2,8-dibromo-5,11-dihydro indolo[3,2-b]carbazole synthesis

Yield:536757-96-7 53.5%

Reaction Conditions:

with sulfuric acid in water;acetic acid at 0 - 70; for 2.08333 h;Inert atmosphere;Schlenk technique;

Steps:

The synthesis of 2,8-dibromoindolo[3,2-b]carbazole (compound 2)

Compound 1 (10 g, 22 mmol) was added into a mixture of AcOH(130 mL) and H₂SO₄ (32 mL) at 0 °C and stirred for 5 min. The mixture was heated up to 30 °C and kept stirring for 1 h. Afterward, the mixture was further risen up to 60-70 °C and stirred for another 1 h. Then it was cooled down to room temperature and poured into ice water with stirring. The greenish solid was filtered off and washed with water and EtOH to neutral pH. Finally, dried and pure 2,8-dibromoindolo[3,2-b]carbazole (compound 2) (4.88 g, yield 53.5%) was achieved. Mp > 300 °C. ¹H NMR (DMSO-d₆) d 11.14(2H, s, and N-H), and 7.1-8.24 (8H, m, and Ar-H).

References:

Shi, Heping;Yuan, Jiandong;Dong, Xiuqing;Cheng, Fangqin [Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy,2014,vol. 133,p. 501 - 508]