The general procedure for the synthesis of 9-carbazoleacetic acid from carbazole and ethyl bromoacetate was as follows: 5 g (0.03 mol) of carbazole was dissolved in 100 mL of DMF, followed by the addition of 6.68 g (0.04 mol) of ethyl bromoacetate. The reaction mixture was stirred continuously at 35 °C for 12 hours. After completion of the reaction, the mixture was poured into 200 mL of water and separated by filtration. The pH of the filtrate was adjusted to 1.0 with 2 M hydrochloric acid. the crude product was collected by filtration and dried. The crude product was recrystallized by dichloromethane/ethanol solvent mixture to give 6.1 g of white crystalline product in 90% yield. The structure of the product was confirmed by 1H NMR (CDCl3, 400 MHz, δ ppm) and 13C NMR (DMSO-d6, 100 MHz, δ ppm): 1H NMR showed δ 13.10 (s, 1H), 8.16 (d, 2H, J = 7.8 Hz), 7.55 (m, 2H), 7.42 (m, 2H), 7.22 ( m, 2H), 5.23 (s, 2H); 13C NMR showed δ 170.2, 140.4, 125.6, 122.2, 120.1, 119.0, 109.2, 43.9.
