title: Metal-free, ionic liquid-mediated synthesis of functionalized quinolines.
abstract: An expedient and metal-free synthetic protocol for construction of substituted quinolines has been developed from anilines and phenylacetaldehydes using imidazolium cation-based ionic liquids as the reaction medium. Mechanistic analysis indicated that the reaction occurs through C-C and C-N bond formation to produce isolable 2,3-disubstituted quinoline intermediates, which undergo C-C bond cleavage to produce 3-substituted quinolines. The reaction proceeds smoothly with a range of functionalities in good to excellent yields. Advantages of this protocol include metal-free, environmentally friendly, recyclable reaction media, higher yields and shorter reaction times, and thus is promising for the efficient combinatorial synthesis of structurally diverse 2,3-disubstituted and 3-substituted quinolines.
authors.affiliation: Medicinal Chemistry Division, CSIR-Indian Institute of Integrative Medicine , Canal Road, Jammu 180001, India.
authors.forename: Jaideep B
authors.initials: JB
authors.lastname: Bharate
authors.forename: Sandip B
authors.initials: SB
authors.lastname: Bharate
authors.forename: Ram A
authors.initials: RA
authors.lastname: Vishwakarma
mesh_terms: D020650:Combinatorial Chemistry Techniques / Q000379:methods; D055772:Green Chemistry Technology / Q000379:methods; D052578:Ionic Liquids / Q000737:chemistry*; D011804:Quinolines / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D052578:Ionic Liquids; D011804:Quinolines
keywords: green chemistry; heterocycle synthesis; ionic liquids; metal-free; quinolines