[Synthesis]
5-Bromo-1,3-dimethyl-1H-indole was synthesized as follows: according to the methods reported in the literature (Fraile, J. M.; Le Jeune, K.; Mayoral, J. A.; Ravasio, N.; Zaccheria, F.; Org. Biomol. Chem. 2013, 11, 4327-4332) Perform the preparation. 5-Bromo-3-methyl-1H-indole (0.30 g, 1.437 mmol, 1.00 equiv) was dissolved in anhydrous THF (5.0 mL) and cooled to 0-5 °C. NaH (60% dispersed in mineral oil, 0.14 g, 2.86 mmol, 2.00 eq.) was added in batches over 10 min. The reaction mixture (RM) was stirred at 0 °C for 1 h. Ethyl iodide (0.21 mL, 2.86 mmol, 2.0 eq.) was added dropwise. Subsequently, the reaction mixture was continued to be stirred at 0 °C for 30 min and then at room temperature for 18 h. The reaction mixture was then stirred for 1 h at room temperature. After completion of the reaction, the reaction mixture was poured into ice water and extracted with ether. The organic layer was washed with brine and dried over Na2SO4. Finally, the solvent was removed by vacuum evaporation to afford the target product 5-bromo-1,3-dimethyl-1H-indole (0.355 g, 1.33 mmol, 93.2% yield; 84% UPLC yield) as a light yellow oil. |