Synthesis of 7-aminocoumarin-AM
To a stirring solution of 7-aminocoumarin 6 (3 mg, 9 μmol) in anhydrous acetonitrile (1 mL) was added silver(I) oxide (6 mg, 30 μmol) followed by acetoxymethyl bromide (1.5 μL, 15 μmol). The reaction was stirred at 25°C for 12 hours, then concentrated in vacuo. The yellow residue was purified by column chromatography (silica gel, 8:1 EtOAc:hexane) to afford 7-aminocoumarin-AM as a light yellow solid