The general procedure for the synthesis of 1-methyl-5-aminoindole using 1-methyl-5-nitroindole as starting material was as follows: 10% Pd/C catalyst (0.18 g/g by mass of the feedstock) was added to the feedstock solution (THF dosage of 54 mL/g of feedstock) dissolved in THF. The reaction flask was sealed and air was removed by vacuum. Subsequently, a hydrogen-filled balloon was attached to the flask. The reaction was stirred continuously at room temperature for 24 to 48 hours or monitored by TLC until the feedstock completely disappeared. Upon completion of the reaction, the mixture was filtered through diatomaceous earth. The filtrate was collected and the solvent was removed by rotary evaporation to give a brown solid product in 100% yield. The structure of the product was confirmed by 1H NMR (DMSO-d6) and 13C NMR (DMSO-d6): 1H NMR (DMSO-d6): δ 7.15-7.05 (m, 2H), 6.71 (dd, J = 3.0, 0.9 Hz, 1H), 6.57 (dd, J = 8.5, 2.1 Hz, 1H), 6.12 (dd, J = 3.0, 0.9 Hz, 1H), 3.67 (s, 3H); 13C NMR (DMSO-d6): δ 141.30, 131.12, 129.49, 129.44, 129.41, 112.31, 110.11, 104.21, 99.13, 32.86.
