title: Unprecedented intramolecular [3 + 2] cycloadditions of azido-ketenimines and azido-carbodiimides. Synthesis of indolo[1,2-a]quinazolines and tetrazolo[5,1-b]quinazolines.
abstract: N-(2-azidomethyl)phenyl ketenimines and N-(2-azidomethyl)phenyl-N'-alkyl(aryl) carbodiimides undergo, under mild thermal conditions, intramolecular [3 + 2] cycloaddition reactions between the azido group and either the C=C or the distal C=N double bonds of the ketenimine and carbodiimide functions respectively. The reaction products are indolo[1,2-a]quinazolines and/or indolo[2,1-b]quinazolines in the case of azido-ketenimines, and tetrazolo[5,1-b]quinazolines in the case of azido-carbodiimides. The formation of the two classes of indoloquinazolines implies the ulterior dinitrogen extrusion from the non-isolated, putative [3 + 2] cycloadducts between the azide and ketenimine functions, whereas in the case of azido-carbodiimides the initial cycloadducts, tetrazoloquinazolines, were cleanly isolated and further converted into 2-aminoquinazolines by thermally induced dinitrogen extrusion.
authors.affiliation: Departamento de Quimica Organica, Facultad de Quimica, Universidad de Murcia, Campus de Espinardo, 30100, Murcia, Spain.
authors.forename: Mateo
authors.initials: M
authors.lastname: Alajarin
authors.forename: Baltasar
authors.initials: B
authors.lastname: Bonillo
authors.forename: Maria-Mar
authors.initials: MM
authors.lastname: Ortin
authors.forename: Raul-Angel
authors.initials: RA
authors.lastname: Orenes
authors.forename: Angel
authors.initials: A
authors.lastname: Vidal
mesh_terms: D001386:Azides / Q000737:chemistry*; D003500:Cyclization; D007094:Imides / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D015394:Molecular Structure; D011799:Quinazolines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D001386:Azides; D007094:Imides; D007097:Imines; D011799:Quinazolines