- Synthesis of Substituted 1H-3,4-Dihydrodiazepinoindol-3-ones, 3,7-Dihydropyranoindol-7-ones and 6H-Oxazoloindoles
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Ethyl 6-substituted 5-hydroxy-2-methylindole-3-carboxylates (1a,b), prepared by Nenitzescu reaction, Vilsmeier-Haack formylation using DMF and POCl3 form the corresponding 4-aldehydes (2a,b).These aldehydes undergo condensation with hydrazine hydrate (80percent) to produce 8-substituted 3,4-dihydro-7-hydroxy-2-methyldiazepinoindol-3-ones (3a,b).The reaction of 2a,b with acetic anhydride and triethylamine under reflux yields 5-substituted 1-carbethoxy-3,7-dihydro-2-methylpyranoindol-7-ones (4a,b).Ethyl 6-substituted 5-hydroxy-2-methyl-4-nitrosoindole-3-carboxylates (5a,b), prepared by nitrosation of 1a,b with acetic acid and sodium nitrite, when refluxed with benzylamine furnish the corresponding 4-substituted 6H-8-carbethoxy-7-methyl-2-phenyloxazoloindoles (6a,b).Following the above sequence of reactions ethyl 5-hydroxy-2-methylbenzindole-3-carboxylate has been converted into 1H-3,4-dihydro-7-hydroxy-2-methylbenzdiazepinoindol-3-one (9), 3-carbethoxy-1,6-dihydro-2-methylbenzpyranoindol-6-one (10) and 6H-4-carbethoxy-5-methyl-2-phenylbenzoxazoloindole (12).
- Hiremath, Shivayogi P.,Badami, Prema S.,Purohit, Muralidhar G.
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p. 437 - 440
(2007/10/02)
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