To a stirrred suspension of 2-bromo-3-chloro-7,8-dihydropyrido[2,3-b]pyrazin-6(5H)-one (Intermediate J) (10 g, 38.1 mmol), p-tolylboronic acid (11.39 g, 84 mmol) in MeCN (400 ml) and water (100 ml) under N2 supply, was added solid K2CO3 (fine mesh) (7.90 g, 57.1 mmol) followed by Pd(PPh3)2Cl2 (1.337 g, 1.905 mmol). The yellow RM was heated to 80° C. and was left stirring for 66 hours. The RM was allowed to cool slowly to RT and then placed in the fridge for 3-4 hours. The fine yellow needles were filtered off under suction and were washed with small quantity of acetonitrile, followed by water. After air drying for 10 min, the solid was transferred, dried in vacuo at 40° C. for 2 hours, to afford the title compound as fine crystalline needles;
