Categories: Synthesis of N-Heterocycles >
Synthesis of 4-quinolones
N-Alkyl-substituted 4-quinolones are present as the key structural motif in many marketed drugs. An efficient and convenient one-step tandem amination approach affords N-alkyl-substituted 4-quinolones in high yields from easily accessible o-chloroaryl acetylenic ketones and functionalized alkyl amines.
J. Shao, X. Huang, X. Hong, B. Liu, B. Xu, Synthesis, 2012, 44, 1798-1808.
An efficient palladium-catalyzed tandem amination approach affords functionalized 4-quinolones in very good yields from easily accessible o-haloaryl acetylenic ketones and primary amines.
T. Zhao, B. Xu, Org. Lett., 2010, 12, 212-215.
Two different protocols for a palladium-catalyzed CO gas-free carbonylative Sonogashira/cyclization sequence enable the preparation of functionalized 4-quinolones from 2-iodoanilines and alkynes in the presence of molybdenum hexacarbonyl as a solid source of CO. The first method yields the cyclized products after only 20 min of microwave heating at 120°C. The second method is a one-pot two-step sequence which runs at room temperature.
L. Åkerbladh, P. Nordeman, M. Wdjdemar, L. R. Odell, M. Larhed, J. Org. Chem., 2015, 80, 1464-1471.
A mild ICl-induced cyclization of heteroatom-substituted alkynones provides a simple, highly efficient approach to various 3-iodochromones, iodothiochromenones, iodoquinolinones and analogues in good to excellent yields. Subsequent palladium-catalyzed transformations afford a rapid increase in molecular complexity.
C. Zhou, A. V. Dubrovsky, R. C. Larock, J. Org. Chem., 2006, 71, 1626-1632.
1,2-Disubstituted 4-quinolones have been prepared via copper-catalyzed heterocyclization of 1-(2-bromophenyl)- and 1-(2-chlorophenyl)-2-en-3-amin-1-ones, readily obtained from α,β-ynones and primary amines. The reaction tolerates a variety of useful functionalities including ester, keto, cyano, and chloro substituents. Quinolone derivatives can also be directly prepared from α,β-ynones.
R. Bernini, S. Cacchi, G. Fabrizi, A. Sferrazza, Synthesis, 2009, 1209-1219.