Process for the preparation of 2-hydroyalkyl paraphenylenediamines, novel 2-hydroxyalkyl paraphenylenediamines, their use for oxydative dyeing, dye compositions and dyeing processes

摘要

2-Hydroxyalkyl-p-phenylene diamines, optionally substituted on position 5, especially those of formula (I), are prepared in a 4-stage synthesis from a 5-halo or 1-4C alkyl-substituted-2-hydroxyalkyl aniline by a) protecting the OH and NH2 groups, b) nitration on the 4-position, c) removing the protecting groups, and d) reducing the 4-nitro to 4-amino, optionally with removal of the 5-halogen atom, if present. The products of the process are preferably of formula (I) n = 1-4; R = H, halogen, 1-6C alkyl, OZ or SZ; Z = 1-6C alkyl, 1-6C monohydroxy alkyl, or 2-6C polyhydroxy alkyl; R1, R2, R3, and R4 = H, 1-6C alkyl, 1-6C monohydroxy alkyl, 2-6C polyhydroxy alkyl, or any of the following in which all alkyl groups have 1-6C: alkoxyalkyl, aminoalkyl, mono- or di-hydroxyalkyl aminoalkyl, mono- or di-alkyl aminoalkyl, protected amino alkyl, carbamyl or alkyl sulfonyl, carboxyalkyl, cyanoalkyl, amidoalkyl, trifluoroalkyl, sulfonamidoalkyl, alkyl carboxyalkyl, alkyl sulfoxyalkyl, alkyl sulfonalkyl, alkyl ketoalkyl, N-alkyl amidoalkyl, N-alkyl sulfonamidoalkyl, such that at least one of NR1R2 and NR3R4 is NH2 . Independent claims cover a) compounds of formula (I) and their acid addition salts per se in which at least one of R1, R2, R3 and R4 is other than H, when R1 and R2 are both H and n is 1, then R is not H, methyl or ethyl, and when R1 and R2 are both H, n is 2 and R3 and R4 are both ethyl, then R is not H, and b) the use of these compounds in hair dyeing formulations.