Syntesis and some reactions of 2-etoxycarbonyl-5-nitro-3-formyl indole

Author: Shota Chikhladze
Keywords: 5-Nitroindole, Pyridazine, Indole, Pyridazino[4, 5-b]indole
Annotation:

Abstract New indole ring containing system 4-chloro-8-nitro-5H-pyridazino[4,5-b]indole has been synthesized. The synthesis of striking product has held in 5 steps. The first stage has been initiated with the reaction of 4-nitrophenylhydrazine and ethyl pyruvate in water to yield corresponding 4-nitrophenylhydrazone what cyclisation was held in polyphosphoric acid at 110°C to get 5-nitro-2-ethoxycarbonyl-(1H)indole. Vilsmeier-Haack reaction has been held on compound 3 transferring to formyl indole, that was refluxed with hydrazine hydrate to obtain 8-nitro-3H,4H,5H-pyridazino[4,5-b]indol-4-one. At the last stage we held halogenation reaction to the keto group on compound 5 with POCl3 to gain 4-chloro-8-nitro-5H-pyridazino[4,5-b]indole.