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.
|Number of pages||16|
|Journal||Journal Of The Chemical Society-Perkin Transactions 1|
|Publication status||Published - 1 Jan 2002|
- Substitution reactions
- Synthesis (chemical)
- Addition reactions
- Chemical bonds