A mixture of compound 209 (3.07 g, 10.3 mmol) and 4-methoxybenzylamine (13.5 mL, 103 mmol) in dry DMSO (27 mL) was stirred under a nitrogen atmosphere at 70° C. (bath temperature) for 141 h. The mixture was cooled and petroleum ether (300 mL) was added. It was stirred at room temperature for 30 min. The layers were allowed to separate and the petroleum ether layer was decanted. This procedure was repeated with more petroleum ether (300 mL). Water (300 mL) was added and the mixture was stirred at room temperature for 30 min. It was filtered and washed sticky solid with water (4×20 mL). The sticky solid was dissolved in minimum acetone (50 mL) and water (200 mL) added. The mixture was stirred at room temperature overnight (22 h). Sticky solid generated again. Thus, the product was extracted into ethyl acetate, which after washed with water several times, was dried (MgSO) and evaporated. The crude product was applied to a silica column (dichloromethane/MeOH=50:1) to give N4-(4-chloro-3-ethynylphenyl)-N6-(4-methoxybenzyl)pyrido[3,4-d]pyrimidine-4,6-diamine (218) (2.30 g, 54%) as a greenish yellow solid, mp 201-203° C.; 1H NMR δ [(CD3)2SO] 9.72 (s, 1H), 8.76 (s, 1H), 8.40 (s, 1H), 8.19 (d, J=2.5 Hz, 1H), 7.96 (dd, J=8.9, 2.5 Hz, 14, 7.56 (d, J=8.9 Hz, 14, 7.39-7.28 (m, 3H), 7.17 (s, 1H), 6.93-6.82 (m, 2H), 4.59 (s, 1H), 4.49 (d, J=6.3 Hz, 2H), 3.71 (s, 34. Anal. Calcd for C23H18ClN5O.0.18hexane: C, 67.04; H, 4.80; N, 16.23%. Found C, 66.76; H, 4.79; N, 15.96%.
