1,1,2-Trimethyl-1H-benz[e]indole

yellow to brown crystalline powder

1,1,2-Trimethyl-1H-benzo[e]indole can be used as an indole pH fluorescent probe and can be used for intracellular pH detection and cell marking. It can also be used as a novel nanocarrier-based near-infrared optical probes for in-vivo tumor imaging.

Isopropyl methyl ketone (9.00 g, 0.1 mol) was added to a solution of 2-naphthylhydrazine hydrochloride (15.80 g, 0.1 mol) in glacial acetic acid (100 mL). The mixture was stirred for 0.5 h at 20 °C and refluxed for 6 h. Then, the reaction mixture was poured onto ice and neutralized with sodium carbonate, a precipitate formed was collected by filtration. The yield was 19.8 g (95%).