To a cooled (0° C.) mixture of (4-methoxyphenoxy)acetaldehyde (33.2 mg, 0.2 mmol) and D-proline (4.6 mg, 0.04 mmol) in chloroform (1.0 mL) was added N-chlorosuccinimide (26.7 mg, 0.2 mmol) with stirring. The mixture was stirred at 0° C. for 30 min, then gradually warmed to ambient temperature for 2 h. To the reaction mixture was added 6-(4-bromo-3-fluorophenyl)-1,2,4-triazin-3-amine (26.9 mg, 0.1 mmol). The reaction mixture was stirred for 1 h and then the solvent was removed under reduced pressure. The residue was dissolved in isopropanol (2 mL) and heated to 100° C. overnight. After cooling, the mixture was filtered and the filtrate was purified by RP-HPLC (pH 10) to afford the desired product. LCMS: (M+H)=415.0/416.9.
