One-Step Catalytic Synthesis of Alkyl-Substituted Quinolines

Abstract

Difficult-to-access alkyl-substituted quinolines are formed directly from commercially available anilines, aldehydes, and alkynes bearing a variety of substituents. Copper(II) triflate catalyzes this three-component coupling without ligand, cocatalyst, solvent, or inert atmosphere. In addition, a two-component Povarov reaction forms 2,3-dialkyl quinolines under the same green conditions that enable the selective three-component synthesis of 2-alkyl quinolines as well as more common aryl quinolines.

Recent synthetic efforts in the preparation of 2-(3,4)-alkenyl (aryl) quinoline molecules towards anti-kinetoplastid agents

“…[147][148][149][150][151][152] A 3 -type Povarov reactions of primary aromatic amine 49, aldehyde 15 and alkyne 71 (A 3 synthesis) to give 2,4-diphenylquinolines 90 (Scheme 26) have become very popular in these recent years can provide a good functional group diversity. These transformations were performed in the presence of Cu(OTf) 2 (5 mol%) 153 or Zn(OTf) 2 (5 mol%) 154 without any solvents. Molecular iodine in MeNO 2 and borane tris(penta-uorophenyl)borane (B(C 6 F 5 ) 3 ) in "wet" DCE were also employed in these acid-catalysed A 3 Povarov reactions.…”

A Green, Solvent-Free One-Pot Synthesis of Disubstituted Quinolines via A3-Coupling Using 1 Mol% FeCl3

“…[58] Both aromatic and aliphatic aldehydes 31 and alkynes 33 were reacted with amines 32 at 80°C or 100°C for 4 hours to produce the desired substituted quinolines in good to excellent yields. [58] Drawbacks of this catalyst system are displayed in Table 6.…”

Porphyrin Cored Amine Functionalized Dendritic Polymer: An Efficient Reusable Catalyst for Quinoline Synthesis

“…Only few catalysts were reported for the effective synthesis of 2,3‐disubstituted 4‐ phenylquinolines ,. L‐Proline was one of the catalysts that was available to catalyse this reaction,, it was not reusable, needed heavy catalyst load (20 mol%) and long reaction time (12 h) .…”

“…[18] Only few catalysts were reported for the effective synthesis of 2,3-disubstituted 4-phenylquinolines. [19,20] L-Proline was one of the catalysts that was available to catalyse this reaction, [21,22] it was not reusable, needed heavy catalyst load (20 mol%) and long reaction time (12 h). [23] Recently, Swathi Bandaru et al have described a Magnetic nano copper ferrite catalyzed one pot synthesis of substituted quinoline derivatives under ultrasonication, which required high catalyst load (500 mg for 10 mmol of reactants).…”