Process for the preparation of 3-(N-aryl-amino)-propyl-2'-sulfatoethyl-sulfonyl compounds

A process for the preparation of a compound of the formula (1)

• Ar--NH--(CH.sub.2).sub.3 --SO.sub.2 --(CH.sub.2).sub.2 --OSO.sub.3 M(I)
• in which
• M is an alkali metal or hydrogen and
• Ar is an aromatic radical of the formula ##STR22## in which n is a number from 0 to 3,
• m is a number from 0 to 3,
• R is C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, amino, C.sub.1 -C.sub.4 -alkylamino, di-(C.sub.1 -C.sub.4)-alkylamino, C.sub.6 -C.sub.10 -arylamino, C.sub.1 -C.sub.4 -acylamino, ureido, nitro or cyano, where C.sub.1 -C.sub.4 -alkyl and C.sub.6 -C.sub.10 -aryl optionally are substituted by one to three radicals selected from the group consisting of C.sub.1 -C.sub.4 -alkoxy, halogen, hydroxy, carboxy, sulfo, sulfato, nitro, cyano and a combination thereof, and
• T is a substituted or unsubstituted benzene or substituted or unsubstituted naphthalene which comprises oxidizing a compound of the formula (3)
• Ar--NH--(CH.sub.2).sub.3 --S--(CH.sub.2).sub.2 --OH (3)
• to give a compound of the formula (4)
• Ar--NH--(CH.sub.2).sub.3 --SO.sub.2 --(CH.sub.2).sub.2 --OH(4),
• and esterifying the compound of the formula (4) with at least one molar equivalent of sulfuric acid, oleum or halosulfonic acid to give a compound of the formula (1).