The reaction of 3-methoxybenzoylacetone (I) with dimethylformamide dimethylacetal (II) gives the dimethylaminomethylene derivative (III), which is cyclized with 2-cyanoacetamide (IV) by means of sodium ethoxide in ethanol yielding the pyridinone (V). The condensation of (V) with dimethylformamide dimethylacetal (II) affords the dimethylaminovinylpyridinone (VI), which is cyclized by means of ammonium acetate in DMF providing the 1,6-naphthyridine (VII). The hydrolysis of the cyano group of (VII) with NaOH gives the corresponding carboxylic acid (VIII), which is finally cyclized with N-hydroxyacetamidine (IX) by means of carbonydimidazole (CDI).