(S)—N-(1-(4-chloro-3-fluorophenyl)-2-methoxyethyl)-5,5-difluoro-2-(tetrahydro-2H-pyran-4-ylamino)-5,6-dihydropyrido[3,4-d]pyrimidine-7(8H)-carboxamide (I-51) To a solution of 197 (0.0854 g, 0.293 mmol) and DCM (5 mL) was added sequentially TEA (0.123 mL, 0.880 mmol) and CDI (0.0476 g, 0.293 mmol) and the solution was stirred at RT for 30 min. To the solution was added dropwise a solution of TEA (0.123 mL, 0.880 mmol), 208 (0.090 g, 0.293 mmol) and DCM (5 mL). The reaction was stirred for 18 h then poured into water and extracted with DCM. The combined organic extracts were dried (MgSO4), filtered, and concentrated in vacuo. The crude product was purified by SiO2 chromatography eluting with 2% MeOH/DCM to afford 0.060 g (40.9%) of I-51: MS m/z (APCI-pos) M+1=499.
