Friedel-Crafts Acylation Reaction Research Articles

A Novel Synthesis Method of Meriolin1

Meriolins, a compound designed and synthesized by the similar structure of natural marine products Meridianins and Variolins, has been proved to be a new kinase inhibitor that can enhance protein kinase selectivity and cell death. It has stronger inhibitory activity, relative selectivity to kinases and antitumor effect. As the first compound in the Meriolins series, Meriolin1 has been studied the most. In this paper, the synthesis methods of Meriolin1 at home and abroad were summarized and analyzed. On this basis, a more economical and effective synthesis route was designed, that is, Meriolin1 was finally obtained from 7-azaindole through Friedel-crafts acylation, protection, aldol condensation and cyclization reaction. This route avoids the disadvantages of the existing routes and has the advantages of mild reaction conditions, simple operation and low cost. The structures of the compounds were confirmed by 1H NMR and 13C NMR.

Research progress on transition-metal-free C–N bonds cleavage of amides in the synthesis of ketones

<p indent="0mm">Amides compounds have a wide range of application, and many transforming strategies have been reported. Transition metals-catalyzed non-decarbonylative cross-coupling reaction of amides has gained considerable attention due to low cost, high efficiency, and good compatibility of functional groups. The reactions have following disadvantages due to the inherent nature of catalytic system: expensive catalysts, complex ligands, cocatalysts and trace metals residues. The transition-metal-free amide activation strategies for synthesis of ketones avoid the above problems with high efficiency and simple treatment. From the perspective of sustainable development, the development of amide activation strategy without transition metals has great significance. In this paper, the synthesis of ketones by C–N bond cleavage of amides without transition metals were reviewed. The main contents as follows: (1) synthesis of ketones by direct addition of alkali metal/alkaline-earth metal reagents to amides; (2) the Brønsted base-promoted non-decarbonylative cross-coupling reaction of amides and alkanes with activated groups; (3) synthesis of ketones by cleavage of amide C–N bond based on activation strategy; (4) acid-promoted Friedel-Crafts acylation reaction of amide; (5) Lewis acid-promoted the non-decarbonylative cross-coupling reaction between amide and alkyl ketone. This review provides inspiration for the subsequent development of economic and green amide activation reaction.

An efficient porous acidic ionic liquid polymer catalyst for Friedel–Crafts acylation reactions

A new function for a porous acidic ionic liquid polymer as a solid catalyst for Friedel–Crafts acylation.

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.

Highly efficient Friedel-Crafts acylation of veratrole over TiO2-SnOx solid solution catalyst

Friedel-Crafts (F-C) acylation reaction is one of the most effective processes to produce aromatic ketones. Classical homogeneous Lewis acid catalysts have difficulty in separation and solid waste generation, which limit their industrial application. Herein, binary metal oxide TiO2-SnOx were prepared, these solid solution catalysts show the highly efficient activity for the F-C reaction of veratrole and 4-chlorobenzoyl chloride (4-CBC). The optimized 0.1TiO2-SnOx catalyst exhibits the veratrole conversion of 74 % and the 4-chloro-3′,4′-dimethoxybenzophenone (CDMB) selectivity of 97 %. Additionally, it shows good stability. The outstanding catalytic performance of TiO2-SnOx can be attributed to homogeneous doping of Ti in SnOx at the atomic level, which results in the strong Lewis acid sites with high density on the surface of solid solution. This work revealed the superior Lewis acid catalyst with solid solution structure, constructed through binary metal oxide, can pave a new avenue for developing the solid Lewis acid with excellent catalytic performance.

AlCl3-Catalyzed Cascade Reactions of 1,2,3-Trimethoxybenzene and Adipoyl Chloride: Spectroscopic Investigations and Density Functional Theory Studies.

The reaction of 1,2,3-trimethoxybenzene with adipoyl chloride in the presence of AlCl3 gave two isomeric cyclopentene derivatives, 1,6-bis(2,3,4-trimethoxyphenyl)hexane-1,6-dione, and two demethylation products of aryl methyl ethers. The cyclopentene derivatives including unconjugated or conjugated enones are products formed in a cascade reaction resulting from first the Friedel-Crafts acylation reaction and then aldol condensation. All compounds were optimized by density functional theory calculated using two functional levels, B3LYP and M06-2X, with the 6-311+G(d,p) basis set. The structural properties were established, natural bond orbital analysis of donor-acceptor interactions was carried out, and charges on the atoms and quantum chemical reactivity identifiers were determined to compare the strength of the intramolecular hydrogen bonds formed and their stabilities. To compare the experimental 1H and 13C NMR chemical shifts with the calculated values, NMR chemical shift calculations were carried out using the gauge-invariant atomic orbital method.

Precise edge functionalization and tailoring of graphene via solvent-controlled reactions

Controllable edge-selective modification and tailoring of graphene are particularly critical for graphene applications. In this study, precise edge functionalization and tailoring of graphene are realized by a solvent-controlled Friedel-Crafts acylation reaction. Specifically, experimental and theoretical studies demonstrate that solvent effects can effectively control the reaction pathways of substituent and ionic mechanisms. Under the substituent mechanism, carboxyl groups are accurately introduced to the edge of graphene, which can be used as new reaction sites for further modification. Under the ionic mechanism, the acylation process can further tear graphene to the desired size. When the reaction is sufficient, graphene can be torn into highly dispersed high-quality quantum dots on a scale of 5 nm. This edge- and size-controllable fabrication method expands potential applications of graphene, such as electronic devices, semiconductors, catalysis and batteries.

Graphitic carbon-wrapped iron nanoparticles derived from a melamine-modified metal-organic framework as efficient Friedel-Crafts acylation catalysts

Developing efficient heterogeneous catalysts for Friedel-Crafts acylation (FCA) reactions is highly attractive for its wide application in green synthesis and biomass conversion. Herein, a series of graphitic carbon-wrapped iron nanoparticles (Fe/C-x, x refers to the heat temperature ranged from 500 to 800 °C) were prepared through pyrolysis of a metal-organic framework (MOF) precursor of Fe-TPA-Mel, synthesized from iron salt, terephthalic acid (TPA) and melamine (Mel). The resultant Fe/C-600 catalyst exhibited excellent catalytic activity for the acylation of aromatic compounds with acyl chlorides, and better recyclability than the reference catalyst of Fe/C-600-ref derived from the Fe-TPA precursor. Various characterization results demonstrated that introducing melamine in the MOF precursor is beneficial for the formation of graphitic carbon-wrapped Fe nanoparticles at relatively low pyrolysis temperature, although the N species existed in the precursor of Fe-TPA-Mel could be nearly completed removed during the pyrolysis process. The relatively uniform graphitic carbon shell could provide an effective protection for the inside active iron species, finally resulting in the generation of stable and easily recycled heterogeneous FCA catalysts.

Preparation and application of polystyrene-divinylbenzene sorbent with weak cation-exchange character for the selective extraction of illicit drugs in environmental water

A novel mixed-mode weak cation-exchange sorbent (PS-DVB-WCX-II) was prepared by the modification of polystyrene-divinylbenzene with mercaptosuccinic acid for the selective extraction of illicit drugs in environmental water. The PS-DVB-WCX-II was synthesized through the Friedel-Crafts acylation reaction on the surface of polystyrene-divinylbenzene, followed by nucleophilic substitution reaction and thiol-ene click reaction. The sorbent can selectively absorb illicit drugs through the reverse-phase interactions provided by benzene ring on the polymer backbone and the ion-exchange interactions provided by functional group (-COOH). As compared with the extraction performance of three commercial SPE cartridges, it was found that the prepared sorbent had better adsorption performance with the recovery values between 84.1% and 106.0% for the selected 11 illicit drugs under the optimized SPE conditions. Illicit drugs in environmental water were extracted by the sorbent, prior to the detection of UHPLC-MS/MS. Two quantitative methods were established respectively for the detection of 11 illicit drugs in different matrices of river water and wastewater. Both methods had good determination coefficient (r2>0.992) in the range of 0.5–50 ng/L, 2.5–250 ng/L, 5–500 ng/L, and low limits of detection (S/N = 3) of 0.17–1.67 ng/L. In the real wastewater samples, the concentration of morphine was 18.3–126.3 ng/L, and the methamphetamine was 12.7–27.4 ng/L. Meanwhile, PS-DVB-WCX-II was compared with Oasis MCX and Oasis HLB in the detection of real wastewater samples. The results revealed that PS-DVB-WCX-II and Oasis MCX had better performance in absorbing methamphetamine than Oasis HLB, and PS-DVB-WCX-II had better ability to remove the matrix. The results suggested that the prepared weak cation-exchange sorbent had the potential in the application of illicit drug detection in environmental water.

Enantioselective Separation of Amino Acids Using Chiral Polystyrene Microspheres Synthesized by a Post-Polymer Modification Approach.

The enantioselective separation of a racemic mixture of amino acids was achieved by chiral amino acid-modified polystyrene (PS) that was developed by a post-polymer modification approach. Styrene was polymerized using the reversible addition-fragmentation chain-transfer (RAFT) polymerization technique and further post-polymer modification was applied by Friedel-Crafts acylation reaction with chiral N-phthaloyl-l-leucine acid chloride to obtain the protected PS-l-Leu. The chiral PS (protected PS-l-Leu) was assembled into microspheres using a surfactant and was used for carrying out the enantioselective separation of amino acid racemic mixtures by enantioselective adsorption followed by a simple filtration process. Compared to as-precipitated chiral PS (protected PS-l-Leu) powder, the protected PS-l-Leu microspheres exhibited a better enantioselective separation efficiency (ee %). Furthermore, the protected PS-l-Leu was deprotected to obtain the amine-functionalized deprotected PS-l-Leu chiral PS, which was also assembled into microspheres and used for carrying out enantioselective separation. Deprotected PS-l-Leu-functionalized chiral PS microspheres could achieve up to 81.6 ee % for the enantioselective separation of a racemic mixture of leucine. This is one of the first reports of the synthesis of amino acid-modified chiral PS microspheres and their application to the simple filtration-based enantioselective separation of native amino acids from their racemic mixtures.

A mild synthetic strategy for removing acetic acid from fast pyrolysis-derived bio-oils utilizing Friedel–Crafts acylation reactions

Acetic acid from fast pyrolysis-derived bio-oils was removed by Friedel–Crafts acylation reactions, generating acetophenones, which possess more than eight carbons and could be converted to valuable components of fuels.

Nanoarchitectonics of Metal-Free Porous Polyketone as Photocatalytic Assemblies for Artificial Photosynthesis.

The main component of natural gas is methane, whose combustion contributes to global warming. As such, sustainable, energy-efficient, nonfossil-based methane production is needed to satisfy current energy demands and chemical feedstocks. In this article, we have constructed a metal-free porous polyketone (TPA-DPA PPK) with donor-acceptor (D-A) groups with an extensive π-conjugation by facile Friedel-Crafts acylation reaction between triphenylamine (TPA) and pyridine-2,6-dicarbonyl dichloride (DPA). TPA-DPA PPK is a metal-free catalyst for visible-light-driven CO2 photoreduction to CH4, which can be used as a solar fuel in the absence of any cocatalyst and sacrificial agent. CH4 production (152.65 ppm g-1) is ∼5 times greater than that of g-C3N4 under the same test conditions. Charge-density difference plots from excited-state time-dependent density functional theory (TD-DFT) calculations indicate a depletion and accumulation of charge density among the donor/acceptor functional groups upon photoexcitation. Most notably, binding energies from DFT demonstrate that H2O is more strongly bound with the pyridinic nitrogen group than CO2, which shed insight into mechanistic pathways for photocatalytic CO2 reduction.

Photophysical Properties of Linked Zinc Phthalocyanine to Acryloyl Chloride:N-vinylpyrrolidone Copolymer.

This paper focuses on the linking of zinc phthalocyanine (ZnPc) to N-vinylpyrrolidone (N-VP): acryloyl chloride (ClAC) copolymer. The synthesis of binary N-VP:ClAC copolymer was performed by the radical polymerization method and then grafted to ZnPc by the Friedel Crafts acylation reaction. We have developed a water-soluble ZnPc:ClAC:N-VP photosensitizer with a narrow absorption band at 970 nm, fluorescence at λem = 825 nm and the decay fluorescence profile with 3-decay relatively longer times of 1.2 µs, 4.6 µs, and 37 µs. The concentration-dependent dark cytotoxicity investigated in normal fibroblasts (NHDF), malignant melanoma (MeWo), adenocarcinoma (HeLa), and hepatocellular carcinoma (HepG2) cell lines incubated to increased concentrations of ZnPc:ClAC:N-VP (up to 40 μM) for 24 h in the dark show low cytotoxicity. Maximum cell viability in HeLa and HepG2 tumor cell lines was observed.

Fabrication of carbonyl-functional hypercrosslinked polymers as solid-phase extraction sorbent for enrichment of chlorophenols from water, honey and beverage samples.

Three carbonyl-functional novel hypercrosslinked polymers (HCP-TPS, HCP-TPA, and HCP-TPP) were successfully fabricated through anone-step Friedel-Crafts acylation reaction by copolymerizing paraphthaloyl chloride with triphenylsilane, triphenylamine, and triphenylphosphine, respectively. The resultant HCPs contained plenty of carbonyl-functional groups. Among the series of such HCPs, HCP-TPS displayed the best adsorption capability to chlorophenols (CPs), and thus it was employed as solid-phase extraction (SPE) adsorbent for enrichment of chlorophenols from water, honey, and white peach beverage prior todetermination by high-performance liquid chromatography. Under the optimal conditions, the detection limits of the method (S/N = 3) were 0.15-0.3ngmL-1 for tap water and leak water, 2.5-6.0ngg-1 for honey sample and 0.4-0.6ngmL-1 for white peach beverage sample. The recoveries of CPs in the spiked water, honey samples, and white peach beverage were in the range of 89.0-108.4%, 81.4-118.2%, and 85.0-113.5%, respectively. This work provides a new strategy for constructing functionalized HCPs as efficient SPE adsorbents. In this work, three novel hypercrosslinked polymers (HCPs) were synthesized by the Friedel-Crafts alkylation reaction (paraphthaloyl chloride as the alkylating agent, triphenylsilane, triphenylamine, and triphenylphosphine as the aromatic units). Then, HCP-TPS was applied to soild-phase extraction sorbent for enrichment CPs from water, honey, and white peach beverage samples.

Catalytic activity and stability of sulfonic-functionalized UiO-66 and MIL-101 materials in friedel-crafts acylation reaction

Sulfonic-containing UiO-66 and MIL-101 MOF materials, prepared by direct synthesis with a sulfonic acid-including benzene dicarboxylate (SO3H-BDC) linker, have been evaluated as acid catalysts in Friedel–Crafts acylation of anisole with acetic anhydride. The catalytic activity of these materials was compared to other conventional acidic sulfonic heterogeneous catalysts, such as commercial Nafion-SAC-13 and Amberlyst-15. The catalytic performance of MOF materials was significantly dependent on their textural properties and the availability of sulphonic acid groups. MIL-101-SO3H material displayed a remarkable anisole conversion and specific activity per sulfonic acid centre due to its open structure and multimodal pore size distribution. The inherent properties of MIL-101-SO3H material allowed a more sustainable catalyst regeneration than those used for conventional heterogeneous catalysts due to the deposition of reagents and products, in particular poly-acetylated compounds. MIL-101-SO3H proved an easy recovery and reusability in successive runs without any loss of activity. These promising results evidenced the potential of MIL-101-SO3H as an alternative catalyst for acid-catalyzed reactions.

Efficient and magnetically recoverable U (VI) adsorbent: Fe3O4 loaded hypercrosslink copoly (styrene/maleic anhydride)

Here, copoly (styrene/maleic anhydride) was hypercrosslinked using a simple Friedel–Crafts acylation reaction to produce a novel porous hypercrosslink polymer bearing carboxy groups (C-SMA). As a support, C-SMA was loaded with Fe3O4 through a solvothermal method to produce a magnetic uranium adsorbent (Fe3O4@C-SMA), which was systematically characterized using FT-IR, TGA, SEM, XRD, VSM, BET, and XPS. Uranium adsorption was carried out by using Fe3O4@C-SMA under different conditions to evaluate its uranium adsorption capacity. The adsorbent shows good uranium adsorption performance (178 mg·g−1 at pH = 6), has excellent stability, and can be readily magnetically recovered. The porous framework of C-SMA avoided the magnetic agglomeration effect of bare Fe3O4. XPS analysis indicates that both the carboxy groups and Fe3O4 contribute to the uranium adsorption on Fe3O4@C-SMA.

Friedel-Crafts acylation reaction over hierarchical Y zeolite modified through surfactant mediated technology

Friedel-Crafts acylation reaction was studied under mild conditions using hierarchical HY zeolite samples prepared through surfactant mediated technology, in the presence of NH4OH, using CTAB or DTAB as surfactants and changing the duration of treatment from 6 to 48 h. The materials were characterized by powder X-ray diffraction, low temperature N2 adsorption isotherms, SEM microscopy and pyridine adsorption followed by FTIR. The catalytic behaviour was studied in the acylation of furan by acetic anhydride. The catalytic results reflect the role of the duration of the treatment as well as the surfactant molecule used. As the time of treatment increases, the enlargement of the pores leads to an increase of the rate constant and turnover frequency (TOF), except for sample modified during longer time, 48 h, due to the occurrence of secondary reactions that produce larger products or reaction intermediates that become trapped inside the pores. The role of the surfactant molecule is also relevant since the sample modified in the presence of the larger surfactant molecule, CTAB, a significant increase in product yield and rate constant is obtained when compared with the sample prepared in the same conditions using DTAB. However, in that case, by prolonging the treatment a substantial decrease in the same parameters occurs due to the occurrence of deactivation phenomena, pointing out that the optimized modification of porosity needs to be customized according to the needs of each catalytic system.

Improving the performance of quaternized SEBS based anion exchange membranes by adjusting the functional group and side chain structure

Polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) has attracted more and more attention recently for using as the matrix of anion exchange membranes (AEMs) in fuel cells due to its low cost, superior mechanical properties and ether-free total C-C bond backbone. In this work, the short side chain of chloromethyl and long side chain of bromohexanoyl groups are grafted into the SEBS copolymer via the chloromethylation and Friedel-Crafts acylation reactions. After quaternized by different nitrogen heterocyclic compounds including 1-methylimidazole (Im), 1-methylpyrrolidine (Mpy), N-methylpiperidine (Pip) and 2-methyl-1-pyrroline (Mpyl), various SEBSCn-x AEMs are prepared. Combing with small molecule model experiment results, Mpy and Pip cations grafted SEBS membranes are confirmed to possess good alkali resistance, while SEBSC1-x membranes with Im and Mpyl cations are not suitable for AEMs due to their poor alkaline stability. Meanwhile, long side-chain cation grafted SEBSC6-x AEMs with lower ion exchange capacity (IEC) values exhibit higher water uptake, ionic conductivity and mechanical strength simultaneously comparing with short side-chain cation grafted SEBSC1-x AEMs. As an example, the SEBSC6-Pip membrane with an IEC of 0.48 mmol g−1 exhibits a water uptake of 47% at 80 °C, an OH− conductivity of 57.7 mS cm−1 at 80 °C, a tensile strength of 52 MPa at room temperature, and a conductivity retention percent of 75% after 600 h in 1 M KOH at 80 °C, demonstrating a big potential for the AEM fuel cell application.

Application of activated bentonite impregnated with PdO as green catalyst for acylation reaction of aromatic compounds

Friedel-Crafts acylation reaction is a well-known reaction to synthesize acetophenone derivatives, which have a broad spectrum of bioactivity. However, Friedel-Crafts acylation mostly used acetyl chloride as a reagent with Lewis acid as a homogeneous catalyst, which is a nonenvironmental friendly process. In this work, a simple and efficient Friedel-Crafts acylation reaction is reported using the activated bentonite impregnated with PdO (PdOAB) as the heterogeneous catalyst. The PdOAB catalyst material was prepared through a two-steps reaction, i.e., an acid activation of natural bentonite and impregnation of palladium(II) nitrate under alkaline conditions. The optimum condition of the acetophenone synthesis was evaluated using the catalyst material by varying the catalyst mass and reaction time. The acetophenone derivatives with R = -H, -Cl, -CH3, -OCH3, -OH, and -NH2 at the para position were successfully synthesized from its corresponding aromatic compounds with glacial acetic acid in 86.6%, 7.9%, 91.7%, 86.6%, 82.7%, and 78.9% yield, respectively. From the experimental results, we proposed that the catalysis mechanism was mainly facilitated by the acid sites of the PdOAB catalyst material. The PdOAB catalyst material did not significantly lose its catalytic activity after four-cycle processes. Therefore, a green method for acetophenone synthesis was established because the byproduct is water, and the catalyst material can be recovered.

A Review on Selective Production of Acetophenone from Oxidation of Ethylbenzene over Heterogeneous Catalysts in a Decade

The consumption of acetophenone (AP) is increasing worldwide because of its applications in products such as alcohol, aldehydes, resins, esters, fragrances, and pharmaceuticals. AP is manufactured via several methods like decomposition of cumene hydroperoxide, Hock process, and Friedel–Crafts acylation reaction using homogeneous catalysts with solvent and oxidant. However, it causes several environmental problems that deteriorate the production of AP with these methods. Oxidation of ethylbenzene (EB) is one of the promising methods to synthesize AP in liquid and vapor phases reaction using heterogeneous catalysts, which plays a vital role for selective production of AP. In this review, numerous heterogeneous catalysts are discussed including transition metal nanoparticles, transition metal complexes, and metal free catalysts (carbon nanotubes) used in last 10 years for oxidation of EB. Additionally, catalyst activity along with reaction parameters and its effect, mechanisms, and kinetics study are summarized in this article. The future scope of this reaction is also highlighted. Moreover, this work identifies best catalysts for bulk production of AP with high yield to satisfy global requirement.