636-95-3

99-09-2

51516-96-2

Example 28: Synthesis of 3-methyl-1H-indol-6-amine 1. 3-Nitroaniline (27.6 g, 0.2 mol) was dissolved in a mixed solution of water (40 mL) and 37% hydrochloric acid (40 mL). 2. A solution of sodium nitrite (NaNO2, 13.8 g, 0.2 mol) in water (60 mL) was slowly added to the above solution at 0 °C. 3. Subsequently, a 37% hydrochloric acid (100 mL) solution of tin chloride dihydrate (SnCl2-2H2O, 135.5 g, 0.6 mol) was added, maintaining the reaction temperature at 0 °C. 4. After continuous stirring of the reaction mixture at 0 °C for 0.5 h, the insoluble solid was separated by filtration and washed with cold water to afford (3-nitrophenyl)hydrazine hydrochloride (27.6 g, 73% yield). Example 49: Synthesis of 6-amino-1H-indole-2-carbonitrile 1. 3-Nitroaniline (28 g, 0.20 mol) was dissolved in a mixture of water (40 mL) and 37% hydrochloric acid (40 mL). 2. A solution of sodium nitrite (NaNO2, 14 g, 0.20 mol) in water (60 mL) was slowly added to the above solution at 0 °C. 3. Subsequently, a 37% hydrochloric acid (100 mL) solution of tin chloride dihydrate (SnCl2-2H2O, 140 g, 0.60 mol) was added, maintaining the reaction temperature at 0 °C. 4. After continuous stirring of the reaction mixture at 0 °C for 0.5 h, the insoluble solid was separated by filtration and washed with cold water to afford (3-nitrophenyl)hydrazine hydrochloride (28 g, 73% yield).