无溶剂条件下碳基固体酸催化一锅法合成酰胺烷基萘酚(英文)

An efficient, environmentally friendly procedure for the synthesis of amidoalkyl naphthols through the one‐pot, three‐component reaction of β‐naphthol, aryl aldehydes, and acetamide in the presence of a carbon‐based solid acid under thermal solvent‐free conditions is described. The beneficial fea-tures of this new synthetic approach include short reaction time, high yields, clean reaction profiles, and a simple work‐up procedure. Furthermore, the catalyst can be readily recycled and reused four times without obvious significant loss of activity. The structure of the catalyst was confirmed by Fourier transform infrared spectroscopy, N2 adsorption/desorption analysis, and X‐ray diffraction.     

以聚(4-乙烯基吡啶)硫酸氢盐为催化剂三组分一锅法合成苯并[f]茚并喹啉(英文)

7‐Aryl‐8H‐benzo[f]indeno[2,1‐b]quinoline‐8‐one derivatives were synthesized by means of a one‐pot condensation of 2‐naphthylamine, aromatic aldehydes, and indane‐1,3‐dione in ethanol under refluxing conditions in the presence of poly(4‐vinylpyridinium) hydrogen sulfate, a solid acid catalyst. This method has the advantages of high yield, clean reaction, simple methodology, and short reaction time. The catalyst could be recycled and reused four times without significant loss of activity. The structure of the novel compounds was confirmed by IR, 1H NMR, and 13C NMR spec-troscopy and elemental analysis.     

硅胶键合N-丙基哌嗪n-丙酸钠作为可循环使用催化剂催化4H-吡喃衍生物合成(英文)

Silica‐bonded N‐propylpiperazine sodium n‐propionate(SBPPSP) was found to act as an efficient solid base for the preparation of a series of 4H‐benzo[b]pyran derivatives. SBPPSP was used as a recyclable heterogeneous solid base catalyst for the synthesis of 3,4‐dihydropyrano[c]chromenes, 2‐amino‐4H‐pyrans, 1,4‐dihydropyrano[2,3‐c]pyrazoles, and 2‐amino‐4H‐benzo[e]‐chromenes via the condensation reaction of dimedone, ethyl acetoacetate, 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐ one, and α‐naphthol, respectively, with aromatic aldehydes and malononitrile in refluxing aqueous ethanol. The heterogeneous solid base showed similar efficiency when reused in consecutive reactions.     

聚(4-乙烯基吡啶)硫酸氢盐: 一个新的高效催化剂用于无溶剂条件下合成13-芳香基-茚并 [1,2-b] 石脑油 [1,2-e] 吡喃-12(13H)-酮（英文）

An facile and efficient protocol for the synthesis of 13‐aryl‐indeno[1,2‐b]naphtha[1,2‐e]pyran‐ 12(13H)‐ ones has been developed that proceeds via the one‐pot three‐component sequential reaction of an aromatic aldehyde with β‐naphthol and 2H‐indene‐1,3‐dione under solvent‐free conditions in the presence of a poly(4‐vinylpyridinium)hydrogen sulfate(P(4‐VPH)HSO4) catalyst. The catalyst can be reused several times, making this procedure facile, practical, and sustainable. The simple experimental procedure, solvent‐free reaction conditions, use of an inexpensive catalyst, short react time, and excellent yields are some of the major advantages of this methodology.     

Keplerate巨型纳米多孔聚氧钼酸盐作为可重复使用催化剂用于合成1,2,4,5-四取代咪唑(英文)

The Keplerate‐type giant nanoporous isopolyoxomolybdate (NH4)42[MoVI72MoV60O372‐(CH3COO)30(H2O)72], denoted {Mo132}, has been used as a catalyst for the synthesis of1,2,4,5‐tetrasubstituted imidazoles by the one‐pot, four‐component thermal reaction of benzil with aromatic aldehydes, primary amines, and ammonium acetate under solvent‐free conditions. The catalyst was prepared according to a previously published literature procedure using inexpensive and readily available starting materials, and subsequently characterized by FT‐IR, UV and X‐ray diffraction spectroscopy, as well as microanalysis. The results showed that {Mo132} exhibited high catalytic activity towards the synthesis of 1,2,4,5‐tetrasubstituted imidazoles, with the desired products being formed in good to high yields. Furthermore, the catalyst was recyclable and could be reused at least three times without any discernible loss in its catalytic activity. Overall, this new catalytic method for the synthesis of 1,2,4,5‐tetrasubstituted imidazoles provides rapid access to the desired compounds following a simple work‐up procedure, and avoids the use of harmful organic solvents. This method therefore represents a significant improvement over the methods currently available for the synthesis of tetrasubstituted imidazoles.     

Keplerate巨型纳米多孔聚氧钼酸盐作为可重复使用催化剂用于合成1,2,4,5-四取代咪唑(英文)

The Keplerate‐type giant nanoporous isopolyoxomolybdate (NH4)42[MoVI72MoV60O372‐(CH3COO)30(H2O)72], denoted {Mo132}, has been used as a catalyst for the synthesis of1,2,4,5‐tetrasubstituted imidazoles by the one‐pot, four‐component thermal reaction of benzil with aromatic aldehydes, primary amines, and ammonium acetate under solvent‐free conditions. The catalyst was prepared according to a previously published literature procedure using inexpensive and readily available starting materials, and subsequently characterized by FT‐IR, UV and X‐ray diffraction spectroscopy, as well as microanalysis. The results showed that {Mo132} exhibited high catalytic activity towards the synthesis of 1,2,4,5‐tetrasubstituted imidazoles, with the desired products being formed in good to high yields. Furthermore, the catalyst was recyclable and could be reused at least three times without any discernible loss in its catalytic activity. Overall, this new catalytic method for the synthesis of 1,2,4,5‐tetrasubstituted imidazoles provides rapid access to the desired compounds following a simple work‐up procedure, and avoids the use of harmful organic solvents. This method therefore represents a significant improvement over the methods currently available for the synthesis of tetrasubstituted imidazoles.     

Cu(II)salen配合物催化三组分偶联反应合成炔丙胺(英文)

A one pot three‐component coupling reaction of phenylacetylene, aldehyde, and amine derivatives in the presence of Cu(II) Salen complex as an efficient heterogeneous catalyst under solvent‐free conditions is reported. The catalyst displayed high activity and afforded the corresponding propargylamines in good to excellent yields. This method provides a wide range of substrate applicability. The catalyst was reused several times without significant loss of its catalytic activity.     

三(羟甲基)氨基甲烷改性SiO_2固载钯纳米粒子:合成、表征及其催化Heck偶联反应活性（英文）

The preparation of supported Pd nanoparticles on Tris(tris(hydroxymethyl)aminomethane)‐ modi‐fied Si O2 gel and their catalytic application in Heck coupling are investigated. The catalyst was char‐acterized using a combination of X‐ray diffraction, transmission electron microscopy, field‐emission scanning electron microscopy, and scanning electron microscopy/energy‐dispersive X‐ray spec‐troscopy. The supported Pd nanoparticles were found to be a highly active and reusable catalyst for the Heck reaction at a low Pd loading(0.02 mol%) because of stabilization by the Tris moieties. Several reaction parameters, including the type and amount of solvent, base, and temperature, were evaluated. The heterogeneity of the catalytic system was investigated using different approaches, and showed that slight Pd leaching into the reaction solution occurred under the reaction condi‐tions. Despite this metal leaching, the catalyst can be reused seven times without significant loss of its activity.     

MgO纳米晶负载镍催化剂用于甲烷蒸汽重整反应(英文)

Nanocrystalline MgO with a relatively high surface area and mesoporous structure was synthesized by a surfactant assisted precipitation method for use as the support of nickel catalysts for steam reforming of methane. The samples were characterized by X‐ray diffraction, N2 adsorption, temperature‐programmed reduction, temperature‐programmed oxidation, scanning electron microscopy, and transmission electron microscopy. The catalysts showed high catalytic activity and good stability in the steam reforming of methane. Increasing the nickel loading up to 10 wt% gave increased activity. Catalysts with higher nickel loadings showed more deposited carbon after reaction. The excellent anti‐coking performance of the catalysts was attributed to the formation of a nickel‐magnesia solid solution, basicity of the support surface, and nickel‐support interaction.     

以对二甲苯氧化为对苯二甲酸为例简要综述一级C–H键活化(英文)

The oxidation of para‐xylene to terephthalic acid has been commercialised as the AMOCO process(Co/Mn/Br) that uses a homogeneous catalyst of cobalt and manganese together with a corrosive bromide compound as a promoter. This process is conducted in acidic medium at a high tempera‐ture(175–225 °C). Concerns over environmental and safety issues have driven studies to find mild‐er oxidation reactions of para‐xylene. This review discussed past and current progress in the oxida‐tion of para‐xylene process. The discussion concentrates on the approach of green chemistry in‐cluding(1) using heterogeneous catalysts with promising high selectivity and mild reaction condi‐tion,(2) application of carbon dioxide as a co‐oxidant, and(3) application of alternative promoters. The optimisation of para‐xylene oxidation was also outlined.     

Irreversible cleavage of a carbene-rhodium bond in Rh-N-heterocyclic carbene complexes: implications for catalysis

Despite the generally accepted belief that carbene-metal bonds are strong and do not dissociate, the reaction of Rh-N-heterocyclic carbene complexes with triphenylphosphine in dichloroethane was determined to take place via cleavage of the Rh-carbene bond. The products of this reaction are Wilkinson’s catalyst and a bisimidazolium salt derived from reaction between dichloroethane and two equivalents of the carbene. The implications of this reaction for catalysis are significant since the carbene complex shows lower activity than Wilkinson’s catalyst in hydrogenation reactions. In non-halogenated solvents, the catalyst shows higher stability, such that the rate of exchange with free phosphine could be measured, and was determined to be ca. 10 times slower than in Wilkinson’s catalyst.     

Room temperature ionic liquid promoted synthesis of 1,5-benzodiazepine derivatives under ambient conditions

The reaction of o-phenylenediamines with both acyclic and cyclic ketones in the ionic liquid 1,3-di-n-butylimidazolium bromide afforded 1,5-benzodiazepines in excellent isolated yields in the absence of a catalyst at ambient temperature.     

Iron fluoride: the most efficient catalyst for one-pot synthesis of 4H-pyrimido[2,1-b]benzothiazoles under solvent-free conditions

A new iron fluoride assisted convenient and efficient strategy for the preparation of 4H-pyrimido[2,1-b]benzothiazoles derivatives in solvent-free media is described. The reactions can be performed at low-catalyst loadings with excellent functional group tolerance. The catalyst can be readily recovered and reused for next reaction for at least three runs without any significant impact on the yields of the products. The easy recovery of the catalyst and high yield of the products make the protocol attractive, sustainable, and economic.     

聚(4-乙烯基吡啶丁烷磺酸)硫酸氢盐:一个高效的多相聚(离子液体)固体酸催化剂用于无溶剂条件下一锅法合成1-酰氨基-2-萘酚和取代喹啉(英文)

Poly(4-vinylpyridinium butane sulfonic acid) hydrogen sulfate has been used as an efficient dual acidic catalyst for the one-pot preparation of 1-amidoalkyl-2-naphthols and substituted quinolines under solvent-free conditions.The catalyst was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermo-gravimetric analysis. The results revealed several advantages to our new catalyst system,including its reusability,facile work-up procedure, eco-friendly reaction conditions,short reaction time,and high product yields.     

Efficient catalysis of Ullmann-type arylation reactions by a novel trinuclear copper(I) complex with a chelating tricarbene ligand

A novel trinuclear copper(I) complex with a chelating tricarbene ligand is shown to be an efficient catalyst for the arylation of different classes of compounds containing N-H or O-H functions. Different kinds of azole rings (pyrazole, imidazole, 1,2,4-triazole) can be arylated with comparable efficiencies at relatively mild temperatures (100 °C). The catalyst activates aryl iodides, bromides and even chlorides for the reaction. An unusually strong influence of the nature of the aryl substituent on the reaction yield is observed. The synthetic protocol can be extended to other substrate classes, such as phenols and amides, although the catalytic efficiency with amides is significantly reduced.     

pTSA-catalyzed condensation of xylenols and aldehydes under solvent-free conditions: One-pot synthesis of 9H-xanthene or bisphenol derivatives

A simple and efficient procedure for the synthesis of 9H-xanthene or bisphenol derivatives has been developed by one-pot condensation of xylenols with aromatic aldehydes in the presence of p-toluenesulfonic acid (pTSA) as a catalyst under solvent-free conditions at 100 °C. It is noteworthy that the condensation reaction of 3,5-xylenol with aldehydes produces 9H-xanthene derivatives, while the reaction with other xylenols leads to the corresponding bisphenol derivatives. Different types of aromatic aldehydes are used in the reaction and in every case the products were obtained in good to excellent yields. The structures of these compounds were established on the basis of IR, ¹H NMR, ¹³C NMR and CHN data.     

Synthesis of 1,2,4,5-tetrasubstituted imidazoles using silica-bonded propylpiperazine N-sulfamic acid as a recyclable solid acid catalyst

A simple and efficient procedure for the preparation of silica-bonded propylpiperazine-N-sulfamic acid (SBPPSA) by the reaction of 3-piperazine-N-propylsilica (3-PNPS) and chlorosulfonic acid in chloroform is described. Silica-bonded propylpiperazine-N-sulfamic acid is employed as a recyclable catalyst for the synthesis of highly substituted imidazoles from the reaction of benzil, aromatic aldehydes, ammonium acetate and amines under solvent-free conditions. The heterogeneous catalyst was recycled for five runs upon the reaction of benzil, 4-methylbenzaldehyde, benzylamine, and ammonium acetate without losing its catalytic activity.     

聚(4-乙烯基吡啶)硫酸氢盐: 一个新的高效催化剂用于无溶剂条件下合成13-芳香基-茚并 [1,2-b] 石脑油 [1,2-e] 吡喃-12(13H)-酮（英文）简

An facile and efficient protocol for the synthesis of 13-aryl-indeno[1,2-b]naphtha[1,2-e]pyran- 12(13H)- ones has been developed that proceeds via the one-pot three-component sequential reaction of an aromatic aldehyde with β-naphthol and 2H-indene-1,3-dione under solvent-free conditions in the presence of a poly(4-vinylpyridinium)hydrogen sulfate (P(4-VPH)HSO₄) catalyst. The catalyst can be reused several times, making this procedure facile, practical, and sustainable. The simple experimental procedure, solvent-free reaction conditions, use of an inexpensive catalyst, short react time, and excellent yields are some of the major advantages of this methodology.     

Tandem versus single C-C bond forming reaction under palladium-copper catalysis: regioselective synthesis of α-pyrones fused with thiophene

We herein report a highly convenient protocol for rapid construction of α-pyrone fused with thiophene. This includes one-pot and regioselective synthesis of 4,5-disubstituted and 5-substituted thieno[2,3-c]pyran-7-ones, 6,7-disubstituted and 6-substituted thieno[3,2-c]pyran-4-ones. The synthesis of thieno[2,3-c]pyran-7-ones involves palladium mediated cross coupling of 3-iodothiophene-2-carboxylic acid with terminal alkynes in a simple synthetic operation. The coupling-cyclization reaction was initially studied in the presence of Pd(PPh₃)₂Cl₂ and CuI in a variety of solvents. 5-Substituted 4-alkynylthieno[2,3-c]pyran-7-ones were isolated in good yields when the reaction was performed in DMF. Similarly, 6-substituted 7-alkynylthieno[3,2-c]pyran-4-ones were synthesized via palladium-catalyzed cross coupling of 2-bromothiophene-3-carboxylic acid with terminal alkynes. A tandem C-C bond forming reaction in the presence of palladium catalyst rationalizes the formation of coupled product in this apparently three-component reaction. The cyclization step of this coupling-cyclization-coupling process occurs in a regioselective fashion to furnish products containing six-membered ring only. This sequential C-C bond forming reaction however, can be restricted to the formation of single C-C bond by using 10% Pd/C-Et₃N-CuI-PPh₃ as catalyst system in the cross coupling reaction. 5-Substituted thieno[2,3-c]pyran-7-ones were obtained in good yields when the coupling reaction was performed under this condition. Some of the compounds synthesized were tested in vitro for their anticancer activities.     

A novel isocyanide-based three-component reaction: a facile synthesis of substituted 2H-pyran-3,4-dicarboxylates

An efficient method for synthesis of 2H-pyran-3,4-dicarboxylates using the three-component reaction of dithiocarbamates, dialkyl acetylenedicarboxylates, and isocyanides in solvent-free conditions is described. In these reactions, synthesis of dithiocarbamates is possibly based on the one-pot reaction of secondary amines, CS₂, and alkyl halides in solvent-free conditions without using a catalyst. The mild reaction conditions and high yields of the reaction exhibit the good synthetic advantage of these methods.