Organic Reactions in Water: A Distinct Approach for the Synthesis of Quinoline Derivatives Starting Directly from Nitroarenes¹

Abstract

Three-component reactions of nitroarenes, aldehydes, and phenylacetylene in the presence of indium in dilute hydrochloric acid produce the corresponding quinoline derivatives under reflux. The conversion in this one-pot synthesis involves the following steps: (i) reduction of the nitroarenes to anilines, (ii) coupling of the anilines, aldehydes, and phenylacetylene, (iii) cyclization of the resulting species, and (iv) dehydrogenation of the cyclic intermediates. Several new quinolines have been prepared.

Synthesis of Quinoline Derivatives by Multicomponent Reaction Using Niobium Pentachloride as Lewis Acid

“…In Table can be noted, that independent of the Lewis acid used , the presence of solvent and high temperatures are necessary to obtain good yields on synthesis of quinoline derivatives. The NbCl 5 when compared with other Lewis acids is efficient and present similar results, with good reaction times and competitive yields.…”

“…In Table 2, the results obtained in this work are compared with other studies described in the literature. [34][35][36][37][38][39][40][41] In Table 2 can be noted, that independent of the Lewis acid used [34][35][36][37][38][39][40][41], the presence of solvent and high temperatures are necessary to obtain good yields on synthesis of quinoline derivatives. The NbCl 5 when compared with other Lewis acids is efficient and present similar results, with good reaction times and competitive yields.…”

“…Because of the applicability of several Lewis acids in this type of reaction , in this work we have reported our studies on the use of niobium pentachloride (NbCl 5 ) as a catalyst in these multicomponent reactions. The NbCl 5 forms chloro‐bridged dimers in its solid state, in which each metal is surrounded by a distorted octahedron of chlorine atoms.…”

Facile Synthesis and Photophysical Characterization of New Quinoline Dyes

“…a Yields of isolated products after recrystallization are shown the yields when compared to others catalysts [24,[73][74][75][76][77][78][79][80], we note that the NbCl 5 promotes MCRs with good yields in milder conditions. The efficiency of this catalyst is highlighted by the conduction of reactions at room temperature and pressure, and air atmosphere.…”

A Decade of Indium‐Catalyzed Multicomponent Reactions (MCRs)

“…The nitro group is reduced in situ, generating the corresponding aniline, which further undergoes the already described coupling/cycloisomerization/oxidation process, allowing the preparation of the desired derivatives in overall very good yields. [31] In another example, propargylamines (25 examples) were prepared from dibenzylamine, different alkynes, and acetals, in replacement of aldehydes (Scheme 9B). Acyclic and cyclic acetals were deprotected in situ to the corresponding aldehydes by indium(III) chloride, which further catalyzed a typical A 3 -coupling, affording the final propargylamines in overall very good yields (lower yields were observed when using cyclic acetals or strongly withdrawing substituents, such as p-nitro groups).…”