4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride → (S)-N-(2'-amino-3-chloro-1-fluoro-5',6'-dihydrospiro[chromeno[2,3-c]pyridine-5,4'-[1,3]oxazin]-7-yl)-5-chloropicolinamide

A mixture of (S)-3-chloro-1-fluoro-5′,6′-dihydrospiro[chromeno[2,3-c]pyridine-5,4′-[1,3]oxazine]-2′,7-diamine (0.048 g, 0.143 mmol) and 5-chloro-2-pyridinecarboxylic acid (0.025 g, 0.158 mmol) was purged with N2 followed by the addition of THF (2 mL) and MeOH (0.5 mL). 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (0.046 g, 0.158 mmol) was added in one portion and the resulting reaction mixture was stirred at rt for 3 h. The reaction mixture was quenched with saturated NaHCO3, diluted with water and extracted with EtOAc. The combined organics were dried over Na2SO4, filtered, concentrated and chromatographed on silica gel using 0-4% MeOH/DCM and repurified by HPLC to afford (S)—N-(2′-amino-3-chloro-1-fluoro-5′,6′-dihydrospiro[chromeno[2,3-c]pyridine-5,4′-[1,3]oxazin]-7-yl)-5-chloropicolinamide as a white solid (0.0258 g, 0.054 mmol, 37.9% yield). MS m/z=474.0 [M+H]+.