A new, simple synthesis of 1,2-dihydroquinolines via cyclocondensation using zeolite catalyst

Abstract

A new, environmentally-friendly synthesis of dihydroquinolines from aniline and ketones using a small pore size zeolite as catalyst is described. This method is simple, cheap and gives the dihydroquinolines in high yield.

Heterogeneous Catalytic Solvent-free Synthesis of Quinoline Derivatives via the Friedländer Reaction

“…Recently we have published the synthesis of 2,4-disubstituted 1,2-dihydroquinolines in the modified Döbner-von Miller reaction [19].In this paper we present our results obtained during the examination of the Friedländer synthesis.…”

“…The moderately acidic small pore-size zeolite Ersorb-4a (E4a) [19] in ethanol at 80°C proved to be inefficient for the cyclization of 1a and acetophenone. We tried acetone as substrate and solvent as well, in these experiments after the formation of the enamine, acetone was exchanged to xylene and the reaction was continued at 140°C.…”

Green synthesis of TiO2 nanoparticles as an efficient heterogeneous catalyst with high reusability for synthesis of 1,2‐dihydroquinoline derivatives

“…palladium, ruthenium, silver, and gold . They catalyzed anilines reactions with various reagents, like alkynes, scandium triflate, silicotungstic acid, indium triflate, HNO 3, and zeolite . Moreover, reactivity of amines towards α‐ketoesters was studied catalytically by using indium which mediated allylation of quinolones as catalysts.…”

Brønsted‐Acid‐Catalyzed Substrate‐Controlled and Site‐Selective Friedel–Crafts Alkylation: A New Strategy for Post‐Modification of 1,2‐Dihydroquinolines

“…

Av ariety of C3-, C6-, C8-and C13-functionalized 1,2-dihidroquinolines (1,2-DHQs)h ave been prepared through post-modification of simple 1,2-DHQs by regioselective Friedel-Crafts alkylations. For example, transition metals such as palladium, [8] ruthenium,s ilver,a nd gold catalyzed reactions of anilines with alkynes, [9] (Scheme 1a); scandium triflate, [10] silicotungstic acid, [11] HNO 3 , [12] iodine, [13] zeolite, [14] MgBr 2 and Li 2 CO 3 , [15] organo-catalyst [16] catalyzed reactions of anilines with ketones and other miscellaneous methodsw ith specific substrates [17] (Scheme 1a). For instances, 1, 2-DHQs were widely used as antibacterial, [1] antitrypanosomal, [2] antioxidant [3] anda ntidiabetic agents, [4] anti-juvenile hormonei nsecticides, ( Figure 1).

…”

“…For example, transition metals such as palladium, [8] ruthenium,s ilver,a nd gold catalyzed reactions of anilines with alkynes, [9] (Scheme 1a); scandium triflate, [10] silicotungstic acid, [11] HNO 3 , [12] iodine, [13] zeolite, [14] MgBr 2 and Li 2 CO 3 , [15] organo-catalyst [16] catalyzed reactions of anilines with ketones and other miscellaneous methodsw ith specific substrates [17] (Scheme 1a). Recently,e fficient strategies toward the synthesis of dihydroquinolines have been focusedo nac atalytic version.…”