Bakers’ yeast catalyzed synthesis of polyhydroquinoline derivatives via an unsymmetrical Hantzsch reaction

Bakers’ yeast efficiently catalyzes the unsymmetrical Hantzsch reaction through a four-component coupling of aldehydes, β-ketoesters, dimedone and ammonium acetate to form polyhydroquinoline derivatives in good to excellent yields.     

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.     

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.     

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.     

Hafnium (IV) bis(perfluorooctanesulfonyl)imide complex catalyzed synthesis of polyhydroquinoline derivatives via unsymmetrical Hantzsch reaction in fluorous medium

A facile and efficient synthesis of polyhydroquinoline derivatives was reported via four-component condensation reaction of aldehydes, dimedone, active methylene compounds, and ammonium acetate in the presence of Hf(NPf₂)₄ in C₁₀F₁₈ at 60 °C. The method offers several advantages including high yields, short reaction time, simple work-up procedure and catalyst reusability.     

Introduction of a tropine-based dication ionic liquid catalyst for the synthesis of polyhydroquinoline and 1,8-dioxodecahydroacridine derivatives

Research on Chemical Intermediates - In this work, 1,1-(butane-1,4-diyl)bis(tropinium)chloride is prepared, identified and used for the promotion of the synthesis of polyhydroquinoline and...     

Sulfonated organic heteropolyacid salts as a highly efficient and green solid catalysts for the synthesis of 1,8-dioxo-decahydroacridine derivatives in water

In the present study, we introduce two nonconventional ionic liquids [MIMPS]₃PW₁₂O₄₀ (a) and [TEAPS]₃PW₁₂O₄₀ (b) as green and highly efficient solid acid catalysts for the synthesis of 1,8-dioxo-decahydroacridine derivatives. The one-pot three component reaction of 1,3-cyclohexanediones, aromatic aldehydes and aromatic amines or ammonium acetate in water afforded the corresponding 1,8-dioxo-decahydroacridines in excellent yields. This reaction has been carried out in the presence of 1 mol% of catalysts at room temperature. The reusability of the catalysts was demonstrated by a five-run test. Additionally, the catalysts pose several advantages including mild reaction conditions, cleaner reactions and shorter reaction times.     

3-甲基-1-磺酸咪唑硫酸氢盐催化剂用于四组分一锅法合成不对称聚羟基喹啉衍生物(英文)

3-Methyl-1-sulfonic acid imidazolium hydrogen sulfate has been used as an efficient, halogen-free,and reusable Brnsted acidic ionic liquid catalyst for the synthesis of ethyl-4-aryl/heteryl- hexahydro-trimehtyl-5-oxoquinoline-3-carboxylates via the one-pot condensation of dimedone with aryl/heteryl aldehydes, ethyl acetoacetate, and ammonium acetate under solvent-free conditions. This method has the advantage of being clean and simple, as well as providing the desired product in high yield over a short reaction time. Furthermore, the catalyst could be recycled and reused four times without any discernible reduction in activity.     

Formation of derivatives of 5,6-dihydro-1,3-thiazines in the reaction of acetothioacetic acid ethyl ester under the conditions of the Hantzsch synthesis

Derivatives of 2H-5,6-dihydro-1,3-thiazine are formed by the reaction of acetothioacetic acid ethyl ester with aromatic aldehydes on heating in ethanol in the presence of aqueous ammonia.Latvian Institute of Organic Chemistry, Riga LV-1006, Latvia; e-amil: arcady@osi.lv. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 978–985, July, 2000.     

A clean procedure for the synthesis of 1,4-dihydropyridines via Hantzsch reaction in water

A clean and efficient procedure was established to synthesize 1,4-dihydropyridines via one-pot Hantzsch reactions in aqueous medium without the use of a catalyst and/or organic solvent. The reaction with stoichiometric molar ration could be carried out in a sealed vessel with a water steam, air, or nitrogen atmosphere to afford Hantzsch esters in good to excellent yields and purities. After the simple filtration, the 1,4-dihydropyridines were isolated, and the filtrate could be recycled and reused without significantly decreasing the yields and purities. The novel and clean methodology offers the advantages including short reaction time, good yields, operational simplicity, less leaks, and environmentally benign.     

A facile method for synthesis of polysubstituted naphthalene derivatives through pyrrolidine catalyzed domino reaction

A novel synthetic method for polysubstituted naphthalene derivatives via a pyrrolidine-mediated cascade Michael/Henry reaction was developed, in which easily prepared 2-(2-oxoethyl)benzaldehydes and nitroalkenes were employed as the starting materials. The reaction consists of four consecutive reactions that include a cascade Michael/Henry reaction, a dehydration reaction, and an aromatization reaction in one pot to afford synthetically important naphthalene derivatives with moderate yields.     

One-pot synthesis of quinoline-4-carboxylic acid derivatives in water: Ytterbium perfluorooctanoate catalyzed Doebner reaction

Ytterbium perfluorooctanoate [Yb(PFO)₃] has been proved to be an efficient catalyst for Doebner reaction of pyruvic acid, aldehydes and amines under mild conditions in water to afford quinoline-4-caboxylic acid derivatives with three component one-pot method in good yields. The process is operationally simple and environmentally benign and the catalyst has readily been recycled for several times with consistent activity. Furthermore, a plausible mechanism for this transformation is also presented.     

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.     

Efficient and green synthesis of 4H-pyrans and 4H-pyrano[2,3-c] pyrazoles catalyzed by task-specific ionic liquid [bmim]OH under solvent-free conditions

Abstract

A facile and convenient procedure for the synthesis of 4H-pyrans from aldehydes, malononitrile, and ethyl acetoacetate/acetylacetone and also synthesis of 4H-pyrano[2,3-c]pyrazoles from three-component condensation of aldehydes, malononitrile, and pyrazolone or four-component condensation of aldehydes, malononitrile, ethyl acetoacetate, and hydrazine monohydrate using [bmim]OH as task-specific ionic liquid has been described. The protocol proves to be efficient and environmentally benign in terms of high yields, low reaction times, ease of recovery, and reusability of reaction medium.

     

Rapid and efficient one-pot synthesis of 1,4-dihydropyridine and polyhydroquinoline derivatives through the Hantzsch four component condensation by zinc oxide

A one-pot four-component reaction of aldehydes, ethyl acetoacetate/5,5-dimethyl-1,3-cyclohexanedione, ethyl acetoacetate and ammonium acetate in the presence of 10 mol% of ZnO as a heterogeneous catalyst for the synthesis of corresponding 1,4- dihydropyridine and polyhydroquinoline derivatives via the Hantzsch condensation is described. The present methodology offers several advantages such as simple procedure, excellent yields, and short reaction time.     

Nano-Fe3O4@silica sulfuric acid as a reusable and magnetically separable potent solid acid catalyst in Biginelli-type reaction for the one-pot multicomponent synthesis of fused dihydropyrimidine derivatives: A greener NOSE and SFRC approach

An efficient, highly product selective, eco-friendly, one-pot multicomponent synthesis of dihydropyrimidine derivatives via Biginelli reaction has been described. The reaction was developed by greener nanoparticle-catalyzed organic synthesis enhancement (NOSE) chemistry and solvent free reaction condition (SFRC) approaches, which helped us in making the procedure greener. The reaction went smoothly with a diverse range of aromatic, aliphatic, hetero-aromatic aldehydes, different amine sources, as well as various β-dicarbonyl compounds, showing the flexibility of this methodology. Magnetically separable nano-Fe₃O₄@SiO₂@SO₃H, which acts as a potent solid acid catalyst, was characterized by FT-IR, SEM, EDX and TEM, VSM, and TGA analyses. The catalyst was recycled from the reaction mixture easily by an external magnet and reused in five more consecutive runs without much decrease in catalytic activity. Its catalytic efficiency was compared to other nano and bulk solid acid catalyst in order to ascertain the best combination for the conversion.     

A green and convenient protocol for the synthesis of diarylmethanes via a one-pot,three-component reaction catalyzed by a novel silica tungstic acid (STA) under solvent-free conditions

A cost-effective and eco-friendly synthesis of diarylmethanes derivatives has been developed through the Mannich type Friedel–Crafts addition reaction of tertiary aromatic amine formaldehydes with β-naphthol/indole using silica-supported tungstic acid (STA) as a recyclable heterogeneous acid catalyst in solvent-free condition. Here, we proposed two schemes using the same catalyst. The effects of different solvents have been studied and a comparison of silica-supported tungstic acid with different acid catalysts has also been made.     

Synthesis of Some New 1,4‐Dihydropyridine Derivatives through a Facile One‐pot Hantzsch Condensation Catalyzed by Triethylamine

A facile and efficient synthesis of new 1,4‐dihydropyridine derivatives was reported via Hantzsch three‐component condensation reaction of aldehydes or formylphenylboronic acids, ethyl acetoacetate, and ammonium acetate in the presence of a catalytic amount of triethylamine under solvent‐free conditions. The method described here offers several advantages including high yields, short reaction times, and simple work‐up procedure.     

Regioselective synthesis of 3,4,6,7-tetrahydro-3,3-dimethyl-9-phenyl-2H-xanthene-1,8(5H,9H)-diones through ascorbic acid catalyzed three-component domino reaction

An efficient, three-component domino reaction of dimedone 1, aromatic aldehydes (2a–o), and 1,3-cyclohexanedione 1a in the regio-selective synthesis of 3,3-dimethyl-9-phenyl-2H-xanthene-1,8(5H,9H)-diones (3a–o) is reported. The desired product, 3 is efficiently promoted by ascorbic acid as an organo catalyst.     

Silica supported perchloric acid (HClO4-SiO2): a green,reusable, and highly efficient heterogeneous catalyst for the synthesis of thioethers under solvent-free conditions at room temperature

Abstract

A highly efficient and clean procedure is described for the synthesis of thioethers with excellent yields under solvent-free conditions at room temperature using a catalytic amount of HClO₄-SiO₂. The catalyst is easily prepared, stable, and reusable without much loss of catalytic activity, and is efficient under the reaction conditions.