Method for the synthesis of 2-hydroxyalkyl-para-phenylenediamines, new 2-hydroxyalkyl-para-phenylenediamines, their use for oxidation dyeing, dyeing compositions and methods of dyeing

A 2-Hydroxyalkyl-para-phenylenediamine of the formula (I′), or an acid addition salt thereof:

• in which:
• n is an integer from 1 to 4 inclusive;
• R1, R2, R3 and R4, which are identical or different, are selected from a hydrogen atom and the following radicals:
• C1-C6 alkyl,
• C1-C6 monohydroxyalkyl,
• C2-C6 polyhydroxyalkyl,
• C1-C6 alkoxy-C1-C6 alkyl,
• C1-C6 aminoalkyl,
• mono- or dihydroxy(C1-C6 alkyl)amino(C1-C6 alkyl),
• (C1-C6 mono- or dialkyl)amino(C1-C6 alkyl),
• aminoalkyl whose amine is protected with a (C1-C6 alkyl)carbonyl, carbamyl or (C1-C6 alkyl)sulfonyl radical,
• C1-C6 carboxyalkyl,
• C1-C6 cyanoalkyl,
• C1-C6 amidoalkyl,
• C1-C6 trifluoroalkyl,
• C1-C6 sulfonamidoalkyl,
• (C1-C6 alkyl)carboxy(C1-C6 alkyl),
• (C1-C6 alkyl)sulfoxy(C1-C6 alkyl),
• (C1-C6 alkyl)sulfone(C1-C6 alkyl),
• (C1-C6 alkyl)keto(C1-C6 alkyl),
• (C1-C6 N-alkyl)amido(C1-C6 alkyl) and
• (C1-C6 N-alkyl)sulfonamido(C1-C6 alkyl);
• R designates a hydrogen atom, a halogen atom, a C1-C6 alkyl radical or a group OZ or SZ in which Z designates a C1-C6 alkyl, C1-C6 monohydroxyalkyl or C2-C6 polyhydroxyalkyl nradical;
• it being understood
• that at least one of the groups —NR1R2 and —NR3R4 designates an —NH2 group;
• and
• that at least one of R, R1, R2, R3 and R4 is different from a hydrogen atom;
• and
• that when R1 and R2 simultaneously represent a hydrogen atom, n is equal to 1, R3 represents an ethyl group, and R4 represents methylcarboxyethyl, then R is not equal to a methyl group;
• or
• that when R1, R2, and R3 simultaneously represent a hydrogen atom, n is equal to 1, and R4 represents an amidomethyl group, then R is not equal to a methyl group;
• or
• that when R1 and R2 simultaneously represent a hydrogen atom, n is equal to 1, R3 is methyl acetate, and R4 represents an ethyl group, then R is not equal to a methyl group;
• or
• that when R1, R2, and R3 simultaneously represent a hydrogen atom, n is equal to 1, and R4 represents methylcarboxyethyl, then R is not equal to a hydrogen atom;
• or
• that when R1 and R2 simultaneously represent a hydrogen atom, n is equal to 1, R3 represents a β-hydroxy ethyl group and R4 represents an amido methyl group, then R is not equal to hydrogen;
• or
• that when R1 and R2 represent H, n is equal to 1, R3 represents ethyl, R4 represents C1-C6alkylcarboxymethyl, then R is not equal to H or CH3;
• or
• that when R1 and R2 represent H, n is equal to 1, 2, 3 or 4, R3 represents H, (C1-C6)alkyl, (C1-C6)monohydroxyalkyl, (C2-C6)polyhydroxyalkyl, (C1-C6)alkoxy(C1-C6)alkyl or an aminoalkyl whose amine is protected with a (C1-C6)alkylcarbonyl or a methylsulphonyl radical, R4 represents H, (C1-C6)alkyl, monohydroxy(C1-C6)alkyl, (C2-C6)polyhydroxyalkyl, (C1-C6)alkoxy(C1-C6)alkyl, C1-C6carboxyalkyl or aminoalkyl whose amine is protected with a (C1-C6)alkylcarbonyl or a methylsuiphonyl radical, then R is not equal to H, halogen or C1-C6 alkyl;
• or
• that when R1 and R2 represent H, n is equal to 1, R3 represents H or (C1-C6)alkyl, R4 represents H or (C1-C6)alkyl, then R is not equal to H, (C1-C6)alkoxy;
• or
• that when R3 and R4 represent H, n is equal to 1, 2, 3 or 4, R1 and R2, independently of one another, represent H, C1-C6alkyl, C1-C6monohydroxyalkyl, (C1-C6)alkoxy(C1-C6)alkyl, C2-C6polyhydroxyalkyl or an aminoalkyl whose amine is protected with a (C1-C6)alkylcarbonyl or a methylsulphonyl radical, then R is not equal to H, halogen, C1-C6alkyl, or C1-C6alkoxy.