Acylation Of Aromatic Compounds Research Articles

Targeted development of sustainable green catalysts for regioselective acylation of aromatic ethers with carboxylic acidsviachlorosulfonic acid coated on poly(guanidine–triazine–sulfonamide) grafted quartz–γ-Fe2O3

Friedel–Crafts (FC) acylation of aromatic compounds is considered one of the essential and valuable reactions in organic synthesis.

Friedel-Crafts Acylation of Aminocarboxylic Acids in Strong Brønsted Acid Promoted by Lewis Base P4O10.

The amino group in aminocarboxylic acids is sufficiently basic to be protonated in strong acids, and consequently, ionization of the carboxylic acid to an acylium ion is blocked due to charge-charge repulsion. Thus, acylation of aromatic compounds is significantly retarded in Friedel-Craft type reactions. We found that Friedel-Crafts acylation with aminocarboxylic acids can proceed smoothly even in a strong Brønsted acid (triflic acid, TfOH) if the Lewis base P4O10 is added. Here we describe the Friedel-Crafts acylation reactions of anthranilic acid and α- to δ-aminocarboxylic acids with benzene derivatives in the presence of P4O10. Non-amino-containing carboxylic acids as well as N-containing heteroaromatic carboxylic acids are available, and α-amino acids can be directly utilized without any protective group. Most substrates afford acylation products in high yields, although some epimerization/racemization may occur. Density functional theory (DFT) calculations suggested that P4O10 neutralizes the protonated amine, converting the N-H covalent bond to a N-hydrogen bond and allowing the carboxylic acid OH functionality to serve as a good leaving group.

C–H Bond Functionalization Using Pd- and Au-Supported Catalysts with Mechanistic Insights of the Active Species

AbstractThe process of C–H functionalization has been extensively studied as a direct C–C bond-forming reaction with high atomic efficiency. Efforts have also been made on such reactions by using supported catalysts, which are superior in terms of catalyst separation from the reaction mixture and reusability. In this review, an overview of C–H functionalization reactions, especially those involving Pd- and Au-supported catalysts, is presented. In particular, we discuss reaction mechanisms, active species, leaching, reusability, etc.1 Introduction2 Types of Supported Metal Catalysts and Their Active Species3 Modes of C–H Bond Activation4 Oxidative C–H C–H Coupling of Aryl Compounds5 C–H C–H Coupling Where One Side Is Aromatic6 C–H Acylation of Aromatic Compounds and Related Reactions7 Conclusion

ChemInform Abstract: Acetamide/SO2Cl2 as an Efficient Reagent for Friedel—Craft′s Acylation of Aromatic Compounds under Ultrasonic and Microwave Conditions.

AbstractFriedel—Craft′s acetylation of aromatic compounds by acetamide/SO2Cl2 proceeds under microwave irradiation in high yields and short reaction times.

Friedel-crafts acylation of aromatic compounds using Triflat bismuth

Friedel-Crafts acylation of aromatic compounds with acetic anhydride as acylating reagent was investigated in the presence of Lewis acid. Bismuth trifluoromethanesulfonate was found to be efficient catalyst for Friedel-Crafts acetylation under mild conditions. Bismuth triflate is safe-to-handle, simple and clean work-up, good yield and short reaction time

Acetamide/SO2Cl2 as an efficient reagent for Friedel–Craft’s acylation of aromatic compounds under ultrasonic and microwave conditions

Acetamide/SO2Cl2 reagent has been developed for effective Friedel–Craft’s acylation of aromatic compounds. Acylation of aromatic compounds with acetamide/SO2Cl2 was much more effective and faster than analogous (acetamide/SOCl2) and (acetamide/POCl3) reagents even under conventional conditions. However, microwave and ultrasonic assisted reactions afforded high yields of products in very short reaction times (30–40min under sonication and 3–4min under microwave assisted conditions).

Sand: A natural and potential catalyst in renowned Friedel Craft's acylation of aromatic compounds

The aim of this work is to develop a cheap and green chemical process and this paper describes the catalytic commotion of locally collected sand in Friedel–Craft's Acylation of aromatic compounds like benzene, anisole, aniline, naphthalene and phenol etc. The sand consists of silica and alumina as analyzed by means of EDAX and acts as a green Lewis acid. The catalyst was also characterized by using BET, SEM, and XRD techniques.

Acylation of aromatic compounds by acid anhydrides using Preyssler's anion [NaP5W30O110]14- and heteropolyacids as green catalysts

Acylation of aromatic compounds by acid anhydrides using Preyssler's anion [NaP5W30O110]14- and heteropolyacids as green catalysts The Preyssler, Wells-Dowson and Keggin heteropolyacids are efficient and eco-friendly solid acid catalysts for the acylation of electron-rich aromatic compounds with acid anhydrides. The performance of different forms of heteropolyacids was compared. In all the cases, the best results were obtained using the Preyssler heteropolyacid as the catalyst. In the presence of 25 mol% (with respect to H+ equivalency) Preyssler catalyst, highly para-selective acetylation of anisole occurs using two equivalents of acetic anhydride, in 15 min at room temperature. The isolated yield of the p-methoxyacetophenone product is 98%.

ChemInform Abstract: Regioselective, Directed Meta Acylation of Aromatic Compounds.

A new method for the directed meta acylation of aromatic compounds is described. This method involves an ortho lithiation procedure combined with zirconocene−benzyne chemistry. 3-Acyl-1-substituted benzene derivatives were obtained by acidic hydrolysis of the azazirconacycle intermediate which results from the coupling of a nitrile with a zirconocene−benzyne complex. Similarly, 3-acyl-2-iodo-1-substituted benzene derivatives were obtained by the iodination of the same intermediate followed by acidic hydrolysis. These procedures, which utilize simple, readily available starting materials, give good yields of regiochemically pure products.

Simple and Efficient Procedure for the Friedel–Crafts Acylation of Aromatic Compounds with Carboxylic Acids in the Presence of P2O5/AL2O3 Under Heterogeneous Conditions

An efficient and chemoselective method for the Friedel–Crafts acylation of aromatic compounds using P2O5/Al2O3 and carboxylic acids. Both aromatic and aliphatic carboxylic acids reacted easily to afford the corresponding aromatic ketones in good yields.

Friedel-Crafts Acylation of Aromatic Compounds in Ionic Liquids

This article first reviews the application of ionic liquids in Friedel-Crafts acylation reactions. Ionic liquids can be used as catalyst solvents, the active component on solid carriers, or just as the solvent. One advantage of using ionic liquids in acylation reactions is the enhanced reaction rates, conversion, and selectivity. The acylation mechanisms of aromatic compounds in ionic liquids are also reviewed and analyzed. The acetylium cation [RCO]+ was confirmed to be the key intermediate in the acetylation reactions, and the replacement of a traditional solvent with the ionic liquid did not alter the acylation mechanism. With good consideration, we propose two rational acylation mechanisms for the Friedel-Crafts acylation of aromatics in the Lewis acidic ionic liquid and in the Lewis acid-ionic liquid system. Although the reaction rates, the conversion, and the selectivity for the acylation in ionic liquids are high, the separation of aryl ketone products from ionic liquids and the recycle of the ionic liquids are still a problem.

Titanium Dioxide‐Mediated Friedel–Crafts Acylation of Aromatic Compounds in Solvent‐Free Condition under Microwave Irradiation

Friedel–Crafts acylation of different arenes was carried out in the presence of titanium dioxide under microwave irradiation in solvent‐free condition. Activated substrates undergo acylation predominantly at the para‐position. An efficient, simple, selective acylation reaction affords good yield of the products and the catalyst could be easily recovered and recycled.

Acylation of Aromatic Compounds with Isocyanates Catalyzed by Ytterbium(III) Triflate: Environmentally Friendly.

AbstractFor Abstract see ChemInform Abstract in Full Text.

The Friedel?Crafts acylation of aromatic compounds with carboxylic acids by the combined use of perfluoroalkanoic anhydride and bismuth or scandium triflate

Aromatic ketones were synthesized by solventless Friedel–Crafts acylation of anisole, mesitylene, xylenes, and toluene with acetic acid and benzoic acid in the presence of trifluoroacetic anhydride by use of bismuth or scandium triflate at 30 °C. Toluene, benzene, and even deactivated substrate such as chlorobenzene were benzoylated by the combined use of heptafluorobutyric anhydride and bismuth triflate at 75–100 °C. The catalyst could be easily recovered and reused repeatedly for the reaction.

Acylation of aromatic compounds with isocyanates catalyzed by ytterbium(III) triflate : environmentally friendly

Aromatic compounds can be acylated by isocyanates in the presence of catalytic amount of ytterbium(III) triflate [Yb(OTf) 3 ] to obtain the corresponding N-substituted benzamides in good yields under neutral conditions. The catalyst can easily be recovered and reused without any loss of activity.

Solvent‐Free Friedel—Crafts Acylation of Aromatic Compounds with Carboxylic Acids in the Presence of Trifluoroacetic Anhydride and Aluminum Dodecatungstophosphate.

Abstract The stable and non-hygroscopic aluminum dodecatungstophosphate (AlPW 12 O 40 ), was found to be an effective catalyst (3 mol%) for the solvent-free Friedel–Crafts acylation of aromatic compounds with carboxylic acids in the presence of trifluoroacetic anhydride under mild reaction conditions.

ChemInform Abstract: Acylation of Aromatic Compounds Using Moisture Insensitive InCl3 Impregnated Mesoporous Si‐MCM‐41 Catalyst.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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.

ACYLATION OF AROMATIC COMPOUNDS USING MOISTURE INSENSITIVE MESOPOROUS Si-MCM-41 SUPPORTED Ga2O3 CATALYST

ABSTRACT Mesoporous Si-MCM-41 supported Ga2O3 is a highly active catalyst for the acylation of aromatic compounds with different acyl chlorides. Moreover, this catalyst is not deactivated by water and hence does not require moisture-free reaction conditions.

Acylation of aromatic compounds using moisture insensitive InCl 3 impregnated mesoporous Si-MCM-41 catalyst

Acylation of aromatic compounds (benzene, toluene, p-xylene, mesitylene, anisole, naphthalene, methylnaphthalene and methoxynaphthalene) by an acyl chloride (benzoyl chloride, phenylacetyl chloride, propionyl chloride or butyryl chloride) in high yield, in a short reaction period (3 h), even in the presence of moisture in the aromatic substrate or solvent (dichloroethane), can be accomplished at low temperature (80±1°C) using an InCl 3 impregnated Si-MCM-41 catalyst in low catalyst concentration.

On the acylation reactions of anisole using α,β-unsaturated organic acids as acylating agents and solid acids as catalysts: a mechanistic overview

The mechanism of the acylation of anisole with α,β-unsaturated acids, i.e. acrylic, crotonic and methylcrotonic acid, has been investigated using phosphotungstic acid (H 3PW 12O 40), as pure form, supported on SiO 2 and in the form of cesium salts as catalysts. Since α,β-unsaturated acid can either alkylate and/or acylate the aromatic compound, the influence of the catalyst on the selectivity for these two competing reactions was studied. Analysis of products obtained on the acylation of aromatic compounds with α,β-unsaturated acids shows that all the catalysts are more active for acylation than alkylation. Secondary products coming from intermolecular reactions of the acylated product with anisole as well as tertiary products coming from its further decomposition and recombination with another anisole molecule were observed. Heteropolyacids supported on silica were found to be more active and selective towards acylation reactions than zeolites HY and Hβ, even when the activity per acid site was considered. Zeolites and cesium salts from heteropolyacids favor acid polymerization reaction rather than the acylation of the aromatic compound.