title: Regioselective synthesis of 1,2-dihydroquinolines by a solvent-free MgBr2-catalyzed multicomponent reaction.
abstract: A highly efficient and regioselective synthesis of 1,2-dihydroquinolines via a multicomponent reaction between an aniline and two ketones is described. This reaction was catalyzed by magnesium bromide and carried out under solvent-free conditions. When the reaction was performed by using 3-substituted anilines and nonsymmetrically substituted ketones, principally a single product was found among the four expected regioisomers. A variety of anilines and ketones, including cyclic ketones, were evaluated providing a series of 1,2-dihydroquinolines with diverse substitution patterns. A study of the mechanism is discussed. There is evidence of the in situ formation of the imine as a result of the reaction between the aniline and one of the ketones, before annulation to the heterocyclic ring.
authors.affiliation: Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional , Prol Carpio y Plan de Ayala, 11340 México, D.F., Mexico.
authors.forename: Rsuini U
authors.initials: RU
authors.lastname: Gutiérrez
authors.forename: Hans C
authors.initials: HC
authors.lastname: Correa
authors.forename: Rafael
authors.initials: R
authors.lastname: Bautista
authors.forename: José Luis
authors.initials: JL
authors.lastname: Vargas
authors.forename: Alberto V
authors.initials: AV
authors.lastname: Jerezano
authors.forename: Francisco
authors.initials: F
authors.lastname: Delgado
authors.forename: Joaquín
authors.initials: J
authors.lastname: Tamariz
mesh_terms: D001965:Bromides / Q000737:chemistry*; D002384:Catalysis; D017616:Magnesium Compounds / Q000737:chemistry*; D015394:Molecular Structure; D011804:Quinolines / Q000138:chemical synthesis* / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001965:Bromides; D017616:Magnesium Compounds; D011804:Quinolines; D012997:Solvents; C586611:magnesium bromide