4-METHYL-2-(METHYLSULFANYL)-7H,8H-PYRIDO[2,3-D]PYRIMIDIN-7-ONE; 2-(Methylthio)-4-Methyl-8H-pyrido[2,3-d]pyriMidin-7-one; 4-Methyl-2-(methylthio)pyrido[2,3-d]pyrimidin-7(8H)-one;