Azomethine direct dyes or reduced precursors of azomethine direct dyes obtained from 2-alkylresorcinols, and hair dyeing process using these dyes or precursors

A compound of formula (I) or (II):

• the salts thereof with an organic or mineral acid, geometrical isomers thereof, tautomers thereof, and solvates thereof including hydrates;
• in which formula (I) or (II):
• R1, which may be identical or different, represent:
• a chlorine atom;
• a (C1-C3) alkyl radical optionally substituted with one or more hydroxyl groups;
• a (C1-C3) alkoxy radical optionally substituted with one or more hydroxyl groups;
• R2 represents a (C1-C3) alkyl radical;
• X, which may be identical or different, represent:
• a hydroxyl radical;
• a radical —NR3R4 with R3 and R4 representing, independently of each other:
• i) a hydrogen atom;
• ii) a C1-C5 alkyl radical optionally substituted with one or more groups chosen from hydroxyl, (C1-C3)alkoxy, amino, (C1-C3)alkylamino, di(C1-C3) alkylamino, amino-carbonyl, carboxylic —COOH, sulfonic —SO3H, tri(C1-C3) alkylammonium and (C1-C3)alkyl-imidazolium;
• a pyrrolidinyl radical optionally substituted with a group chosen from hydroxyl, (C1-C3)alkoxy, amino, (C1-C3)alkylamino, di (C1-C3)alkylamino, tri(C1-C3)alkylammonium and (C1-C3) alkylimidazolium;
• a piperidine radical optionally substituted with a group chosen from hydroxyl, (C1-C3)alkoxy, amino, (C1-C3)alkylamino, di(C1-C3)alkylamino, tri(C1-C3)alkylammonium and (C1-C3)alkylimid-azolium and;
• n represents an integer between 0 and 3 inclusive;
• with the proviso that when X and/or R3 and/or R4 comprise a cationic group, the electrical neutrality of the compound of formula (I) or (II) is achieved with an anionic counterion or a mixture of anionic counterions that are cosmetically acceptable, including chlorides, bromides and sulfates.