title: Ring closure of azo compounds to 1,2-annulated benzimidazole derivatives and further evidence of reversibility of the azo-coupling reaction.
abstract: The reaction between 1,3,5-tris(N,N-dialkylamino)benzene derivatives and 2 equiv of p-substituted benzenediazonium salts gives dicationic species which collapse to new benzimidazole derivatives with expulsion of p-substituted anilines. The presence of electron-withdrawing groups on the benzenediazo moiety of the dicationic species plays a key role in this unexpected ring closure reaction. The observed chemical behavior has been rationalized in terms of the already reported reversibility of azo coupling reactions and provided further evidence for it.
authors.affiliation: Department of Industrial Chemistry 'Toso Montanari', Alma Mater Studiorum, Università di Bologna , Viale del Risorgimento, 4, 40136 Bologna, Italy.
authors.forename: Erminia
authors.initials: E
authors.lastname: Del Vecchio
authors.forename: Carla
authors.initials: C
authors.lastname: Boga
authors.forename: Luciano
authors.initials: L
authors.lastname: Forlani
authors.forename: Silvia
authors.initials: S
authors.lastname: Tozzi
authors.forename: Gabriele
authors.initials: G
authors.lastname: Micheletti
authors.forename: Silvia
authors.initials: S
authors.lastname: Cino