Quinoline synthesis by improved Skraup–Doebner–Von Miller reactions utilizing acrolein diethyl acetal

Recent Advances in Metal-Free Quinoline Synthesis

“…Ramann and Cowen [18] described the synthesis of heteroring-unsubstituted quinolines through a modified Doebner-Von Miller route. After initial trials using acrolein in a biphasic reaction medium, they found acrolein diethyl acetal to be a superior annulation partner ( Figure 9).…”

“…Lin et al [24] reported a molecular iodine-catalyzed version of the Povarov reaction (Figure 11), in which quinoline derivatives were obtained directly from aniline (1), aldehyde (9), and alkyne (18) precursors. The aniline 1 first forms a Schiff base with the aldehyde 9, which then coordinates with the Lewis acidic I2.…”

An efficient 3-acylquinoline synthesis from acetophenones and anthranilviaC(sp3)–H bond activation mediated by Selectfluor

“…1). [12][13][14] The synthesis of quinolines has been an active area for many years and as a result, a number of efficient synthetic methods have been developed, [15][16][17][18][19][20] such as the classical Skraup, [21][22][23] Combes, [24][25][26] Friedlander, [27][28][29] Gould-Jacobs, [30][31][32] and Doebner-von Miller reactions. [33][34][35][36] More recently, alternative strategies for the quinoline synthesis such as domino cycloadditions [37][38][39][40][41] and transition-metal mediated methods [42][43][44][45] have been introduced.…”

Transition metal/Brønsted acid cooperative catalysis enabled facile synthesis of 8-hydroxyquinolines through one-pot reactions of ortho-aminophenol, aldehydes and alkynes

“…The classical Skraup's procedure for quinoline derivatives suffered from harsh reaction conditions and poor yields. [24][25][26] The Friedlander reaction was limited due to the instability of 2-aminobenzaldehyde, which is mostly in situ generated by reduction of 2-nitrobenzaldehyde derivatives. 27,28 In the last 20 years, transition-metal or Brønsted-acid catalysis toward quinoline derivatives have been extensively studied.…”