TY - JOUR
T1 - Intramolecular addition of acyldiazenecarboxylates onto double bonds in the synthesis of heterocycles
AU - Prata, José V.
AU - Clemente, Dina Telma V.
AU - Prabhakar, Alberto Sundaresan
AU - Lobo, Ana Maria Félix Trindade
AU - Mourato, Isabel
AU - Branco, Paula Cristina de Sério
PY - 2002/1/1
Y1 - 2002/1/1
N2 - 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.
AB - 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.
KW - Substitution reactions
KW - Synthesis (chemical)
KW - Addition reactions
KW - Chemical bonds
KW - Derivatives
KW - Oxidation
UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-0036008095&origin=resultslist&sort=plf-f&src=s&st1
U2 - 10.1039/b110414d
DO - 10.1039/b110414d
M3 - Article
SN - 1472-7781
VL - NA
SP - 513
EP - 528
JO - Journal Of The Chemical Society-Perkin Transactions 1
JF - Journal Of The Chemical Society-Perkin Transactions 1
IS - 4
ER -