To a solution of tert-butyl {2-[4-(phenylacetyl)phenyl]-5,8-dioxaspiro[3.4]oct-2-yl}carbamate (1-7) (8.8 g, 20.8 mmol) in DMF (100 mL) was added potassium carbonate (14.4 g, 104 mmol) and tert-butyl (2-chloro-3-formyl-4-pyridinyl)carbamate (1-8) (5.33 g, 20.8 mmol) and the reaction mixture was heated 80° C. over night. The reaction mixture was poured into saturated sodium bicarbonate, extracted with EtOAc, dried over sodium sulfate, filtered and concentrated. The crude residue was purified by column chromatography eluting with 1-80% EtOAc/Hexane. The appropriate fractions were combined and the solvent removed in vacuo to give tert-butyl {2-[4-(5-chloro-3-phenyl-1,6-naphthyridin-2-yl)phenyl]-5,8-dioxaspiro[3.4]oct-2-yl}carbamate (1-9). MS (M+H)+: 545.
