A mixture of 0.155 g (0.40 mmol) of 6-(2,6-dichlorophenyl)-2-methanesulfonyl-8-methyl-8H-pyrido[2,3-d]pyrimidin-7-one of Example 39 and 0.400 g (2.60 mmol) of 3,5-dimethoxyaniline was heated in a 160° C. oil bath for 5 minutes. At ca. 100° C., 1 mL of glacial acetic acid was added to the melt to dissolve. Water (10 mL) was added to precipitate a gum. Decanted and dissolved gum in 35 mL of methylene chloride. The solution was washed with 2×20 mL of water, dried over magnesium sulfate, charcoaled, filtered, and concentrated. The remaining gum was purified silica gel chromatography eluting with chloroform and then with 2:1 hexane:ethyl acetate to obtain the fraction containing the pure product. The eluent was evaporated to near dryness when crystals separated. The crystals were filtered and washed with 0.5 mL of ether; wt 0.059 g; mp 228°-230° C.
