To a suspension of NaH (60% in mineral oil, 38 mg) in 8 mL of dimethylformamide was added 2-amino-6-(2,6-dichlorophenyl)-pyrido[2,3-d]pyrimidin-7(8H)-one (208 mg, 0.68 mmol). The mixture was heated at 50° C. for 1 hour, resulting in a clear solution. 4-Methoxybenzyl chloride (130 μL, 0.95 mmol) was added, and the reaction mixture was heated at 50° C. for 30 minutes, then poured onto ice water. The resulting precipitate was removed by filtration and washed with water. The solid was purified by flash chromatography, eluting with 1:1 hexane:ethyl acetate, then dried in vacuo to provide 208 (72%) mg of 2-amino-6-(2,6-dichlorophenyl)-8-(4-methoxybenzyl)-8H-pyrido[2,3-d]pyrimidin-7-one; mp 208°-209° C.
