To a solution of 3-Dimethylaminomethylene-1-(2-methyl-5-nitro-phenyl)-piperidin-4-one (12.06 gm, 41.7 mmol)[as prepared in reference 1] in Ethanol (250 ml) were added N-(4-Chloro-phenyl)-guanidine (28.32 gm, 167 mmol) and sodium acetate (27.32 gm, 334 mmol) and solution was heated under reflux for 12 hours. After cooling to room temperature, the reaction mixture was diluted with water, extracted with ethyl acetate. The organic layer was washed with brine, dried [sodium sulfate] and concentrated under vacuum. The crude product obtained was further purified by silica gel chromatography using 5-10% Methanol/Chloroform as eluent to give pure desired product [11] i.e., (4-Chloro-phenyl)-[6-(2-methyl-5-nitro-phenyl)-5,6,7,8-tetrahydro-pyrido[4,3-d]pyrimidin-2-yl]-amine as yellow solid. (Yield: 2.50 gm, 15.2%)
