2-(4-amino)phenyidiazinecarboximidamide type of formula (I) defined below.
This discovery forms the basis of the present invention.
The present invention is thus novel azo compounds of formula (I) below, and acid addition salts thereof:
in which:
R
1
and R
2
, independently of each other, represent a hydrogen atom; a C
1
-C
6
alkyl radical; a 5- or 6-membered cycloalkyl radical; a 5- or 6-membered aromatic ring; a 5- or 6-membered aromatic ring substituted with a C
1
-C
6
alkyl radical, a halogen atom, an amino radical, a hydroxyl radical or a C
1
-C
6
alkoxy radical; or R
1
and R
2
form, together with the nitrogen atom to which they are attached, a 4- to 8-membered heterocycle, said heterocycle containing one or more hetero atoms chosen from sulfur, nitrogen and oxygen;
R
3
and R
4
, independently of each other, represent a hydrogen atom, a C
1
-C
6
alkyl radical, a C
1
-C
6
monohydroxyalkyl radical or a C
2
-C
5
polyhydroxyalkyl radical; and
A is a 5- to 6-membered aromatic ring which can be interrupted by one or more hetero atoms chosen from sulfur, nitrogen and oxygen, or fused to another 5- to 6-membered aromatic ring.
When used to dye keratin fibers, the compounds of formula (I) in accordance with the invention have good solubility in water, in water/alcohol mixtures and more generally in common dye supports, and give colourings in a very intense coppery-orange shade which are particularly resistant to the various treatments to which the fibers may be subjected, such as washing, light, bad weather and perspiration. The coppery-orange colourings obtained using the compounds of formula (I) in accordance with the invention are, in particular, more intense than those obtained under the same conditions with 4-amino-2′-methyl-4′-[N,N′-bis(b-hydroxyethyl)amino]phenylazobenzene mentioned above.
In formula (I) above, the alkyl, monohydroxyalkyl and polyhydroxyalkyl radicals may be linear or branched.
Among the C
1
-C
6
alkyl radicals of the compounds of formula (I) above, preferred alkyl radicals are: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl and isohexyl radicals.
Among the C
1
-C
6
monohydroxyalkyl radicals, preferred monohydroxyl radicals are: hydroxymethyl, hydroxyethyl, hydroxypropyl and hydroxybutyl radicals.
Among the C
2
-C
6
polyhydroxyalkyl radicals, preferred polyhydroxylalkyl radicals are: dihydroxyethyl, dihydroxypropyl, trihydroxypropyl and dihydroxybutyl radicals.
Among the cycloalkyl radicals which can be represented by the radicals R
1
and R
2
, preferred cycloalkyl radicals are: cyclohexyl and cyclopentyl.
Among the aromatic rings which can be represented by the radicals R
1
and R
2
, preferred aromatic rings are, for example, phenyl rings; phenyl rings substituted with a C
1
-C
6
alkyl radical, a halogen atom or an amino, hydroxyl or C
1
-C
6
alkoxy radical; benzyl, pyrimidine, pyridazine and benzimidazole rings.
Among the heterocycles which can be formed by the radicals R
1
and R
2
together, preferred heterocycles are: imidazole, benzotriazole, benzimidazole, pyrrolidine, piperidine and morpholine rings.
Among the rings which can be represented by the aromatic ring A, preferred rings are, for example, 6-membered rings such as phenyl, pyrimidine and pyridine rings, and 5-membered rings such as pyrrole and pyrazole rings.
The radicals R
1
, R
2
, R
3
and R
4
, independently of each other, preferably represent a hydrogen atom or a methyl radical.
Among the compounds of formula (I), mention may be made in particular of:
2-(4-amino)phenyldiazinecarboximidamide,
N,N-dimethyl-2-(4-amino )phenyldiazinecarboximidamide,
N,N-diethyl-2-(4-amino)phenyldiazinecarboximidamide,
N,N-diisopropyl-2-(4-amino)phenyldiazinecarboximidamide,
N,N-dibutyl-2-(4-amino)phenyldiazinecarboximidamide,
2-(5-amino)-2-pyridyldiazinecarboximidamide,
and the acid addition salts thereof.
The compounds of formula (I) in accordance with the invention can readily be obtained, according to methods well known in the state of the art, which comprise, in a first step, carrying out, in a solvent medium, a reduction reaction on a compound of formula (III) below:
in which A, R
1
and R
2
can take the same meanings as those indicated above for the compounds of formula (I), to give a compound of 2-(4-amino)phenylhydrazinecarboximidamide type of formula (II) below:
in which A, R
1
, R
2
, R
3
and R
4
have the same meanings as those indicated above for the compounds of formula (I), which product, in a second step, is oxidized, in a solvent medium, to give the corresponding compound of formula (I).
According to a variant of this synthetic process, and when, in the compounds of formula (I), at least one of the radicals R
3
and R
4
is other than a hydrogen atom, the process then includes an intermediate step of substituting the amine according to the known standard methods.
When the synthesis is complete, the compounds of formula (I) in accordance with the invention can, where appropriate, be recovered by methods which are well known in the state of the art, such as crystallization or distillation.
The solvent(s) used in steps 1 and 2 above is (are) preferably chosen from water, C
1
-C
4
alkanols such as methanol, ethanol or isopropanol, and mixtures thereof.
The reduction reaction used in the first step is preferably a catalytic hydrogenation, the catalyst being, for example, palladium on charcoal.
The oxidizing agents which can be used in the second step are preferably chosen from sodium iodate, sodium periodate, atmospheric oxygen, magnesium phthalate monoperoxide, hydrogen peroxide and hydrogen peroxide in the presence of metal salts such as, for example, manganese diacetate, potassium ferricyanide, silver oxide and ferric chloride.
The pH of the synthetic medium used in the first and second steps is not a critical factor, and preferably ranges from approximately 4 to 10. It can be adjusted using basifying or acidify
Henrion Jean-Christophe
Philippe Michel
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
L'Oreal (S.A.)
Powers Fiona T.
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