To a solution of ethyl-4-oxo-3H-phthalazin-1-ylacetate (1.0 g) and sodium hydride (60% w/w dispersion in mineral oil) in dimethylformamide (30 ml) was added 2-bromomethylquinoline (1.05 g). The resulting solution was stirred at room temperature for 30 minutes, poured onto water (100 ml) containing 1N HCl (5 ml), and extracted with ethyl acetate. The organic extract was washed with water (3×50 ml), dried and evaporated to obtain ethyl 3-(quinolin-2ylmethyl)-4-oxo-phthalazin-1-ylacetate (1.54 g). This substance was dissolved in a water/dioxane mixture (70 ml/70 ml). To the solution was added 5N potassium hydroxide (5 ml). The solution was allowed to stir at room temperature for 15 minutes, concentrated to remove excess dioxane, diluted with water (150 ml) and extracted with ethyl acetate (3×70 ml). The aqueous layer was adjusted to pH 2 with concentrated HCl. The precipitated solid was triturated with hot ethyl acetate and then filtered to obtain the title compound (0.54 g; m.p. 193°-194° C.).
