溴化镁催化的1,2,3,4-四氢吡啶酮无溶剂合成研究

An efficient and environmentally friendly procedure for the one-pot synthesis of tetrahydropyrimidinones from aldehydes, β-diketones and urea/thiourea by using magnesium bromide as an inexpensive and easily available catalyst under solvent-free conditions was described. Compared with the classical Biginelli reaction conditions, this new method has the advantage of good to excellent yields (74%-94%) and short reaction time (45-90 min). The structure of the Biginelli reaction product from β-diketone, salicylaldehyde and urea has been proposed to possess an oxygen-bridge by cyclization (intramolecular Michael-addition).     

Green Biginelli‐type Reaction: Solvent‐free Synthesis of 5‐unsubstituted 3,4‐dihydropyrimdin‐2(1H)‐ones

The Biginelli‐type compounds, 5‐unsubstituted 3,4‐dihydropyrimdin‐2(1H)‐ones were synthesized by a one‐pot three‐component condensation of aromatic aldehydes, aromatic ketones and urea in the presence of SnCl₄ · 5H₂O under solvent‐free conditions. The advantages of this method are short reaction time (4–10 min), excellent yields (74–97%), inexpensive catalyst and solvent‐free conditions. A plausible mechanism was proposed.     

One‐pot solvent‐free synthesis of novel functionalized ethyl 2‐(alkylimino)‐4‐methyl‐3‐(alkanoyl)‐2,3‐dihydrothiazole‐5‐carboxylates

A green and efficient one‐pot two‐step synthesis of ethyl 2‐(alkylimino)‐4‐methyl‐3‐(alkanoyl)‐2,3‐dihydrothiazole‐5‐carboxylates from the reaction between acyl chlorides, ammonium thiocyanate, primary alkylamines, and ethyl 2‐chloroacetoacetae under mild, solvent‐ and catalyst‐free conditions at room temperature is presented. This efficient and straightforward technique gave the expected products in good to high yields in 2–4 hr without the creation of any by‐product in all reactions.     

One‐Pot,Three‐Component Condensation of Aldehydes, 2‐Naphthol and 1,3‐Dicarbonyl Compounds

A practical and efficient procedure for the one‐pot multicomponent couping of aryl aldehydes, 2‐naphthol and cyclic 1,3‐dicarbonyl compounds using perchloric acid adsorbed on silica gel (HClO₄‐SiO₂) as a highly efficient, inexpensive, convenient, reusable heterogeneous catalyst under solvent‐free conditions has been developed. Various biologically important 12‐aryl‐8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐one derivatives have been efficiently synthesized in high to excellent yields. The present approach offers several advantages such as shorter reaction times, simple work‐up, excellent yields, low cost, and mild reaction conditions. Furthermore, the catalyst can be recovered simply and reused without appreciable loss of its catalytic activity.     

One‐Pot Four‐Component Synthesis of Thieno[2,3‐d]pyrimidin‐4‐amines via Sequential Gewald/Cyclocondensation Reactions

A one‐pot four‐component synthesis of thieno[2,3‐d]pyrimidin‐4‐amines via sequential Gewald/cyclocondensation reactions is described. 2‐Aminothiophene‐3‐carbonitriles obtained from the Gewald reaction between cyclic ketones, malononitrile, and sulfur underwent a condensation? cyclization reaction with benzonitriles under solvent‐free conditions to afford the title compounds in excellent yields.     

Ligand‐ and solvent‐free synthesis of 2‐aminobenzothiazoles by copper‐catalyzed tandem reaction of 2‐haloanilines with isothiocyanates

We report an environmentally friendly, efficient and practical method for the synthesis of 2‐aminobenzothiazoles by a copper(II)‐catalyzed tandem reaction of 2‐haloanilines with isothiocyanates under ligand‐ and solvent‐free conditions in air. The developed methodology conforms to the principles of 'green chemistry' and addresses the shortage of such methods for the synthesis of 2‐aminobenzothiazoles. The reaction is quite general and generates a variety of 2‐aminobenzothiazoles in good to excellent yields. Copyright © 2012 John Wiley & Sons, Ltd.     

In(OTf)3‐Catalyzed Synthesis of Functionalized 1,5‐Benzodiazepines from o‐Phenylenediamine and Alkyl Propiolates under Solvent‐Free Reaction Conditions

A simple, environmental‐friendly, and practical method for the synthesis of benzodiazepine derivatives through a reaction of substituted o‐phenylenediamines with alkyl propiolates has been developed. The reactions generated the 1,5‐benzodiazepines in good to excellent yields in the presence of catalytic amount of In(OTf)₃ under solvent‐free reaction conditions.     

An efficient synthesis of 3‐triazolyl‐2(1H)‐quinolones by CuTC‐catalyzed azide–alkyne cycloaddition reaction

A facile and efficient Cu(I)‐catalyzed azide–alkyne cycloaddition reaction for the synthesis of a series of 3‐triazolyl‐2(1H)‐quinolones 3 have been developed using 3‐azido‐quinolin‐2(1H)‐one as the coupling partner. The optimized reaction conditions involve the use of eco‐ friendly ethanol as the solvent in the presence of copper(I) thiophene‐2‐carboxylate as the catalyst, to afford good to excellent yields of 3‐triazolyl‐2(1H)‐quinolone derivatives of biological interest. Copyright © 2013 John Wiley & Sons, Ltd.     

Facile one‐pot synthesis of a series of 7‐aryl‐8H‐benzo[h]indeno[1,2‐b]quinoline‐8‐one derivatives catalyzed by cellulose‐based magnetic nanocomposite

A sulfonated magnetic cellulose‐based nanocomposite was applied as an efficient, inexpensive and green catalyst for the one‐pot three‐component synthesis of 7‐aryl‐8H ‐benzo[h ]indeno[1,2‐b ]quinoline‐8‐ones starting from 1,3‐indanedione, aromatic aldehydes and 1‐naphthylamine under solvent‐free conditions in high yields (79–98%) within short reaction times (2–5 min). The nanobiostructure catalyst can be easily separated from the reaction mixture by using an external magnet and reused several times.     

Gallium(III) Iodide‐catalyzed Biginelli‐type Reaction Under Solvent‐free Conditions: Efficient Synthesis of Dihydropyrimidine‐2(1H)‐one Derivatives

The Biginelli‐type condensation of ethyl acetoacetate/cycloketone, aldehyde and urea/thiourea under solvent‐free condition catalyzed by 10% gallium(III) iodide to form dihydropyrimidine‐2(1H)‐one derivatives was described. This process offered one way to constructing dihydropyrimidine‐2(1H)‐ones in good to excellent yields with simple procedure and short reaction time.     

A New and Efficient Procedure for Synthesis of 1,5‐Benzodiazepine Derivatives in Solution and under Solvent‐Free Conditions

Borax/phosphorous oxychloride (BPO) efficiently catalyzes the preparation of 1,5‐benzodiazepine derivatives of o‐phenylenediamines and ketones in solvent‐free and solution conditions. The reaction proceeds efficiently under ambient conditions giving excellent yields of the products. This new protocol allows the recycling of catalyst with no loss in its potency.     

Me3SiCl and Et3SiI‐promoted one‐pot synthesis of 1,4‐dihydropyridine derivatives

An efficient synthesis of 1,4‐dihydropyridine derivatives has been achieved by the one‐pot cyclocondensation reaction of methyl 3‐aminocrotonate and a range of aldehydes in the presence of chlorotrimethylsilane as a promoter under solvent‐free conditions. The cyclocondenstion reaction requires a very short time and takes place in good to excellent yields. Furthermore iodotriethylsilane, generated in situ by the reaction of triethylsilane and methyl iodide in the presence of palladium chloride, has been investigated for the synthesis of 1,4‐dihydropyridine derivatives. This facile and efficient method affords high yields for the preparation of 1,4‐dihydropyridines at room temperature and short reaction times. Copyright © 2009 John Wiley & Sons, Ltd.     

Cobalt manganese oxide nanoparticles as recyclable catalyst for efficient synthesis of 2‐aryl‐1‐arylmethyl‐1H‐1,3‐benzimidazoles under solvent‐free conditions

Cobalt manganese oxide nanocatalyst was synthesized and it was found that it is a highly efficient green catalyst for the synthesis of 2‐aryl‐1‐arylmethyl‐1H‐1,3‐benzimidazoles under solvent‐free conditions. The marked advantages of this method are the simple experimental procedures, shorter reaction times, high yields of product, reusable and non‐toxic catalyst and solvent‐free conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

Selective Synthesis of 2‐Aryl‐1‐benzylated‐1H‐benzimidazoles

An efficient and simple procedure was developed for the green synthesis of various 2‐aryl‐1‐ben‐zylated‐1H‐benzimidazoles in high yields by condensation of o‐phenylenediamine with aldehydes with P₂O₅/SiO₂ as catalyst under solvent‐free and ambient conditions.     

Alumina Supported 12‐Tungstophosphoric Acid as an Efficient and Reusable Catalyst for Synthesis of 1,5‐Benzodiazepines

Alumina supported 12‐tungstophosphoric acid catalyzes efficiently the reaction of o‐phenylenediamine with ketones under solvent‐free condition to afford the corresponding 1,5‐benzodiazepines in good to excellent yields. The catalyst can be recovered and reused.     

TiO2 as a Reusable Catalyst for the One‐Pot Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones under Solvent‐Free Conditions

An efficient solvent‐free method for the synthesis of various 3,4‐dihydropyrimidin‐2(1H)‐ones using TiO₂ as a recyclable heterogeneous catalyst is described. Compared to known methods, satisfactory results are obtained with excellent yields, short reaction times, and simplicity in the experimental procedure.     

Preparation and Application of Perchloric Acid Supported on Alumina (Al2O3-HClO4) to the Synthesis of α-(α-Amidobenzyl)-β-naphthols

Preparation of perchloric acid supported on alumina and its primary application as a solid supported heterogeneous catalyst to the synthesis of α-(α-amidobenzyl)-β-naphthols by a one-pot, three-component condensation of benzaldehydes, β-naphthol and acetamide or benzamide under thermal solvent-free conditions were described. The present methodology offers several advantages such as simple procedure, shorter reaction time, and excellent yields.     

L-Proline Catalyzed Enamination of β-Dicarbonyl Compounds under Solvent-free Conditions

A simple, general and efficient method has been developed for synthesis of various β-enamino ketones and esters by reacting β-dicarbonyl compounds with amines using a catalytic amount of L-proline at room temperature under solvent-free conditions in excellent yields.     

Magnetic Nanoparticle Supported Ionic Liquid Assisted Green Synthesis of Pyrazolopyranopyrimidines and 1,6‐diamino‐2‐oxo‐1,2,3,4‐tetrahydropyridine‐3,5‐ dicarbonitriles

A simple and eco‐friendly green protocol was used for synthesis of pyrazolopyranopyrimidines via four‐component reaction of hydrazine hydrate, ethyl acetoacetate, barbituric acid or dimethyl barbituric acid, and aromatic aldehydes under thermal and solvent‐free conditions in the presence of magnetic nanoparticle supported silica bonded n‐propyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane chloride (MNPs@DABCO⁺Cl^?) as an efficient, recyclable heterogeneous catalyst. MNPs@DABCO⁺Cl^? also catalyzed the synthesis of 1,6‐diamino‐2‐oxo‐1,2,3,4‐tetrahydropyridine‐3,5‐dicarbonitrile derivatives by four‐component reaction of hydrazine hydrate, malononitrile, ethyl cyanoacetate and ketones under thermal and solvent‐free conditions at 80 °C. These methods are practical and offer many advantages, such as high yields, short reaction times, and simple work‐up.     

无溶剂条件下利用微波促进下的多组分反应对2,6-二芳基-4-苯乙烯基吡啶化合物进行非预期的绿色简易合成

在无溶剂条件下,通过微波促进下的3-芳基丙烯醛肟、1-芳基乙酮及醋酸铵的多组分反应,非预期地实现了2,6-二芳基-4-苯乙烯基吡啶化合物的绿色简易合成。该方法具有环境友好、反应时间短、产率高、成本低、操作简便以及适用范围广等优点。