4-(6-Chloro-4-(ethoxycarbonyl)chroman-7-yloxy)benzoic acid (1 g, 2.65 mmol) was diluted with DCM (10 mL) followed by the addition of oxalyl chloride in DCM (2M) (1.46 mL, 2.92 mmol) and DMF (1 drop). After stirring for 20 minutes, 6-bromopyridin-2-amine (0.505 g, 2.92 mmol) and DIEA (1.16 mL, 6.64 mmol) were added and the reaction was stirred overnight at ambient temperature. The reaction was loaded directly onto a biotage 40 cartridge and eluted with 5% ethyl acetate/hexanes to 70% ethyl acetate/hexanes to provide the desired product.
