4-(3-Bromo-4-fluoro-benzyl)-5,6,7,8-tetrahydro-2H-phthalazin-1-one → 2-Fluoro-5-(4-oxo-3,4,5,6,7,8-hexahydrophthalazin-1-ylmethyl)benzonitrile

To a solution of 4-(3-bromo-4-fluoro-benzyl)-5,6,7,8-tetrahydro-2H-phthalazin-1-one (9) (9.53 g, 28.2 mmol), in dry DMF (95 ml) was added copper (I) cyanide (3.5 g, 42.3 mmol) in one portion. The mixture was heated to 160° C. for 18 hours. The reaction was then cooled and filtered through celite and washed though with methanol (30 ml). The filtrate was concentrated in vacuo to afford a brown oil. Main peak in LC-MS, (8.01 g, 66% purity) and was taken through crude to the next transformation; m/z (LC-MS, ESP), RT=3.50 mins (M+H 284.3).