Diisopropylethylamine → 4H-Pyrido[1,2-a]pyrimidin-4-one

A mixture of 6-bromopurine (0.02040 g, 0.1025 mmol), 2-(aminomethyl)-3-(3-fluorophenyl)-6-methyl-4H-pyrido[1,2-a]pyrimidin-4-one (0.02420 g, 0.08542 mmol), and DIEA (0.04464 mL, 0.2563 mmol) in 1-butanol (2.000 mL) was stirred at 110° C. After 18 h, the mixture was removed from the heat and concd under reduced pressure. The crude mixture was purified by revered-phase semi-prep HPLC using 20-70% gradient of CH3CN (0.1% of TFA) in water (0.1% of TFA) over 40 min as eluent. The acetonitrile was concd under reduced pressure and to the remaining acidic aq layer was added satd NaHCO3 to neutralize the TFA salt. The resulting precipitate was collected by filtration and washed with water to give 3-(3-fluorophenyl)-6-methyl-249H-purin-6-ylamino)methyl)-4H-pyrido[1,2-a]pyrimidin-4-one as a light yellow solid: 1H NMR (400 MHz, DMSO-d6) δ ppm 12.87 (1 H, s), 8.07-8.16 (2 H, m), 7.68 (1 H, dd, J=9.0, 7.0 Hz), 7.55 (1 H, s), 7.39-7.51 (2 H, m), 7.24-7.31 (2 H, m), 7.15-7.23 (1 H, m), 6.92-7.00 (1 H, m), 4.51 (2 H, br. s.), 2.92 (3 H, s); Mass Spectrum (ESI) m/e=402.1 (M+1).