Facile Ionic Liquids-Promoted One-Pot Synthesis of PolyhydroquinolineDerivatives under Solvent Free Conditions

Abstract

An efficient synthesis of polyhydroquinoline derivatives were reported via four-component coupling reactions of aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of a catalytic amount of ionic liquid under solvent free conditions. In the meantime, the catalytic effect of different ionic liquids on the reaction has also been investigated.

Vanadatesulfuric Acid-catalyzed Novel and Eco-benign one-pot Synthesis of Polyhydroquinoline Derivatives under Solvent-free Conditions

“…The solvent was evaporated and the crude products were recrystallized from ethanol, gave the pure products in 80-95% yields based on the starting aldehyde ( Table 2). The products were characterized by IR, 1 H NMR, 13 …”

“…Therefore, numerous promotions, such as using ionic liquids 13,14 , microwaves [15][16][17] , grinding 18 , silica-supported acids 19,20 , L-proline 21 , HY-zeolite 22 , Bu 4 NHSO 4 23 , boronic acids 24,25 , TMSCl-NaI 26 , ceric ammonium nitrate 27,28 , metal triflates 29,30 , p-TSA 31 , and baker's yeast 32,33 have been developed. However, many of these methods still suffer from several limitations, such as unsatisfactory yield, use of environmentally suspected organic solvents, long reaction time, high temperature, and using expensive and non reusable catalysts.…”

Microwave Assisted Fast Synthesis of CuO Nanoflakes: Catalytic Application in the Synthesis of 1,4-Dihydropyridine

“…Some of the synthetic methods are use of microwave irradiation technique [25,26], refluxing at high temperature [27][28][29][30][31], use of ionic liquid [32], use of catalysts like SiO 2 /HClO 4 [33], SiO 2 /NaHSO 4 [34], I [35], bakers' yeast [36], metal triflates [37], tetrabutylammonium hydrogen sulfate [38], organocatalysts [39], PTSA [40], iron trifluoroacetate [41], TMSCl [42] and Ni nanoparticles [43].…”

One-pot synthesis of polyhydropyridine derivatives via Hantzsch four component condensation in water medium: Use of a recyclable Lewis acid [Ce(SO₄)₂.4H₂O] catalyst

“…Numerous synthetic methods have been reported for the preparation of 1,4-dihydropyridines under classical or modified conditions [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. However, the low yields, occurrence of several side products, use of stoichimetric amount of reagents, expensive metal precursors, catalysts that are harmful to environment, use of expensive and toxic transition metallic reagents, complicated work-up methods and longer reaction times limit the use of these methods.…”