Condensation Of Indole Research Articles

Catalytic “triangles”: binding of iron in task-specific ionic liquids

A new class of task-specific ionic liquids (ILs) which contain septuply positively charged {Fe(3)(III)O(RCOO)(6)L(3)}(7+) triangles has been synthesized and structurally characterized. Such metal-containing ILs can be repeatedly used as alternative catalysts in the synthesis of 2-pyrrolo-3'-yloxindole or the condensation of indoles with various aldehydes.

ω-Sulfonic-perfluoroalkylated poly(styrene–maleic anhydride)/silica hybridized nanocomposite as a new kind of solid acid catalyst

A new kind of ω-sulfonic-perfluoroalkylated poly(styrene–maleic anhydride)/silica hybrid nanocomposite FSMA/SiO2 has been synthesized under mild conditions by perfluoroalkylation of styrene–maleic anhydride copolymer (SMA) with ω-fluorosulfonylperfluorodiacyl peroxides (SFAP), and followed in turn by aminolysis using (3-aminopropyl)triethoxysilane (APTES), alkali hydrolysis, gelation with tetraethoxysilane (TEOS) and finally acidification. The hybrid solid acid FSMA/SiO2 with terminal perfluoroalkylsulfonic and carboxyl groups was characterized by FTIR, SEM, TEM, TGA, XPS, EDX, acidimetry and nitrogen sorption technique. Its pore structure, acid strength and acid amount were easily modulated by controlling the gelation and perfluoroalkylation conditions. The catalytic activity and selectivity, as well as reusability of FSMA/SiO2 were tested in three important reactions, namely, cyclization of pseudoionone, condensation of indole and esterification of benzoic acid. Owing to the higher exchange capacity than that of Nafion/SiO2, and the stronger acidity than that of Amberlyst-15, the nanocomposite FSMA/SiO2 showed higher activity and selectivity than these commercial solid acids in the reactions.

Application of Natural Kaolin Supported Sulfuric Acid as an Ecofriendly Catalyst for the Efficient Synthesis of bis(indolyl)methanes

The acidified kaolin with sulfuric acid (2% w/w) is introduced as a novel, mild, highly efficient, easily prepared, very cheap, recyclable and ecofriendly catalyst in organic synthesis. This catalyst has been used successfully for the synthesis of bis(indolyl)methanes via the condensation of indoles with aldehydes at room temperature. The simplicity, efficiency, mild reaction condition, high yield of product, easy work up procedure, and recyclability of the catalyst are the advantages of this procedure.

PEG-SO3H as a Catalyst for the Preparation of Bis-Indolyl and Tris-Indolyl Methanes in Aqueous Media

A facile, efficient, and green synthesis of bis-indolyl and tris-indolyl methanes has been developed by one-pot condensation of indole with structurally diverse aldehydes and ketones in the presence of poly(ethylene glycol)–bound sulfonic acid as catalyst at room temperature.

Synthesis of bis(indolyl)methanes under catalyst-free and solvent-free conditions

Condensation of indole with aromatic aldehydes has been carried out without using any catalyst and solvent to give bis(indolyl)methanes.

5′,11′-Dihydrodispiro[cyclohexane-1,6′-indolo[3,2-b]carbazole-12′,1′′-cyclohexane

The title compound, C28H30N2, is a symmetrical 2:2 product from the condensation of indole and cyclo­hexa­none. It is the only reported 5,11-dihydro­indolo[3,2-b]carbazole compound in which the spiro atoms are quaternary C atoms. Crystals were grown by vapor diffusion in a three-zone electric furnace. The mol­ecule resides on a crystallographic inversion center. The cyclo­hexyl rings are in a slightly distorted chair conformation, whereas the indole units and the spiro-carbons are coplanar within 0.014 Å.

ChemInform Abstract: Pyridinium Tribromide Catalyzed Condensation of Indoles and Aldehydes to Form Bisindolylalkanes.

Abstract An efficient synthetic method for bis(indol-3-yl)alkane derivatives has been developed. In the presence of 5 mol% of pyridinium tribromide (PTB), the condensation of indoles and aldehydes proceeded smoothly under mild conditions, giving rise to the corresponding bis(indol-3-yl)alkanes in good to excellent yields.

PEG-SO3H as a new, highly efficient and homogeneous polymeric catalyst for the synthesis of bis(indolyl)methanes and 4,4′-(arylmethylene)-bis(3-methyl-1-phenyl-1Hpyrazol-5-ol)s in water

In this work, a green, simple and highly efficient procedure for the synthesis of bis(indolyl)methanes and 4,4′- (arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s [as an important class of bis(pyrazolyl)methanes] is described. The condensation of indoles or 1-phenyl-3-methylpyrazol-5-one with carbonyl compounds catalyzed by poly(ethylene glycol)-bound sulfonic acid (PEG-SO3H) in water affords the title compounds in high yields and relatively short reaction times.

Efficient and solvent-free synthesis of bis-indolylmethanes using silica gel supported aluminium chloride as a reusable catalyst

Abstract Stable and non-hygroscopic silica gel supported aluminium chloride (SiO 2 –AlCl 3 ), which is prepared easily from cheap and commercially available compounds was found to be an environmentally friendly heterogeneous catalyst for the condensation of indole with aldehydes and ketones to afford bis-indolylmethanes at room temperature under solvent-free conditions. The catalyst can be reused up to five times after simple washing with ether.

ChemInform Abstract: Ytterbium Triflate Catalyzed Synthesis of β‐Functionalized Indole Derivatives.

AbstractUltrasound‐assisted condensation of indole, aldehydes, and dimethyl malonate represents the first example of the Yonemitsu three‐component reaction catalyzed by a Lewis acid without the need of other promoters such as amines.

Pyridinium tribromide catalyzed condensation of indoles and aldehydes to form bisindolylalkanes

Abstract An efficient synthetic method for bis(indol-3-yl)alkane derivatives has been developed. In the presence of 5 mol% of pyridinium tribromide (PTB), the condensation of indoles and aldehydes proceeded smoothly under mild conditions, giving rise to the corresponding bis(indol-3-yl)alkanes in good to excellent yields.

On Water: Br?nsted Acidic Ionic Liquid [(CH2)4SO3HMIM][HSO4] Catalysed Synthesis of Oxindoles Derivatives

AbstractSome oxindoles derivatives are synthesized from the condensation of indoles with isatins in the presence of green and recycable catalyst [(CH2)4SO3HMIM][HSO4] in water at room temperature.

Plants contain two distinct classes of functional tryptophan synthase beta proteins

Tryptophan synthase β-subunits (TSBs) catalyze the last step in tryptophan biosynthesis, i.e. the condensation of indole and serine yielding tryptophan. In microorganisms two subfamilies of TSBs (here designated as type 1 and type 2) are known, which are only distantly related. Surprisingly, in all genomes of multicellular plants analyzed genes encoding both types are present. While type 1 enzymes are well established as components of tryptophan synthase complexes, type 2 enzymes in plants have not yet been characterized. Tissue specific expression of the TSB genes from Arabidopsis thaliana was analyzed. While AtTSB1 is the predominantly expressed isoform in vegetative tissues, AtTSB1 and AtTSBtype2 reach similar transcript levels in seeds. AtTSBtype2 protein was expressed in Escherichia coli and purified. It converted indole and serine to tryptophan with a strikingly low K m-value for indole of ca. 74 nM. Attsbtype2 T-DNA insertion mutants showed no obvious deviation from the wild type phenotype, indicating that AtTSBtype2 function is not essential under standard growth conditions. As example for a monocot enzyme, maize TSB type 2 was analyzed and found to be transcribed in various tissues. ZmTSBtype2 was also catalytically active and here a K m-value for indole of ca. 7 μM was determined. These data indicate that TSB type 2 enzymes generally are functionally expressed in plants. Their potential biological role is discussed.

Silica-Supported LiHSO4 as a Highly Efficient, Mild, Heterogeneous, and Reusable Catalytic System for the Solvent-Free Synthesis of Bis(indolyl)methanes

Silica-supported LiHSO4 (LiHSO4/SiO2) is used as a green, cheap, and efficient catalytic system for the synthesis of bis(indolyl)methanes via the condensation of indoles with carbonyl compounds under solvent-free conditions. The reactions proceed rapidly at room temperature, and the title compounds are obtained in high to excellent yields.

Synthesis of Indolo[3,2-a]carbazoles by Reaction of Indoles with 1,2-Diones

Described here is an acid-catalyzed synthesis of indolo[3,2-a]carbazole derivatives by the condensation of indoles with 1,2-diones. Indolocarbazoles of type C were obtained when indoles were treated with benzil derivatives B while cyclobutene-1,2-diones D, upon treatment with indoles, gave indolocarbazoles E in good to high yields. Among other screened acid catalysts [AuCl3, Cu(OTf)3, Yb(OTf)3, SnCl4, Sc(OTf)3, BF3·OEt2], PTSA was found to be the best for this process. Reaction of indole with 2,3-butanedione gave a very low yield (12%) of C.

Some applications of zirconium(IV) tetrachloride (ZrCl4) and zirconium(IV) oxydichloride octahydrate (ZrOCl2.8H2O) as catalysts or reagents in organic synthesis

Both ZrCl4 and ZrOCl2.8H2O are commercially available solid chemicals. Due to their low toxicities (LD50 [ZrCl4 oral rate] = 1688 mg/kg), (LD50 [ZrOCl2.8H2O oral rate] = 2950 mg/kg), low costs, ease of handling, high activity, the zirconium(IV) compounds are potential green catalysts or reagents which are of importance from different views. In this review we have paid attention to the applications of these compounds as reagents or catalysts in Friedel-Crafts reactions, Fries rearrangements, reduction and oxidation reactions, cycloaddition and hydrometalation reactions, protection and deprotection of functional groups, reactions of epoxides, iodination of alcohols, S-alkylation of thiols with alcohols, Michael addition, condensation of indoles with carbonyl compounds, Claisen ester condensation, Baylis-Hillman reaction, preparation of organozirconium compounds and some other miscellaneous reactions.

Various tri(indolyl)methanes were synthesized by condensation of indole and its derivatives with indole‐3‐carboxaldehyde using acidic ionic liquids [hmim]HSO4/EtOH as an efficient and green catalyst system.

AbstractVarious tri(indolyl)methanes were synthesized by condensation of indole and its derivatives with indole‐3‐carboxaldehyde using acidic ionic liquids [hmim]HSO4/EtOH as an efficient and green catalyst system.

Efficient RuIII‐Catalyzed Condensation of Indoles and Aldehydes or Ketones.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Efficient RuIII-catalyzed condensation of indoles and aldehydes or ketones

Synthesis of bis(indolyl)methanes through condensation of indoles and various aldehydes or ketones, using RuIII as catalyst, is reported. It was found that the catalytic system involving RuIII affords the products smoothly under very mild conditions in good to high yields.Key words: aldehydes, ketones, bis(indolyl)methanes, indoles, ruthenium.

A novel base-promoted synthesis of β-indolylketones via a three-component condensation under ultrasonic irradiation

A convenient, efficient, and practical method for the synthesis of β-indolylketones via a condensation of indole, aromatic aldehydes, and deoxybenzoin under ultrasonic irradiation was described. It provided a novel base-promoted approach for the one-pot synthesis of β-indolylketones.