According to Scheme 9 Step 2: To a Solution of 2-(3-Aminophenyl)-4-(4-chlorobenzyl)-6-methoxy-1,2,4-triazine-3,5(2H,4H)-dione (125 mg, 0.34 mmol) in ethanol (10 ml) was added bromothiazole (124 μL, 1.4 mmol) and 5 mL of concentrated hydrochloric acid. The reaction mixture was heated to 100° C. for 48 hours. The reaction mixture was quenched and neutralised with sat NaHCO3 and extracted in ethyl acetate (×3). The organic layers were combined and successively washed with water, brine, dried over MgSO4, filtered and concentrated. The crude oily solid was purified by flash chromatography, 10 g prepacked column, cyclohexane/ethyl acetate 70/30 to afford 4-(4-chlorobenzyl)-6-methoxy-2-(3-(thiazol-2-ylamino)phenyl)-1,2,4-triazine-3,5(2H,4H)-dione 4.144 (10 mg (Yield=6.5%) as a white solid.
