According to Scheme 2 Step 3: To a solution of 6-bromo-4-(4-chlorobenzyl)-1,2,4-triazine-3,5(2H,4H)-dione (0.400 g, 1.3 mmol) in DMF (8 mL) were added 2-(hydroxymethyl)phenylboronic acid (0.29 g, 1.9 mmol), copper(II) acetate (0.23 g, 1.3 mmol) and pyridine (0.20 g, 2.5 mmol) and the mixture was left stirring overnight at 60° C. The reaction mixture was quenched with a saturated sodium bicarbonate solution. The precipitate formed was filtered, washed first with water and then with diethyl ether. 330 mg (Yield=62%) of 6-bromo-4-(4-chlorobenzyl)-2-(2-(hydroxymethyl)phenyl)-1,2,4-triazine-3,5(2H,4H)-dione were recovered. The product was pure enough to be used without any purification.
