1: ethyl 1,2-dihydro-1-oxophthalazin-4-ylacetate With sodium hydroxide in tetrahydrofuran T=40 - 50°C; 0.5 h; 2: 1-bromo-4-bromomethyl-3-fluorobenzene in tetrahydrofuran T=50 - 60°C; 2 h; 3: With acetic acid in tetrahydrofuran; water pH=2 - 3;