Add 1-chloro-4-(4-fluorophenyl)-phthalazine (3.00 g, 11.6 mmol) to a solution of methyl-piperidin-4-yl-carbamic acid tert-butyl ester (2.98 g, 13.9 mmol) and triethylamine (3.52 g., 34.8 mmol) in DMF (30 mL). Heat at 130° C. for 3 days. Dissolve the reaction mixture in dichloromethane and wash with brine. Dry the organic phase with sodium sulfate, filter, and concentrate under reduced pressure. Purify the resulting residue by flash chromatography (20:5:1, hexane:ethyl acetate: 2 M ammonia in methanol) to yield the title compound as a solid (4.45 g, 88%). ES/MS m/z 437.2 (M+1).
