A solution of 0.100 g (0.25 mmol) of 6-(2,6-dichlorophenyl)-8-ethyl-2-methanesulfonyl-8H-pyrido[2,3-d]pyrimidin-7-one of Example 68 and 0.061 g (0.50 mmol) of 4-methoxyaniline in 0.5 mL of dimethylformamide was heated at reflux for 10 minutes. Three drops of water were added. Crystals separated on inducement. An additional 3 drops of water were added to precipitate additional tacky solid. After decantation, the solid was triturated with 0.5 mL of ethyl acetate and 0.5 mL of petroleum ether. The solids were filtered and washed with 50% ethyl acetate/petroleum ether and dried; wt 0.080 g. Purification was effected by filtering an ethyl acetate solution through a layer of silica gel. Concentration of the filtrate to 1 mL volume yielded pure crystalline product; wt 0.033 g; mp 213°-215° C.
