Process for preparing pyrrolidinyl-functional para-phenylenediamine derivatives substituted by a nitrogenous radical, and intermediate compounds

A process for synthesizing a para-phenylenediamine derivative compound comprising a pyrolidinyl group and substituted by a nitrogenous radical, wherein the para-phenylenediamine derivative compound is chosen from those of formula (I):

• wherein:
• the carbon with the substituent R2 on the pyrrolidine ring may be in either (R) or (S) configuration,
• n is an integer ranging from 0 to 4, such that, when n is greater than or equal to 2, the radicals R1 may be identical or different;
• R1 is chosen from halogen atoms;
• saturated and unsaturated, C3–C8 alicyclic, and C1–C6 linear and branched aliphatic, hydrocarbon chains;
• aryl radicals;
• and arylalkyl radicals wherein the alkyl chain is chosen from C1–C6 alkyl chains, it being possible for at least one carbon atom of the hydrocarbon chain and of the alkyl chain of the arylalkyl radical to be replaced by an entity chosen from oxygen, nitrogen, silicon and sulfur atoms and by SO2 groups;
• with the proviso that the radical R1 does not contain a peroxide linkage, nor diazo, nitro or nitroso radicals;
• and
• R2 is chosen from cationic and noncationic nitrogenous radicals;
• comprising the following successive steps:
• a) a para-substituted aniline of the formula (VII):
• wherein R1 and n are as defined above for formula (I), and X is a precursor group of an amine functional group,
• is condensed with a derivative of formula (VIII):
• wherein Y is a leaving group, to give a compound of the formula (IX):
• wherein X, R1 and n are as defined above;
• b) the compound of formula (IX) is activated, to give a compound of formula (X):
• wherein X, R1 and n are as defined above and Z′ is a leaving group;
• c) the compound of formula (X) is reacted with a group chosen from:
• ammonia;
• a primary, secondary and tertiary amine;
• or a compound bearing a nitrogen-containing aromatic heterocycle;
• to give a compound of formula (XI):
• wherein X, R1, R2 and n are as defined above;
• and
• d) the group X is converted to an amine functional group, to give the compound of formula (I).