Novel biodegradable protonic ionic liquid for the Fischer indole synthesis reaction

Novel eco-friendly tetramethylguanidinium propanesulfonic acid trifluoromethylacetate ([TMGHPS][TFA]) ionic liquid was developed as catalyst and medium for the Fischer indole synthesis of a wide variety of hydrazines and ketones. The indole products were isolated in high yields and with minimal amounts of organic solvent. This reaction showed that [TMGHPS][TFA] can be regenerated and reused with reproducible yields without eroding the integrity of the ionic liquid.     

p-TsOH promoted Fischer indole synthesis of multi-substituted 2-trifluoromethyl indole derivatives

A p-TsOH promoted one-pot synthesis of multi-substituted 2-trifluoromethyl indole derivatives, for instance, 2-trifluoromethyl-3-phenylindoles, 2-trifluoromethyl-indole-3-propanoates, and 2-trifluoromethyl-indole-3-butanoates from reactions of 1,1,1-trifluoro-3-phenylacetone and simply prepared ω-trifluoromethyl substituted δ and ?-ketoesters with arylhydrazines via Fischer indole synthesis has been developed.     

Iron‐containing ionic liquid as an efficient and recyclable catalyst for the synthesis of C3‐substituted indole derivatives

A facile and efficient protocol for the synthesis of C3‐substituted indole derivatives has been developed under mild condition. The iron‐containing ionic liquid, 1‐(2‐hydroxyethyl)‐1,4‐diazabicyclo[2.2.2] octanylium tetrachloroferrate ([Dabco‐C₂OH][FeCl₄]) as a recyclable catalyst has been successfully used in the synthesis of trisindolines, bis(3‐indolyl) methanes and β‐indolyl alcohols for the first time. The products of trisindolines and bis(3‐indolyl) methanes are easily separated and purified without chromatographic technique. The catalyst was recycled six times without significant activity loss.     

Mild,efficient Fischer indole synthesis using 2,4,6-trichloro-1,3,5-triazine (TCT)

Mild and efficient protocol for the Fischer indole synthesis using TCT has been described. TCT serves as a mild and inexpensive catalyst. Under these conditions several functional groups such as ester, cyano, sulfone, amides, and ethers are tolerated. By this method, many functionalized analytically pure indoles were prepared easily without the need of purification.     

功能化离子液体催化合成柠檬酸三丁酯的研究

柠檬酸三丁酯(TBC)是一种新型无毒塑料增塑剂,具有相溶性好、增塑效率高、无毒、不易挥发、抗霉性、耐候性强等特点而备受关注,成为首选替代邻苯二甲酸酯类的绿色环保产品.随着人们环保意识的增强及法规的日益完善,开发生产柠檬酸三丁酯具有极好的发展前景.     

Fischer indole synthesis of the indoloquinoline alkaloid: cryptosanguinolentine

A new synthesis of an indoloquinoline alkaloid, isolated from Cryptolepis sanguinolenta, is described using a Fischer indole cyclization. 4-Hydroxy-1-methyl-1H-quinolin-2-one reacted directly with phenylhydrazine hydrochloride to give the indoloquinoline, which was reacted with POCl₃ and then the resultant halide hydrogenolysed to give cryptosanguinolentine.     

Exploitation the unique acidity of novel cerium-tungstate catalysts in the preparation of indole derivatives under eco-friendly acid catalyzed Fischer indole reaction protocol

Solid acidic cerium tungstate catalysts containing different molar ratios of cerium and tungstate were prepared by direct solvothermal methodology. The structure of the prepared catalysts was deeply studied and confirmed based on different characterization techniques such as DTA-TGA, FTIR, Raman spectra, XRD and N₂ adsorption measurements. Moreover, FTIR and TPD of chemically adsorbed pyridine techniques were conducted to fully address the nature and the strength of the acidic sites of the prepared catalysts. The study showed that at a lower molar ratio of tungstate, the catalyst contains cerium oxide phase and slight participation of cerium tungstate phase, which gradually increases with further increase of tungstate molar ratio. This phase change was also accompanied by a noticeable change in the thermal stability, surface area and acidic properties of the prepared catalysts. Additionally, the techniques used to study the acidic properties showed an excellent enhancement in the acidic centers. It was also noted that the strength of these acidic centers reached the maximum in the case of using tungstate: cerium molar ratio 2:1 (CeW2.0) catalyst, and slightly decreased thereafter. By exploiting the acidic properties of the prepared catalysts, a series of indole derivatives were synthesized via the Fischer indole synthesis strategy. The results also showed that ～100% of indole derivatives were obtained using 0.02 g catalyst at 80 °C after 2 h only. Moreover, the Reuse experiment demonstrated the possibility of recycling and reusing the catalyst through many cycles with high efficiency, indicating its wonderful constancy and reusability.     

Fischer吲哚合成法合成舒马普坦

舒马普坦是一种起效快耐受性好的治疗偏头痛的标准药物,目前市场前景看好。本研究用Fischer吲哚合成法,以4-肼基-N-甲基苯甲烷磺酰胺盐酸盐（Ⅰ）和4．N,N-二甲胺基丁醛缩二甲醇（Ⅱ）为原料,在甲醇／乙酸溶剂中先缩合形成腙不经分离在浓盐酸催化下一步直接得到了舒马普坦。实验表明,该方法操作简单且重复性好,粗产品通过高效液相色谱测定其含量为56％;产品经柱色谱纯化后产率为37％。产物结构经红外光谱、氢核磁共振谱分析得以确认。     

酸性离子液体催化合成三吲哚甲烷化合物

在酸性离子液体催化下,通过吲哚及其衍生物和吲哚甲醛反应合成了一系列三吲哚甲烷化合物。[hmim]HSO₄/EtOH 对于该反应来说,是一个高效、绿色的催化体系。     

Fischer吲哚合成法的研究进展

吲哚及其衍生物具有某些生物活性, 其合成方法很多. 其中Fischer吲哚合成是最便捷和经济的合成方法, 应用最多. 对此法近十年来的合成工艺进行了综述和评价.     

Solvent-free synthesis of quinoline derivatives via the Friedländer reaction using 1,3-disulfonic acid imidazolium hydrogen sulfate as an efficient and recyclable ionic liquid catalyst

A convenient, highly versatile and eco-friendly protocol for the synthesis of quinoline derivatives via the Friedländer reaction is presented. The method is based on the use of 1,3-disulfonic acid imidazolium hydrogen sulfate (DSIMHS) as an efficient and reusable ionic liquid catalyst. A variety of ketones afforded the substituted quinolines in excellent yields during relatively short reaction times under solvent-free conditions; the catalyst could be easily recovered and reused for several times without any appreciable loss of activity.     

Cobalt nanoparticles supported on ionic liquid‐functionalized multiwall carbon nanotubes as an efficient and recyclable catalyst for Heck reaction

A novel and environmentally friendly cobalt nanoparticle catalyst supported on ionic liquid‐functionalized multiwall carbon nanotubes was successfully prepared and evaluated as a heterogeneous catalyst for the Mizoroki–Heck reaction. Several reaction parameters, including type and amount of solvent and base, were evaluated. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.     

A convenient synthesis of coumarins using reusable ionic liquid as catalyst

Abstract

An efficient and convenient method has been developed for the synthesis of substituted coumarin derivatives using a Brønsted acidic ionic liquid as catalyst under solvent-free conditions. The catalyst can be reused for six consecutive runs without significant loss of activity.     

An imidazolium tosylate salt as efficient and recyclable catalyst for acetylation in an ionic liquid

A novel non-metallic salt, 1-butyl-3-methylimidazolium tosylate ([bmim][OTs]) dissolved in the ambient temperature ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]), was found to be the efficient catalyst for acetylation with the advantages of good recyclability, avoidance of metal contamination, mild reaction conditions, and wide availability for substrates (alcohols, phenols, and amines), could completely replace organic bases, metal Lewis acids, or metallic triflates to fulfill acetylation by a nucleophilic catalytic mechanism, which was supported by ¹³C NMR analysis. Correspondence: Ye Liu, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Chemistry Department of East China Normal University, Shanghai 200062, China.     

Synthesis,characterization, and application of silica supported ionic liquid as catalyst for reductive amination of cyclohexanone with formic acid and triethyl amine as hydrogen source

A silica supported ionic liquid was synthesized and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption-desorption, and thermogravimetric analysis. All these techniques, especially SEM results indicated the presence of well-defined spherical particles having diameters larger than the pristine silica particles, confirming the successful immobilization of the ionic liquid. The prepared silica supported ionic liquid was used in the reductive amination of cyclohexanone under different conditions with different azeo-tropic mixtures of formic acid and triethyl amine as a hydrogen source. The catalyst showed effi-cient catalytic performance and excellent yields of N-cyclohexyl amine derivatives in the range of 58%to 84%at 30 °C. After completion of the reaction, the catalyst was easily recovered by simple filtration and reused for another five cycles without any significant impact on product yields. The obtained catalytic performance indicates that the present catalyst is green, very active, and reusable for the reductive amination of cyclohexanone.     

Synthesis of imidazole derivatives: Ester and hydrazide compounds with antioxidant activity using ionic liquid as an efficient catalyst

The pyrrolidinium hydrogen sulfate (PHS) was used as an excellent ionic liquid catalyst for the preparation of many imidazoles moiety, which have biologically application via one-pot multicomponent reaction. Imidazoles were afforded through the reaction of equimolar from 1,2-diphenylethane-1,2-dione, ammonium acetate, different aromatic aldehydes, and ethyl glycinate hydrochloride. This method has the advantages of giving excellent yield, shortened reaction times, and ease of establishment. Moreover, the yielded of imidazoles components can be purified and crystallized by a nonchromatographic technique, and the catalyst can be reused. These entire novel synthesized components have been identified by spectral data: IR, NMR and mass spectra. These compounds have an in vivo antioxidant activity on experimental animals (rats).     

Novel approach to arylhydrazones, the precursor for Fischer indole synthesis, via diazo esters derived from α-amino acid esters

A novel method for synthesizing arylhydrazones, the precursor for Fischer indole synthesis, using aryllithium reagents and α-diazo esters that are easily obtained from α-amino acid esters, is described.     

离子液体催化合成乙二醇丁醚醋酸酯

以乙二醇单丁醚和冰醋酸为原料,在离子液体N-甲基吡咯烷酮硫酸氢盐([Hnmp] HSO4)催化下,合成了乙二醇丁醚醋酸酯.考察了催化剂用量、物料配比、反应时间、带水剂等因素对反应收率的影响.利用气相色谱仪分析了产物的纯度;利用核磁共振谱仪和质谱仪表征了产物的结构.结果表明,合成产物的纯度大于99.0％.[Hnmp]H ...     

新型磺酸功能化吡啶盐酸盐离子液体催化剂用于六氢喹啉合成(英文)

Sulfonic acid functionalized pyridinium chloride [pyridine-SO3 H]Cl has been synthesized as a novel Brnsted acidic ionic liquid and characterized on the basis of its FT-IR,1H and 13C NMR,MS,ther-mogravimetry,and derivative thermogravimetry data.The material has also been used as a highly efficient,homogeneous,and reusable catalyst for the preparation of hexahydroquinolines according to the one-pot multi-component condensation of arylaldehydes,dimedone(5,5-dimethylcyclohexane-1,3-dione),β-ketoesters,and ammonium acetate under solvent-free conditions.     

Convenient and Efficient Synthesis of 1-Oxo-1,2,3,4-tetrahydrocarbazoles via Fischer Indole Synthesis

A convenient synthesis of 1-oxo-1,2,3,4-tetra-hydrocarbazoles has been developed by reaction of 2-aminocyclohexanone hydrochlorides with various phenylhydrazine hydrochlorides via Fischer indole synthesis under mild conditions. The method is more satisfactory in terms of the easy availability of starting materials and the simple one-pot operation.