946505-09-5

946505-08-4

946505-09-5

Step C: Preparation of 2-(4-fluorophenyl)-3-oxo-2,3-dihydropyridazine-4-carboxylic acid; (E)-5-(2-(2-(4-fluorophenyl)hydrazinylidene)ethylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (0.60 g, 2.05 mmol) was mixed with NaOMe (0.133 g, 2.46 mmol) in a MeOH (10 mL) solution were mixed and heated to reflux for 15 hours. After completion of the reaction, the reaction mixture was treated with cold 1N HCl solution, and the organic phase was extracted with CH2Cl2, dried over MgSO4, and concentrated to give 0.42 g (87% yield) of the target compound.1H NMR (400 MHz, CDCl3) δ 13.57 (br s, 1H), 8.29 (m, 2H), 7.63 (m, 2H), 7.24 ( m, 2H); 19F NMR (376 MHz, CDCl3) δ -110.7. lRMS (ESI pos) m/e 235.1 (M + 1).