Revisit to the Biginelli reaction: a novel and recyclable bioglycerol-based sulfonic acid functionalized carbon catalyst for one-pot synthesis of substituted 3,4-dihydropyrimidin-2-(1H)-ones

A simple and efficient synthetic protocol has been developed for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones by using a novel bioglycerol-based sulfonic acid functionalized carbon catalyst, devoid of moisture sensitive metal catalysts and corrosive acidic reagents. The developed method has the advantages of good to excellent yields, short reaction times, operational simplicity, and a recyclable catalyst. The catalyst can be prepared by a simple procedure from inexpensive and readily available glycerol and has been shown to be recoverable and reusable up to four cycles without any loss of activity.     

Silica gel supported AlCl3 catalyzed Friedel-Crafts acylation of aromatic compounds

<正>Silica gel supported aluminium trichloride(SiO_2-AlCl_3) has been shown to be a mild,efficient,and chemoseiective heterogeneous Lewis acid catalyst for the acylation of aromatic compounds with acid chlorides.The catalyst can be reused up to five times after simple washing with ether and is stable(as a bench top catalyst).     

Sulfonated Porous Carbon (SPC)-Catalyzed Synthesis of Benzothiazole Derivatives in Water

Abstract

A simple and efficient procedure has been developed for the synthesis of benzothiazole derivatives in water by the condensation of 2-aminothiophenol with aldehydes in the presence of Sulfonated porous carbon (SPC). This method provides a simple and efficient protocol in terms of mild reaction conditions, clean reaction profiles, small quantity of catalyst, and simple workup procedure.     

Silica supported perchloric acid （HClO4-SiO2）： A mild,reusable and highly efficient heterogeneous catalyst for the synthesis of amidoalkyl naphthols

An efficient and direct procedure has been developed for the preparation of amidoalkyl naphthols by a one-pot condensation of aryl aldehydes, 2-naphthol and urea or amides, in the presence of HClO4-SiO2 as a heterogeneous catalyst. The reactions were carried out under reflux and solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, easy work-up and ecofriendly reaction condition. The catalyst is easily prepared, stable, reusable and efficient under the reaction conditions.     

Bioglycerol-Based Sulfonic Acid-Functionalized Carbon Catalyst as an Efficient and Reusable Catalyst for One-Pot Synthesis of 3- Substituted-2H-1,4-Benzothiazines

Abstract

A simple and efficient synthetic protocol has been developed for the synthesis of 3-substituted-2H-1,4-benzothiazines by using bioglycerol-based sulfonic acid-functionalized carbon catalyst, devoid of corrosive acidic and basic reagents. The developed method has the advantages of good to excellent yields, short reaction times, operational simplicity, and a recyclable catalyst.     

An efficient and economical synthesis of 5-substituted 1H-tetrazoles via Pb(II) salt catalyzed [3+2] cycloaddition of nitriles and sodium azide

A simple, mild and efficient method is developed for the synthesis of 5-substituted 1H-tetrazoles. Out of three used Pb(II) catalysts, lead chloride (PbCl₂) has been found to be an efficient catalyst for [3+2] cycloaddition of NaN₃ with aromatic and aliphatic nitriles to afford 5-substituted 1H-tetrazoles. The catalyst is reusable up to four cycles with consistent activity. The cost effectiveness and easy availability of the catalyst, simple methodology, excellent yield and easy work-up are the additional advantages.     

Nano ceria catalyzed synthesis of α-aminophosphonates under ultrasonication

A simple, efficient and general method has been developed for the one-pot three component syntheses of α-aminophosphonates. The condensation of aldehyde, amine and triethyl phosphite by employing CeO₂ nanoparticles as catalyst gave α-aminophosphonates. The catalyst showed good recyclability. Nano CeO₂ has been found to be an excellent catalyst for the green synthesis of α-aminophosphonates under ultrasound irradiation and solvent-free condition. The α-aminophosphonates are obtained in good to excellent yield. This catalyst provides cleaner conversion, short reaction time and high selectivity which makes the protocol feasible and economical attractive.     

Simple route to indeno[1, 2-b]quinoline derivatives via a coupling reaction catalyzed by TiO2 nanoparticles

A simple,efficient and high yielding approach for the synthesis of indeno[1,2-b]quinolinediones has been developed by a one-pot,four-component,coupling reaction utilizing TiO₂ nanoparticles（TiO₂-NPs） as a heterogeneous catalyst at 80℃in aqueous media.     

Silica supported sodium hydrogen sulfate(NaHSO4/SiO2): A mild and efficient reusable catalyst for the synthesis of aryl-14-H-dibenzo[a,j]xanthenes under solvent-free conditions

A simple and efficient procedure for the preparation of aryl-14-H-dibenzo[a,j]xanthenes by a one-pot condensation reaction of 2-naphthol and aryl aldehydes,in the presence of silica supported sodium hydrogen sulfate(NaHSO_4/SiO_2)as a catalyst and in the absence of solvent has been developed.The present method offers several advantages such as excellent yields,short reaction time (10-30 min),mild condition,simple work-up,and the use of a cheap and environmentally friendly catalyst with remarkable reusability.     

Hydroxyapatite-supported palladium-catalyzed efficient synthesis of (E)-2-alkene-4-ynecarboxylic esters. Intense fluorescence emission of selected compounds

A simple procedure for the synthesis of substituted (E)-2-alkene-4-ynecarboxylic esters has been achieved using hydroxyapatite-supported palladium as efficient catalyst surface. The catalyst is recycled, and the turnover number (TON) based on Pd is 16000. A naphthyl-substituted derivative gives very intense fluorescence emission.     

Enantioselective Pd-catalyzed hydrogenation of fluorinated imines: facile access to chiral fluorinated amines

An enantioselective hydrogenation of simple fluorinated imines has been developed using Pd(OCOCF(3))(2)/(R)-Cl-MeO-BIPHEP as a catalyst, and up to 94% ee was achieved. This method provides an efficient route to enantioenriched fluorinated amines.     

Silica Phosphoric Acid (SPA) as a Highly Active,Reusable, Heterogeneous Catalyst for the Synthesis of 2-Amino/Anilino-5-ARYL-1,3,4-Thiadiazine Bromide Derivatives

Silica phosphoric acid has been found to be an efficient catalyst for the synthesis of 2-amino/anilino-5-aryl-1,3,4-thiadiazine bromide derivatives from the reaction of thiosemicarbazide and α-bromoketones in acetonitrile at room temperature. The catalyst can be reused for four times without any significant loss of catalytic activity. The experimental procedure is simple, and the products are obtained in high yield.     

Copper Schiff base functionalized polyaniline (Cu‐SB/PANI): A highly efficient polymer based organometallic catalyst for the synthesis of 2‐amino chromene derivatives

Copper Schiff Base functionalized Polyaniline (Cu‐SB/PANI) has been synthesized as an efficient, recyclable and heterogeneous polymer based organometallic catalyst by simple method. The catalyst has been well characterized with different spectroscopic techniques such as FTIR, SEM/EDX, elemental mapping, XRD, TEM, TG, XPS, EPR and ICP‐AES analyses. The catalytic potential of the catalyst has been explored by synthesizing 2‐amino chromene derivatives. The catalyst efficiently catalyzed the reaction affording excellent yield of the products (95–97%) in very short reaction time period (6–8 min). The catalyst could be reused for five times with insignificant loss in catalytic activity.     

Iodine as a catalyst for efficient conversion of ketones to gem-dihydroperoxides by aqueous hydrogen peroxide

Iodine has been shown to be an efficient catalyst for the selective dihydroperoxidation of ketones with aqueous hydrogen peroxide. Ketones were directly converted to their corresponding gem-dihydroperoxides using a "green" oxidant (30% aq H(2)O(2)) and a simple catalyst (iodine) under neutral conditions in acetonitrile. The yield of hydroperoxidation of various cyclic ketones was 60-98% including androstane-3,17-dione, and acyclic ketones were converted with a similar efficiency. [reaction: see text]     

Facile,efficient synthesis of polyfunctionalized 2-aminoimidazoles via vinyl azides and cyanamide

A simple and direct synthesis of 2-aminoimidazoles from vinyl azides and cyanamide was developed. An attractive feature of this protocol is that the desired products are generated in a highly efficient and eco-friendly manner without the use of a catalyst. A plausible mechanism has been proposed.     

Solvent-Free NaHSO4-SiO2-Catalyzed Efficient Tetrahydropyranylation of Alcohols and Phenols

A simple and efficient tetrahydropyranylation of alcohols and phenols has been developed using NaHSO₄-SiO₂ (0.5 mol%) as a catalyst under solvent-free conditions to yield corresponding tetrahydropyranyl ethers in excellent yields.     

Convenient and Efficient One-Pot Method for the Synthesis of 2-Amino-tetrahydro-4H-chromenes and 2-Amino-4H-benzo[h]-chromenes Using Catalytic Amount of Amino-Functionalized MCM-41 in Aqueous Media

A convenient and efficient one-pot method for the synthesis of 2-amino-tetrahydro-4H-chromene and 2-amino-4H-benzo[h]-chromene derivatives has been developed using a catalytic amount of amino-functionalized MCM-41 in aqueous medium. This efficient technique has the advantages of giving 4H-tetrahydro-chromene and 4H-benzo[h]chromene building blocks using a reusable catalyst in good to excellent yields, to be completed in short reaction times with a simple product isolation procedure.     

Reductive carbonylation of aryl and heteroaryl iodides using Pd(acac)2/dppm as an efficient catalyst

Palladium catalyzed simple and efficient protocol for reductive carbonylation of aryl and heteroaryl compounds has been developed. The formylation of aryl and heteroaryl iodides takes place in the presence of Pd(acac)₂/dppm catalyst at 10 bar pressure of synthetic gas to give the desired aromatic and heteroaromatic aldehydes in good to excellent yields. Easy work-up, stability of the catalyst, low catalyst loading and less reaction time are the advantages of this method.     

Room‐Temperature Suzuki‐Miyaura Reaction Catalyzed by Palladium Nanoparticles in Lactate‐Anion Ionic Liquid

A palladium nanoparticle catalyst (PdNPs@[Bmim]Lac) has been prepared by a simple, mild and efficient chemical approach using 1‐butyl‐3‐methylimidazolium lactate ([Bmim]Lac) ionic liquid) as a stabilizer. This catalyst exhibits excellent activity, stability, recyclability and simple manipulation in Suzuki‐Miyaura reactions at room temperature in air.     

Al(HSO4)3: an efficient and heterogeneous reusable catalyst for the synthesis of 1-amidoalkyl-2-naphthols under thermal solvent-free conditions

An efficient green protocol for the synthesis of 1-amidoalkyl-2-naphthols using a three-component, one-pot condensation reaction of 2-naphthol, aromatic aldehyde and amides in the presence of Al(HSO₄)₃ as heterogeneous catalyst under thermal solvent-free conditions has been described. The present procedure offers advantages such as shorter reaction times, simple work-up procedure, excellent yields, recovery and reusability of catalyst.