title: Mild and efficient Winterfeldt oxidation of 1,2,3,4-tetrahydro-γ-carbolines for the synthesis of dihydropyrrolo[3,2-b]-quinolones and pyrrolo[3,2-b]quinolones.
abstract: The Winterfeldt oxidation (NaOH, DMF, air, rt) of substituted 1,2,3,4-tetrahydro-γ-carbolines has been developed, which provides a convenient and efficient method for the synthesis of the corresponding dihydropyrrolo[3,2-b]quinolones in moderate to excellent yields (38-94%). The generality and substrate scope of this reaction are explored and a possible mechanism is proposed. The results imply that electron-withdrawing groups on N2 of tetrahydro-γ-carbolines and N5-H are necessary. The synthesis of 5 or 7-substituted pyrrolo[3,2-b]quinolones in near quantitative yields was also achieved through deprotection and aromatization of N1-Boc-dihydropyrrolo[3,2-b]quinolones.
authors.affiliation: ZJU-ENS Joint Laboratory of Medicinal Chemistry, Zhejiang University, Hangzhou, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Sheng
authors.forename: Jiangwei
authors.initials: J
authors.lastname: Zhu
authors.forename: Yongzhou
authors.initials: Y
authors.lastname: Hu
mesh_terms: D002243:Carbolines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D015363:Quinolones / Q000138:chemical synthesis*; D013055:Spectrophotometry, Infrared
chemical_list: D002243:Carbolines; D015363:Quinolones; C055572:gamma-carboline