An efficient one-step synthesis of 1,4-dihydropyridines via a triphenylphosphine-catalyzed three-component Hantzsch reaction under mild conditions

Microwave-Assisted Synthesis of Bioactive Six-Membered Heterocycles and Their Fused Analogues

“…The reactions were performed under solvent-free conditions using lanthanum oxide as a catalyst. This new method provided the expected products 35 in excellent yields (90%-98%) after short reaction times (40-80 s) in comparison to the classical Hantzsch methods (Scheme 7) [44][45][46]. Ladani et al [47] synthesized new 1,4-dihydropyridine derivatives by a MW-assisted Hantzsch condensation via three-components reactions involving tetrazolo[1,5-a]quinoline-4-carbaldehydes 36, ethyl/methyl acetoacetate 37 and ammonium acetate (Scheme 8).…”

“…The reactions were performed under solvent-free conditions using lanthanum oxide as a catalyst. This new method provided the expected products 35 in excellent yields (90%-98%) after short reaction times (40-80 s) in comparison to the classical Hantzsch methods (Scheme 7) [44][45][46]. Surprisingly, very few examples of 1,4-dihydropyridines syntheses under MW-irradiation have been described.…”

“…The reactions were performed under solvent-free conditions using lanthanum oxide as a catalyst. This new method provided the expected products 35 in excellent yields (90%-98%) after short reaction times (40-80 s) in comparison to the classical Hantzsch methods (Scheme 7) [44][45][46]. 1,4-Dihydropyridine derivatives have a wide range of biological and pharmaceutical activities and are also involved in hydride transfer from the reduced nicotinamide adenine dinucleotide (NADH and NADPH) coenzymes, and analogues thereof, which mediate hydrogen transfer reactions in biological systems [35][36][37].…”

Synthesis and photodegradation studies of analogues of muscle relaxant 1,4-dihydropyridine compounds

“…Microwave (MW) irradiation represents a novelty of the synthetic strategy due to its ability of reducing reaction times, improving yields and simplifying the work-up processes (28,29). The synthetic route used is outlined in Scheme 1.…”

A simple and efficient approach for synthesis of 1,4-dihydro-pyridines using nano-crystalline solid acid catalyst

“…However, the yield of 1,4-DHP obtained by Hantzsch method is generally low [13][14][15]. Various methods for the synthesis of dihydropyridine derivatives are described in the literature including condensation of aromatic aldehydes, β-dicarbonyl compounds and ammonium acetate using of microwave [16], ionic liquids [17], tetrabutylammonium hydrogen sulfate [18], silica gel/NaHSO 4 [19], AlCl 3 .6H 2 O [20], TMSI [21], triphenylphosphine [22], InCl 3 [23], I 2 [24], cellulose sulfuric acid [25], alumina sulfuric acid [26], SiO 2 /HClO 4 [27], metal triflate [28], Fe(CF 3 CO 2 ) 3 [29], nano CuO [30], nano MgO [31], ultrasound irradiation [32], solvent free [33], and aqueous media [34].…”