“…To the residue in ethanol (2.0 mL) were added 2-vinylquinoline (100 mg, 0.65 mmol) and acetic acid (30 µL, 0.53 mmol), and the mixture was stirred at 80°C for 12 h. After cooling at room temperature, the mixture was partitioned between saturated NaHCO 3 aqueous solution and EtOAc. The organic layer was washed with brine, dried over MgSO 4 , filtered and concentrated in vacuo. The residue was purified by silica gel column chromatography (1-10% MeOH in CHCl 3 ) to give a pale brown solid, which was dissolved in MeOH (5.0 mL) and 4 M HCl/dioxane (0.25 mL, 1.00 mmol) was added to the mixture.…”