To a solution of 3.79 g (14.19 mmol) of 4-hydroxy-3-(3-methoxy-phenyl)-2H-isoquinolin-1-one in N,N-dimethylacetamide (90 mL), 3.18 g (14.19 mmol) of (2-bromo-ethyl)-carbamic acid tert-butyl ester and 5.09 g (15.6 mmol) of cesium carbonate were added and the resulting mixture was stirred at room temperature for 2 hours under argon. Water was added to the reaction mixture and this was extracted twice with ethyl acetate. The combined organic layers were washed at least three times with water and then evaporated to dryness. The crude was purified by flash chromatography (eluant: ethyl acetate/hexane 1/1) to afford 3.2 g of the title compound (55%).
