A new and efficient method for the synthesis of 3-(2-nitrophenyl)pyruvic acid derivatives and indoles based on the Reissert reaction

• Published in: Tetrahedron letters 2018-10, Vol.59 (44), p.3923-3925
• Main Authors: Mamedov, Vakhid A., Mamedova, Vera L., Syakaev, Victor V., Khikmatova, Gul'naz Z., Korshin, Dmitry E., Kushatov, Temur A., Latypov, Shamil K.
• Format: Article
• Language: English
• Subjects: 3-(2-Nitrophenyl)oxirane-2-carboxamide; 3-(2-Nitrophenyl)pyruvic acid derivatives; 5-(2-Nitrobenzyliden)-2,2-dimethyl-1,3-oxazolidin-4-one; Indole-2-carboxylic acid derivatives; Intramolecular reductive cyclization
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2018.09.039

[Display omitted] •3-(2-Nitrophenyl)oxirane-2-carboxylate is used as a new reagent.•3-(2-Nitrophenyl)pyruvic acid derivatives are used in the synthesis of indoles.•3-(2-Nitrophenyl)oxirane-2-carboxamide is used as a new reagent.•Methyl indol-2-carboxylate is obtained from 3-(2-nitrophenyl)oxirane-2-carboxylate. The formation of 3-(2-nitrophenyl)pyruvic acid and its amide and ester derivatives – key compounds for the Reissert indole synthesis – was achieved under various reaction conditions via the acid catalyzed hydrolysis of 5-(2-nitrobenzyliden)-2,2-dimethyl-1,3-oxazolidin-4-one, which is readily available from 3-(2-nitrophenyl)oxirane-2-carboxamide. A new and highly efficient method for the synthesis of indole-2-carboxylic acid derivatives via the intramolecular reductive cyclization of o-nitrophenylpyruvic acid and its amide and ester derivatives was developed using Na2S2O4 in dioxane/water at reflux.