To a solution of 1-methyl-1H-imidazole-4-carboxylic acid (7.0 g, 56 mmol) in DMA (200 mL) was added EDC (11 g, 56 mmol) and HOBt (8.5 g, 56 mmol) and the reaction mixture was stirred at room temperature for 1 hour. Then tert-butyl {2-[4-(5-hydrazino-3-phenyl-1,6-naphthyridin-2-yl)phenyl]-5,8-dioxaspiro[3.4]oct-2-yl}carbamate (1-10) (30 g, 56 mmol) was added and the reaction stirred at room temperature for an additional 1 hour at which time acetic acid (17 g, 280 mmol) was added and the reaction was stirred overnight at 80° C., The reaction mixture was cooled to room temperature, quenched with 1N NaOH, poured into saturated sodium bicarbonate, extracted with EtOAc, dried (Na2SO4), filtered and concentrated. The crude residue was purified by column chromatography eluting with 10% methanol in DCM. The appropriate fractions were concentrated and the resulting solid was recrystallized from methanol to give tert-butyl (2-{4-[3-(1-methyl-1H-imidazol-4-yl)-9-phenyl[1,2,4]triazolo[3,4-f]-1,6-naphthyridin-8-yl]phenyl}-5,8-dioxaspiro[3.4]oct-2-yl)carbamate (1-11) as a white solid. MS (M+H)+: 630.
