Condensation of methyl 4-chloroanthranilate (I) with dimethyl butynedioate (II), followed by cyclization in the presence of potassium tert-butoxide leads to the quinolone dicarboxylate (III). Partial hydrolysis of diester (III) under basic conditions affords mono-acid (IV), which is converted to acid chloride (V) by treatment with SOCl2. Condensation of acid chloride (V) with pyrrolidine provides the corresponding amide (VI). The methyl ester group of (VI) is subsequently hydrolyzed with NaOH to afford the intermediate acid (VII).

Treatment of 3-butyn-2-ol (VIII) with methanesulfonyl chloride and triethylamine produces the propargyl chloride (IX). This is then condensed with tert-butyl carbazate to yield the Boc-protected propargylhydrazine (X). Acylation of (X) with the quinolonecarboxylic acid (VII) affords hydrazide (XI). Palladium-catalyzed coupling between acetylene (XI) and the aryl halide (XII) produces the arylpropinyl compound (XIII). This is finally cyclized in the presence of methanesulfonic acid to the target pyridazinoquinoline.