[Synthesis]
General procedure for the synthesis of 4-anilino-pyrido[3,2-d]pyrimidine methanesulfonate from 4-chloropyrido[3,2-d]pyrimidine: 4-chloropyrido[3,2-d]pyrimidine (84 mg, 0.5 mmol), aniline (56 mg, 0.6 mmol), and triethylamine (62 mg, 0.6 mmol) were dissolved in ethanol (2 mL) under nitrogen protection. reflux stirring for 2 hours. Upon completion of the reaction, the crude product was purified by preparative thin layer chromatography plate (silica gel) using chloroform solution containing 3% methanol as eluent. The major bands were collected, concentrated to dryness under reduced pressure, and the residual solids were dissolved in acetone (5 mL), filtered, and methanesulfonic acid (32 μL, 0.5 mmol) was added slowly. The precipitate was collected by filtration, washed with acetone and dried in a vacuum oven to afford 4-anilino-pyrido[3,2-d]pyrimidine methanesulfonate (91 mg, 57% yield) as dark yellow needle-like crystals.1H NMR (DMSO) δ 11.75 (1H, s, br), 9.11 (1H, dd, J = 1.5, 4.3 Hz), 8.97 (1H, s ), 8.32 (1H, dd, J = 1.5, 8.4 Hz), 8.12 (1H, dd, J = 4.3, 8.5 Hz), 7.88 (2H, d, J = 8.2 Hz), 7.49 (2H, t, J = 8.0 Hz), 7.32 (1H, t, J = 7.0 Hz), 2.34 (3H, s). |