GENERAL PROCEDURE: Following the above procedure, the crude reaction mixture was diluted with methanol (MeOH) and cooled to 0 °C. Sulfoxide chloride (SOCl2, 36 μL, 0.5 mmol) was then slowly added and the reaction was stirred at room temperature for 3 hours. Upon completion of the reaction, additional methanol (MeOH) was added and the reaction mixture was heated to reflux for 6 hours. At the end of the reaction, the reaction was quenched with deionized water (H2O) and extracted with ethyl acetate (EtOAc, 3 times). All organic layers were combined and dried with anhydrous magnesium sulfate (MgSO4) and subsequently concentrated under reduced pressure. Finally, the crude product was purified by preparative thin layer chromatography (TLC, unfolding reagent ratio petroleum ether: ethyl acetate = 7:3) to afford the target compounds, methyl 5-methylindole-3-carboxylate (5a-b).
