6-Methoxy-3-pyridinylamine → 2-aminopyrido[2,3-d]pyrimidin-7(8H)-one 41

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 0.50 g (4.00 mmol) of 5-amino-2-methoxypyridine was heated, with stirring, in a 160° C. oil bath. The resulting solution was heated for 10 minutes and cooled to room temperature. Water (10 mL) was added to precipitate a gum. The mixture was decanted, and the remaining gum was triturated with 5 mL of water. The brown solid that developed was filtered, washed well with water, and dried; wt 0.135 g. Purification was effected by silica gel chromatography eluting with chloroform and then with ethyl acetate to obtain the fraction containing pure product. The eluent was concentrated to 2 mL volume. The crystals that separated on inducement were filtered and washed with 0.2 mL of ethyl acetate and then 0.5 mL of ether; wt 0.045 g; mp 233°-235° C.