- A new synthesis of quinoline derivatives
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Unsymmetrical azodicarbonyl compounds incorporating an appropriately located aryl group undergo smooth ring closure to form N-substituted dihydroquinolones or spiro N-substituted 2-pyrrolidone derivatives.
- Clemente, Dina-Telma V.,Lobo, Ana M.,Prabhakar, Sundaresan,Marcelo-Curto, M. Joao
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- Intramolecular addition of acyldiazenecarboxylates onto double bonds in the synthesis of heterocycles
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Appropriate aryl-substituted unsymmetrical azodicarbonyl compounds, generated from bishydrazides by oxidation, undergo intramolecular cyclisations to furnish a variety of useful heterocycles such as N-substituted oxindoles, carbostyrils, benzazepinones, benzazocinones, benzimidazolones, benzoxazinones and pyrazolones in varying degrees of efficiency. Methods are described to remove the N-acyl groups from the heteroaromatic compounds. Under mildly acidic conditions where equal opportunities are available for an ipso or a normal cyclisation it is the former process that occurs preferentially. Evidence is presented in favour of a C-to-C migration in the ipso product for the formation of a methoxy-substituted carbostyril derivative. One of the spiro substances is shown to participate in dienone-phenol rearrangement to provide the corresponding quinolone-phenol in high yield.
- Prata, Jose V.,Clemente, Dina-Telma S.,Prabhakar, Sundaresan,Lobo, Ana M.,Mourato, Isabel,Branco, Paula S.
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p. 513 - 528
(2007/10/03)
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