- Transformations of 3-formylindoles under the action of acids
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Under the influence of acids 3-formylindole forms urorosein (the salt of di(indol-3-yl)methylium) which is unstable in solution and decomposes to give a series of indole derivatives, among which 6-(indol-3-yl)-5H,7H-indolo[2,3-b]carbazole and tri(indol-3-yl)methylium salt predominate. N,N′-Dimethylurorosein in solution also forms a mixture of indole derivatives, from which tri(1-methylindol-3-yl)methylium salt, 5N,11N-dimethylindolo[3,2-b]carbazole and its 6-(1-methylindol-3-yl) derivative were isolated. 1999 KluwerAcademic/Plenum Publishers.
- Korolev,Yudina,Lazhko,Reznikova,Preobrazhenskaya
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p. 561 - 569
(2007/10/03)
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- Intermolecular trapping by indole of a spiroindolenine intermediate formed during the Bischler-Napieralski cyclisation of N-acetyltryptamine
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The Bischler-Napieralski cyclisation of N-acetyltryptamine (1a) in the presence of indole (15) affords a moderate yield of the diastereomeric spiroindolines 9 and 10 suggesting the intermediacy of a spiroindolenine 2a in this reaction. Evidence is provided to show that the minor reaction products 2-methyltryptamine (11), tris-(3-indolyl)methane (12) and 6-[(o-aminophenyl) methyl]-5,11-dihydroindolo[3,2-b]carbazole (13) are derived from the spiroindolines 9 and 10.
- Frost, Jonathan R.,Gaudilliere, Bernard R.P.,Kauffmann, Elisabeth,Loyaux, Denis,Normand, Nadine,Petry, Genevieve,Poirier, Philippe,Wenkert, Ernest,Wick, Alexander E.
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p. 175 - 182
(2007/10/02)
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- Reactions of Ethyl 3-Ethoxymethylene-2,4-dioxovalerate and Ethyl Ethoxymethyleneoxaloacetate with Indole Analogs
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The reactions of ethyl 3-ethoxymethylene-2,4-dioxovalerate (1a) and ethyl ethoxymethyleneoxaloacetate (1b) with indole analogs (2, 14, 17-19) are described.Treatment of 1a, b with 2 in ethanol followed by refluxing in acetic anhydride afforded 3,4,10-trisubstituted pyrimidoindoles (4a, b).Hydrogenation or nucleophilic addition of 4a, b was found to occur on the pyrimidine ring in a 1,4-fashion.Compounds 1a, b were also reacted with 14 in ethanol under ice cooling to give the 3,4-disubstituted 9H-pyrimidoindoles (15a, b) directly.Indole (17) or 2-methylindole (18) reacted with 1a (or 1b) to give a mixture of 3-indolylmethylene derivatives (20a, b and 21a, b) and tris-(3-indolyl)-methanes (23 and 24).
- Kurihara, Takushi,Tani, Tsutomu,Imai, Hiromi,Nasu, Keiko
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p. 2972 - 2979
(2007/10/02)
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