RESUMO
Carbodiimides 4, obtained from aza-Wittig reactions of iminophosphorane 3 with aryl isocyanates, reacted with secondary amines in the presence of a catalytic amount of sodium alkoxide to give 1,2,4,5-tetrasubstituted imidazoles 7 in good yields. However, 4-acylimidazoles 11 were obtained, as phenols were used in the presence of a catalytic amount of potassium carbonate due to further air oxidation of the expected products 10.
Assuntos
Carbodi-Imidas/química , Carbodi-Imidas/síntese química , Imidazóis/síntese química , Catálise , Imidazóis/química , Isomerismo , Estrutura MolecularRESUMO
A new sequential Ugi-Staudinger-aza-Wittig-nucleophilic addition reaction was developed to construct indolo[1,2-c]quinazoline derivatives, starting from the easily accessible 2-azidobenzaldehyde, carboxylic acid, 2-acylaniline and isocyanide. It is noteworthy that this is the first report of the cyclization of the Ugi adduct to give a dihydroindole ring system with two quaternary carbon centers, via the nucleophilic addition reaction of the methine group to the carbonyl group.