Succinimide-N-sulfonic acid: An efficient catalyst for the synthesis of xanthene derivatives under solvent-free conditions

A mild, simple and convenient procedure for the synthesis of xanthene derivatives is described via three component condensation of aldehydes with 2-naphthol, 1,3-cyclohexanedione and/or a mixture of 2-naphthol and 1,3-cyclohexanediones using succinimide-N-sulfonic acid as an efficient, cheap and readily synthesis catalyst under solvent-free conditions. The structures of the products were characterized by their physical constants, comparison with authentic samples and IR, ¹H NMR and ¹³C NMR spectroscopy. The present methodology offers several advantages such as high yields, simple procedure, low cost, short reaction times, solvent-free and mild reaction conditions and use of a reusable catalyst.     

Efficient synthesis of N-substituted-N'-arylcarbonylthioureas under solvent-free conditions

A convenient method for the synthesis of N-substituted-N'-arylcarbonylthioureas under solvent-free conditions has been developed. Ammonium thiocyanate and acid chlorides were mixed, and stirred at room temperature without a solvent, to give the corresponding isothiocyanates, which reacted smoothly with arylamines to produce the aryl(alkyl)carbonylthioureas in good yields. Unusually large values of ⁵ J _FH=12.2–15.1 Hz are observed for 1-(2-fluorobenzoyl)-thiourea derivatives, which provide information about the Ar-C-N-H torsions in these compounds.     

Mannich reaction catalyzed by a novel catalyst under solvent-free conditions

An acidic catalyst [Py][CF₃COO] (pyridinium trifluoroacetate) was synthesized and used in the Mannich reaction of various kinds of aromatic aldehydes, aromatic ketones and aromatic amines. β-Amino carbonyl compounds were obtained in reasonable yields when the Mannich reaction was carried out at room temperature under solvent-free conditions. The products could be separated from the catalyst simply via washing with water and after removing water, the catalyst could be recycled and reused for up to four times without noticeably decreasing in catalytic activity.     

Brönsted acidic ionic liquid as an efficient catalyst for chemoselective synthesis of 1,1-diacetates under solvent-free conditions

We introduce a simple and efficient procedure for preparation of (1-H-3-methyl-imidazolium hydrogen sulfate) as a Brönsted acidic ionic liquid using 1-methylimidazole in the presence of concentrated sulfuric acid. Further, this Brönsted acidic room temperature ionic liquid has been employed as a catalyst for the synthesis of 1,1-diacetates from aldehydes under mild and solvent-free conditions at room temperature.     

Ammonium chloride catalyzed one-pot synthesis of diindolylmethanes under solvent-free conditions

It has been found that ammonium chloride, which is a very inexpensive and readily available reagent, can efficiently catalyzed electrophilic substitution reactions of indoles. Diindolylmethanes were afforded by reaction of indoles with aldehydes and ketones under solvent-free conditions at 90 °C in the presence of ammonium chloride in good to excellent yields.     

Silica sulfuric acid as a mild and chemoselective catalyst for dithioacetalization under solvent-free conditions

Various carbonyl compounds have been protected as dithioacetals in very good yields using silica sulfuric acid as a mild, chemoselective catalyst under solvent-free conditions.     

Mesoporous MCM-41-nPr-NHSO3H as novel and effective nanoreactor catalyst for the synthesis of multi-substituted imidazoles under solvent-free conditions

Journal of Porous Materials - Herein, we report the synthesis and application of mesoporous siliceous MCM-41-nPr-NHSO3H, which was characterized by XRD, IR, TGA and nitrogen physisorption...     

HClO4–SiO2 as a novel and recyclable catalyst for the synthesis of 2,4,6-triarylpyridines under solvent-free conditions

A simple and efficient synthesis of 2,4,6-triarylpyridines using a variety of aromatic and heteroaromatic aldehydes in the presence of solid-supported perchloric acid (HClO₄–SiO₂) as a heterogeneous catalyst at 120 °C under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, shorter reaction times (4–6 h), milder conditions and the catalyst exhibited remarkable reusable activity.     

Montmorillonite K10 catalyzed efficient synthesis of amidoalkyl naphthols under solvent free conditions

An efficient green protocol for the preparation of amidoalkyl naphthols, employing a three-component one-pot condensation reaction of β-naphthol, aromatic aldehyde, amides or urea in the presence of montmorillonite K10 clay under solvent free conditions has been described. The present procedure offers advantages such as shorter reaction time (<2 h), simple workup, excellent yields, recovery and reusability of catalyst.     

Synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones using ZrOCl2/mont K10 under microwave assisted solvent-free conditions

ZrOCl₂·8H₂O supported on montmorillonite K10 (ZrOCl₂/mont K10) catalyzed Biginelli reaction under solvent-free conditions is reported. The catalysts were characterized by XRD, FTIR, BET surface area analysis, and thermogravimetric analysis. The activity of montmorillonite K10, montmorillonite KSF, ZrOCl₂·8H₂O, SO₄ ^2?/ZrO₂, and ZrOCl₂/mont K10s was investigated by Biginelli reaction of benzaldehyde, ethylacetoacetate and urea. The reactions were carried out by addition of ZrOCl₂/mont K10 to a mixture of aldehyde, ethylacetoacetate and urea/thiourea with thorough stirring in the absence of solvent under conventional heating or microwave irradiation to prepare 3,4-dihydropyrimidin-2(1H)-one/thione derivatives at 80?°C in good yields.     

Amidation of alcohols with nitriles under solvent-free conditions using molecular iodine as a catalyst

The reactions of alcohols with nitriles under solvent-free conditions, using molecular iodine as a catalyst, were investigated. The reaction of 1-phenylethanol with propanenitrile produced the amide N-(1-phenylethyl)propanamide, by dehydration and tautomerization, in 71% yield, under the following conditions: temperature=90°C, alcohol:iodine molar ratio=1:0.2, alcohol:nitrile molar ratio=1:5, and reaction time=5 h. The amidation reactivity depended on the stability of the cationic intermediate formed from the alcohol. The reaction of (-)-borneol with benzonitrile produced a racemic amide in 83% yield.     

An efficient synthesis of 2,4,6-triarylpyridines catalyzed by heteropolyacid under solvent-free conditions

Preyssler type heteropolyacid is found to be an efficient catalyst for the synthesis of 2,4,6-triarylpyridines in good yields. The catalyst is recycled and reused several times.     

An efficient synthesis of 2,4,6-triarylpyridines catalyzed by heteropolyacid under solvent-free conditions

Preyssler type heteropolyacid is found to be an efficient catalyst for the synthesis of 2,4,6-triarylpyridines in good yields. The catalyst is recycled and reused several times.     

Ionic liquid catalyzed solvent-free synthesis of chalcone and its derivatives under mild conditions

An ionic liquid(IL) catalyzed solvent-free process was developed for the direct synthesis of chalcone and its derivatives by using substituted acetophenones and benzaldehydes via aldol reaction under mild conditions. A series of acidic and basic ILs were selected and screened. The influences of cations and reaction conditions on product yield and selectivity were systematically investigated. The [Bmim]OH was identified as the optimal IL, with the highest yield and selectivity reaching up to 96.7% and 100%, respectively. A reaction mechanism-based kinetic model was established and regressed with experimental data, revealing the b-Hydroxylketone dehydrolysis with activation barrier of 37.8 k J·mol~(-1) was observed as the ratecontrolling step.     

Wet 2,4,6-trichloro[1,3,5]triazine (TCT) an efficient catalyst for synthesis of -bis(substituted-benzylidene) cycloalkanones under solvent-free conditions

An array of aromatic aldehydes undergo crossed aldol condensation with ketones in the presence of catalytic amounts of wet-TCT under solvent-free conditions to afford the corresponding α,α^′-bis(substituted-benzylidene) cycloalkanones in excellent yields. Contrary to the existing methods, which use classical Lewis acids a new catalyst (TCT) is employed. This method is also general with respect to all types of aromatic aldehydes and is an eco friendly procedure.     

负载型NaOH/蒙脱石固体碱催化剂的制备及在生物柴油中的应用

多相催化生产生物柴油因其环境友好和经济效益突出而成为研究热点.以高纯蒙脱石为原料,用HCl酸化制得活性白土,再用Ca(OH)2改性,制备出具有阴离子交换性的碱性蒙脱石,然后负载NaOH制备蒙脱石固体碱催化剂,并将其用于制备生物柴油的酯交换反应.结果表明,在m(NaOH)∶m(碱性蒙脱石)=0.7、负载时间18 h和碱性...     

Zirconium sulfate supported on activated carbon as catalyst for esterification of oleic acid by n-butanol under solvent-free conditions

It has been shown that the activated carbon-supported zirconium sulfate (ZS) is an efficient solid catalyst for the esterification of oleic acid by n-butanol under solvent-free condition. The effect of mole ratio of the reactant, time and catalyst loading on the conversion was examined. The correlation among XRD, nitrogen adsorption data and catalytic activity suggested that ZS has been finely dispersed on activated carbon, which are active in the esterification of oleic acid. The reaction shows that the supported ZS exhibits a higher activity than that of parent ZS and conventional resins.     

Copper(II) tetrafluoroborate as a mild and efficient catalyst for the one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions

A simple, mild and efficient procedure for the synthesis of dihydropyrimidinones using copper(II) tetrafluoroborate as a new catalyst is described under solvent-free conditions in shorter reaction times at room temperature.     

A facile and efficient synthesis of aryl toluenesulfonhydrazides and aryl toluenesulfonates under solvent-free conditions

A rapid, efficient method is described for synthesis of aryl toluenesulfonhydrazides from toluene-sulfonyl chloride and substituted phenylhydrazines and for the synthesis of aryl toluenesulfonates from toluenesulfonyl chloride and substituted phenols. The procedure is simple, environmentally benign and occurs in good yields.     

LiOH-modified montmorillonite K-10 as catalyst for selective glycerol etherification to diglycerol

Acid treated montmorillonite K-10 (MK-10) was intercalated with LiOH (Li/MK-10) to catalyze selective production of diglycerol via solvent free glycerol etherification reaction. The structure, surface properties and basic strength of parent and modified clay were successfully characterized using XRD, SEM, ICP, BET surface analyzer and Hammett indicators to elucidate their physical and chemical properties. The glycerol etherification reaction was conducted at 240 °C with 2 wt.% lithium intercalated catalyst under inert atmosphere. High diglycerol selectivity of about 53% was obtained in 12 h with this catalyst at a glycerol conversion of about 98%.