A mixture of intermediate 15, ethyl 3-(benzyloxy)-9-bromo-4-oxo-6,7-dihydro-4H-pyrido[1,2-a]pyrimidine-2-carboxylate, (0.477 g, 1.18 mmol) in acetonitrile (15 ml) and water (15 ml) was treated with phenylboronic acid (0.190 g, 1.53 mmol), sodium carbonate (0.275 g, 2.6 mmol) and tetrakis(triphenylphosphine)palladium(0) (0.200 g). The reaction mixture was degassed, flushed with argon and heated at 90° C. for 30 min. The reaction mixture was then concentrated in vacuo, diluted with ethyl acetate, washed with water and brine, dried over anhydrous magnesium sulfate and concentrated. Chromatography of the residue on silica gel (elution gradient of ethyl acetate in hexane) gave 0.325 g (68% yield) of the title material as a clear oil. 1HNMR 400 MHz (CDCl3) δ (PPM): 1.26 (3H, t, J=7.1 Hz, CH3), 2.68 (2H, m, CH2), 4.27 (2H, q, J=7.1 Hz, OCH2), 4.32 (2H, t, J=7.6 Hz, CH2), 5.34 (2H, s, OCH2), 6.73 (1H, t, J=4.8 Hz, CH), 7.3–7.55 (10H, m, aromatics). HRMS (ESI+) calculated for C24H23N2O4 [M+H+]: 403.1658; found: 403.1659.
