Nickel nanoparticle-catalyzed facile and efficient one-pot synthesis of polyhydroquinoline derivatives via Hantzsch condensation under solvent-free conditions

Polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized Nickel (Ni) as a heterogeneous catalyst. The present method does not involve any hazardous organic solvents or catalysts. The smaller size of Ni (80 ± 0.5 nm) having a higher surface to volume ratio has promising features for the reaction response such as the shortest reaction time, excellent product yields, simple work-up procedure, and purification of products by non-chromatographic methods.     

PPA-SiO_2 catalyzed efficient synthesis of polyhydroquinoline derivatives through Hantzsch multicomponent condensation under solvent-free conditions

Silica gel-supported polyphosphoric acid（PPA-SiO₂） was found to be an efficient catalyst for the one-pot four-component Hantzsch condensation reaction of aryl aldehydes,dimedone,ethyl acetoacetate and ammonium acetate to afford the corresponding polyhydroquinoline derivatives in high yields.The main advantages of the present approach are short reaction times,clean reaction profiles,simple experimental and workup procedures.     

Molecular iodine-catalyzed one-pot synthesis of 4-substituted-1,4-dihydropyridine derivatives via Hantzsch reaction

A simple, inexpensive and efficient one-pot synthesis of 1,4-dihydropyridine derivatives at room temperature using catalytic amount of iodine were reported with excellent product yields. An easy access to various substituted 1,4-dihydropyridine derivatives quantitatively using commercially available iodine as a catalyst.     

Cerium(Ⅳ) ammonium nitrate catalysed facile and efficient synthesis of polyhydroquinoline derivatives through Hantzsch multicomponent condensation

A general and convenient practical approach for the synthesis of polyhydroquinoline derivatives has been achieved via one-pot four-component Hantzsch condensation of aromatic aldehydes,dimedone,ethyl acetoacetate and ammonium acetate in the presence of a catalytic amount of cerium(Ⅳ) ammonium nitrate (CAN),in ethanol solvent at ambient temperature.Simple work-up,mild reaction conditions,inexpensive and non-toxic catalyst,and excellent product yields are the advantageous features of this method.     

P-TSA catalyzed facile and efficient synthesis of polyhydroquinoline derivatives through hantzsch multi-component condensation

A facile and efficient synthetic route to polyhydroquinolines has been developed via four-component condensation reactions of aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of p-toluenesulfonic acid (p-TSA) catalyst in ethanol at ambient temperature through Hantzsch reaction. Simple work-up procedure, environmentally friendly, inexpensive and non-toxic catalyst, shorter reaction times along with excellent product yields are the significant features of this practical method.     

Facile Yb(OTf)3 promoted one-pot synthesis of polyhydroquinoline derivatives through Hantzsch reaction

Yb(OTf)₃ catalyzed efficient Hantzsch reaction via four-component coupling reactions of aldehydes, dimedone, ethyl acetoacetate and ammonium acetate at ambient temperature was described as the preparation of polyhydroquinoline derivatives. The process presented here is operationally simple, environmentally benign and has excellent yield. Furthermore, the catalyst can be recovered conveniently and reused efficiently.     

ZnO-nanoparticle-promoted synthesis of polyhydroquinoline derivatives via multicomponent Hantzsch reaction

Abstract  

Zinc oxide nanoparticles are used as an effective and reusable catalyst for one-pot, four-component couplings of aldehydes, dimedone, active methylene compounds, and ammonium acetate to produce polyhydroquinoline derivatives under solvent-free conditions at room temperature. Compared with other methods, satisfactory results are obtained with high yields, short reaction times, and simplicity in the experimental procedure. The catalyst could easily be recycled and reused four times without noticeable decrease in catalytic activity.     

二氧化锡纳米粒子催化四组分Hantzsch缩合合成多氢喹啉衍生物(英文)

Tin dioxide (SnO2 ) nanoparticles efficiently catalyzed unsymmetrical four-component Hantzsch condensations of various aldehydes, dimedone, ethyl acetoacetate, and ammonium acetate to form polyhydroquinoline derivatives in excellent yields. This novel method offers several advantages over the traditional method of synthesizing these compounds, including safety, mild conditions, short reaction times, high yields, and an easy workup.     

Synthesis of polyhydroquinoline derivatives through unsymmetric Hantzsch reaction using organocatalysts

A novel and green approach for efficient and rapid synthesis of polyhydroquinoline derivatives via unsymmetric Hantzsch reaction using organocatalysts at room temperature was reported. The process is a simple, environmentally friendly, rapid, and high yielding reaction for the synthesis of polyhydroquinoline derivatives. The catalytic efficiency of various small organocatalysts such as l-proline, trans-4-hydroxy-l-proline, l-thiaproline, dl-phenylglycine, and (−)-cinchonidine was studied under aqueous, organic, and solvent free conditions.     

Organocatalyzed highly efficient synthesis of densely functionalized pyrrole-fused 1,4-dihydropyridine derivatives

Abstract

An organo base catalyzed diverse pyrrole-fused 1,4-dihydropyridines were synthesized. This one-pot, three-component domino reaction of enamino imides, aromatic aldehydes, and malononitrile/ethyl cyanoacetate was achieved by 10?mol% of DMAP under refluxing ethanol. In addition, novel bis-pyrrole-fused 1,4-dihydropyridine derivatives were also prepared by using terephthalaldehyde as a linker instead of simple aromatic aldehydes. This transformation proceeds via Knoevenagel condensation/Michael addition and N-cyclization reaction sequence and have some salient features including the use of a cost-effective catalyst, short reaction time and high atom economy. Moreover, the reusability of the catalyst was also performed up to five runs without any significant loss in activity.     

Rapid and efficient one-pot synthesis of octahydroquinazolinone derivatives using lanthanum oxide under solvent-free condition

A simple, efficient and cost-effective method for the synthesis of octahydroquinazolinone derivatives using dimedone, urea/thiourea and aromatic aldehydes using lanthanum oxide as a catalyst under solvent free condition in microwave irradiation is reported. The present method does not involve any hazardous organic solvents. This catalyst has promising features for the reaction response such as the shortest reaction time, excellent product yields, simple work-up procedure and purification of products by non-chromatographic methods.     

One-step, synthesis of Hantzsch esters and polyhydroquinoline derivatives using new organocatalyst

<正>Herein we report an efficient organocatalyst for the multicomponent Hantzsch reaction under mild condition.The product easily isolated by simple filtration and catalyst can be recovered.     

One-step, synthesis of Hantzsch esters and polyhydroquinoline derivatives in fluoro alcohols

Hantzsch 1,4-dihydropyridine, polyhydroquinoline and 1,8-dioxodecahydroacridines derivatives were synthesized in excellent yields in trifluoroethanol (TFE). The solvent (TFE) can be readily separated from reaction products and recovered in excellent purity for direct reuse.     

An efficient and rapid Mn(III) complex catalyzed synthesis of polyhydropyridine derivatives via Hantzsch 4 component condensation

A facile and an efficient one-pot synthesis of polyhydroquinoline derivatives in high yields using N,N′-bis (benzoylacetone) ethylenediamine manganese (III) chloride as an environmentally friendly mild Lewis acid catalyst with high catalytic activity and reusability via the Hantzsch reaction in short reaction time was reported. The reaction proceeded to completion within 5–25 min in 90–97% yield. All of the obtained compounds were obtained in high purity without any use of more purification and characterized by physical and spectroscopic data.     

Ceric Ammonium Nitrate (CAN) catalyzes the one-pot synthesis of polyhydroquinoline via the Hantzsch reaction

A facile and efficient one-pot synthesis of high yields of polyhydroquinoline derivatives at ambient temperature using Ceric Ammonium Nitrate (CAN) as catalyst via the Hantzsch reaction was reported. The process is simple and environmentally benign and the catalyst is commercially available and inexpensive.     

Rapid synthesis and biological evaluation of 1,4-dihydropyridine derivatives containing a benzothiazolyl moiety

A series of N-(6-methylbenzothiazolyl)-2,3,5,6-tetrasubstituted-4-(aryl)-1,4-dihydropyridines were synthesized by reaction of 2-amino-6-methylbenzothiazole, aromatic aldehyde and active methylene compound in methanol by conventional, as well as, microwave irradiation (solvent free and solid support) methods. The microwave irradiation technique gives better yield and shorter reaction time. Among solid supported microwave irradiation better yields are obtained in acidic alumina as compared to silica, neutral alumina, and basic alumina. All compounds were tested for antibacterial and antifungal activities and results have been compared with standard drugs. Entomological activities were also tested. The results showed that a change in the substitution pattern in 1,4-dihydropyridine derivatives may cause a marked effect on their antimicrobial activity.     

Magnesium oxide nanotubes: synthesis,characterization and application as efficient recyclable catalyst for pyrazolyl 1,4-dihydropyridine derivatives

Magnesium oxide nanotubes were prepared by electrospinning technique. The nanocatalysts have been characterized by various sophisticated techniques, including XRD, SEM, and TEM. The activities of these NT catalysts are promoting pyrazolyl 1,4-dihydropyridine syntheses have been extensively investigated. Various advantages associated with these protocols simple workup procedure, short reaction times, high yields and reusability of the catalyst.