The reaction of 2-bromo-5-methoxybenzoic acid (I) with ethyl 2-amino-4-chlorobenzoate (II) by means of Cu(OAc)2 and 1-methyl-2-pyrrolidone in DIEA, followed by cyclization by means of polyphosphoric acid ethyl ester in refluxing chloroform gives the acridone (III), which is hydrolyzed with NaOH in refluxing ethanol yielding the carboxylic acid (IV). The condensation of (IV) with N,N-dimethylethylenediamine (V) by means of CDI in DMF affords the corresponding amide (VI), which is cyclized with phosgene in chloroform to provide the pyrimidoacridinetrione (VII). The reaction of (VII) with N,N-dimethyleythylenediamine (V) gives the final intermediate (VIII), which is demethylated with refluxing 48% HBr.