4-Nitroaniline → HCID 3755607, compound

Participants

Reaction Steps

The synthesis of intermediates g started from the commercially available 1-acetyl-3-hydroxyindole a. Condensation of intermediate a with 4-nitroaniline, under refluxing conditions in acetic acid, yielded 3-((4-nitrophenyl)amino)indole (b) (Valezheva et al.; Chem. Heterocycl. Compd. (Engl.Transl.); 14; 1978; 757,759,760; Khim.Geterotsikl.Soedin.; 14; 1978; 939). Deacylation of intermediate b with triethylamine in refluxing methanol and formylation of intermediate c using phosphorus oxychloride in dimetylformamide resulted in intermediate d (Ryabova, S. Yu.; Tugusheva, N. Z.; Alekseeva, L. M.; Granik, V. G.; Pharm. Chem. J. (Engl. Transl.); EN; 30; 7; 1996; 472-477; Khim.Farm.Zh.; RU; 30; 7; 1996; 42-46). Knoevenagel condensation of intermediate d with ethyl cyanoacetate in the presence of a catalytic amount of triethylamine and subsequent intramolecular cyclisation of intermediate e under reflux in 1,2-ethanediol, yielded intermediate f (1-(4-nitro-phenyl)-2-oxo-2,5-dihydro-1H-pyrido[3,2-b]indole-3-carbonitrile) (Ryabova, S. Yu.; Alekseeva, L. M.; Granik, B. G.; Chem. Heterocycl. Compd. (Engl.Translat.)36; 3; 2000; 301-306; Khim.Geterotsikl.Soedin.; RU; 3; 2000; 362-367). N-methylation using methyl iodide led to intermediate g (5-methyl-1-(4-nitro-phenyl)-2-oxo-2,5-dihydro-1H-pyrido[3,2-b]indole-3-carbonitrile).

Provenance & Evidence