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To better understand the benzene alkylation with chloroaluminate ionic liquids (ILs) as catalyst, the interfacial properties between the benzene/butene binary reactants and chloroaluminate ILs with varying cation alky chain length and different anions were investigated using molecular dynamics (MD) simulations. The results indicate that ILs can obviously improve the interfacial width, solubility and diffusion of reactants compared to H2SO4. The longer alkyl chains of cations present a density enrichment at the interface and protrude into the binary reactants phase. Furthermore, the ILs consisting of 1-octyl-3-methylimidazolium cations ([Omim]+) and the stronger acidity heptachlorodialuminateanions ([Al2Cl7]–) are more beneficial to promote the interfacial width and facilitate the dissolution and diffusion of benzene in both the IL bulk and the interfacial region in comparison to the ones with shorter alkyl chains cations and weaker acidity anions. The information gives us a better guideline for the design of ILs for benzene alkylation.

Side-chain alkylation of toluene with methanol is a green pathway to realize the one-step production of styrene under mild conditions, but the low selectivity of styrene is difficult to be improved with by-products of ethylbenzene and xylene. In this study, a new way is introduced to improve the catalytic performance by means of assisting basic compounds as co-catalysts during the toluene side-chain alkylation with methanol to styrene. As a result, high activity of side-chain alkylation appears over the basic Cs-modified zeolite catalysts prepared by ion exchange and impregnation methods. This high performance should be mainly attributed to two co-catalysis actions: (1) the promotion of basic compounds for methanol dehydrogenation to formaldehyde as the intermediate for side-chain alkylation; (2) the suppression of the styrene transfer hydrogenation on basic Cs-modified zeolites to avoid the formation of ethylbenzene. Especially for Cs2O/CsX-ex catalyst, the addition of 2 mol% 2-picoline in reaction mixture could achieve both 12.3% toluene conversion and 84.1% styrene selectivity. Whereas the higher concentration of 2-picoline (>6 mol%) caused an inhibition to the catalytic activity because the excessive basic compound poisoned the combined acid-base pathway required for the side-chain alkylation process. In addition, two possible side-chain alkylation reaction routes on Cs-modified zeolite under the different 2-picoline absorption were described.

Chitosan exhibits moderate antimicrobial properties. Here, we enhanced the antimicrobial properties of chitosan through alkylation and chlorination and evaluated the effect of alkylation on chitosan's hydrophobicity, bacterial attachment, chlorination, biocidal property, and stability. First, chitosan films were prepared through casting and were then immersed in a hexanal solution of different concentrations. The aldehyde groups of hexanal reacted with the amino group in chitosan through a Schiff base reaction. Next, the hexanal-modified chitosan films were soaked in 10 % bleach to form N-halamine. The results demonstrated that the surface became more hydrophobic, and chitosan films with increased hexanal-grafting concentrations exhibited less bacterial attachment. However, the degree of chlorination decreased as the degree of alkylation increased, further reducing the diameter of the zone of inhibition. Nevertheless, all chlorinated samples could kill ~5 log of Staphylococcus aureus and Escherichia coli within 30 min. Unlike previous results for chlorinated chitosan, in this study, alkylation before chlorination enhanced antibacterial properties and bactericidal ability and decelerated the degradation of chlorinated samples. The results of a systematic evaluation indicated that a hexanal-grafting concentration of approximately 80 mM maintains the equilibrium of the various properties of chitosan. Alkylated and chlorinated chitosan has considerable potential application as mask filter layers.

In the present study, a series of ordered nanostructured KIT-6 silica, functionalized with different numbers of sulfonic groups (–SO3H) introduced by grafting or co-condensation, were synthesized. The obtained samples were subjected to thorough physicochemical characterization using X-ray diffraction, transmission electron microscopy, low temperature nitrogen sorption, infrared spectroscopy and elemental analysis. It has been observed that the amount of the used functional group precursor clearly affects the structural and textural parameters of the studied materials synthesized by co-condensation. On the other hand, the samples modified by grafting, irrespective of the number of the introduced –SO3H groups, exhibit a stable mesoporous structure with Ia3d symmetry, characteristic of KIT-6 materials. The developed synthesis procedures yielded potential solid acid catalysts, which were used in the test catalytic reactions: Friedel-Crafts alkylation, fatty acid esterification and Pechmann condensation. Both the developed synthesis algorithm and the catalytic reaction procedures comprised elements of "green chemistry", as the transformation of the functional groups precursor (–SH to –SO3H) took place in the presence of H2O2, an oxidant considered to be environmentally friendly, while the catalytic reactions were carried out without solvents and under microwave-assisted conditions, which allowed a significant shortening of the reaction time.

A systematic study on the use of noble metals (Pd, Pt, Au) supported on titanate nanotubes (NT-Ti) for selectively producing BTX and p-cymene from waste tire pyrolysis is provided here. All the materials were characterized for chemical, textural and structural properties using a range of analytical techniques. The M/NT-Ti (M: Pd, Pt, or Au) catalysts exhibit low nanoparticle sizes (1.8 Pt ≈ Au > support > non-catalyst. The Py-GC/MS suggest that the catalysts participate in the secondary reactions of dealkylation, dehydrogenation, isomerization, aromatization, and cyclization leading to a higher formation of BTX than the uncatalyzed reaction. Finally, a comprehensive reaction pathway describing the catalytic pyrolysis of WT over Pd/NT-Ti was proposed by studying the catalytic pyrolysis of individual polymers constituting the waste tires, and D, L -Limonene.

Lanthanum-containing (LaX) and cerium-containing X zeolites (CeX) were prepared by a double-exchange, double-calcination method. By changing the calcination atmospheres between nitrogen and air, the CeIV contents in CeX zeolites were adjusted and their impacts on physicochemical properties and catalytic performance in isobutane alkylation were established. The crystallinity of CeX zeolite was found to be negative correlated with the CeIV content. This is believed to be due to the water formed during the oxidation of CeIII, which facilitates the framework dealumination. As a consequence, calcining in air results in a great elimination of strong Bronsted acid sites while under nitrogen protection, this phenomenon was mostly hindered and the sample's acidity was preserved. When tested in a continuously flowed slurry reactor, the catalyst lifetime for isobutane alkylation was found to be linearly related with the strong Bronsted acid concentration. In addition, Ce3+ was found more benefit for the hydride transfer compared with La3+, which is ascribed to the stronger polarization effect on the C-H bond of isobutane. Moreover, the decline of hydride transfer activity can be slowed down by the catalytic cracking of the bulky molecules. Based on the product distribution, a new catalytic cycle of dimethylhexanes (DMHs) involving a direct formation of isobutene rather than tert-butyl carbocation was proposed in isobutane alkylation.

Cyclohexylphenol (CHP) is a high added-value chemical, extensively used for the preparation of dyes, resins and biocides. This molecule is currently synthetized by phenol alkylation with cyclohexene/cyclohexanol using highly polluting mineral Bronsted acids as catalysts. The present contribution reports the one-pot production of cyclohexylphenol via hydroalkylation, using phenol as the only organic reactant, over a number of bifunctional catalysts consisting of Co2P (5 wt.% Co) supported over different zeolites (ferrierite, mordenite, beta and MCM-22). Phenol conversion increased in the order: Co2P/Mordenite (30%)

An efficient photocatalytic alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester has been developed. The transformation is taken advantage of alkyl radicals to attack allylic amide with the assist of inexpensive rose bengal as photocatalyst to prepare a series of alkyl substituted oxazolines in moderate to excellent yields. High regioselectivity, operational safety, mild conditions and excellent substrate generality give this protocol broad application prospects.

Herein, an efficient molecular oxygen-mediated method for the selective hydroxyalkylation and alkylation of quinoxalin-2(1H)-ones with alkylboronic acids under transition-metal free conditions has been developed. This strategy demonstrates a broad scope of quinoxalin-2(1H)-ones and alkylboronic acids, giving 3-hydroxyalkylquinoxalin-2(1H)-ones and 3-alkylquinoxalin-2(1H)-ones in moderate-to-good yield. Control experiments reveal that a radical pathway is involved.

The development of innovative strategies and methods to provide natural product-like macrocycles not accessible by biosynthesis, but endowed with novel bioactivities and simplified structure, is highly desirable. Inspired by the key scaffolds of rapamycin and FR252921, herein, we report a Rh(III)-catalyzed C–H alkylation macrocyclization, which enables access to CF3-substituted macrolides. DFT calculations reveal that the chemoselectivity between C–H alkylation and olefination macrocyclization was highly controllable. Moreover, the unique CF3-substituted macrolides showed potent anti-inflammation activities against TNF-α, IL-6 and CCL2 mRNA expression.

N6-methyl adenosine (m6A) is an eminent epigenetic mark in mRNAs that affects a broad range of biological functions in diverse species. However, the chemically inert methyl group prevents a direct labeling of this modification for subsequent detection and sequencing. Therefore, most current approaches for the labeling of m6A still have limitations of relying on the utilization of corresponding methyltransferases, which resulted in the lacking of efficiency. Here we present an approach which selectively alkylated the N6-formyl adenosine (f6A), the key intermediate during chemical oxidation of m6A, with an alkyne functionality that can be further labeled with click reactions. This covalent labeling approach will be able to facilitate in the affinity purification, detection and genome-wide profiling studies.

ispartof: JOURNAL OF CATALYSIS vol:406 pages:206-212 status: published

Here, a rhodium(III)-catalyzed benzo[c]azepine-1,3(2H)-dione synthesis via tandem C–H alkylation and intramolecular amination of N-methoxylbenzamide with 3-bromo-3,3-difluoropropene as the alkylation agent is reported. The substituted benzamides and protected indoles are all tolerated, yielding the corresponding products in moderate to good yields. Further study revealed those bioactive compounds such as piperic acid and a key precursor of Roflumilast all perform well, highlighting the synthetic utility of this method.

A palladium-catalyzed 2-alkylation of indoles with α-bromo esters is developed by employing a P,P=O ligand. The method features excellent regioselectivities, mild reaction conditions, and good functional group compatibility. The employment of the P,P=O ligand as well as 4A molecular sieves were crucial for the success of the transformation. Mechanistic studies indicate the reaction proceed through a radical pathway.

Earth abundant metals are much less expensive, promising, valuable metals and could be served as catalysts for the borrowing hydrogen reaction, dehydrogenation and heterocycles synthesis, instead of noble metals. The uniformly dispersed zinc composites were designed, synthesized and carefully characterized by means of XPS, EDS, TEM and XRD. The resulting zinc composite showed good catalytic activity for the N-alkylation of amines with amines, ketones with alcohols in water under base-free conditions, while unsaturated carbonyl compounds could also be synthesized by tuning the reaction conditions. Importantly, it was the first time to realize the synthesis of 2-aryl-1H-benzo[d]imidazole derivatives by using this zinc composite under green conditions. Meanwhile, this zinc catalyst could be easily recovered and reused for at least five times.

A sulfonium ylide participated alkylation and arylation under transition-metal free conditions is described. The disparate reaction pattern allowed the separate activation of non-ylidic S-alkyl and S-aryl bond. Under acidic conditions, sulfonium ylides serve as alkyl cation precursors which facilitate the alkylations. While under alkaline conditions, cleavage of non-ylidic S-aryl bond produces O-arylated compounds efficiently. The robustness of the protocols were established by the excellent compatibility of wide variety of substrates including carbohydrates.

The fabrication of stable and efficient catalysts for green and economic catalytic transformation is significant. Here, highly stable covalent triazine frameworks (CTF-1) were used as the supporting material for anchoring ultrafine Pd nanoparticles (NPs) via a facile impregnation process and a one-pot calcination-reduction strategy. The widespread dispersion of ultrafine Pd NPs was a result of the abundant high nitrogen-content triazine groups of CTF-1 that endowed the catalyst Pd@CTF-1 with high catalytic activity. The catalytic performance of Pd@CTF-1 was demonstrated by the one-pot N-alkylation of benzaldehyde with aniline (or nitrobenzene) under mild reaction conditions, and Pd@CTF-1 exhibited a wide range of general applicability for N-alkylation reactions. The reaction mechanism for the N-alkylation reaction was also studied in detail. In addition, the Pd@CTF-1 catalyst exhibited high thermal and chemical stability, maintaining good catalytic efficiency after multiple reaction cycles. This study provides new insights for the fabrication of organic supporting materials with highly dispersed active catalytic sites that can lead to excellent catalytic performance for efficient, economical, and green reactions.

One of the most popular building blocks for producing organic semiconductors is 2,7-dibromo-9H-carbazole and its derivatives. Building blocks based on 9H-carbazole are among the most expensive building blocks. The article presents new, highly effective, and “green” methods for the synthesis of 2,7-dibromo-9H-carbazole and its derivatives under microwave irradiation. The use of a flow-type microwave reactor significantly reduced the synthesis time. The methods described differ in efficiency, simplicity, performance, and a significant reduction in time compared to classical methods. The research was conducted in accordance with the principles of green chemistry.

International audience; Alcohols and epoxides are arguably ideal electrophiles for the Friedel-Crafts alkylation, since they are widely available, require no pre-activation, and produce no stoichiometric waste beyond water. However, neither primary aliphatic alcohols nor most classes of terminal epoxides are compatible with existing intermolecular Friedel-Crafts methodologies, and sequential Friedel-Crafts reactions starting from epoxides consequently remain underexplored. Here, we report that these limitations are easily overcome using Brønsted acid catalysis in hexafluoroisopropanol (HFIP) as a solvent. Electron-poor aromatic epoxides and aliphatic epoxides undergo stereospecific arylation to give an alcohol which, depending on the reaction conditions, can partake in a second nucleophilic substitution with a different arene in one pot. Phenyl ethanols react through a phenonium intermediate, whereas simple aliphatic alcohols participate in a rare intermolecular SN2 Friedel-Crafts process, delivering linear products exclusively. This work provides an alternative to metal-catalyzed cross-couplings for accessing important scaffolds, widening the range of applications of the Friedel-Crafts reaction

A series of calcined HTLcs catalysts were prepared and modified with potassium phosphate by impregnation method to clarify the influence of catalyst alkalinity on the side chain alkylation of toluene with methanol for synthesis of ethylbenzene and styrene,. The catalysts were characterized by X-ray diffraction (XRD), N2 physical adsorption-desorption, Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), X-ray photoelectron spectrometry (XPS), NH3 temperature-programmed desorption (NH3-TPD) and CO2 temperature-programmed desorption （CO2-TPD）. It was found that the selectivity of styrene was highest (39.25%) when the K3PO4 loading was 7.5wt%. And the total yield of styrene and ethylbenzene could reach 65.08% with 10 wt% K3PO4 loading. This might due to the fact that the addition of K3PO4 could adjust the acid and basic sites of catalysts. In addition, appropriate strength and amount of basic sites were favorable to producing more styrene.

Acidic cesium salt of tungstophosphoric heteropoly acid, Cs2.5H0.5PW12O40 (CsPW), is an excellent solid acid catalyst for the reaction of phenylacetaldehyde with biorenewable monoterpenic alkenes: limonene, α-terpineol, α-pinene and β-pinene. Simultaneously with a conventional oxonium-ene cyclization to give an oxabicyclo[3.3.1]nonene compound, phenylacetaldehyde undergoes Friedel-Crafts alkylation by the monoterpenes resulting in a new product with an unusual fused tetracyclic structure, obtained in ca. 80 % yield. A combined yield for both products was up to 95 %. Styrene oxide can be also used as a starting material for these reactions to give the same products in up to 85 % combined yield. A novel one-pot tandem process thus developed involves the isomerization of styrene oxide into phenylacetaldehyde and cycloaddition of the latter to the monoterpene, with both steps being catalyzed by CsPW. The reactions were performed in green solvents diethylcarbonate or anisole, which have high sustainability ranks in modern solvent selection guides, comparable to those of ethanol and water.

The application of asymmetric catalysis in industrial processes is limited by the high cost of chiral ligands and the difficulty associated with recovering precious metal catalysts. Here, based on a FeCl3-catalyzed Friedel–Crafts alkylation reaction, an aromatic amino acid was crosslinked with 4,4′-bis(chloromethyl)-1,1′-biphenyl to produce a novel porous chiral catalyst support, hypercrosslinked amino acid polymer (HCP-AA). Subsequently, metal catalysts were loaded on HCP-AA through the coordination of the metal ion with amino acid residues to generate heterogeneous asymmetric catalysts, HCP-AA-M. The resulting catalysts were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The HCP-AA-M samples were employed to catalyze the heterogeneous asymmetric reaction, and they achieved high enantioselectivities (up to 99% ee). Meanwhile, the catalysts could be readily recovered through filtration, and they exhibited good recycling performances. The results suggested that the utilization of inexpensive amino acids as raw materials for producing porous chiral supports for recyclable high-performance asymmetric catalysts is an effective strategy.

A well-defined hexamethylenetetramine (abbreviated as HMTA) based two-dimensional (2D) MOFs metalloligand (termed Zn-HMTA), with free uncoordinated tertiary amine groups, has been synthesized via solution diffusion method for the first time. The crystal structure of 2D Zn-HMTA metalloligand was determined by the single crystal X-ray diffraction (SCXRD). The SCXRD and X-ray photoelectron spectroscopy (XPS) analyses have revealed that the 2D Zn-HMTA metalloligand is rich in- free tertiary amine groups, which are of strong coordination ability to transition metal ions (e.g. Ni2+, Co2+, Zn2+, Cu2+). As a result, a 2D bimetallic Co@Zn-HMTA MOFs was synthesized via coordination-assisted impregnation (CAI) strategy attributed to the unique feature of strong coordinated ability of free tertiary amine groups. Furthermore, a series of self-supported Co-ZnO-CN nanocatalysts were afforded upon the as-synthesized Co@Zn-HMTA MOFs served as a self-sacrificial template for pyrolysis at different temperatures. The optimized catalyst (termed as Co-ZnO@CN-CAI) demonstrated the excellent catalytic performance for hydrogenation-alkylation tandem reaction in comparison with the classic ZnO@CN composite (derived from Zn-HMTA MOFs) supported metallic Co catalyst (Co-ZnO@CN-IWI) prepared by incipient wetness impregnation method. Moreover, the kinetic study was also performed to confirm that the alkylation is the rate-determining step in the hydrogenation-alkylation tandem reaction. The origin of enhanced catalytic performance of Co-ZnO@CN-CAI and the role of Co@Zn- HMTA MOFs precursor have been explored by way of various characterizations, e.g. HADDF-STEM-EDS, SEM-EDS, 13C MAS NMR, XRD, Raman and XPS, etc. It is anticipated that the prepared low-cost and easily prepared 2D Zn-HMTA metalloligand will become a general template for synthesis of highly self-supported catalysts with coordination-assisted impregnation strategy (CAI) for various catalytic reactions.

In situ formation of composite micro-mesoporous dendritic fibrous nano-silica (DFNS) and Al-DFNS was prepared using a cetylpyridinium bromide (CPB) template synthetic system. Dealumination is induced by impregnation of zirconium with flux followed by a sulfuric acid treatment. This procedure results in a series of highly uniform nano-spheres, which exhibit stronger acid property than that of Al-MCM-41. In the selective alkylation of anthracene with tert‑amyl alcohol, SO42− modified Zr-contained dealuminated Al-DFNS (SZ-DeAl-DFNS) shows great catalytic activity and higher conversion (60.8%). The DFNS samples were characterized with XRD, SEM, TEM, NH3-TPD and other techniques. The results reveal that DFNSs consist of center-radial micro-mesopores and that the acid contribution of SZ-DeAl-DFNS is much broader, as compared with amorphous aluminosilicate

With the development of coal chemical industry, large amounts of naphthalene and n-butene are produced, and converting them into high value-added products through alkylation has gained particular importance and interest. In this work, liquid coordination complexes (LCCs) were used as acid catalysts for the first time in the naphthalene alkylation reaction under mild conditions to obtain multi-butylnaphthalenes with high yield. Various reaction conditions were thoroughly investigated. The LCC consisting of urea and AlCl3 showed excellent catalytic performance under optimal reaction conditions, giving 100% conversion of naphthalene and 99.66% selectivity towards multi-butylnaphthalenes. Combining the catalyst properties and catalytic results, a plausible reaction mechanism was proposed. The lubricating properties of the synthesized products were investigated for their potential application as lubricating base oils. The synthesized multi-butylnaphthalenes showed comparable physicochemical properties and tribological performances as the commercial cycloalkyl base oil.

This work presents a novel strategy for engineering a GC stationary phase with high selectivity, inertness and thermal stability by introducing the 3D π-rich TP moieties to the terminals of a polar chain polymer. Herein, we provide the first example, i.e., a new TP-terminated polycaprolactone polymer (TPP) as the stationary phase for GC analyses. As demonstrated, the TPP column achieved distinctly improved inertness to fatty acids and aldehydes, and dramatically enhanced thermal stability (about 100 °C higher) over the PCL column. Also, the TPP column exhibited high resolving capability towards the positional isomers of phenols, anilines and alkylated/halobenzenes and showed good potential in detecting minor impurities in chemical products. Importantly, the proposed strategy is facile, feasible and generally applicable to analogous polymers.

The photo-/electrocatalytic functionalization of quinoxalin-2(1H)-ones has emerged as a promising and powerful approach for post-synthetic modification of quinoxalin-2(1H)-ones. This review provides an overview of recent developments in photo-/electrocatalytic functionalization of quinoxalin-2(1H)-ones including arylation, alkylation, fluoroalkylation, amination, phosphorylation, acylation, alkoxylation, thiolation, silylation, and annulation. The reaction scope and the related mechanism are also well discussed.

Summary The first catalytic asymmetric synthesis of N–N axially chiral compounds has been accomplished via a quinidine catalyzed N-allylic alkylation reaction. These N–N axially chiral frameworks are a new addition to the families of axially chiral molecules and to the atropisomerism involving heteroatom(s), e.g., N, O, and S. The reaction takes place smoothly under mild conditions and displays excellent functional group tolerance, allowing facile access to a variety of N–N axially chiral 1-aminopyrroles and 3-aminoquinazolinones in high yields and excellent enantioselectivities. DFT calculations have been applied to understand the origin of enantioselectivity and provide guidance for the design of additional molecules of this type. The investigation of N–N axis atropisomerism holds promise for new discoveries in medicinal chemistry and asymmetric catalysis.

Cellulose derivatives such as hydroxyethylmethylcellulose (HEMC), and hydroxypropylmethylcellulose (HPMC), which are originated from biomass, were used as mesoporous directing agent for the synthesis of hierarchical ZSM-5 zeolite. Hierarchical ZSM-5 zeolites with outstanding mesoporosity and high hierarchy factors were achieved by hydrothermal method in the presence of bio-mesoporogen. The as-synthesized hierarchical ZSM-5 zeolites were characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption (BET), scanning electron microscope (SEM) to determine the structure of samples. The influences of different mesoporogens with different dosage in the synthetic process on the physicochemical and catalytic properties of hierarchical ZSM-5 zeolite were investigated. Possession of the high mesopores, high surface areas and abundant accessible acid sites, the hierarchical zeolites exhibited excellent catalytic performance in the alkylation reaction of benzene and benzyl alcohol.

Surface reaction kinetics and light absorption properties of a photocatalyst are essential demands for efficiently solar to chemical energy converting. In this study, plasmonic WO3–x was firstly applied to photocatalytic alkylation of arenes under red light irradiation. The oxygen vacancies, both on the surface and in the bulk of WO3–x, allow abundant free electrons to increase carrier densities and support its LSPR using low energy photons. The surface oxygen vacancies have more functions: they not only release surface tungsten sites which ensure the chemisorption of alcohols due to the coordianation ability but also promote the activation of alcohols via an efficient transport of the holes on the neighbouring O sites to chemisorption alcohol species. In brief, the bulk oxygen vacancies provide abundant charges and the surface vacancies promote the bond adsorption and activation abilities, which ensure the high efficiency of photocatalytic alkylation of C–H.

2-(N-alkylamino)pyrimidines are important heterocycles widely found in various pharmaceutically important drugs. Here, we have disclosed a new cooperative ruthenium complex catalyzed tandem multicomponent synthesis of 2-(N-alkylamino)pyrimidines directly from guanidine salt and alcohols. The reactions proceeded through the dehydrogenation of alcohols, followed by C C coupling and sequential C N coupling with guanidine and primary alcohol, with the elimination of three equivalents of hydrogen gas. In this work, application of both the acceptorless dehydrogenative coupling (ADC) and borrowing hydrogen (BH) strategies were accomplished in a single reaction. This catalytic method tolerated a wide range of substrates. The viability of the current method was demonstrated by preparative scale synthesis of a few products. A plausible catalytic cycle was proposed based on various control experiments, mechanistic studies and DFT calculations. Remarkably, 42 new 2-(N-alkylamino)pyrimidines were synthesized following this catalytic protocol.

A strategy for the synthesis of alkenyl ketones via the α-alkylation of ketones with alkenyl ketones has proposed and accomplished. In the presence of a metal–ligand bifunctional catalyst [Cp*Ir(2,2′-bpyO)(H2O)], a series of desirable products were obtained in high yields. Mechanistic investigation revealed that functional groups in the ligand are crucial for the activity of catalyst and selective transfer hydrogenation is the determining step of the formation of alkenyl ketones as products. Notably, the present research exhibited also the unique potential of metal–ligand bifunctional catalysts for the activation of unsaturated alcohols as electrophiles for hydrogen auto-transfer process.

The reactions of imino phenols 3,5-But2-2-HOC6H2CH=NX (X = 8-C9H6N, 2-MeO-5-MeC6H3 and 2-PhOC6H4) with Sc(CH2SiMe3)3(THF)2 in toluene proceed with silane elimination and reductive alkylation of the C N group affording dimeric base-free monoalkyl scandium complexes. X-ray analysis of the two complexes revealed their dimeric structures due to μ-bridging amidophenolato dianions. The complexes catalyze hydrophosphination of styrene, phenylacetylene and tolane with Ph2PH as well as dehydrogenative coupling of anisole with hydrosilanes.

Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good yields (32%–91%). In addition, a gram-scale reaction, late-stage modification of drug, synthetic transformation of the product, and further application of the catalytic strategy were also performed. Preliminary studies indicate that the reaction undergoes a radical process.

Summary The C–H alkylation of arenes with N-based directing groups typically requires high temperatures and/or harsh reaction conditions, which has traditionally reduced its functional group compatibility and applicability for late-stage functionalization. We report that a cyclometallated Ru complex is able to perform the C–H alkylation of arenes bearing a variety of N-directing groups with primary alkyl bromides at room temperature and under mild reaction conditions. We demonstrate this with an extended substrate scope, which includes several examples of late-stage alkylation of drug molecules, thus showcasing the “real-world” capabilities of this method. Mechanistic studies show that, in contrast to previous mechanistic proposals, the reaction proceeds via a bis-cyclometallated Ru intermediate, followed by an SN2-type oxidative addition.

This research reports the success of the fabrication of hydrophobically modified chitosan cryogel. Chitosan was modified with alkyl groups through reductive animation. By varying the alkyl chain length and the substitution degree, the resulting cryogel could be optimized for strength, and the adsorption and release of hydrophobic dye, a model for hydrophobic medicines. By optimizing these attributes, the hydrogel was found to have the potential as a biomedical material.

A novel route for tandem C–C/C–N formation, annulation and aromatization of hydrazones with 1,2-dichloroethane to synthesize 1H-pyrazoles has been developed. Furthermore, the 1,2-dichloroethane serves as alkylation reagent in good to excellent yields. This methodology features mild reaction conditions and good functional group tolerance, providing a direct approach for the preparation of 1H-pyrazoles.

C4 alkylate oil is an ideal blending component of automotive gasoline, and the green removal of sulfuric acid and sulfates from the high-temperature sulfuric acid alkylation reaction products (SAARP) has always been a hot issue in the field of clean alkylation production. In this paper, a novel coalescence separation-depth adsorption (CS-DA) coupling dry separation technique is introduced to efficiently separate acid-hydrocarbon emulsions, with the aim to supersede the alkaline washing-water washing (AW-WW) process in alkylation unit. Lateral line tests were conducted on the coupling treatment of the alkylation reaction products (ARP) produced in the STRATCO alkylation unit of Sinopec Tianjin Branch. The sulfur morphology analysis shows that the sulfides in the ARP mainly come from C4 feedstocks and alkylation reaction, including mercaptans, thioethers, thiophenes, trace hydrogen sulfide and sulfur dioxide. The mechanism of coalescence separation reveals that the efficient removal process of sulfuric acid by fiber coalescence separation also has a function similar to "pickling extraction" to remove sulfates. In addition, we investigated the influence of CS-DA coupling treatment on the total sulfur and sulfuric acid content in the ARP and performed the copper corrosion and water-soluble acid assays. The research findings indicated that the back sideline of the acid coalescer had the most outstanding separation effect relative to the front and rear lateral lines of the heat exchanger. The total sulfur content in the ARP after separation can be reduced to less than 5 mg/L, without water-soluble acid and copper corrosion (1a). The industrial application shows that the CS-DA coupling dry separation technique can completely replace the AW-WW process, which makes the various indicators of alkylate oil strictly controlled and the sulfur content up to the industrial standard. The novel dry separation technique provides a promising alternative for solving the difficulties in the emulsion treatment of high-temperature sulfuric acid alkylation and promoting the clean production of alkylation.

Low rank coal- and biomass-derived liquids generally contain a mixture of alkylphenols, which can be dealkylated over zeolites into phenol as a basic chemical. Zeolites with different pore structures were evaluated for the dealkylation of 4-iso-propylphenol as a model alkylphenol, among which HZSM-5 and HMCM-22 displayed the highest phenol selectivity above 96 %. However, HZSM-5 deactivated fastest among the catalysts due to coke deposition. Thus, mesopores were introduced by desilication into HZSM-5 catalysts to improve the catalytic stability. The mesopore incorporation enhanced the connectivity of the micropores with the crystal surface, and shortened the diffusion lengths. Coke location analysis revealed that micropore occlusion by the coke shell occurred on the parent HZSM-5, whereas the acid sites in the desilicated catalysts were more accessible for fully utilization, even though the coke mainly deposited in the micropores. Furthermore, the coke on the desilicated HZSM-5 displayed a lower graphitization degree.

When treated with an alkoxide base like t-BuOK in aprotic solvent, N-diphenylmethyl imino oxindoles, made conveniently through condensation of corresponding isatins with N-diphenylmethyl amine, are deprotonated to form azaallyl anions. Allylation and alkylation of this type of intermediates proceed smoothly with diverse C-electrophiles. Acidic work up finishes 3-amino-3-allyl/alkyl oxindoles. The overall transformation equals to an umpolung process at the C3 of isatins.

Lignocellulosic biomass is a promising feedstock for the synthesis of value-added chemicals and biofuels. However, one of the biggest challenges for producing high-quality diesel fuels is the lack of sufficient carbon-chain length in biomass derivatives. In this study, a C17 diesel precursor 1,1,1-tris(5-methyl-2-furyl)ethane (TEMF) with a yield of ca. 70% was synthesized from the cascade acetylation-hydroxyalkylation/alkylation of bio-based 2-methylfuran (MF) with acetic anhydride (AA) catalyzed by acid-treated montmorillonite with enhanced acidity and improved porosity. The catalytic mechanism of the cascade reaction process was investigated over different types of acid species (Bronsted acid and Lewis acid), and the influence of in situ formed acetic acid was also examined. A synergistic effect was observed to enable the synthesis of TEMF from the trimerization of MF with AA, in which Lewis acid and weak Bronsted acid species mainly catalyze the acetylation and hydroxyalkylation processes, while the subsequent alkylation step is mainly catalyzed by strong Bronsted acid.

Summary Direct alkylation and arylation of allylic C(sp3)–H bonds are straightforward approaches for accessing allylic C–C products. However, the engagement of allylic C–C bond-forming reaction without introducing extraneous functional groups and stoichiometric oxidant or reductant has proved difficult. Here, we report a general and mild strategy using semiconductor quantum dots (QDs) as photocatalysts for coupling a broad range of available allylic C(sp3)–H bonds with α-amino C–H bonds or heteroarenes, respectively, under sunlight irradiation (> 85 examples). The protocol bypasses stoichiometric oxidant or reductant and pre-functionalization of both the coupling partners and produces hydrogen (H2) as the byproduct. The outstanding efficiency and selectivity and step- and atom-economy represents the first direct alkylation and arylation of allylic C(sp3)–H bonds with hydrogen evolution powered by solar energy.

The high value-added products such as alkyl substituted phenols (A-Ps) are very important from lignin-derived feedstocks. Herein, the selective conversion of guaiacol, an important chemical of lignin-derived bio-oil, to A-Ps over hydrothermally synthesized bulk MoS2 (HT-MoS2) was examined under supercritical methanol conditions without any gaseous hydrogen input. HRTEM confirms the formation of MoS2 with the nanosheet-like structure and XPS analysis exhibited the presence of Mo5+ and S22- species which are likely the active species for demethoxylation (DMO) and alkylation of guaiacol. The possible reaction pathways along with their plausible intermediates of guaiacol conversion are proposed. The HT-MoS2 catalyst can be reused up to 4 catalytic runs without loss of its catalytic activity.

Stoichiometry and stability of electron donor–acceptor complexes formed by dibenzothiophene and its alkylated derivatives with DDQ and TCNE in nonpolar organic solvents has been investigated. 4,6-Dimethyldibenzothiophene produces the most stable 1: 1 complex with DDQ in agreement with energy levels of the π-donors HOMOs and π-acceptors LUMOs calculated by DFT. The results make possible an employment of the complexes for multiplex determination of polycyclic aromatic pollutants using surface enhanced Raman spectroscopy.

Chloroaluminate ionic liquids (CIL) mixed with small amounts of aromatics are highly selective catalysts for the alkylation of isobutane and 2-butene. The effects of aromatics on the alkylation reaction were investigated by experimental methods and theoretical calculations. Through NMR, in situ IR, and Raman characterizations, it was found that the aromatics interacted with ions and formed aromatic–AlCl4−, aromatic–Al2Cl7−, and [aromatic–H]+ species. These new species buffer the acidity at a lower level and modify the activity of CIL. Theoretical calculations show that only the aromatics enriched at the acid–hydrocarbon interface and with appropriate charge transfer can effectively affect the CIL alkylation. The aromatic–ion interaction inhibited the polymerization side reactions and promoted hydride transfer from isobutane to C8+. These new insights have improved our understanding of the effects of ions on the CIL alkylation reaction.

A nickel(II)-catalyzed asymmetric alkylation of acyclic oxocarbenium ions generated in situ from corresponding acetals with carboxylic acid derivatives to prepare β-alkoxyl carbonyl moieties with diverse α-substituents has been disclosed. The method exhibited broad scope of acetals and carboxylic acid derivatives with excellent enantioselectivity and good functional group compatibility, and can be conducted in a gram-scale without obvious loss of efficiency.

Recently, DNA-encoded library (DEL) technology has emerged as an innovative screening modality for the rapid discovery of therapeutic candidates in pharmaceutical settings. This platform enables a cost-effective, time-efficient, and large-scale assembly and interrogation of billions of small organic ligands against a biological target in a single experiment. An outstanding challenge in DEL synthesis is the necessity for water-compatible transformations under ambient conditions. To access uncharted chemical space, the adoption of photoredox catalysis in DELs, including Ni-catalyzed manifolds and radical/polar crossover reactions, has enabled the construction of novel structural scaffolds through regulated odd-electron intermediates. Herein, a critical discussion of the validation of photoredox-mediated alkylation in DEL environments is presented. Current synthetic gaps are highlighted and opportunities for further development are speculated upon.

New N-Boc-alkyl(2-alkynylcyclopropyl)amines were synthesized from 1-alkynyl-1-chlorocyclopropanes and N-Boc- alkylamines under the action of ButOK in DMSO, the intermediates having been the corresponding conjugated alkynylcyclopropenes. The Boc-derivatives can be converted into free secondary 2-alkynylcyclopropylamines, as well as ββ-lithiated with subsequent alkylation.

The Phillips Cr(VI)/silica catalyst, used worldwide to manufacture polyethylene, must first be reduced and alkylated to display polymerization activity. This is accomplished commercially by exposure to ethylene, in a reaction that is still uncertain after 60 years of investigation. Here we report that other non-olefinic hydrocarbons can also be used in this self-alkylation mechanism, and we track, through isotopic labeling and other analyses, the fate of such hydrocarbons when used to initiate (reduce and alkylate) Cr(VI). A part of the reductant hydrocarbon is converted into oxygenated ligands, which remain attached as a permanent component of the active catalyst, thus influencing its behavior. Another part is used to alkylate the Cr, and it becomes incorporated into the first polymer chain. Each hydrocarbon reductant produces a unique catalyst, with unique ligands, displaying its own activity and sometimes producing distinctive polymer. The implication of this situation, in contrast to more traditional findings from the field, is one of opportunity to create novel varieties of new Phillips catalysts.

A hydrocarbon polymer of poly (isatine-phenylene) (PiP), which was synthesized in a super acid-catalyzed polyhydroxy alkylation reaction, was introduced as an alternative conducting material in PEMFC. The sulfonimide acid in super gas-phase acidity was used to modify the sulfonic PiP (SPiP) to improve the dimensional stability and enhance proton conductivity. The PiP (SIPiP) showed considerably higher ion exchange capacity (IEC) and proton conductivity than SPiP controls. All the synthesized polymers revealed excellent thermal stability (