Acylation of 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid (I) with 2,3-dichlorobenzoyl chloride (II) under Schotten-Baumann conditions afforded the dichlorobenzamido compound (III). The diazonium salt (V), prepared by diazotization of 2,5-dimethoxy-4-nitroaniline (IV), was then coupled to naphthol disulfonate (III) yielding the diazo adduct (VI). Subsequent nitro group reduction in (VI) employing sodium sulfide produced the amino derivative (VII).

Similarly, amide (IX) was prepared by acylation of (I) with 2,4-dichlorobenzoyl chloride (VIII) using the same method as in Scheme 22470201a.

Diazotization of aniline (VII) produced the diazonium salt (X), which was finally coupled to the naphthol derivative (IX) producing the title bis-diazo compound.