Displacement of the 2-fluoro group in 2,3,6-trifluorobenzonitrile (I) with aqueous ammonia leads to 2-amino-3,6-difluorobenzonitrile (II). Addition of hydroxylamine to the nitrile (II) in the presence of NaOMe affords benzamidoxime (III). Subsequent catalytic hydrogenation of (III) over Raney nickel furnishes benzamidine (IV).
4-Piperidone ethylene ketal (V) is acylated with 6-bromonicotinic acid (VI) employing 1,1'-carbonyldiimidazole to yield amide (VII). The bromide group of (VII) is then displaced with CuCN in hot DMF producing nitrile (VIII). Finally, condensation between N-acylpiperidone (VIII) and amidine (IV) in refluxing EtOH leads to the target spiro quinazoline.