Friedel-Crafts Process Research Articles

Cinnamyl Chalcone Based AIE Fluorescent Probes for Sensitive Detection of Hydrazine and its Application in Living Cells.

Widely utilized in the chemical industry and agriculture, hydrazine is easily absorbed by living things and can cause physical harm when in touch for an extended period of time. As a result, a novel cinnamaldehyde chalcone C5 was produced by Friedel Crafts process and aldol condensation reaction. Triphenylamine was used as the raw material for hydrazine determination in both reactions. Chalcone C5 exhibits significant AIE behavior in a mixed mixture of ethanol and water in addition to having great selectivity and a low detection limit (0.119nm) for hydrazine. The solvent effect test revealed a linear relationship between the Stokes shift of C5 in the solvent and the rise in solvent orientation polarization. It is important to note that C5 is not harmful to MCF-7 cells, mouse kidney cells, or pig kidney cells. Furthermore, research on cell imaging has demonstrated that probe C5 may be utilized to image the fluorescence of hydrazine in active MCF-7 cells.

Unlocking the Friedel-Crafts arylation of primary aliphatic alcohols and epoxides driven by hexafluoroisopropanol

Unlocking the Friedel-Crafts arylation of primary aliphatic alcohols and epoxides driven by hexafluoroisopropanol

Influence of Functional Group Concentration on Hypercrosslinking of Poly(vinylbenzyl chloride) PolyHIPEs: Upgrading Macroporosity with Nanoporosity.

With the aim to study the influence of monomer ratio in poly(high internal phase emulsions) (polyHIPEs) on the polymer network architecture and morphology of poly(vinylbenzyl chloride-co-divinylbenzene-co-styrene) after hypercrosslinking via the internal Friedel–Crafts process, polyHIPEs with 80% overall porosity were prepared at three different initial crosslinking degrees, namely 2, 5, and 10 mol.%. All had typical interconnected cellular morphology, which was not affected by the hypercrosslinking process. Nitrogen adsorption and desorption experiments with BET and t-plot modelling were used for the evaluation of the newly introduced nanoporosity and in combination with elemental analysis for the evaluation of the extent of the hypercrosslinking. It was found that, for all three initial crosslinking degrees, the minimum amount of functional monomer, 4-vinylbenzyl chloride, was approximately 30 mol.%. Hypercrosslinking of polymers with lower concentrations of functional monomer did not result in induction of nanoporosity while the initial crosslinking degree had a much lower impact on the formation of nanoporosity.

Toluene Methylation by Methyl Mercaptan and Methanol over Zeolites—A Comparative Study

In this study, we show that the Friedel–Crafts (FC) alkylation of aromatic hydrocarbons by thiols to form C–C bond is feasible. The gas-phase reaction between toluene and CH3SH catalyzed by HZSM-5 zeolite was chosen as model reaction. In the temperature range of 350–550 °C, the alkylation of toluene to produce xylenes was the main reaction involved in the process. The reaction between toluene and CH3SH was compared with the well-known reaction between toluene and CH3OH. Significant similarities exist, notably the ability of both CH3SH and CH3OH to generate methoxonium species on the zeolite surface and to methylate the aromatic ring in a typical FC process. The maximum alkylation yield of 41% for CH3OH was reached at 350 °C, while that of 67.3% for CH3SH was reached at 450 °C. This difference in temperature can be correlated with the energy barriers required for the formation of methoxonium species (i.e., 24.6 kcal/mol (CH3OH) and 26.4 kcal/mol (CH3SH)). The high performance in alkylation proved by CH3SH ...

Alkylation of toluene with dichloromethane in the presence of triisobutylaluminum and perfluorophenylborates

1H NMR method showed that in systems based on triisobutylaluminum (TIBA) and triphenylcyclopropenylium [Ph3C3]+[B(C6F5)4]–(CPB) or triphenylmethylium [Ph3C]+[B(C6F5)4]–(TB) perfluorophenylborates in a toluene–dichloromethane mixture the Friedel–Crafts process occurs with the formation of ditolylmethane (DTM) accompanied by the complete decomposition of TIBA to form isobutane. 19F NMR spectroscopy showed that the [B(C6F5)4]–anion decomposes in the systems to form B(C6F5)3 and HC6F5. The short-living [AlBu2 i]+ cation formed in the reaction of perfluorophenylborates with TIBA is assumed to be the species initiating the process. It has been shown that CPB is less reactive than TB. The addition of a stoichiometric amount of Ph2CCpFluHfMe2 exerts no effect on the process with the CPB-containing system but inhibits the reaction in the case of TB.

Enantioselective synthesis of hexahydrofuro[3,2-c] quinolines through a multicatalytic and multicomponent process. A new “aromatic sandwich” model for BINOL-phosphoric acid catalyzed reactions

A new and straightforward metal–organo orthogonal-relay catalytic asymmetric reaction for the enantioselective synthesis of hexahydrofuro[3,2-c]quinolines is reported. The process involves a three-component coupling reaction between an alkynol, an aldehyde and an arylamine catalyzed by a gold complex and a chiral BINOL-derived phosphoric acid. Quantum chemical calculations of the reaction mechanism suggest that the involved acid-catalyzed Povarov reaction is better described as a sequential Mannich/intramolecular Friedel–Crafts process between the 5-phenyl-2,3-dihydrofuran and protonated N-phenylaldimine reactants generated in situ. Moreover, computations of the reaction mechanisms for the formation of the four stereoisomers of the hexahydrofuro[3,2-c]quinoline adduct using (R)-TRIP-suggested a rationale for the face selectivity of the asymmetric Povarov cycloaddition. With a single coordination mode by ion pairing of the chiral phosphoric acid and the imine, the preferred approach of 5-phenyl-2,3-dihydrofuran to the iminium ion results from a combination of more favourable π-stacking and reduced steric interactions in the Re-exo transition state relative to the alternative diastereoisomeric orientations.

ChemInform Abstract: Synthesis of 3‐(Tosylalkyl)indazoles and Their Desulfonylation Reactions — A New Entry to 3‐Substituted Indazoles by an Unprecedented Friedel—Crafts Process.

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.

A rapid and efficient synthesis of a new pyrrolobenzodiazocines via an intramolecular Friedel–Crafts reaction

New pyrrolobenzodiazocines 3 have been prepared by an intramolecular Friedel–Crafts process from pyrrolobenzoacrylamides 2. The cyclisation process involving a 1,4-intramolecular addition of a pyrrole onto acrylamide led to the formation of an eight-membered ring.

Synthesis of 3‐(Tosylalkyl)indazoles and their Desulfonylation Reactions – A New Entry to 3‐Substituted Indazoles by an Unprecedented Friedel–Crafts Process

AbstractReaction of indazoles with aldehydes in the presence of p‐toluenesulfinic acid affords the corresponding sulfonyl indazoles in satisfactory yields. The reported Friedel–Crafts process is rather unusual on indazoles because of the reduced electronic density of the heterocycle. The obtained sulfonyl indazoles can be desulfonylated under reductive conditions, finally leading to 3‐alkylated indazoles.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

A Journey Across Recent Advances in Catalytic and Stereoselective Alkylation of Indoles

AbstractFor Abstract see ChemInform Abstract in Full Text.

A Journey Across Recent Advances in Catalytic and Stereoselective Alkylation of Indoles

In this Account our recent results in relation to the catalytic and stereoselective Friedel-Crafts (FC) alkylation of indoles are described. Over the last decade, remarkable efforts have been devoted towards the replacement of the primal approaches with new more efficient, reliable, and environmentally benign strategies for the functionalization of indoles. Moreover, the emerging area of catalytic asymmetric FC processes is addressed and some examples of enantioselective alkylations of indoles via 1,4-additionto α,β-un-saturated systems and asymmetric ring-opening reaction of aromatic epoxides are described.

Solid Acid‐Catalysed Michael‐Type Conjugate Addition of Indoles to Electron‐Poor CC Bonds: Towards High Atom Economical Semicontinuous Processes

AbstractIn this paper a novel application of solid acid catalysts in the chemoselective Friedel–Crafts (FC) alkylation of indoles is reported. The optimal protocol allows highly functionalised indolyl compounds to be synthesised in excellent yields through conjugate addition of indoles with α,β‐unsaturated ketones and nitro compounds. Finally, the use of commercial Amberlyst‐15 as the heterogeneous catalyst for highly atom efficient continuous and semicontinuous Friedel–Crafts processes is described.

Acylation of aroyl chlorides via a template Friedel–Crafts process: synthesis of indan-1,3-diones

Variously substituted indan-1,3-diones have been regioselectively prepared in a one-pot synthesis by sequential cross-condensation–cycloacylation of aromatic acyl chlorides and acetyl chloride or malonyl dichloride, electrophilic acylation of aromatic acyl chlorides representing the key step in the process. The synergism of the aromatic carbonyl enolization and the organization of the reacting system promoted by the metal is emphasized to account for the mild reaction conditions.

A new ring synthesis for 3- and polysubstituted furans; directing effects of a 3-(arenesulfonyl) group in metalation and Friedel-Crafts processes

Primary and secondary α-bromoketones react with the potassium salt (3) to afford 2-[E-2-(p-toluenesulfonyl)-ethenyloxy]-ketones. On treatment with LDA followed by p-TsOH, good yields of the corresponding 3- or 2,3-substituted-4-tosylfuran are obtained, from which the 4-substituent may be reductively removed. 3-Aryl or alkyl-4-tosylfurans undergo regiospecific metalation at C-5 and Friedel-Crafts acylation at C-2. These processes permit the conversion of bromoketones to 2,3-, 2,4- or 2,3,5-substituted furans.

CpMoCo 2(CO) 8CCO +: Synthesis and characterization of a mixed metal acylium cation

CpMoCo 2(CO) 8CCO 2CHMe 2 in propionic anhydride reacts with HPF 6 to yield the mixed metal acylium cation CpMoCo 2(CO) 8CCO + which reacts with a variety of nucleophiles, e.g., ROH, R 2NH, yielding cluster-bound esters and amides, respectively. The cation also reacts with PhNMe 2 in a Friedel-Crafts process. In the presence of water, Co 3(CO) 9CCO + can also decompose to yield the neutral dimer [(Co 3(CO) 9C] 2.

Template catalysis via non-transition metal complexes. New highly selective syntheses on phenol systems

Abstract

Aromatic radical-ion formation using lewis acid catalysts

The formation of radical ions from interactions between organic compounds with transition metal chlorides (Pt, Pd, Rh, Ru, Ir), their potassium salts, and other Lewis acid catalysts has been studied by electron spin resonance. The possible importance of these e.s.r. active species in catalytic reactions such as self-activation in isotopic hydrogen exchange and Friedel-Crafts processes has been investigated. A number of organic donors have been examined including polycyclic aromatic hydrocarbons, aromatic mines, alkenes, chloropromazine, and phenothiazine. Effect of water of crystallization, oxygen, ultraviolet radiation, and methyl substituents on the e.s.r. has been evaluated. A study has been made of the factors affecting the formation of these e.s.r. species in solution when compared with solid state interactions using as acceptors iodine, and the halides of iron, cadmium, boron, tellurium, and titanium. The results have been interpreted in terms of the formation of radical ions. It is proposed that in the solid state, the transferred electrons are weakly coupled as in a diradicaloid triplet state.