Conjugate Addition Of Indoles Research Articles

Conjugate Addition of Indoles to <i>α,β</i>-Unsaturated Ketones Using Bismuth (III) Bromide

An efficient method for the conjugate addition of indoles to a variety of chalcones using BiBr3 in ethanol (190 proof) is reported. Products are isolated by a simple procedure that avoids an aqueous work up and extensive chromatography, thus minimizing waste. Bismuth (III) compounds are especially attractive from a green chemistry perspective because they are remarkably nontoxic, non-corrosive and relatively inexpensive.

ZrOCl2·SiO2-catalyzed synthesis of bis(indoles) via conjugate addition of indole with electron-deficient alkenes in water

Abstract This report provides a description of an efficient and environmentally benign procedure for the synthesis of bis(indole) derivatives via reaction of indole with electron-deficient alkenes. The remarkable advantages of this method for obtaining bis(indoles) are the simplicity of the experimental procedure, short reaction times, and high yields with the green aspects by avoiding toxic catalysts and solvents.

ChemInform Abstract: Conjugate Addition of Indoles and Pyrroles to Dihydronitronaphthalenes in Water: Synthesis of 3,4‐Fused Tetrahydro‐β‐carbolines.

AbstractThe products of the conjugate addition can be used for further transformations: the halogen moieties undergo Suzuki couplings, and the nitro group can be reduced and applied in a Pictet—Spengler cyclization to yield fused β‐carbolines (XVI).

Conjugate Addition of Indoles and Pyrroles to Dihydronitronaphthalenes in Water: Synthesis of 3,4‐Fused Tetrahydro‐β‐carbolines

AbstractA catalyst‐free conjugate addition of indoles and pyrroles to 1,2‐dihydro‐3‐nitronaphthalenes in water has been developed. A variety of indoles containing electron‐rich and ‐deficient functional groups including aza‐indoles and pyrroles reacted smoothly with a number of dihydro‐3‐nitronaphthalenes, especially bromo derivatives. For structural elaboration, the bromo functionality (dihydronitronaphthalene unit as well as indolyl unit) of the addition products was utilized for Suzuki coupling reactions and provided moderate to good yields of the desired coupling compounds. The utility of the method was further demonstrated by the synthesis of 3,4‐fused tetrahydro‐β‐carbolines, a new class of compounds, from the addition products through reduction of the nitro group to the amine and subsequent Pictet–Spengler cyclization.

Poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide), N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide as new reagents for conjugate addition of indole, pyrrole with α,β-unsaturated ketones

Poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide) [PBBS] and N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide[TBBDA] were used as efficient reagents for conjugate addition of indole and pyrrole with α,β-unsaturated ketones and also, double-conjugate 1,4-addition of indoles to dibenzylidenacetones.

Catalytic conjugate addition of indole to α,β-unsaturated ketones by Co(ClO4)2·6H2O/bis-Schiff base complexes

Abstract Co(ClO4)2·6H2O/bis-Schiff base complexes promoted the conjugate addition of indole to α,β-unsaturated ketones under mild conditions, giving the corresponding addition products with high yields. And the complex has been characterized with XRD and IR.

ChemInform Abstract: Iodine‐Catalyzed Conjugate Addition of Indoles onto En‐1,4‐dione: A Novel Synthesis of 3‐(1‐(1H‐Indol‐3‐yl)‐2‐oxo‐2‐phenylethyl)indolin‐2‐ones as Antibacterial and Antifungal Agents.

AbstractSome of the compounds synthesized show moderate antibacterial and antifungal properties.

Novel Brønsted Acidic Ionic Liquids Based on Benzimidazolium Cation: Synthesis and Catalyzed Conjugate Addition of Indoles with α,β-unsaturated Ketones

Brønsted acidic ionic liquids based on benzimidazolium cation was synthesized and employed as an efficient catalysts for the Michael addition reaction of indoles to α,β-unsaturated ketones under mild conditions to afford the corresponding conjugate addition products in high yields (90%-98%). The catalyst 1-butyl-3-(3-sulfopropyl)benzimidazolium p-toluenesulfonate ([PSbbim][p-CH3PhSO3]) could be reused at least three times without a noticeably decrease in its activity.

Synthesis and application of modified silica sulfuric acid as a solid acid heterogeneous catalyst in Michael addition reactions

AbstractModified silica sulfuric acid (MSSA) as a new type of silica sulfuric acid was prepared and effectively used in the conjugate addition of indole, pyrrole, and thiols with Michael acceptors under mild conditions at room temperature. Also, MSSA was used as a catalyst for the synthesis of 1,1,3‐tri‐indolyl compounds in good to excellent yield at room temperature. J. Heterocyclic Chem., (2011).

Catalytic activity of choline modified Fe(III) montmorillonite

A series of mixed-cation organoclays, containing both Fe 3+ and choline + cations, were prepared using montmorillonite and tested for catalytic activity in three Fe 3+-mediated reactions: the oxidative coupling of 2-naphthol, coupling of anthrone and a Lewis-acid catalysed indole conjugate addition. Clays with different Fe 3+:choline + ratios were required to achieve maximum catalytic activity in each reaction. For coupling of both 2-naphthol and anthrone, the most effective catalysts, as measured by the turnover frequency (TOF), were mixed Fe 3+/choline + clays of varying ratios, but the catalytic efficiency of Fe 3+ montmorillonite in the conjugate addition of indole with methyl vinyl ketone decreased with the addition of choline +. This result could potentially be explained by the effect of choline + decreasing the accessibility of Lewis acid domains. The results of this study provide proof that it is possible to tune mixed-cation clays with maximum catalytic activity in specific reaction types for specific substrates. Such mixed-cation organoclays offer advantages over traditional clay-based sorbents in environmental remediation applications, as they have the potential to bind organic contaminants selectively, via interaction with surface-exchanged organic cations, and neutralise organic molecules through catalytic exchange cations that are also present on the clay surface.

ChemInform Abstract: Catalyst‐Free Conjugate Addition of Indoles and Pyrroles to Nitro Alkenes under Solvent‐Free Condition (SFC): An Effective Greener Route to Access 3‐(2‐Nitro‐1‐phenylethyl)‐1H‐indole and 2‐(2‐Nitro‐1‐phenylethyl)‐1H‐pyrrole Derivatives.

Catalyst free conjugate addition of reactive hetero aromatics (pyrrole and indoles) to nitro alkenes under solvent free condition is described. This method provides several advantages, such as operational simplicity, solvent-free conditions and good yields of products. Also it is environmentally friendly and more cost effective alternative to existing protocols.

ChemInform Abstract: Supported Cobalt Complex‐Catalyzed Conjugate Addition of Indoles, Amines and Thiols to α,β‐Unsaturated Compounds.

AbstractA supported cobalt complex is successfully used as a reusable catalyst for the Michael addition of thiols (I), amines (VI), and indoles (VIII) to alkenes (II) and (IV) under solvent‐free conditions.

ChemInform Abstract: Gallium Trichloride‐Catalyzed Conjugate Addition of Indole and Pyrrole to α,β‐Unsaturated Ketones in Aqueous Media.

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 of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Study on the Conjugate Addition of Indole with 1,5‐Diaryl‐1,4‐pentadien‐3‐ones Catalyzed by AlCl3 under Ultrasonication.

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 of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of 3‐(2‐Nitroalkyl) Indoles by Reaction of 3‐(1‐Arylsulfonylalkyl) Indoles with Nitroalkanes.

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.

Enantioselective Conjugate Addition of Indoles to Enones

Enantioselective Conjugate Addition of Indoles to Enones

Conjugate Addition of Indoles with Electron‐Deficient Olefins Catalyzed by Fe‐Exchanged Montmorillonite K10.

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.

Thermal and Microwave‐Assisted Conjugate Additions of Indole on Electron‐Deficient Nitro‐olefins

Conjugate addition of indole on nitro‐olefins was carried out by three different methods: (i) thermal heating in a sealed tube, (ii) reaction with indolyl magnesium iodide, and (iii) microwave irradiation. Comparison of the results indicated that the microwave technique is most efficient.

Conjugate Addition of Indoles with Electron‐Deficient Olefins Catalyzed by Fe‐Exchanged Montmorillonite K10

Conjugate addition of indoles with a variety of electron‐deficient olefins in the presence of Fe‐exchanged montmorillonite K10 affords the corresponding Michael adduct in excellent yields with high selectivity. The catalyst was also found to be recyclable.

Copper(II) Bromide–Catalyzed Conjugate Addition of Indoles to α,β‐Enones

Copper(II) bromide was found to be an efficient catalyst for the conjugate addition of indoles to α,β‐enones in acetonitrile at room temperature.