Prata, José V.Clemente, Dina-Telma S.Prabhakar, SundaresanLobo, Ana M.Mourato, IsabelBranco, Paula Sério2020-06-092020-06-092002-01-23PRATA, José V.; [et al] – Intramolecular addition of acyldiazenecarboxylates onto double bonds in the synthesis of heterocycles. Journal of the Chemical Society, Perkin Transactions 1. ISSN 1470-4358. N.º 4 (2002), pp. 513-5281470-4358http://hdl.handle.net/10400.21/11815Appropriate 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.engIntramolecularAcyldiazenecarboxylatesSynthesisHeterocyclesjournal article10.1039/B110414D