Process for preparing primary intermediates for dyeing keratin fibers

A process for the preparation of 2-methoxymethyl-1,4-benzenediamine (IV-a), other compounds of formula (IV), and the salts thereof comprising:

• a. performing a carbonyl reduction of a compound of formula (I) to prepare a compound of formula (II);
• b. performing an etherification of the compound of formula (II) to prepare a compound of formula (III);
• and
• c. performing a hydrogenation of the compound of formula (III) to prepare a compound of formula (IV);
• wherein R1, R2, and R3 are substituents selected from the group consisting of:
• i. C-linked substituents selected from the group consisting of:
• a) alkyl groups;
• b) aryl groups;
• and
• c) substituents selected from the group consisting of COOA1, CONA1, CONA1COA2, C(=NA1)NA1A2, and CN;
• wherein the C-linked substituents comprise from 1 to about 10 carbon atoms and from 0 to about 5 heteroatoms selected from the group consisting of O, F, Cl, N, P, Si, and combinations thereof;
• ii. S-linked substituents selected from the group consisting of SA1, SO2A1, SO3A1, SSA1, SOA1, SO2NA1A2, SNA1A2, and SONA1A2;
• iii. O-linked substituents selected from the group consisting of OA1, ONA1A2;
• iv. N-linked substituents selected from the group consisting of NA1A2;
• (NA1A2A3)+, NA1SA2, NO2;
• v. halogens selected from the group consisting of F, Cl, Br, and I;
• vi. hydrogen;
• and
• vii. combinations thereof;
• wherein A1, A2, and A3 are alkyl groups comprising from 1 to about 10 carbon atoms and from 0 to about 5 heteroatoms selected from the group consisting of O, F, Cl, N, P, Si, and combinations thereof;
• wherein R5 is an alkyl group;
• and
• wherein R6 and R7 are selected from the group consisting of hydrogen, alkyl groups, aminoalkyl groups, hydroxyalkyl groups, and combinations thereof, and further comprising inserting a nitro function into anthranilic acid or compounds thereof in the presence of a nitrating agent and a solvent to prepare the compound of formula (I):