A mixture of 0.226 g (0.58 mmol) of 6-(2,6-dichlorophenyl)-2-methanesulfonyl-8-methyl-8H-pyrido[2,3-d]pyrimidin-7-one of Example 39 and 0.40 g (2.42 mmol) of 3-aminobenzoic acid, ethyl ester was fused in a 170° C. oil bath to give a clear melt. After 6 minutes, the melt was cooled to ca. 100° C. Glacial acetic acid (1 mL) was added to dissolve the melt. Water (5 mL) was added to precipitate a solid. The solid was filtered, washed well with water, and triturated with 2 mL of methanol. The mixture was filtered, and the cake was washed with 1 mL of methanol and then ether; wt 0.194 g. Recrystallization from ethyl acetate gave pure product; wt 0.075 g; mp 238°-240° C.
