Based on previously reported literature procedures, 1H-indol-3-yl acetate (50 mg, 0.29 mmol) was suspended in 1.6 mL degassed 1.5 M aqueous NaOH solution (purged with N2 for 30 min or subjected to 3 freeze-pump-thaw cycles) under Ar atmosphere. The mixture was heated to 100 °C for 15 min, after which the resulting greenish solution was cooled to 0 °C and the respective aldehyde (0.29 mmol) in MeOH (0.3 mL) was added. The reaction mixture was stirred at room temperature for 3-5 days at rt, diluted with 5 mL water, and extracted with EtOAc (3 × 15 mL). The combined organic layers were dried over Na2SO4 and concentrated.